From e46d649c2e40078ed161c83fdc1690456f09f43a Mon Sep 17 00:00:00 2001
From: Guozhang Wang <wangguoz@gmail.com>
Date: Wed, 9 Dec 2015 20:31:25 -0800
Subject: [PATCH 01/14] v1

---
 .../apache/kafka/streams/kstream/KStream.java |  35 ++-
 ...StreamWindowed.java => SlidingWindow.java} |  45 ++-
 .../kstream/SlidingWindowSupplier.java        | 266 ------------------
 .../streams/kstream/TransformerSupplier.java  |   1 -
 .../apache/kafka/streams/kstream/Window.java  |  36 ++-
 .../kafka/streams/kstream/WindowDef.java      |  58 ++++
 .../kafka/streams/kstream/WindowSupplier.java |  25 --
 .../kstream/internals/KStreamImpl.java        |  26 +-
 .../kstream/internals/KStreamWindow.java      |  68 -----
 .../internals/KStreamWindowedImpl.java        |  67 -----
 .../kstream/internals/KStreamJoinTest.java    | 195 -------------
 .../internals/KStreamWindowedTest.java        |  91 ------
 .../apache/kafka/test/UnlimitedWindowDef.java |   4 +-
 13 files changed, 151 insertions(+), 766 deletions(-)
 rename streams/src/main/java/org/apache/kafka/streams/kstream/{KStreamWindowed.java => SlidingWindow.java} (51%)
 delete mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindowSupplier.java
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/WindowDef.java
 delete mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/WindowSupplier.java
 delete mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamWindow.java
 delete mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamWindowedImpl.java
 delete mode 100644 streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamJoinTest.java
 delete mode 100644 streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamWindowedTest.java

diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
index d3931efc9f4ad..51d383ce60219 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
@@ -83,14 +83,6 @@ public interface KStream<K, V> {
      */
     <V1> KStream<K, V1> flatMapValues(ValueMapper<V, Iterable<V1>> processor);
 
-    /**
-     * Creates a new windowed stream using a specified window instance.
-     *
-     * @param windowDef the instance of Window
-     * @return the windowed stream
-     */
-    KStreamWindowed<K, V> with(WindowSupplier<K, V> windowDef);
-
     /**
      * Creates an array of streams from this stream. Each stream in the array corresponds to a predicate in
      * supplied predicates in the same order. Predicates are evaluated in order. An element is streamed to
@@ -149,7 +141,7 @@ public interface KStream<K, V> {
     /**
      * Applies a stateful transformation to all elements in this stream.
      *
-     * @param transformerSupplier the class of TransformerDef
+     * @param transformerSupplier the class of valueTransformerSupplier
      * @param stateStoreNames the names of the state store used by the processor
      * @return the instance of KStream that contains transformed keys and values
      */
@@ -158,7 +150,7 @@ public interface KStream<K, V> {
     /**
      * Applies a stateful transformation to all values in this stream.
      *
-     * @param valueTransformerSupplier the class of TransformerDef
+     * @param valueTransformerSupplier the class of valueTransformerSupplier
      * @param stateStoreNames the names of the state store used by the processor
      * @return the instance of KStream that contains the keys and transformed values
      */
@@ -177,9 +169,30 @@ public interface KStream<K, V> {
      *
      * @param ktable the instance of KTable joined with this stream
      * @param joiner ValueJoiner
-     * @param <V1>   the value type of the other stream
+     * @param <V1>   the value type of the table
      * @param <V2>   the value type of the new stream
      */
     <V1, V2> KStream<K, V2> leftJoin(KTable<K, V1> ktable, ValueJoiner<V, V1, V2> joiner);
 
+    /**
+     * Combines values of this stream with another KStream on a window basis using Join.
+     *
+     * @param kstream the instance of KStream joined with this stream
+     * @param joiner ValueJoiner
+     * @param windowDef the window definition
+     * @param <V1>   the value type of the other stream
+     * @param <V2>   the value type of the new stream
+     * @param <W>   the window definition type
+     */
+    <V1, V2, W extends WindowDef<? extends Window>> KStream<K, V2> join(KStream<K, V1> kstream, ValueJoiner<V, V1, V2> joiner, W windowDef);
+
+    /**
+     * Aggregate values of this stream by key on a window basis.
+     *
+     * @param aggregateSupplier the class of aggregateSupplier
+     * @param windowDef the window definition
+     * @param <T>   the value type of the aggregated table
+     * @param <W>   the window definition type
+     */
+    <T, W extends WindowDef<? extends Window>> WindowedKTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, W windowDef);
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KStreamWindowed.java b/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindow.java
similarity index 51%
rename from streams/src/main/java/org/apache/kafka/streams/kstream/KStreamWindowed.java
rename to streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindow.java
index 4d73128839f21..33c2e35e7892a 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KStreamWindowed.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindow.java
@@ -17,22 +17,39 @@
 
 package org.apache.kafka.streams.kstream;
 
-/**
- * KStreamWindowed is an abstraction of a stream of key-value pairs with a window.
- */
-public interface KStreamWindowed<K, V> extends KStream<K, V> {
+
+import java.util.Collection;
+import java.util.Collections;
+
+public class SlidingWindow extends WindowDef<Window> {
+
+    private long size;
+
+    private SlidingWindow(long size) {
+        this.size = size;
+    }
 
     /**
-     * Creates a new stream by joining this windowed stream with the other windowed stream.
-     * Each element arrived from either of the streams is joined with elements in a window of each other.
-     * The resulting values are computed by applying a joiner.
-     *
-     * @param other  the other windowed stream
-     * @param joiner ValueJoiner
-     * @param <V1>   the value type of the other stream
-     * @param <V2>   the value type of the new stream
-     * @return KStream
+     * Returns a half-interval sliding window definition with the window size in milliseconds
      */
-    <V1, V2> KStream<K, V2> join(KStreamWindowed<K, V1> other, ValueJoiner<V, V1, V2> joiner);
+    public static SlidingWindow of(long size) {
+        return new SlidingWindow(size);
+    }
+
+    @Override
+    public Collection<Window> windowsFor(long timestamp) {
+        // TODO
+        return Collections.EMPTY_LIST;
+    }
+
+
+    @Override
+    public boolean equals(WindowDef<Window> other) {
+        if (!other.getClass().equals(SlidingWindow.class))
+            return false;
+
+        SlidingWindow otherWindow = (SlidingWindow) other;
 
+        return this.size == otherWindow.size;
+    }
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindowSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindowSupplier.java
deleted file mode 100644
index 80e548f94c704..0000000000000
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindowSupplier.java
+++ /dev/null
@@ -1,266 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.kafka.streams.kstream;
-
-import org.apache.kafka.clients.producer.ProducerRecord;
-import org.apache.kafka.common.serialization.ByteArraySerializer;
-import org.apache.kafka.common.serialization.Deserializer;
-import org.apache.kafka.common.serialization.IntegerDeserializer;
-import org.apache.kafka.common.serialization.IntegerSerializer;
-import org.apache.kafka.common.serialization.Serializer;
-import org.apache.kafka.streams.kstream.internals.FilteredIterator;
-import org.apache.kafka.streams.kstream.internals.WindowSupport;
-import org.apache.kafka.streams.processor.StateRestoreCallback;
-import org.apache.kafka.streams.processor.internals.RecordCollector;
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.internals.Stamped;
-
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.Iterator;
-import java.util.LinkedList;
-import java.util.Map;
-
-public class SlidingWindowSupplier<K, V> implements WindowSupplier<K, V> {
-    private final String name;
-    private final long duration;
-    private final int maxCount;
-    private final Serializer<K> keySerializer;
-    private final Serializer<V> valueSerializer;
-    private final Deserializer<K> keyDeserializer;
-    private final Deserializer<V> valueDeserializer;
-
-    public SlidingWindowSupplier(
-            String name,
-            long duration,
-            int maxCount,
-            Serializer<K> keySerializer,
-            Serializer<V> valueSerializer,
-            Deserializer<K> keyDeseriaizer,
-            Deserializer<V> valueDeserializer) {
-        this.name = name;
-        this.duration = duration;
-        this.maxCount = maxCount;
-        this.keySerializer = keySerializer;
-        this.valueSerializer = valueSerializer;
-        this.keyDeserializer = keyDeseriaizer;
-        this.valueDeserializer = valueDeserializer;
-    }
-
-    @Override
-    public String name() {
-        return name;
-    }
-
-    @Override
-    public Window<K, V> get() {
-        return new SlidingWindow();
-    }
-
-    public class SlidingWindow extends WindowSupport implements Window<K, V> {
-        private final Object lock = new Object();
-        private ProcessorContext context;
-        private int partition;
-        private int slotNum; // used as a key for Kafka log compaction
-        private LinkedList<K> list = new LinkedList<K>();
-        private HashMap<K, ValueList<V>> map = new HashMap<>();
-
-        @Override
-        public void init(ProcessorContext context) {
-            this.context = context;
-            this.partition = context.id().partition;
-            SlidingWindowRegistryCallback restoreFunc = new SlidingWindowRegistryCallback();
-            context.register(this, true, restoreFunc);
-
-            for (ValueList<V> valueList : map.values()) {
-                valueList.clearDirtyValues();
-            }
-            this.slotNum = restoreFunc.slotNum;
-        }
-
-        @Override
-        public Iterator<V> findAfter(K key, final long timestamp) {
-            return find(key, timestamp, timestamp + duration);
-        }
-
-        @Override
-        public Iterator<V> findBefore(K key, final long timestamp) {
-            return find(key, timestamp - duration, timestamp);
-        }
-
-        @Override
-        public Iterator<V> find(K key, final long timestamp) {
-            return find(key, timestamp - duration, timestamp + duration);
-        }
-
-        /*
-         * finds items in the window between startTime and endTime (both inclusive)
-         */
-        private Iterator<V> find(K key, final long startTime, final long endTime) {
-            final ValueList<V> values = map.get(key);
-
-            if (values == null) {
-                return Collections.emptyIterator();
-            } else {
-                return new FilteredIterator<V, Value<V>>(values.iterator()) {
-                    @Override
-                    protected V filter(Value<V> item) {
-                        if (startTime <= item.timestamp && item.timestamp <= endTime)
-                            return item.value;
-                        else
-                            return null;
-                    }
-                };
-            }
-        }
-
-        @Override
-        public void put(K key, V value, long timestamp) {
-            synchronized (lock) {
-                slotNum++;
-
-                list.offerLast(key);
-
-                ValueList<V> values = map.get(key);
-                if (values == null) {
-                    values = new ValueList<>();
-                    map.put(key, values);
-                }
-
-                values.add(slotNum, value, timestamp);
-            }
-            evictExcess();
-            evictExpired(timestamp - duration);
-        }
-
-        private void evictExcess() {
-            while (list.size() > maxCount) {
-                K oldestKey = list.pollFirst();
-
-                ValueList<V> values = map.get(oldestKey);
-                values.removeFirst();
-
-                if (values.isEmpty()) map.remove(oldestKey);
-            }
-        }
-
-        private void evictExpired(long cutoffTime) {
-            while (true) {
-                K oldestKey = list.peekFirst();
-
-                ValueList<V> values = map.get(oldestKey);
-                Stamped<V> oldestValue = values.first();
-
-                if (oldestValue.timestamp < cutoffTime) {
-                    list.pollFirst();
-                    values.removeFirst();
-
-                    if (values.isEmpty()) map.remove(oldestKey);
-                } else {
-                    break;
-                }
-            }
-        }
-
-        @Override
-        public String name() {
-            return name;
-        }
-
-        @Override
-        public void flush() {
-            IntegerSerializer intSerializer = new IntegerSerializer();
-            ByteArraySerializer byteArraySerializer = new ByteArraySerializer();
-
-            RecordCollector collector = ((RecordCollector.Supplier) context).recordCollector();
-
-            for (Map.Entry<K, ValueList<V>> entry : map.entrySet()) {
-                ValueList<V> values = entry.getValue();
-                if (values.hasDirtyValues()) {
-                    K key = entry.getKey();
-
-                    byte[] keyBytes = keySerializer.serialize(name, key);
-
-                    Iterator<Value<V>> iterator = values.dirtyValueIterator();
-                    while (iterator.hasNext()) {
-                        Value<V> dirtyValue = iterator.next();
-                        byte[] slot = intSerializer.serialize("", dirtyValue.slotNum);
-                        byte[] valBytes = valueSerializer.serialize(name, dirtyValue.value);
-
-                        byte[] combined = new byte[8 + 4 + keyBytes.length + 4 + valBytes.length];
-
-                        int offset = 0;
-                        offset += putLong(combined, offset, dirtyValue.timestamp);
-                        offset += puts(combined, offset, keyBytes);
-                        offset += puts(combined, offset, valBytes);
-
-                        if (offset != combined.length)
-                            throw new IllegalStateException("serialized length does not match");
-
-                        collector.send(new ProducerRecord<>(name, partition, slot, combined), byteArraySerializer, byteArraySerializer);
-                    }
-                    values.clearDirtyValues();
-                }
-            }
-        }
-
-        @Override
-        public void close() {
-            // TODO
-        }
-
-        @Override
-        public boolean persistent() {
-            // TODO: should not be persistent, right?
-            return false;
-        }
-
-        private class SlidingWindowRegistryCallback implements StateRestoreCallback {
-
-            final IntegerDeserializer intDeserializer;
-            int slotNum = 0;
-
-            SlidingWindowRegistryCallback() {
-                intDeserializer = new IntegerDeserializer();
-            }
-
-            @Override
-            public void restore(byte[] slot, byte[] bytes) {
-
-                slotNum = intDeserializer.deserialize("", slot);
-
-                int offset = 0;
-                // timestamp
-                long timestamp = getLong(bytes, offset);
-                offset += 8;
-                // key
-                int length = getInt(bytes, offset);
-                offset += 4;
-                K key = deserialize(bytes, offset, length, name, keyDeserializer);
-                offset += length;
-                // value
-                length = getInt(bytes, offset);
-                offset += 4;
-                V value = deserialize(bytes, offset, length, name, valueDeserializer);
-
-                put(key, value, timestamp);
-            }
-        }
-    }
-
-}
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/TransformerSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/TransformerSupplier.java
index 2c2d8dd28c924..93d930df93b2f 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/TransformerSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/TransformerSupplier.java
@@ -20,5 +20,4 @@
 public interface TransformerSupplier<K, V, R> {
 
     Transformer<K, V, R> get();
-
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/Window.java b/streams/src/main/java/org/apache/kafka/streams/kstream/Window.java
index a1456f6c421b6..b1827f9a4e59f 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/Window.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/Window.java
@@ -17,20 +17,26 @@
 
 package org.apache.kafka.streams.kstream;
 
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.StateStore;
 
-import java.util.Iterator;
-
-public interface Window<K, V> extends StateStore {
-
-    void init(ProcessorContext context);
-
-    Iterator<V> find(K key, long timestamp);
-
-    Iterator<V> findAfter(K key, long timestamp);
-
-    Iterator<V> findBefore(K key, long timestamp);
-
-    void put(K key, V value, long timestamp);
+public abstract class Window implements Comparable<Window> {
+
+    /**
+     * Returns the start timestamp of this window, inclusive
+     */
+    public abstract long start();
+
+    /**
+     * Returns the end timestamp of this window, exclusive
+     */
+    public abstract long end();
+
+    @Override
+    public int compareTo(Window other) {
+        if (this.start() > other.start())
+            return 1;
+        else if (this.start() < other.start())
+            return -1;
+        else
+            return 0;
+    }
 }
\ No newline at end of file
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/WindowDef.java b/streams/src/main/java/org/apache/kafka/streams/kstream/WindowDef.java
new file mode 100644
index 0000000000000..b3c0cfab7c7e2
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/WindowDef.java
@@ -0,0 +1,58 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.kstream;
+
+import java.util.Collection;
+
+public abstract class WindowDef<W extends Window> {
+
+    private static long DEFAULT_EMIT_DURATION = 1000L;
+
+    private static long DEFAULT_MAINTAIN_DURATION = 24 * 60 * 60 * 1000L;   // one day
+
+    private long emitDuration;
+
+    private long maintainDuration;
+
+    abstract public boolean equals(WindowDef<W> other);
+
+    abstract public Collection<W> windowsFor(long timestamp);
+
+    protected WindowDef() {
+        this.emitDuration = DEFAULT_EMIT_DURATION;
+        this.maintainDuration = DEFAULT_MAINTAIN_DURATION;
+    }
+
+    /**
+     * Set the window emit duration in milliseconds of system time
+     */
+    public WindowDef<W> emit(long duration) {
+        this.emitDuration = duration;
+
+        return this;
+    }
+
+    /**
+     * Set the window maintain duration in milliseconds of system time
+     */
+    WindowDef<W> until(long duration) {
+        this.maintainDuration = duration;
+
+        return this;
+    }
+}
\ No newline at end of file
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/WindowSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/WindowSupplier.java
deleted file mode 100644
index 46a2b9ee91622..0000000000000
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/WindowSupplier.java
+++ /dev/null
@@ -1,25 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.kafka.streams.kstream;
-
-public interface WindowSupplier<K, V> {
-
-    String name();
-
-    Window<K, V> get();
-}
\ No newline at end of file
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
index 67a2d27c4c0f5..8898169c93621 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
@@ -19,6 +19,7 @@
 
 import org.apache.kafka.common.serialization.Deserializer;
 import org.apache.kafka.common.serialization.Serializer;
+import org.apache.kafka.streams.kstream.AggregateSupplier;
 import org.apache.kafka.streams.kstream.KStreamBuilder;
 import org.apache.kafka.streams.kstream.KTable;
 import org.apache.kafka.streams.kstream.KeyValue;
@@ -26,11 +27,12 @@
 import org.apache.kafka.streams.kstream.ValueJoiner;
 import org.apache.kafka.streams.kstream.ValueTransformerSupplier;
 import org.apache.kafka.streams.kstream.KStream;
-import org.apache.kafka.streams.kstream.KStreamWindowed;
 import org.apache.kafka.streams.kstream.KeyValueMapper;
 import org.apache.kafka.streams.kstream.Predicate;
 import org.apache.kafka.streams.kstream.ValueMapper;
-import org.apache.kafka.streams.kstream.WindowSupplier;
+import org.apache.kafka.streams.kstream.Window;
+import org.apache.kafka.streams.kstream.WindowDef;
+import org.apache.kafka.streams.kstream.WindowedKTable;
 import org.apache.kafka.streams.processor.ProcessorSupplier;
 
 import java.lang.reflect.Array;
@@ -131,15 +133,6 @@ public <V1> KStream<K, V1> flatMapValues(ValueMapper<V, Iterable<V1>> mapper) {
         return new KStreamImpl<>(topology, name, sourceNodes);
     }
 
-    @Override
-    public KStreamWindowed<K, V> with(WindowSupplier<K, V> windowSupplier) {
-        String name = topology.newName(WINDOWED_NAME);
-
-        topology.addProcessor(name, new KStreamWindow<>(windowSupplier), this.name);
-
-        return new KStreamWindowedImpl<>(topology, name, sourceNodes, windowSupplier);
-    }
-
     @Override
     @SuppressWarnings("unchecked")
     public KStream<K, V>[] branch(Predicate<K, V>... predicates) {
@@ -251,4 +244,15 @@ public <V1, R> KStream<K, R> leftJoin(KTable<K, V1> other, ValueJoiner<V, V1, R>
         return new KStreamImpl<>(topology, name, allSourceNodes);
     }
 
+    @Override
+    public <V1, V2, W extends WindowDef<? extends Window>> KStream<K, V2> join(KStream<K, V1> kstream, ValueJoiner<V, V1, V2> joiner, W windowDef) {
+        // TODO
+        return null;
+    }
+
+    @Override
+    public <T, W extends WindowDef<? extends Window>> WindowedKTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, W windowDef) {
+        // TODO
+        return null;
+    }
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamWindow.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamWindow.java
deleted file mode 100644
index 29239364a8093..0000000000000
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamWindow.java
+++ /dev/null
@@ -1,68 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.kafka.streams.kstream.internals;
-
-import org.apache.kafka.streams.kstream.Window;
-import org.apache.kafka.streams.kstream.WindowSupplier;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
-
-public class KStreamWindow<K, V> implements ProcessorSupplier<K, V> {
-
-    private final WindowSupplier<K, V> windowSupplier;
-
-    KStreamWindow(WindowSupplier<K, V> windowSupplier) {
-        this.windowSupplier = windowSupplier;
-    }
-
-    public WindowSupplier<K, V> window() {
-        return windowSupplier;
-    }
-
-    @Override
-    public Processor<K, V> get() {
-        return new KStreamWindowProcessor();
-    }
-
-    private class KStreamWindowProcessor extends AbstractProcessor<K, V> {
-
-        private Window<K, V> window;
-
-        @Override
-        public void init(ProcessorContext context) {
-            super.init(context);
-            this.window = windowSupplier.get();
-            this.window.init(context);
-        }
-
-        @Override
-        public void process(K key, V value) {
-            synchronized (this) {
-                window.put(key, value, context().timestamp());
-                context().forward(key, value);
-            }
-        }
-
-        @Override
-        public void close() {
-            window.close();
-        }
-    }
-}
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamWindowedImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamWindowedImpl.java
deleted file mode 100644
index c71c11b774583..0000000000000
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamWindowedImpl.java
+++ /dev/null
@@ -1,67 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- * <p>
- * http://www.apache.org/licenses/LICENSE-2.0
- * <p>
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.kafka.streams.kstream.internals;
-
-import org.apache.kafka.common.KafkaException;
-import org.apache.kafka.streams.kstream.KStream;
-import org.apache.kafka.streams.kstream.KStreamBuilder;
-import org.apache.kafka.streams.kstream.KStreamWindowed;
-import org.apache.kafka.streams.kstream.ValueJoiner;
-import org.apache.kafka.streams.kstream.WindowSupplier;
-
-import java.util.HashSet;
-import java.util.Set;
-
-public final class KStreamWindowedImpl<K, V> extends KStreamImpl<K, V> implements KStreamWindowed<K, V> {
-
-    private final WindowSupplier<K, V> windowSupplier;
-
-    public KStreamWindowedImpl(KStreamBuilder topology, String name, Set<String> sourceNodes, WindowSupplier<K, V> windowSupplier) {
-        super(topology, name, sourceNodes);
-        this.windowSupplier = windowSupplier;
-    }
-
-    @Override
-    public <V1, V2> KStream<K, V2> join(KStreamWindowed<K, V1> other, ValueJoiner<V, V1, V2> valueJoiner) {
-        String thisWindowName = this.windowSupplier.name();
-        String otherWindowName = ((KStreamWindowedImpl<K, V1>) other).windowSupplier.name();
-        Set<String> thisSourceNodes = this.sourceNodes;
-        Set<String> otherSourceNodes = ((KStreamWindowedImpl<K, V1>) other).sourceNodes;
-
-        if (thisSourceNodes == null || otherSourceNodes == null)
-            throw new KafkaException("not joinable");
-
-        Set<String> allSourceNodes = new HashSet<>(sourceNodes);
-        allSourceNodes.addAll(((KStreamWindowedImpl<K, V1>) other).sourceNodes);
-
-        KStreamJoin<K, V2, V, V1> joinThis = new KStreamJoin<>(otherWindowName, valueJoiner);
-        KStreamJoin<K, V2, V1, V> joinOther = new KStreamJoin<>(thisWindowName, reverseJoiner(valueJoiner));
-        KStreamPassThrough<K, V2> joinMerge = new KStreamPassThrough<>();
-
-        String joinThisName = topology.newName(JOINTHIS_NAME);
-        String joinOtherName = topology.newName(JOINOTHER_NAME);
-        String joinMergeName = topology.newName(MERGE_NAME);
-
-        topology.addProcessor(joinThisName, joinThis, this.name);
-        topology.addProcessor(joinOtherName, joinOther, ((KStreamImpl) other).name);
-        topology.addProcessor(joinMergeName, joinMerge, joinThisName, joinOtherName);
-        topology.copartitionSources(allSourceNodes);
-
-        return new KStreamImpl<>(topology, joinMergeName, allSourceNodes);
-    }
-}
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamJoinTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamJoinTest.java
deleted file mode 100644
index 12bed1788fa35..0000000000000
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamJoinTest.java
+++ /dev/null
@@ -1,195 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.kafka.streams.kstream.internals;
-
-import org.apache.kafka.common.KafkaException;
-import org.apache.kafka.common.serialization.IntegerDeserializer;
-import org.apache.kafka.common.serialization.StringDeserializer;
-import org.apache.kafka.common.utils.Utils;
-import org.apache.kafka.streams.kstream.KStream;
-import org.apache.kafka.streams.kstream.KStreamBuilder;
-import org.apache.kafka.streams.kstream.KStreamWindowed;
-import org.apache.kafka.streams.kstream.KeyValue;
-import org.apache.kafka.streams.kstream.KeyValueMapper;
-import org.apache.kafka.streams.kstream.ValueJoiner;
-import org.apache.kafka.streams.kstream.ValueMapper;
-import org.apache.kafka.test.KStreamTestDriver;
-import org.apache.kafka.test.MockProcessorSupplier;
-import org.apache.kafka.test.UnlimitedWindowDef;
-import org.junit.Test;
-
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.HashSet;
-import java.util.Set;
-
-import static org.junit.Assert.assertEquals;
-
-public class KStreamJoinTest {
-
-    private String topic1 = "topic1";
-    private String topic2 = "topic2";
-    private String dummyTopic = "dummyTopic";
-
-    private IntegerDeserializer keyDeserializer = new IntegerDeserializer();
-    private StringDeserializer valDeserializer = new StringDeserializer();
-
-    private ValueJoiner<String, String, String> joiner = new ValueJoiner<String, String, String>() {
-        @Override
-        public String apply(String value1, String value2) {
-            return value1 + "+" + value2;
-        }
-    };
-
-    private ValueMapper<String, String> valueMapper = new ValueMapper<String, String>() {
-        @Override
-        public String apply(String value) {
-            return "#" + value;
-        }
-    };
-
-    private ValueMapper<String, Iterable<String>> valueMapper2 = new ValueMapper<String, Iterable<String>>() {
-        @Override
-        public Iterable<String> apply(String value) {
-            return (Iterable<String>) Utils.mkSet(value);
-        }
-    };
-
-    private KeyValueMapper<Integer, String, KeyValue<Integer, String>> keyValueMapper =
-        new KeyValueMapper<Integer, String, KeyValue<Integer, String>>() {
-            @Override
-            public KeyValue<Integer, String> apply(Integer key, String value) {
-                return KeyValue.pair(key, value);
-            }
-        };
-
-    KeyValueMapper<Integer, String, KeyValue<Integer, Iterable<String>>> keyValueMapper2 =
-        new KeyValueMapper<Integer, String, KeyValue<Integer, Iterable<String>>>() {
-            @Override
-            public KeyValue<Integer, Iterable<String>> apply(Integer key, String value) {
-                return KeyValue.pair(key, (Iterable<String>) Utils.mkSet(value));
-            }
-        };
-
-
-    @Test
-    public void testJoin() {
-        KStreamBuilder builder = new KStreamBuilder();
-
-        final int[] expectedKeys = new int[]{0, 1, 2, 3};
-
-        KStream<Integer, String> stream1;
-        KStream<Integer, String> stream2;
-        KStream<Integer, String> dummyStream;
-        KStreamWindowed<Integer, String> windowed1;
-        KStreamWindowed<Integer, String> windowed2;
-        MockProcessorSupplier<Integer, String> processor;
-        String[] expected;
-
-        processor = new MockProcessorSupplier<>();
-        stream1 = builder.from(keyDeserializer, valDeserializer, topic1);
-        stream2 = builder.from(keyDeserializer, valDeserializer, topic2);
-        dummyStream = builder.from(keyDeserializer, valDeserializer, dummyTopic);
-        windowed1 = stream1.with(new UnlimitedWindowDef<Integer, String>("window1"));
-        windowed2 = stream2.with(new UnlimitedWindowDef<Integer, String>("window2"));
-
-        windowed1.join(windowed2, joiner).process(processor);
-
-        Collection<Set<String>> copartitionGroups = builder.copartitionGroups();
-
-        assertEquals(1, copartitionGroups.size());
-        assertEquals(new HashSet<>(Arrays.asList(topic1, topic2)), copartitionGroups.iterator().next());
-
-        KStreamTestDriver driver = new KStreamTestDriver(builder);
-        driver.setTime(0L);
-
-        // push two items to the main stream. the other stream's window is empty
-
-        for (int i = 0; i < 2; i++) {
-            driver.process(topic1, expectedKeys[i], "X" + expectedKeys[i]);
-        }
-
-        assertEquals(0, processor.processed.size());
-
-        // push two items to the other stream. the main stream's window has two items
-
-        for (int i = 0; i < 2; i++) {
-            driver.process(topic2, expectedKeys[i], "Y" + expectedKeys[i]);
-        }
-
-        assertEquals(2, processor.processed.size());
-
-        expected = new String[]{"0:X0+Y0", "1:X1+Y1"};
-
-        for (int i = 0; i < expected.length; i++) {
-            assertEquals(expected[i], processor.processed.get(i));
-        }
-
-        processor.processed.clear();
-
-        // push all items to the main stream. this should produce two items.
-
-        for (int i = 0; i < expectedKeys.length; i++) {
-            driver.process(topic1, expectedKeys[i], "X" + expectedKeys[i]);
-        }
-
-        assertEquals(2, processor.processed.size());
-
-        expected = new String[]{"0:X0+Y0", "1:X1+Y1"};
-
-        for (int i = 0; i < expected.length; i++) {
-            assertEquals(expected[i], processor.processed.get(i));
-        }
-
-        processor.processed.clear();
-
-        // there will be previous two items + all items in the main stream's window, thus two are duplicates.
-
-        // push all items to the other stream. this should produce 6 items
-        for (int i = 0; i < expectedKeys.length; i++) {
-            driver.process(topic2, expectedKeys[i], "Y" + expectedKeys[i]);
-        }
-
-        assertEquals(6, processor.processed.size());
-
-        expected = new String[]{"0:X0+Y0", "0:X0+Y0", "1:X1+Y1", "1:X1+Y1", "2:X2+Y2", "3:X3+Y3"};
-
-        for (int i = 0; i < expected.length; i++) {
-            assertEquals(expected[i], processor.processed.get(i));
-        }
-    }
-
-    @Test(expected = KafkaException.class)
-    public void testNotJoinable() {
-        KStreamBuilder builder = new KStreamBuilder();
-
-        KStream<Integer, String> stream1;
-        KStream<Integer, String> stream2;
-        KStreamWindowed<Integer, String> windowed1;
-        KStreamWindowed<Integer, String> windowed2;
-        MockProcessorSupplier<Integer, String> processor;
-
-        processor = new MockProcessorSupplier<>();
-        stream1 = builder.from(keyDeserializer, valDeserializer, topic1).map(keyValueMapper);
-        stream2 = builder.from(keyDeserializer, valDeserializer, topic2);
-        windowed1 = stream1.with(new UnlimitedWindowDef<Integer, String>("window1"));
-        windowed2 = stream2.with(new UnlimitedWindowDef<Integer, String>("window2"));
-
-        windowed1.join(windowed2, joiner).process(processor);
-    }
-}
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamWindowedTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamWindowedTest.java
deleted file mode 100644
index c3dc7e08129ae..0000000000000
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamWindowedTest.java
+++ /dev/null
@@ -1,91 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.kafka.streams.kstream.internals;
-
-import org.apache.kafka.common.serialization.IntegerDeserializer;
-import org.apache.kafka.common.serialization.StringDeserializer;
-import org.apache.kafka.streams.kstream.KStream;
-import org.apache.kafka.streams.kstream.KStreamBuilder;
-import org.apache.kafka.streams.kstream.Window;
-import org.apache.kafka.streams.kstream.WindowSupplier;
-import org.apache.kafka.test.KStreamTestDriver;
-import org.apache.kafka.test.UnlimitedWindowDef;
-import org.junit.Test;
-
-import java.util.Iterator;
-
-import static org.junit.Assert.assertEquals;
-
-public class KStreamWindowedTest {
-
-    private String topicName = "topic";
-    private String windowName = "MyWindow";
-
-    private IntegerDeserializer keyDeserializer = new IntegerDeserializer();
-    private StringDeserializer valDeserializer = new StringDeserializer();
-
-    @Test
-    public void testWindowedStream() {
-        KStreamBuilder builder = new KStreamBuilder();
-
-        final int[] expectedKeys = new int[]{0, 1, 2, 3};
-
-        KStream<Integer, String> stream;
-        WindowSupplier<Integer, String> windowSupplier;
-
-        windowSupplier = new UnlimitedWindowDef<>(windowName);
-        stream = builder.from(keyDeserializer, valDeserializer, topicName);
-        stream.with(windowSupplier);
-
-        KStreamTestDriver driver = new KStreamTestDriver(builder);
-        Window<Integer, String> window = (Window<Integer, String>) driver.getStateStore(windowName);
-        driver.setTime(0L);
-
-        // two items in the window
-
-        for (int i = 0; i < 2; i++) {
-            driver.process(topicName, expectedKeys[i], "V" + expectedKeys[i]);
-        }
-
-        assertEquals(1, countItem(window.find(0, 0L)));
-        assertEquals(1, countItem(window.find(1, 0L)));
-        assertEquals(0, countItem(window.find(2, 0L)));
-        assertEquals(0, countItem(window.find(3, 0L)));
-
-        // previous two items + all items, thus two are duplicates, in the window
-
-        for (int i = 0; i < expectedKeys.length; i++) {
-            driver.process(topicName, expectedKeys[i], "Y" + expectedKeys[i]);
-        }
-
-        assertEquals(2, countItem(window.find(0, 0L)));
-        assertEquals(2, countItem(window.find(1, 0L)));
-        assertEquals(1, countItem(window.find(2, 0L)));
-        assertEquals(1, countItem(window.find(3, 0L)));
-    }
-
-
-    private <T> int countItem(Iterator<T> iter) {
-        int i = 0;
-        while (iter.hasNext()) {
-            i++;
-            iter.next();
-        }
-        return i;
-    }
-}
diff --git a/streams/src/test/java/org/apache/kafka/test/UnlimitedWindowDef.java b/streams/src/test/java/org/apache/kafka/test/UnlimitedWindowDef.java
index 3da1ca7ed86d4..b788819319d9d 100644
--- a/streams/src/test/java/org/apache/kafka/test/UnlimitedWindowDef.java
+++ b/streams/src/test/java/org/apache/kafka/test/UnlimitedWindowDef.java
@@ -20,14 +20,14 @@
 import org.apache.kafka.streams.kstream.Window;
 import org.apache.kafka.streams.processor.ProcessorContext;
 import org.apache.kafka.streams.kstream.KeyValue;
-import org.apache.kafka.streams.kstream.WindowSupplier;
+import org.apache.kafka.streams.kstream.WindowDef;
 import org.apache.kafka.streams.kstream.internals.FilteredIterator;
 import org.apache.kafka.streams.processor.internals.Stamped;
 
 import java.util.Iterator;
 import java.util.LinkedList;
 
-public class UnlimitedWindowDef<K, V> implements WindowSupplier<K, V> {
+public class UnlimitedWindowDef<K, V> implements WindowDef<K, V> {
 
     private final String name;
 

From 2167f29ff630577fe63abc93fd8a58aa6c7d3c1c Mon Sep 17 00:00:00 2001
From: Guozhang Wang <wangguoz@gmail.com>
Date: Thu, 10 Dec 2015 11:32:34 -0800
Subject: [PATCH 02/14] option 1 of windowing opeartions

---
 .../streams/kstream/AggregateSupplier.java    | 23 +++++
 .../kstream/internals/KStreamJoin.java        | 84 -------------------
 2 files changed, 23 insertions(+), 84 deletions(-)
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/AggregateSupplier.java
 delete mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamJoin.java

diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/AggregateSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/AggregateSupplier.java
new file mode 100644
index 0000000000000..3ee80756adbb4
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/AggregateSupplier.java
@@ -0,0 +1,23 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.kstream;
+
+public interface AggregateSupplier<K, V, T> {
+
+    Aggregator<K, V, T> get();
+}
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamJoin.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamJoin.java
deleted file mode 100644
index eefb8c9b0641d..0000000000000
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamJoin.java
+++ /dev/null
@@ -1,84 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.kafka.streams.kstream.internals;
-
-import org.apache.kafka.streams.kstream.ValueJoiner;
-import org.apache.kafka.streams.kstream.Window;
-import org.apache.kafka.streams.processor.AbstractProcessor;
-import org.apache.kafka.streams.processor.Processor;
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.processor.ProcessorSupplier;
-
-import java.util.Iterator;
-
-class KStreamJoin<K, V, V1, V2> implements ProcessorSupplier<K, V1> {
-
-    private static abstract class Finder<K, T> {
-        abstract Iterator<T> find(K key, long timestamp);
-    }
-
-    private final String windowName;
-    private final ValueJoiner<V1, V2, V> joiner;
-
-    KStreamJoin(String windowName, ValueJoiner<V1, V2, V> joiner) {
-        this.windowName = windowName;
-        this.joiner = joiner;
-    }
-
-    @Override
-    public Processor<K, V1> get() {
-        return new KStreamJoinProcessor(windowName);
-    }
-
-    private class KStreamJoinProcessor extends AbstractProcessor<K, V1> {
-
-        private final String windowName;
-        protected Finder<K, V2> finder;
-
-        public KStreamJoinProcessor(String windowName) {
-            this.windowName = windowName;
-        }
-
-        @SuppressWarnings("unchecked")
-        @Override
-        public void init(ProcessorContext context) {
-            super.init(context);
-
-            final Window<K, V2> window = (Window<K, V2>) context.getStateStore(windowName);
-
-            this.finder = new Finder<K, V2>() {
-                @Override
-                Iterator<V2> find(K key, long timestamp) {
-                    return window.find(key, timestamp);
-                }
-            };
-        }
-
-        @Override
-        public void process(K key, V1 value) {
-            long timestamp = context().timestamp();
-            Iterator<V2> iter = finder.find(key, timestamp);
-            if (iter != null) {
-                while (iter.hasNext()) {
-                    context().forward(key, joiner.apply(value, iter.next()));
-                }
-            }
-        }
-    }
-
-}

From fb92b2b20f7be6f17c006de6e48cb04065808477 Mon Sep 17 00:00:00 2001
From: Guozhang Wang <wangguoz@gmail.com>
Date: Thu, 10 Dec 2015 21:47:51 -0800
Subject: [PATCH 03/14] v1

---
 .../main/java/org/apache/kafka/streams/kstream/KStream.java   | 2 +-
 .../apache/kafka/streams/kstream/internals/KStreamImpl.java   | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
index 51d383ce60219..357f143a3700d 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
@@ -194,5 +194,5 @@ public interface KStream<K, V> {
      * @param <T>   the value type of the aggregated table
      * @param <W>   the window definition type
      */
-    <T, W extends WindowDef<? extends Window>> WindowedKTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, W windowDef);
+    <T, W extends WindowDef<? extends Window>> KWindowedTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, W windowDef);
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
index 8898169c93621..604bf295ad0cd 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
@@ -22,6 +22,7 @@
 import org.apache.kafka.streams.kstream.AggregateSupplier;
 import org.apache.kafka.streams.kstream.KStreamBuilder;
 import org.apache.kafka.streams.kstream.KTable;
+import org.apache.kafka.streams.kstream.KWindowedTable;
 import org.apache.kafka.streams.kstream.KeyValue;
 import org.apache.kafka.streams.kstream.TransformerSupplier;
 import org.apache.kafka.streams.kstream.ValueJoiner;
@@ -32,7 +33,6 @@
 import org.apache.kafka.streams.kstream.ValueMapper;
 import org.apache.kafka.streams.kstream.Window;
 import org.apache.kafka.streams.kstream.WindowDef;
-import org.apache.kafka.streams.kstream.WindowedKTable;
 import org.apache.kafka.streams.processor.ProcessorSupplier;
 
 import java.lang.reflect.Array;
@@ -251,7 +251,7 @@ public <V1, V2, W extends WindowDef<? extends Window>> KStream<K, V2> join(KStre
     }
 
     @Override
-    public <T, W extends WindowDef<? extends Window>> WindowedKTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, W windowDef) {
+    public <T, W extends WindowDef<? extends Window>> KWindowedTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, W windowDef) {
         // TODO
         return null;
     }

From 0862ec2b4ecb151ea1b3395c74787e4de99891fe Mon Sep 17 00:00:00 2001
From: Guozhang Wang <wangguoz@gmail.com>
Date: Fri, 11 Dec 2015 14:15:02 -0800
Subject: [PATCH 04/14] v1

---
 .../kafka/streams/examples/KStreamJob.java    |   2 +-
 .../kafka/streams/examples/KTableJob.java     | 167 ++++++++++++++++++
 .../kafka/streams/kstream/Aggregator.java     |  42 +++++
 .../kafka/streams/kstream/HoppingWindows.java |  66 +++++++
 .../apache/kafka/streams/kstream/KStream.java |   6 +-
 .../kafka/streams/kstream/KStreamBuilder.java |   6 +-
 .../apache/kafka/streams/kstream/KTable.java  |   9 +
 .../kafka/streams/kstream/KWindowedTable.java | 111 ++++++++++++
 ...SlidingWindow.java => SlidingWindows.java} |  22 +--
 .../streams/kstream/UnlimitedWindow.java      |  52 ++++++
 .../apache/kafka/streams/kstream/Window.java  |  17 +-
 .../kafka/streams/kstream/WindowDef.java      |  39 +---
 .../kafka/streams/kstream/WindowMapper.java   |  23 +++
 .../kstream/internals/AbstractWindows.java    |  52 ++++++
 .../kstream/internals/KStreamImpl.java        |  21 ++-
 .../streams/kstream/internals/KTableImpl.java |   8 +
 .../streams/kstream/KStreamBuilderTest.java   |   6 +-
 .../kstream/internals/KStreamBranchTest.java  |   2 +-
 .../kstream/internals/KStreamFilterTest.java  |   4 +-
 .../kstream/internals/KStreamFlatMapTest.java |   2 +-
 .../internals/KStreamFlatMapValuesTest.java   |   2 +-
 .../kstream/internals/KStreamImplTest.java    |  32 ++--
 .../kstream/internals/KStreamMapTest.java     |   2 +-
 .../internals/KStreamMapValuesTest.java       |   2 +-
 .../internals/KStreamTransformTest.java       |   2 +-
 .../internals/KStreamTransformValuesTest.java |   2 +-
 .../apache/kafka/test/UnlimitedWindowDef.java | 104 -----------
 27 files changed, 605 insertions(+), 198 deletions(-)
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/Aggregator.java
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindows.java
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/KWindowedTable.java
 rename streams/src/main/java/org/apache/kafka/streams/kstream/{SlidingWindow.java => SlidingWindows.java} (72%)
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindow.java
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/WindowMapper.java
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/internals/AbstractWindows.java
 delete mode 100644 streams/src/test/java/org/apache/kafka/test/UnlimitedWindowDef.java

diff --git a/streams/src/main/java/org/apache/kafka/streams/examples/KStreamJob.java b/streams/src/main/java/org/apache/kafka/streams/examples/KStreamJob.java
index 819bd687b18ea..88a89550ab2bd 100644
--- a/streams/src/main/java/org/apache/kafka/streams/examples/KStreamJob.java
+++ b/streams/src/main/java/org/apache/kafka/streams/examples/KStreamJob.java
@@ -45,7 +45,7 @@ public static void main(String[] args) throws Exception {
 
         KStreamBuilder builder = new KStreamBuilder();
 
-        KStream<String, String> stream1 = builder.from("topic1");
+        KStream<String, String> stream1 = builder.stream("topic1");
 
         KStream<String, Integer> stream2 =
             stream1.map(new KeyValueMapper<String, String, KeyValue<String, Integer>>() {
diff --git a/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java b/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
new file mode 100644
index 0000000000000..9b1f4a32b9a35
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
@@ -0,0 +1,167 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.examples;
+
+import org.apache.kafka.common.serialization.IntegerSerializer;
+import org.apache.kafka.common.serialization.StringSerializer;
+import org.apache.kafka.common.serialization.StringDeserializer;
+import org.apache.kafka.streams.kstream.AggregateSupplier;
+import org.apache.kafka.streams.kstream.Aggregator;
+import org.apache.kafka.streams.kstream.HoppingWindows;
+import org.apache.kafka.streams.kstream.KStreamBuilder;
+import org.apache.kafka.streams.StreamingConfig;
+import org.apache.kafka.streams.KafkaStreaming;
+import org.apache.kafka.streams.kstream.KStream;
+import org.apache.kafka.streams.kstream.KTable;
+import org.apache.kafka.streams.kstream.KWindowedTable;
+import org.apache.kafka.streams.kstream.KeyValue;
+import org.apache.kafka.streams.kstream.KeyValueMapper;
+import org.apache.kafka.streams.kstream.ValueJoiner;
+import org.apache.kafka.streams.kstream.Window;
+import org.apache.kafka.streams.kstream.WindowMapper;
+
+import java.util.Properties;
+
+public class KTableJob {
+
+    public static void main(String[] args) throws Exception {
+        Properties props = new Properties();
+        props.put(StreamingConfig.JOB_ID_CONFIG, "example-ktable");
+        props.put(StreamingConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
+        props.put(StreamingConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
+        props.put(StreamingConfig.VALUE_SERIALIZER_CLASS_CONFIG, IntegerSerializer.class);
+        props.put(StreamingConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
+        props.put(StreamingConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
+        props.put(StreamingConfig.TIMESTAMP_EXTRACTOR_CLASS_CONFIG, WallclockTimestampExtractor.class);
+        StreamingConfig config = new StreamingConfig(props);
+
+        KStreamBuilder builder = new KStreamBuilder();
+
+        // stream aggregate
+        KStream<String, Integer> stream1 = builder.stream("topic1");
+
+        KWindowedTable<String, Integer, HoppingWindows> wtable1 = stream1.aggregateByKey(new AggregateSupplier<String, Integer, Integer>() {
+            @Override
+            public Aggregator<String, Integer, Integer> get() {
+                return new Aggregator<String, Integer, Integer>() {
+                    @Override
+                    public Integer initialValue() {
+                        return 0;
+                    }
+
+                    @Override
+                    public Integer add(String aggKey, Integer value, Integer aggregate) {
+                        return aggregate + value;
+                    }
+
+                    @Override
+                    public Integer remove(String aggKey, Integer value, Integer aggregate) {
+                        return aggregate - value;
+                    }
+
+                    @Override
+                    public Integer merge(Integer aggr1, Integer aggr2) {
+                        return aggr1 + aggr2;
+                    }
+                };
+            }
+        }, HoppingWindows.of(1000).every(500));
+
+        // table aggregation
+        KTable<String, String> table1 = builder.table("topic2");
+
+        KTable<String, Integer> table2 = table1.aggregate(new AggregateSupplier<String, KeyValue<String, String>, Integer>() {
+            @Override
+            public Aggregator<String, KeyValue<String, String>, Integer> get() {
+                return new Aggregator<String, KeyValue<String, String>, Integer>() {
+                    @Override
+                    public Integer initialValue() {
+                        return 0;
+                    }
+
+                    @Override
+                    public Integer add(String aggKey, KeyValue<String, String> value, Integer aggregate) {
+                        return aggregate + new Integer(value.value);
+                    }
+
+                    @Override
+                    public Integer remove(String aggKey, KeyValue<String, String> value, Integer aggregate) {
+                        return aggregate - new Integer(value.value);
+                    }
+
+                    @Override
+                    public Integer merge(Integer aggr1, Integer aggr2) {
+                        return aggr1 + aggr2;
+                    }
+                };
+            }
+        }, new KeyValueMapper<String, String, String>() {
+            @Override
+            public String apply(String key, String value) {
+                return value;
+            }
+        });
+
+        // stream-table join
+        KStream<String, Integer> stream2 = stream1.leftJoin(table2, new ValueJoiner<Integer, Integer, Integer>() {
+            @Override
+            public Integer apply(Integer value1, Integer value2) {
+                if (value2 == null)
+                    return 0;
+                else
+                    return value1 * value2;
+            }
+        });
+
+        // table-table join
+        KTable<String, String> table3 = table1.outerJoin(table2, new ValueJoiner<String, Integer, String>() {
+            @Override
+            public String apply(String value1, Integer value2) {
+                if (value2 == null)
+                    return value1 + "-null";
+                else if (value1 == null)
+                    return "null-" + value2;
+                else
+                    return value1 + "-" + value2;
+            }
+        });
+
+        // windowed table self join
+        KWindowedTable<String, Integer, HoppingWindows> wtable2 = wtable1.leftJoin(wtable1, 1000 * 60 * 60 * 24 * 7 /* a week ago*/, new ValueJoiner<Integer, Integer, Integer>() {
+            @Override
+            public Integer apply(Integer value1, Integer value2) {
+                if (value2 == null)
+                    return value1;
+                else
+                    return value1 - value2;
+            }
+        });
+
+        KStream<String, String> stream3 = wtable2.toStream(new WindowMapper<String, Integer, String, String>() {
+            @Override
+            public KeyValue<String, String> apply(String key, Integer value, Window window) {
+                return new KeyValue<>(key + window.start(), value.toString());
+            }
+        });
+
+        stream3.to("topic3");
+
+        KafkaStreaming kstream = new KafkaStreaming(builder, config);
+        kstream.start();
+    }
+}
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/Aggregator.java b/streams/src/main/java/org/apache/kafka/streams/kstream/Aggregator.java
new file mode 100644
index 0000000000000..d715fbdb3df75
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/Aggregator.java
@@ -0,0 +1,42 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.kstream;
+
+public interface Aggregator<K, V, T> {
+    /**
+     * Set the initial aggregate value
+     */
+    T initialValue();
+
+    /**
+     * When a new record with the aggregate key is added,
+     * updating the aggregate value for this key
+     */
+    T add(K aggKey, V value, T aggregate);
+
+    /**
+     * when an old record with the aggregate key is removed,
+     * updating the aggregate value for this key
+     */
+    T remove(K aggKey, V value, T aggregate);
+
+    /**
+     * Merge two aggregate values
+     */
+    T merge(T aggr1, T aggr2);
+}
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindows.java b/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindows.java
new file mode 100644
index 0000000000000..457c2026e5a83
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindows.java
@@ -0,0 +1,66 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.kstream;
+
+import org.apache.kafka.streams.kstream.internals.AbstractWindows;
+
+import java.util.Collection;
+import java.util.Collections;
+
+public class HoppingWindows extends AbstractWindows implements WindowDef<HoppingWindows> {
+
+    private long size;
+
+    private long period;
+
+    private HoppingWindows(long size) {
+        super();
+
+        this.size = size;
+        this.period = size;
+    }
+
+    /**
+     * Returns a half-interval hopping window definition with the window size in milliseconds
+     * of the form &#91; N &#42; size, N &#42; size + size &#41;
+     */
+    public static HoppingWindows of(long size) {
+        return new HoppingWindows(size);
+    }
+
+    /**
+     * Returns a new hopping window definition with the original size but reassign the window
+     * period in milliseconds of the form &#91; N &#42; period, N &#42; period + size &#41;
+     */
+    public HoppingWindows every(long period) {
+        this.period = period;
+
+        return this;
+    }
+
+    @Override
+    public Collection<Window> windowsFor(long timestamp) {
+        // TODO
+        return Collections.<Window>emptyList();
+    }
+
+    @Override
+    public boolean equalTo(HoppingWindows other) {
+        return this.size == other.size && this.period == other.period;
+    }
+}
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
index 357f143a3700d..06f3ed5dfc87d 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
@@ -182,9 +182,8 @@ public interface KStream<K, V> {
      * @param windowDef the window definition
      * @param <V1>   the value type of the other stream
      * @param <V2>   the value type of the new stream
-     * @param <W>   the window definition type
      */
-    <V1, V2, W extends WindowDef<? extends Window>> KStream<K, V2> join(KStream<K, V1> kstream, ValueJoiner<V, V1, V2> joiner, W windowDef);
+    <V1, V2, W extends WindowDef> KStream<K, V2> join(KStream<K, V1> kstream, ValueJoiner<V, V1, V2> joiner, WindowDef<W> windowDef);
 
     /**
      * Aggregate values of this stream by key on a window basis.
@@ -192,7 +191,6 @@ public interface KStream<K, V> {
      * @param aggregateSupplier the class of aggregateSupplier
      * @param windowDef the window definition
      * @param <T>   the value type of the aggregated table
-     * @param <W>   the window definition type
      */
-    <T, W extends WindowDef<? extends Window>> KWindowedTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, W windowDef);
+    <T, W extends WindowDef> KWindowedTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, WindowDef<W> windowDef);
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KStreamBuilder.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KStreamBuilder.java
index 0ed514424a3ca..4140e30b5100a 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KStreamBuilder.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KStreamBuilder.java
@@ -46,8 +46,8 @@ public KStreamBuilder() {
      * @param topics          the topic names, if empty default to all the topics in the config
      * @return KStream
      */
-    public <K, V> KStream<K, V> from(String... topics) {
-        return from(null, null, topics);
+    public <K, V> KStream<K, V> stream(String... topics) {
+        return stream(null, null, topics);
     }
 
     /**
@@ -60,7 +60,7 @@ public <K, V> KStream<K, V> from(String... topics) {
      * @param topics          the topic names, if empty default to all the topics in the config
      * @return KStream
      */
-    public <K, V> KStream<K, V> from(Deserializer<K> keyDeserializer, Deserializer<V> valDeserializer, String... topics) {
+    public <K, V> KStream<K, V> stream(Deserializer<K> keyDeserializer, Deserializer<V> valDeserializer, String... topics) {
         String name = newName(KStreamImpl.SOURCE_NAME);
 
         addSource(name, keyDeserializer, valDeserializer, topics);
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
index c6e7975955abc..9a1b0f6f73f95 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
@@ -138,4 +138,13 @@ public interface KTable<K, V> {
      */
     <V1, V2> KTable<K, V2> leftJoin(KTable<K, V1> other, ValueJoiner<V, V1, V2> joiner);
 
+    /**
+     * Aggregate values of this table by the selected key.
+     *
+     * @param aggregateSupplier the class of aggregateSupplier
+     * @param selector the KeyValue mapper that select the aggregate key
+     * @param <K1>   the key type of the aggregated table
+     * @param <V1>   the value type of the aggregated table
+     */
+    <K1, V1> KTable<K1, V1> aggregate(AggregateSupplier<K1, KeyValue<K, V>, V1> aggregateSupplier, KeyValueMapper<K, V, K1> selector);
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KWindowedTable.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KWindowedTable.java
new file mode 100644
index 0000000000000..ee67faf55d7f9
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KWindowedTable.java
@@ -0,0 +1,111 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.kstream;
+
+/**
+ * KWindowedTable is an abstraction of a change log stream on a window basis.
+ *
+ *
+ * @param <K> the type of keys
+ * @param <V> the type of values
+ * @param <W> the type of window definition
+ */
+public interface KWindowedTable<K, V, W extends WindowDef> {
+
+    /**
+     * Creates a new instance of KTable consists of all elements of this stream which satisfy a predicate
+     *
+     * @param predicate the instance of Predicate
+     * @return the instance of KTable with only those elements that satisfy the predicate
+     */
+    KWindowedTable<K, V, W> filter(Predicate<K, V> predicate);
+
+    /**
+     * Creates a new instance of KTable consists all elements of this stream which do not satisfy a predicate
+     *
+     * @param predicate the instance of Predicate
+     * @return the instance of KTable with only those elements that do not satisfy the predicate
+     */
+    KWindowedTable<K, V, W> filterOut(Predicate<K, V> predicate);
+
+    /**
+     * Creates a new instance of KTable by transforming each value in this stream into a different value in the new stream.
+     *
+     * @param mapper the instance of ValueMapper
+     * @param <V1>   the value type of the new stream
+     * @return the instance of KTable
+     */
+    <V1> KWindowedTable<K, V1, W> mapValues(ValueMapper<V, V1> mapper);
+
+    /**
+     * Transform this windowed table into a stream
+     *
+     * @param windowMapper the class of WindowMapper
+     * @return the instance of KStream that contains transformed keys and values
+     */
+    <K1, V1> KStream<K1, V1> toStream(WindowMapper<K, V, K1, V1> windowMapper);
+
+    /**
+     * Combines values of this KWindowedTable with another KWindowedTable using Inner Join.
+     * The window definition of the other KWindowedTable must be the same.
+     *
+     * @param other the instance of KTable joined with this stream
+     * @param joiner ValueJoiner
+     * @param <V1>   the value type of the other stream
+     * @param <V2>   the value type of the new stream
+     * @return the instance of the KWindowedTable
+     */
+    <V1, V2> KWindowedTable<K, V2, W> join(KWindowedTable<K, V1, W> other, ValueJoiner<V, V1, V2> joiner);
+
+    /**
+     * Combines values of this KWindowedTable with another KWindowedTable using Outer Join.
+     * The window definition of the other WindowedKtable must be the same.
+     *
+     * @param other the instance of KTable joined with this stream
+     * @param joiner ValueJoiner
+     * @param <V1>   the value type of the other stream
+     * @param <V2>   the value type of the new stream
+     * @return the instance of KStream
+     */
+    <V1, V2> KWindowedTable<K, V2, W> outerJoin(KWindowedTable<K, V1, W> other, ValueJoiner<V, V1, V2> joiner);
+
+    /**
+     * Combines values of this KWindowedTable with another KWindowedTable using Left Join.
+     * The window definition of the other KWindowedTable must be the same.
+     *
+     * @param other the instance of KTable joined with this stream
+     * @param joiner ValueJoiner
+     * @param <V1>   the value type of the other stream
+     * @param <V2>   the value type of the new stream
+     * @return the instance of KStream
+     */
+    <V1, V2> KWindowedTable<K, V2, W> leftJoin(KWindowedTable<K, V1, W> other, ValueJoiner<V, V1, V2> joiner);
+
+    /**
+     * Combines values of this KWindowedTable with another KWindowedTable using Left Join.
+     * The window type of the other KWindowedTable must be the same.
+     *
+     * @param other the instance of KTable joined with this stream
+     * @param timeDifference difference in window definition
+     * @param joiner ValueJoiner
+     * @param <V1>   the value type of the other stream
+     * @param <V2>   the value type of the new stream
+     * @return the instance of KStream
+     */
+    <V1, V2> KWindowedTable<K, V2, W> leftJoin(KWindowedTable<K, V1, W> other, long timeDifference, ValueJoiner<V, V1, V2> joiner);
+}
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindow.java b/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindows.java
similarity index 72%
rename from streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindow.java
rename to streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindows.java
index 33c2e35e7892a..047ad09399283 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindow.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindows.java
@@ -18,38 +18,34 @@
 package org.apache.kafka.streams.kstream;
 
 
+import org.apache.kafka.streams.kstream.internals.AbstractWindows;
+
 import java.util.Collection;
 import java.util.Collections;
 
-public class SlidingWindow extends WindowDef<Window> {
+public class SlidingWindows extends AbstractWindows implements WindowDef<SlidingWindows> {
 
     private long size;
 
-    private SlidingWindow(long size) {
+    private SlidingWindows(long size) {
         this.size = size;
     }
 
     /**
      * Returns a half-interval sliding window definition with the window size in milliseconds
      */
-    public static SlidingWindow of(long size) {
-        return new SlidingWindow(size);
+    public static SlidingWindows of(long size) {
+        return new SlidingWindows(size);
     }
 
     @Override
     public Collection<Window> windowsFor(long timestamp) {
         // TODO
-        return Collections.EMPTY_LIST;
+        return Collections.<Window>emptyList();
     }
 
-
     @Override
-    public boolean equals(WindowDef<Window> other) {
-        if (!other.getClass().equals(SlidingWindow.class))
-            return false;
-
-        SlidingWindow otherWindow = (SlidingWindow) other;
-
-        return this.size == otherWindow.size;
+    public boolean equalTo(SlidingWindows other) {
+        return this.size == other.size;
     }
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindow.java b/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindow.java
new file mode 100644
index 0000000000000..f651a6a2a3997
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindow.java
@@ -0,0 +1,52 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.kstream;
+
+import org.apache.kafka.streams.kstream.internals.AbstractWindows;
+
+import java.util.Collection;
+import java.util.Collections;
+
+public class UnlimitedWindow extends AbstractWindows implements WindowDef<UnlimitedWindow> {
+
+    private long start;
+
+    private UnlimitedWindow(long start) {
+        super();
+
+        this.start = start;
+    }
+
+    /**
+     * Returns an unlimited window definition
+     */
+    public static UnlimitedWindow on(long start) {
+        return new UnlimitedWindow(start);
+    }
+
+    @Override
+    public Collection<Window> windowsFor(long timestamp) {
+        // TODO
+        return Collections.<Window>emptyList();
+    }
+
+    @Override
+    public boolean equalTo(UnlimitedWindow other) {
+        return true;
+    }
+}
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/Window.java b/streams/src/main/java/org/apache/kafka/streams/kstream/Window.java
index b1827f9a4e59f..33f9b0a94402d 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/Window.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/Window.java
@@ -17,18 +17,29 @@
 
 package org.apache.kafka.streams.kstream;
 
+public class Window implements Comparable<Window> {
 
-public abstract class Window implements Comparable<Window> {
+    private long start;
+    private long end;
+
+    public Window(long start, long end) {
+        this.start = start;
+        this.end = end;
+    }
 
     /**
      * Returns the start timestamp of this window, inclusive
      */
-    public abstract long start();
+    public long start() {
+        return start;
+    }
 
     /**
      * Returns the end timestamp of this window, exclusive
      */
-    public abstract long end();
+    public long end() {
+        return end;
+    }
 
     @Override
     public int compareTo(Window other) {
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/WindowDef.java b/streams/src/main/java/org/apache/kafka/streams/kstream/WindowDef.java
index b3c0cfab7c7e2..f8f155af6496b 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/WindowDef.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/WindowDef.java
@@ -19,40 +19,9 @@
 
 import java.util.Collection;
 
-public abstract class WindowDef<W extends Window> {
+public interface WindowDef<W extends WindowDef> {
 
-    private static long DEFAULT_EMIT_DURATION = 1000L;
+    boolean equalTo(W other);
 
-    private static long DEFAULT_MAINTAIN_DURATION = 24 * 60 * 60 * 1000L;   // one day
-
-    private long emitDuration;
-
-    private long maintainDuration;
-
-    abstract public boolean equals(WindowDef<W> other);
-
-    abstract public Collection<W> windowsFor(long timestamp);
-
-    protected WindowDef() {
-        this.emitDuration = DEFAULT_EMIT_DURATION;
-        this.maintainDuration = DEFAULT_MAINTAIN_DURATION;
-    }
-
-    /**
-     * Set the window emit duration in milliseconds of system time
-     */
-    public WindowDef<W> emit(long duration) {
-        this.emitDuration = duration;
-
-        return this;
-    }
-
-    /**
-     * Set the window maintain duration in milliseconds of system time
-     */
-    WindowDef<W> until(long duration) {
-        this.maintainDuration = duration;
-
-        return this;
-    }
-}
\ No newline at end of file
+    Collection<Window> windowsFor(long timestamp);
+}
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/WindowMapper.java b/streams/src/main/java/org/apache/kafka/streams/kstream/WindowMapper.java
new file mode 100644
index 0000000000000..00f803b88bea2
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/WindowMapper.java
@@ -0,0 +1,23 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.kstream;
+
+public interface WindowMapper<K, V, K1, V1> {
+
+    KeyValue<K1, V1> apply(K key, V value, Window window);
+}
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/AbstractWindows.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/AbstractWindows.java
new file mode 100644
index 0000000000000..fcbd2c9afc3cf
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/AbstractWindows.java
@@ -0,0 +1,52 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.kstream.internals;
+
+public abstract class AbstractWindows {
+
+    private static final long DEFAULT_EMIT_DURATION = 1000L;
+
+    private static final long DEFAULT_MAINTAIN_DURATION = 24 * 60 * 60 * 1000L;   // one day
+
+    private long emitDuration;
+
+    private long maintainDuration;
+
+    protected AbstractWindows() {
+        this.emitDuration = DEFAULT_EMIT_DURATION;
+        this.maintainDuration = DEFAULT_MAINTAIN_DURATION;
+    }
+
+    /**
+     * Set the window emit duration in milliseconds of system time
+     */
+    public AbstractWindows emit(long duration) {
+        this.emitDuration = duration;
+
+        return this;
+    }
+
+    /**
+     * Set the window maintain duration in milliseconds of system time
+     */
+    public AbstractWindows until(long duration) {
+        this.maintainDuration = duration;
+
+        return this;
+    }
+}
\ No newline at end of file
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
index 604bf295ad0cd..0a89d1f8ca8d9 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
@@ -31,8 +31,8 @@
 import org.apache.kafka.streams.kstream.KeyValueMapper;
 import org.apache.kafka.streams.kstream.Predicate;
 import org.apache.kafka.streams.kstream.ValueMapper;
-import org.apache.kafka.streams.kstream.Window;
 import org.apache.kafka.streams.kstream.WindowDef;
+import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.ProcessorSupplier;
 
 import java.lang.reflect.Array;
@@ -61,7 +61,7 @@ public class KStreamImpl<K, V> extends AbstractStream<K> implements KStream<K, V
 
     private static final String BRANCHCHILD_NAME = "KSTREAM-BRANCHCHILD-";
 
-    private static final String WINDOWED_NAME = "KSTREAM-WINDOWED-";
+    private static final String AGGREGATE_NAME = "KSTREAM-AGGREGATE-";
 
     public static final String SINK_NAME = "KSTREAM-SINK-";
 
@@ -184,7 +184,7 @@ public KStream<K, V> through(String topic,
                                  Deserializer<V> valDeserializer) {
         to(topic, keySerializer, valSerializer);
 
-        return topology.from(keyDeserializer, valDeserializer, topic);
+        return topology.stream(keyDeserializer, valDeserializer, topic);
     }
 
     @Override
@@ -245,13 +245,22 @@ public <V1, R> KStream<K, R> leftJoin(KTable<K, V1> other, ValueJoiner<V, V1, R>
     }
 
     @Override
-    public <V1, V2, W extends WindowDef<? extends Window>> KStream<K, V2> join(KStream<K, V1> kstream, ValueJoiner<V, V1, V2> joiner, W windowDef) {
+    public <V1, V2, W extends WindowDef> KStream<K, V2> join(KStream<K, V1> kstream, ValueJoiner<V, V1, V2> joiner, WindowDef<W> windowDef) {
         // TODO
-        return null;
+        String name = topology.newName(JOINTHIS_NAME);
+
+        topology.addProcessor(name, new ProcessorSupplier() {
+            @Override
+            public Processor get() {
+                return null;
+            }
+        }, this.name);
+
+        return new KStreamImpl<>(topology, name, sourceNodes);
     }
 
     @Override
-    public <T, W extends WindowDef<? extends Window>> KWindowedTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, W windowDef) {
+    public <T, W extends WindowDef> KWindowedTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, WindowDef<W> windowDef) {
         // TODO
         return null;
     }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
index 308e4f5e50364..3a9508a92b70a 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
@@ -19,9 +19,12 @@
 
 import org.apache.kafka.common.serialization.Deserializer;
 import org.apache.kafka.common.serialization.Serializer;
+import org.apache.kafka.streams.kstream.AggregateSupplier;
 import org.apache.kafka.streams.kstream.KStream;
 import org.apache.kafka.streams.kstream.KStreamBuilder;
 import org.apache.kafka.streams.kstream.KTable;
+import org.apache.kafka.streams.kstream.KeyValue;
+import org.apache.kafka.streams.kstream.KeyValueMapper;
 import org.apache.kafka.streams.kstream.Predicate;
 import org.apache.kafka.streams.kstream.ValueJoiner;
 import org.apache.kafka.streams.kstream.ValueMapper;
@@ -233,4 +236,9 @@ public <V1, R> KTable<K, R> leftJoin(KTable<K, V1> other, ValueJoiner<V, V1, R>
         return new KTableImpl<>(topology, name, leftJoin, allSourceNodes);
     }
 
+    @Override
+    public <K1, V1> KTable<K1, V1> aggregate(AggregateSupplier<K1, KeyValue<K, V>, V1> aggregateSupplier, KeyValueMapper<K, V, K1> selector) {
+        // TODO
+        return null;
+    }
 }
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/KStreamBuilderTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/KStreamBuilderTest.java
index d6994a9b997a6..f79063f0d4070 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/KStreamBuilderTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/KStreamBuilderTest.java
@@ -32,7 +32,7 @@ public class KStreamBuilderTest {
     public void testFrom() {
         final KStreamBuilder builder = new KStreamBuilder();
 
-        builder.from("topic-1", "topic-2");
+        builder.stream("topic-1", "topic-2");
 
         builder.addSource(KStreamImpl.SOURCE_NAME + "0000000000", "topic-3");
     }
@@ -59,8 +59,8 @@ public void testMerge() {
 
         KStreamBuilder builder = new KStreamBuilder();
 
-        KStream<String, String> source1 = builder.from(topic1);
-        KStream<String, String> source2 = builder.from(topic2);
+        KStream<String, String> source1 = builder.stream(topic1);
+        KStream<String, String> source2 = builder.stream(topic2);
         KStream<String, String> merged = builder.merge(source1, source2);
 
         MockProcessorSupplier<String, String> processorSupplier = new MockProcessorSupplier<>();
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamBranchTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamBranchTest.java
index 40eba2f103a5f..88366fac3dd24 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamBranchTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamBranchTest.java
@@ -67,7 +67,7 @@ public boolean test(Integer key, String value) {
         KStream<Integer, String>[] branches;
         MockProcessorSupplier<Integer, String>[] processors;
 
-        stream = builder.from(keyDeserializer, valDeserializer, topicName);
+        stream = builder.stream(keyDeserializer, valDeserializer, topicName);
         branches = stream.branch(isEven, isMultipleOfThree, isOdd);
 
         assertEquals(3, branches.length);
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFilterTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFilterTest.java
index d1e5d38a987f7..3bad0416152b1 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFilterTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFilterTest.java
@@ -52,7 +52,7 @@ public void testFilter() {
         MockProcessorSupplier<Integer, String> processor;
 
         processor = new MockProcessorSupplier<>();
-        stream = builder.from(keyDeserializer, valDeserializer, topicName);
+        stream = builder.stream(keyDeserializer, valDeserializer, topicName);
         stream.filter(isMultipleOfThree).process(processor);
 
         KStreamTestDriver driver = new KStreamTestDriver(builder);
@@ -72,7 +72,7 @@ public void testFilterOut() {
         MockProcessorSupplier<Integer, String> processor;
 
         processor = new MockProcessorSupplier<>();
-        stream = builder.from(keyDeserializer, valDeserializer, topicName);
+        stream = builder.stream(keyDeserializer, valDeserializer, topicName);
         stream.filterOut(isMultipleOfThree).process(processor);
 
         KStreamTestDriver driver = new KStreamTestDriver(builder);
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatMapTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatMapTest.java
index 61b5ccd5a1dc4..a55fd30e5c191 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatMapTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatMapTest.java
@@ -60,7 +60,7 @@ public Iterable<KeyValue<String, String>> apply(Integer key, String value) {
         MockProcessorSupplier<String, String> processor;
 
         processor = new MockProcessorSupplier<>();
-        stream = builder.from(keyDeserializer, valDeserializer, topicName);
+        stream = builder.stream(keyDeserializer, valDeserializer, topicName);
         stream.flatMap(mapper).process(processor);
 
         KStreamTestDriver driver = new KStreamTestDriver(builder);
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatMapValuesTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatMapValuesTest.java
index 66faf077885c7..eef7933c627f8 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatMapValuesTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamFlatMapValuesTest.java
@@ -58,7 +58,7 @@ public Iterable<String> apply(String value) {
         MockProcessorSupplier<Integer, String> processor;
 
         processor = new MockProcessorSupplier<>();
-        stream = builder.from(keyDeserializer, valDeserializer, topicName);
+        stream = builder.stream(keyDeserializer, valDeserializer, topicName);
         stream.flatMapValues(mapper).process(processor);
 
         KStreamTestDriver driver = new KStreamTestDriver(builder);
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamImplTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamImplTest.java
index 1e775b8aeba2f..05ddc18409c41 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamImplTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamImplTest.java
@@ -25,7 +25,7 @@
 import org.apache.kafka.streams.kstream.ValueJoiner;
 import org.apache.kafka.streams.kstream.ValueMapper;
 import org.apache.kafka.test.MockProcessorSupplier;
-import org.apache.kafka.test.UnlimitedWindowDef;
+import org.apache.kafka.streams.kstream.UnlimitedWindow;
 import org.junit.Test;
 
 import java.util.Collections;
@@ -40,9 +40,9 @@ public void testNumProcesses() {
         final Deserializer<String> deserializer = new StringDeserializer();
         final KStreamBuilder builder = new KStreamBuilder();
 
-        KStream<String, String> source1 = builder.from(deserializer, deserializer, "topic-1", "topic-2");
+        KStream<String, String> source1 = builder.stream(deserializer, deserializer, "topic-1", "topic-2");
 
-        KStream<String, String> source2 = builder.from(deserializer, deserializer, "topic-3", "topic-4");
+        KStream<String, String> source2 = builder.stream(deserializer, deserializer, "topic-3", "topic-4");
 
         KStream<String, String> stream1 =
             source1.filter(new Predicate<String, String>() {
@@ -101,21 +101,19 @@ public boolean test(String key, Integer value) {
             }
         );
 
-        KStream<String, Integer> stream4 = streams2[0].with(new UnlimitedWindowDef<String, Integer>("window"))
-            .join(streams3[0].with(new UnlimitedWindowDef<String, Integer>("window")), new ValueJoiner<Integer, Integer, Integer>() {
-                @Override
-                public Integer apply(Integer value1, Integer value2) {
-                    return value1 + value2;
-                }
-            });
+        KStream<String, Integer> stream4 = streams2[0].join(streams3[0], new ValueJoiner<Integer, Integer, Integer>() {
+            @Override
+            public Integer apply(Integer value1, Integer value2) {
+                return value1 + value2;
+            }
+        }, UnlimitedWindow.on(0));
 
-        KStream<String, Integer> stream5 = streams2[1].with(new UnlimitedWindowDef<String, Integer>("window"))
-            .join(streams3[1].with(new UnlimitedWindowDef<String, Integer>("window")), new ValueJoiner<Integer, Integer, Integer>() {
-                @Override
-                public Integer apply(Integer value1, Integer value2) {
-                    return value1 + value2;
-                }
-            });
+        KStream<String, Integer> stream5 = streams2[1].join(streams3[1], new ValueJoiner<Integer, Integer, Integer>() {
+            @Override
+            public Integer apply(Integer value1, Integer value2) {
+                return value1 + value2;
+            }
+        }, UnlimitedWindow.on(0));
 
         stream4.to("topic-5");
 
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamMapTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamMapTest.java
index 2ae8a97515dcb..0f7cb6a43e4e0 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamMapTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamMapTest.java
@@ -54,7 +54,7 @@ public KeyValue<String, Integer> apply(Integer key, String value) {
         MockProcessorSupplier<String, Integer> processor;
 
         processor = new MockProcessorSupplier<>();
-        stream = builder.from(keyDeserializer, valDeserializer, topicName);
+        stream = builder.stream(keyDeserializer, valDeserializer, topicName);
         stream.map(mapper).process(processor);
 
         KStreamTestDriver driver = new KStreamTestDriver(builder);
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamMapValuesTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamMapValuesTest.java
index f830c0010b338..68fd285870f71 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamMapValuesTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamMapValuesTest.java
@@ -51,7 +51,7 @@ public Integer apply(String value) {
 
         KStream<Integer, String> stream;
         MockProcessorSupplier<Integer, Integer> processor = new MockProcessorSupplier<>();
-        stream = builder.from(keyDeserializer, valDeserializer, topicName);
+        stream = builder.stream(keyDeserializer, valDeserializer, topicName);
         stream.mapValues(mapper).process(processor);
 
         KStreamTestDriver driver = new KStreamTestDriver(builder);
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamTransformTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamTransformTest.java
index e397dd1fe20dd..0b7b1e788a756 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamTransformTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamTransformTest.java
@@ -73,7 +73,7 @@ public void close() {
 
         KStream<Integer, Integer> stream;
         MockProcessorSupplier<Integer, Integer> processor = new MockProcessorSupplier<>();
-        stream = builder.from(keyDeserializer, valDeserializer, topicName);
+        stream = builder.stream(keyDeserializer, valDeserializer, topicName);
         stream.transform(transformerSupplier).process(processor);
 
         KStreamTestDriver driver = new KStreamTestDriver(builder);
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamTransformValuesTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamTransformValuesTest.java
index c5c9b39893c70..7def9db45bca0 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamTransformValuesTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamTransformValuesTest.java
@@ -72,7 +72,7 @@ public void close() {
 
         KStream<Integer, Integer> stream;
         MockProcessorSupplier<Integer, Integer> processor = new MockProcessorSupplier<>();
-        stream = builder.from(keyDeserializer, valDeserializer, topicName);
+        stream = builder.stream(keyDeserializer, valDeserializer, topicName);
         stream.transformValues(valueTransformerSupplier).process(processor);
 
         KStreamTestDriver driver = new KStreamTestDriver(builder);
diff --git a/streams/src/test/java/org/apache/kafka/test/UnlimitedWindowDef.java b/streams/src/test/java/org/apache/kafka/test/UnlimitedWindowDef.java
deleted file mode 100644
index b788819319d9d..0000000000000
--- a/streams/src/test/java/org/apache/kafka/test/UnlimitedWindowDef.java
+++ /dev/null
@@ -1,104 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.kafka.test;
-
-import org.apache.kafka.streams.kstream.Window;
-import org.apache.kafka.streams.processor.ProcessorContext;
-import org.apache.kafka.streams.kstream.KeyValue;
-import org.apache.kafka.streams.kstream.WindowDef;
-import org.apache.kafka.streams.kstream.internals.FilteredIterator;
-import org.apache.kafka.streams.processor.internals.Stamped;
-
-import java.util.Iterator;
-import java.util.LinkedList;
-
-public class UnlimitedWindowDef<K, V> implements WindowDef<K, V> {
-
-    private final String name;
-
-    public UnlimitedWindowDef(String name) {
-        this.name = name;
-    }
-
-    public String name() {
-        return name;
-    }
-
-    public Window<K, V> get() {
-        return new UnlimitedWindow();
-    }
-
-    public class UnlimitedWindow implements Window<K, V> {
-
-        private final LinkedList<Stamped<KeyValue<K, V>>> list = new LinkedList<>();
-
-        @Override
-        public void init(ProcessorContext context) {
-            context.register(this, true, null);
-        }
-
-        @Override
-        public Iterator<V> find(final K key, long timestamp) {
-            return find(key, Long.MIN_VALUE, timestamp);
-        }
-
-        @Override
-        public Iterator<V> findAfter(final K key, long timestamp) {
-            return find(key, timestamp, Long.MAX_VALUE);
-        }
-
-        @Override
-        public Iterator<V> findBefore(final K key, long timestamp) {
-            return find(key, Long.MIN_VALUE, Long.MAX_VALUE);
-        }
-
-        private Iterator<V> find(final K key, final long startTime, final long endTime) {
-            return new FilteredIterator<V, Stamped<KeyValue<K, V>>>(list.iterator()) {
-                protected V filter(Stamped<KeyValue<K, V>> item) {
-                    if (item.value.key.equals(key) && startTime <= item.timestamp && item.timestamp <= endTime)
-                        return item.value.value;
-                    else
-                        return null;
-                }
-            };
-        }
-
-        @Override
-        public void put(K key, V value, long timestamp) {
-            list.add(new Stamped<>(KeyValue.pair(key, value), timestamp));
-        }
-
-        @Override
-        public String name() {
-            return name;
-        }
-
-        @Override
-        public void flush() {
-        }
-
-        @Override
-        public void close() {
-        }
-
-        @Override
-        public boolean persistent() {
-            return false;
-        }
-    }
-}

From 9558891bdaccc0b8861f882b957b5131556f896c Mon Sep 17 00:00:00 2001
From: Guozhang Wang <wangguoz@gmail.com>
Date: Mon, 14 Dec 2015 16:30:20 -0800
Subject: [PATCH 05/14] address Yasu's comments

---
 .../kafka/streams/examples/KTableJob.java     | 11 ++--
 .../kafka/streams/kstream/HoppingWindow.java  | 25 +++++++++
 .../kafka/streams/kstream/HoppingWindows.java | 13 +++--
 .../apache/kafka/streams/kstream/KStream.java |  8 +--
 .../apache/kafka/streams/kstream/KTable.java  |  3 +-
 .../kafka/streams/kstream/KWindowedTable.java |  4 +-
 .../{WindowDef.java => SlidingWindow.java}    |  9 ++-
 .../kafka/streams/kstream/SlidingWindows.java | 13 +++--
 .../streams/kstream/UnlimitedWindow.java      | 33 +----------
 .../streams/kstream/UnlimitedWindows.java     | 55 +++++++++++++++++++
 .../apache/kafka/streams/kstream/Window.java  |  2 +-
 .../kafka/streams/kstream/WindowMapper.java   |  4 +-
 .../AbstractWindows.java => Windows.java}     | 26 +++++++--
 .../kstream/internals/KStreamImpl.java        |  7 ++-
 .../kstream/internals/KStreamImplTest.java    |  6 +-
 15 files changed, 147 insertions(+), 72 deletions(-)
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindow.java
 rename streams/src/main/java/org/apache/kafka/streams/kstream/{WindowDef.java => SlidingWindow.java} (84%)
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindows.java
 rename streams/src/main/java/org/apache/kafka/streams/kstream/{internals/AbstractWindows.java => Windows.java} (74%)

diff --git a/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java b/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
index 9b1f4a32b9a35..393f591f83350 100644
--- a/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
+++ b/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
@@ -22,6 +22,7 @@
 import org.apache.kafka.common.serialization.StringDeserializer;
 import org.apache.kafka.streams.kstream.AggregateSupplier;
 import org.apache.kafka.streams.kstream.Aggregator;
+import org.apache.kafka.streams.kstream.HoppingWindow;
 import org.apache.kafka.streams.kstream.HoppingWindows;
 import org.apache.kafka.streams.kstream.KStreamBuilder;
 import org.apache.kafka.streams.StreamingConfig;
@@ -55,7 +56,7 @@ public static void main(String[] args) throws Exception {
         // stream aggregate
         KStream<String, Integer> stream1 = builder.stream("topic1");
 
-        KWindowedTable<String, Integer, HoppingWindows> wtable1 = stream1.aggregateByKey(new AggregateSupplier<String, Integer, Integer>() {
+        KWindowedTable<String, Integer, HoppingWindow> wtable1 = stream1.aggregateByKey(new AggregateSupplier<String, Integer, Integer>() {
             @Override
             public Aggregator<String, Integer, Integer> get() {
                 return new Aggregator<String, Integer, Integer>() {
@@ -80,7 +81,7 @@ public Integer merge(Integer aggr1, Integer aggr2) {
                     }
                 };
             }
-        }, HoppingWindows.of(1000).every(500));
+        }, HoppingWindows.of(1000).every(500).emit(1000).until(1000 * 60 * 60 * 24 /* one day */));
 
         // table aggregation
         KTable<String, String> table1 = builder.table("topic2");
@@ -142,7 +143,7 @@ else if (value1 == null)
         });
 
         // windowed table self join
-        KWindowedTable<String, Integer, HoppingWindows> wtable2 = wtable1.leftJoin(wtable1, 1000 * 60 * 60 * 24 * 7 /* a week ago*/, new ValueJoiner<Integer, Integer, Integer>() {
+        KWindowedTable<String, Integer, HoppingWindow> wtable2 = wtable1.leftJoin(wtable1, 1000 * 60 * 60 * 24 * 7 /* a week ago*/, new ValueJoiner<Integer, Integer, Integer>() {
             @Override
             public Integer apply(Integer value1, Integer value2) {
                 if (value2 == null)
@@ -152,9 +153,9 @@ public Integer apply(Integer value1, Integer value2) {
             }
         });
 
-        KStream<String, String> stream3 = wtable2.toStream(new WindowMapper<String, Integer, String, String>() {
+        KStream<String, String> stream3 = wtable2.toStream(new WindowMapper<String, Integer, HoppingWindow, String, String>() {
             @Override
-            public KeyValue<String, String> apply(String key, Integer value, Window window) {
+            public KeyValue<String, String> apply(String key, Integer value, HoppingWindow window) {
                 return new KeyValue<>(key + window.start(), value.toString());
             }
         });
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindow.java b/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindow.java
new file mode 100644
index 0000000000000..fcfe017db36cd
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindow.java
@@ -0,0 +1,25 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.kstream;
+
+public class HoppingWindow extends Window {
+
+    public HoppingWindow(long start, long end) {
+        super(start, end);
+    }
+}
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindows.java b/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindows.java
index 457c2026e5a83..671289794f0c7 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindows.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindows.java
@@ -17,12 +17,10 @@
 
 package org.apache.kafka.streams.kstream;
 
-import org.apache.kafka.streams.kstream.internals.AbstractWindows;
-
 import java.util.Collection;
 import java.util.Collections;
 
-public class HoppingWindows extends AbstractWindows implements WindowDef<HoppingWindows> {
+public class HoppingWindows extends Windows<HoppingWindow> {
 
     private long size;
 
@@ -60,7 +58,12 @@ public Collection<Window> windowsFor(long timestamp) {
     }
 
     @Override
-    public boolean equalTo(HoppingWindows other) {
-        return this.size == other.size && this.period == other.period;
+    public boolean equalTo(Windows other) {
+        if (!other.getClass().equals(HoppingWindows.class))
+            return false;
+
+        HoppingWindows otherWindows = (HoppingWindows) other;
+
+        return this.size == otherWindows.size && this.period == otherWindows.period;
     }
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
index 06f3ed5dfc87d..76c5edcbb6910 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
@@ -179,18 +179,18 @@ public interface KStream<K, V> {
      *
      * @param kstream the instance of KStream joined with this stream
      * @param joiner ValueJoiner
-     * @param windowDef the window definition
+     * @param windows the window definition
      * @param <V1>   the value type of the other stream
      * @param <V2>   the value type of the new stream
      */
-    <V1, V2, W extends WindowDef> KStream<K, V2> join(KStream<K, V1> kstream, ValueJoiner<V, V1, V2> joiner, WindowDef<W> windowDef);
+    <V1, V2, W extends Window> KStream<K, V2> join(KStream<K, V1> kstream, ValueJoiner<V, V1, V2> joiner, Windows<W> windows);
 
     /**
      * Aggregate values of this stream by key on a window basis.
      *
      * @param aggregateSupplier the class of aggregateSupplier
-     * @param windowDef the window definition
+     * @param windows the window definition
      * @param <T>   the value type of the aggregated table
      */
-    <T, W extends WindowDef> KWindowedTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, WindowDef<W> windowDef);
+    <T, W extends Window> KWindowedTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, Windows<W> windows);
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
index 9a1b0f6f73f95..a9ab7317d53f7 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
@@ -143,8 +143,9 @@ public interface KTable<K, V> {
      *
      * @param aggregateSupplier the class of aggregateSupplier
      * @param selector the KeyValue mapper that select the aggregate key
+     * @param name the name of the resulted table
      * @param <K1>   the key type of the aggregated table
      * @param <V1>   the value type of the aggregated table
      */
-    <K1, V1> KTable<K1, V1> aggregate(AggregateSupplier<K1, KeyValue<K, V>, V1> aggregateSupplier, KeyValueMapper<K, V, K1> selector);
+    <K1, V1> KTable<K1, V1> aggregate(AggregateSupplier<K1, KeyValue<K, V>, V1> aggregateSupplier, KeyValueMapper<K, V, K1> selector, String name);
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KWindowedTable.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KWindowedTable.java
index ee67faf55d7f9..80dc5dc6e29d1 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KWindowedTable.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KWindowedTable.java
@@ -25,7 +25,7 @@
  * @param <V> the type of values
  * @param <W> the type of window definition
  */
-public interface KWindowedTable<K, V, W extends WindowDef> {
+public interface KWindowedTable<K, V, W extends Window> {
 
     /**
      * Creates a new instance of KTable consists of all elements of this stream which satisfy a predicate
@@ -58,7 +58,7 @@ public interface KWindowedTable<K, V, W extends WindowDef> {
      * @param windowMapper the class of WindowMapper
      * @return the instance of KStream that contains transformed keys and values
      */
-    <K1, V1> KStream<K1, V1> toStream(WindowMapper<K, V, K1, V1> windowMapper);
+    <K1, V1> KStream<K1, V1> toStream(WindowMapper<K, V, W, K1, V1> windowMapper);
 
     /**
      * Combines values of this KWindowedTable with another KWindowedTable using Inner Join.
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/WindowDef.java b/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindow.java
similarity index 84%
rename from streams/src/main/java/org/apache/kafka/streams/kstream/WindowDef.java
rename to streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindow.java
index f8f155af6496b..e0a79040ac74a 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/WindowDef.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindow.java
@@ -17,11 +17,10 @@
 
 package org.apache.kafka.streams.kstream;
 
-import java.util.Collection;
 
-public interface WindowDef<W extends WindowDef> {
+public class SlidingWindow extends Window {
 
-    boolean equalTo(W other);
-
-    Collection<Window> windowsFor(long timestamp);
+    public SlidingWindow(long start, long end) {
+        super(start, end);
+    }
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindows.java b/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindows.java
index 047ad09399283..e19ee4fd66ab8 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindows.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindows.java
@@ -18,12 +18,10 @@
 package org.apache.kafka.streams.kstream;
 
 
-import org.apache.kafka.streams.kstream.internals.AbstractWindows;
-
 import java.util.Collection;
 import java.util.Collections;
 
-public class SlidingWindows extends AbstractWindows implements WindowDef<SlidingWindows> {
+public class SlidingWindows extends Windows<SlidingWindow> {
 
     private long size;
 
@@ -45,7 +43,12 @@ public Collection<Window> windowsFor(long timestamp) {
     }
 
     @Override
-    public boolean equalTo(SlidingWindows other) {
-        return this.size == other.size;
+    public boolean equalTo(Windows other) {
+        if (!other.getClass().equals(SlidingWindows.class))
+            return false;
+
+        SlidingWindows otherWindows = (SlidingWindows) other;
+
+        return this.size == otherWindows.size;
     }
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindow.java b/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindow.java
index f651a6a2a3997..5e2bb07871147 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindow.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindow.java
@@ -17,36 +17,9 @@
 
 package org.apache.kafka.streams.kstream;
 
-import org.apache.kafka.streams.kstream.internals.AbstractWindows;
+public class UnlimitedWindow extends Window {
 
-import java.util.Collection;
-import java.util.Collections;
-
-public class UnlimitedWindow extends AbstractWindows implements WindowDef<UnlimitedWindow> {
-
-    private long start;
-
-    private UnlimitedWindow(long start) {
-        super();
-
-        this.start = start;
-    }
-
-    /**
-     * Returns an unlimited window definition
-     */
-    public static UnlimitedWindow on(long start) {
-        return new UnlimitedWindow(start);
-    }
-
-    @Override
-    public Collection<Window> windowsFor(long timestamp) {
-        // TODO
-        return Collections.<Window>emptyList();
-    }
-
-    @Override
-    public boolean equalTo(UnlimitedWindow other) {
-        return true;
+    public UnlimitedWindow(long start) {
+        super(start, Long.MAX_VALUE);
     }
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindows.java b/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindows.java
new file mode 100644
index 0000000000000..5d35a7eeea0dc
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindows.java
@@ -0,0 +1,55 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.kstream;
+
+import java.util.Collection;
+import java.util.Collections;
+
+public class UnlimitedWindows extends Windows<UnlimitedWindow> {
+
+    private long start;
+
+    private UnlimitedWindows(long start) {
+        super();
+
+        this.start = start;
+    }
+
+    /**
+     * Returns an unlimited window definition
+     */
+    public static UnlimitedWindows on(long start) {
+        return new UnlimitedWindows(start);
+    }
+
+    @Override
+    public Collection<Window> windowsFor(long timestamp) {
+        // TODO
+        return Collections.<Window>emptyList();
+    }
+
+    @Override
+    public boolean equalTo(Windows other) {
+        if (!other.getClass().equals(UnlimitedWindows.class))
+            return false;
+
+        UnlimitedWindows otherWindows = (UnlimitedWindows) other;
+
+        return this.start == otherWindows.start;
+    }
+}
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/Window.java b/streams/src/main/java/org/apache/kafka/streams/kstream/Window.java
index 33f9b0a94402d..5ebe6ab7b595e 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/Window.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/Window.java
@@ -17,7 +17,7 @@
 
 package org.apache.kafka.streams.kstream;
 
-public class Window implements Comparable<Window> {
+public abstract class Window implements Comparable<Window> {
 
     private long start;
     private long end;
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/WindowMapper.java b/streams/src/main/java/org/apache/kafka/streams/kstream/WindowMapper.java
index 00f803b88bea2..27d3885129374 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/WindowMapper.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/WindowMapper.java
@@ -17,7 +17,7 @@
 
 package org.apache.kafka.streams.kstream;
 
-public interface WindowMapper<K, V, K1, V1> {
+public interface WindowMapper<K, V, W extends Window, K1, V1> {
 
-    KeyValue<K1, V1> apply(K key, V value, Window window);
+    KeyValue<K1, V1> apply(K key, V value, W window);
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/AbstractWindows.java b/streams/src/main/java/org/apache/kafka/streams/kstream/Windows.java
similarity index 74%
rename from streams/src/main/java/org/apache/kafka/streams/kstream/internals/AbstractWindows.java
rename to streams/src/main/java/org/apache/kafka/streams/kstream/Windows.java
index fcbd2c9afc3cf..3c1ed367ce111 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/AbstractWindows.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/Windows.java
@@ -15,9 +15,11 @@
  * limitations under the License.
  */
 
-package org.apache.kafka.streams.kstream.internals;
+package org.apache.kafka.streams.kstream;
 
-public abstract class AbstractWindows {
+import java.util.Collection;
+
+public abstract class Windows<W extends Window> {
 
     private static final long DEFAULT_EMIT_DURATION = 1000L;
 
@@ -27,7 +29,7 @@ public abstract class AbstractWindows {
 
     private long maintainDuration;
 
-    protected AbstractWindows() {
+    protected Windows() {
         this.emitDuration = DEFAULT_EMIT_DURATION;
         this.maintainDuration = DEFAULT_MAINTAIN_DURATION;
     }
@@ -35,7 +37,7 @@ protected AbstractWindows() {
     /**
      * Set the window emit duration in milliseconds of system time
      */
-    public AbstractWindows emit(long duration) {
+    public Windows emit(long duration) {
         this.emitDuration = duration;
 
         return this;
@@ -44,9 +46,21 @@ public AbstractWindows emit(long duration) {
     /**
      * Set the window maintain duration in milliseconds of system time
      */
-    public AbstractWindows until(long duration) {
+    public Windows until(long duration) {
         this.maintainDuration = duration;
 
         return this;
     }
-}
\ No newline at end of file
+
+    public long emitEveryMs() {
+        return this.emitDuration;
+    }
+
+    public long maintainMs() {
+        return this.maintainDuration;
+    }
+
+    abstract boolean equalTo(Windows other);
+
+    abstract Collection<Window> windowsFor(long timestamp);
+}
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
index 0a89d1f8ca8d9..8ceca6ff608de 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
@@ -31,7 +31,8 @@
 import org.apache.kafka.streams.kstream.KeyValueMapper;
 import org.apache.kafka.streams.kstream.Predicate;
 import org.apache.kafka.streams.kstream.ValueMapper;
-import org.apache.kafka.streams.kstream.WindowDef;
+import org.apache.kafka.streams.kstream.Window;
+import org.apache.kafka.streams.kstream.Windows;
 import org.apache.kafka.streams.processor.Processor;
 import org.apache.kafka.streams.processor.ProcessorSupplier;
 
@@ -245,7 +246,7 @@ public <V1, R> KStream<K, R> leftJoin(KTable<K, V1> other, ValueJoiner<V, V1, R>
     }
 
     @Override
-    public <V1, V2, W extends WindowDef> KStream<K, V2> join(KStream<K, V1> kstream, ValueJoiner<V, V1, V2> joiner, WindowDef<W> windowDef) {
+    public <V1, V2, W extends Window> KStream<K, V2> join(KStream<K, V1> kstream, ValueJoiner<V, V1, V2> joiner, Windows<W> windows) {
         // TODO
         String name = topology.newName(JOINTHIS_NAME);
 
@@ -260,7 +261,7 @@ public Processor get() {
     }
 
     @Override
-    public <T, W extends WindowDef> KWindowedTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, WindowDef<W> windowDef) {
+    public <T, W extends Window> KWindowedTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, Windows<W> windows) {
         // TODO
         return null;
     }
diff --git a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamImplTest.java b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamImplTest.java
index 05ddc18409c41..94a3afa734786 100644
--- a/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamImplTest.java
+++ b/streams/src/test/java/org/apache/kafka/streams/kstream/internals/KStreamImplTest.java
@@ -25,7 +25,7 @@
 import org.apache.kafka.streams.kstream.ValueJoiner;
 import org.apache.kafka.streams.kstream.ValueMapper;
 import org.apache.kafka.test.MockProcessorSupplier;
-import org.apache.kafka.streams.kstream.UnlimitedWindow;
+import org.apache.kafka.streams.kstream.UnlimitedWindows;
 import org.junit.Test;
 
 import java.util.Collections;
@@ -106,14 +106,14 @@ public boolean test(String key, Integer value) {
             public Integer apply(Integer value1, Integer value2) {
                 return value1 + value2;
             }
-        }, UnlimitedWindow.on(0));
+        }, UnlimitedWindows.on(0));
 
         KStream<String, Integer> stream5 = streams2[1].join(streams3[1], new ValueJoiner<Integer, Integer, Integer>() {
             @Override
             public Integer apply(Integer value1, Integer value2) {
                 return value1 + value2;
             }
-        }, UnlimitedWindow.on(0));
+        }, UnlimitedWindows.on(0));
 
         stream4.to("topic-5");
 

From e6373cbc4229637100c97bbb440555c2f0719d03 Mon Sep 17 00:00:00 2001
From: Guozhang Wang <wangguoz@gmail.com>
Date: Mon, 14 Dec 2015 17:50:17 -0800
Subject: [PATCH 06/14] add built-in aggregates

---
 .../streams/kstream/AggregateSupplier.java    |  2 +-
 .../apache/kafka/streams/kstream/KStream.java | 17 +++++++++++++++++
 .../kstream/internals/KStreamImpl.java        | 19 +++++++++++++++++++
 3 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/AggregateSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/AggregateSupplier.java
index 3ee80756adbb4..cd6d317c99acc 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/AggregateSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/AggregateSupplier.java
@@ -19,5 +19,5 @@
 
 public interface AggregateSupplier<K, V, T> {
 
-    Aggregator<K, V, T> get();
+    Aggregator<K, V, T> get(Class<K> keyClass, Class<V> valueClass, Class<T> aggClass);
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
index 76c5edcbb6910..caa5fc5c46b08 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
@@ -21,6 +21,8 @@
 import org.apache.kafka.common.serialization.Serializer;
 import org.apache.kafka.streams.processor.ProcessorSupplier;
 
+import java.util.Collection;
+
 /**
  * KStream is an abstraction of a stream of key-value pairs.
  *
@@ -193,4 +195,19 @@ public interface KStream<K, V> {
      * @param <T>   the value type of the aggregated table
      */
     <T, W extends Window> KWindowedTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, Windows<W> windows);
+
+    /**
+     * Sum values of this stream by key on a window basis.
+     */
+    <W extends Window> KWindowedTable<K, V, W> sumByKey(Windows<W> windows);
+
+    /**
+     * Count number of records of this stream by key on a window basis.
+     */
+    <W extends Window> KWindowedTable<K, Long, W> countByKey(Windows<W> windows);
+
+    /**
+     * Get the top-k records of this stream by key on a window basis.
+     */
+    <W extends Window> KWindowedTable<K, Collection<V>, W> topKByKey(int k, Windows<W> windows);
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
index 8ceca6ff608de..266280c1b0248 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
@@ -37,6 +37,7 @@
 import org.apache.kafka.streams.processor.ProcessorSupplier;
 
 import java.lang.reflect.Array;
+import java.util.Collection;
 import java.util.HashSet;
 import java.util.Set;
 
@@ -265,4 +266,22 @@ public <T, W extends Window> KWindowedTable<K, T, W> aggregateByKey(AggregateSup
         // TODO
         return null;
     }
+
+    @Override
+    public <W extends Window> KWindowedTable<K, V, W> sumByKey(Windows<W> windows) {
+
+        return this.aggregateByKey(new SumSupplier<>(), windows);
+    }
+
+    @Override
+    public <W extends Window> KWindowedTable<K, Long, W> countByKey(Windows<W> windows) {
+
+        return this.aggregateByKey(new CountSupplier<>(), windows);
+    }
+
+    @Override
+    public <W extends Window> KWindowedTable<K, Collection<V>, W> topKByKey(int k, Windows<W> windows) {
+
+        return this.aggregateByKey(new TopKSupplier<>(k), windows);
+    }
 }

From 66e122adc8911334e924921bc7fa67275445bd71 Mon Sep 17 00:00:00 2001
From: Guozhang Wang <wangguoz@gmail.com>
Date: Mon, 14 Dec 2015 19:17:59 -0800
Subject: [PATCH 07/14] add built-in aggregates in KTable

---
 .../kafka/streams/examples/KTableJob.java     | 60 ++-----------------
 .../apache/kafka/streams/kstream/KTable.java  | 19 +++++-
 .../streams/kstream/internals/KTableImpl.java | 21 ++++++-
 3 files changed, 43 insertions(+), 57 deletions(-)

diff --git a/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java b/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
index 393f591f83350..a68bbe216897c 100644
--- a/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
+++ b/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
@@ -56,67 +56,17 @@ public static void main(String[] args) throws Exception {
         // stream aggregate
         KStream<String, Integer> stream1 = builder.stream("topic1");
 
-        KWindowedTable<String, Integer, HoppingWindow> wtable1 = stream1.aggregateByKey(new AggregateSupplier<String, Integer, Integer>() {
-            @Override
-            public Aggregator<String, Integer, Integer> get() {
-                return new Aggregator<String, Integer, Integer>() {
-                    @Override
-                    public Integer initialValue() {
-                        return 0;
-                    }
-
-                    @Override
-                    public Integer add(String aggKey, Integer value, Integer aggregate) {
-                        return aggregate + value;
-                    }
-
-                    @Override
-                    public Integer remove(String aggKey, Integer value, Integer aggregate) {
-                        return aggregate - value;
-                    }
-
-                    @Override
-                    public Integer merge(Integer aggr1, Integer aggr2) {
-                        return aggr1 + aggr2;
-                    }
-                };
-            }
-        }, HoppingWindows.of(1000).every(500).emit(1000).until(1000 * 60 * 60 * 24 /* one day */));
+        KWindowedTable<String, Integer, HoppingWindow> wtable1 = stream1.sumByKey(HoppingWindows.of(1000).every(500).emit(1000).until(1000 * 60 * 60 * 24 /* one day */));
 
         // table aggregation
         KTable<String, String> table1 = builder.table("topic2");
 
-        KTable<String, Integer> table2 = table1.aggregate(new AggregateSupplier<String, KeyValue<String, String>, Integer>() {
+        KTable<String, Integer> table2 = table1.sum(new KeyValueMapper<String, String, KeyValue<String, Integer>>() {
             @Override
-            public Aggregator<String, KeyValue<String, String>, Integer> get() {
-                return new Aggregator<String, KeyValue<String, String>, Integer>() {
-                    @Override
-                    public Integer initialValue() {
-                        return 0;
-                    }
-
-                    @Override
-                    public Integer add(String aggKey, KeyValue<String, String> value, Integer aggregate) {
-                        return aggregate + new Integer(value.value);
-                    }
-
-                    @Override
-                    public Integer remove(String aggKey, KeyValue<String, String> value, Integer aggregate) {
-                        return aggregate - new Integer(value.value);
-                    }
-
-                    @Override
-                    public Integer merge(Integer aggr1, Integer aggr2) {
-                        return aggr1 + aggr2;
-                    }
-                };
+            public KeyValue<String, Integer> apply(String key, String value) {
+                return new KeyValue<>(value, new Integer(key));
             }
-        }, new KeyValueMapper<String, String, String>() {
-            @Override
-            public String apply(String key, String value) {
-                return value;
-            }
-        });
+        }, "table2");
 
         // stream-table join
         KStream<String, Integer> stream2 = stream1.leftJoin(table2, new ValueJoiner<Integer, Integer, Integer>() {
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
index a9ab7317d53f7..d08e547746257 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
@@ -20,6 +20,8 @@
 import org.apache.kafka.common.serialization.Deserializer;
 import org.apache.kafka.common.serialization.Serializer;
 
+import java.util.Collection;
+
 /**
  * KTable is an abstraction of a change log stream.
  *
@@ -147,5 +149,20 @@ public interface KTable<K, V> {
      * @param <K1>   the key type of the aggregated table
      * @param <V1>   the value type of the aggregated table
      */
-    <K1, V1> KTable<K1, V1> aggregate(AggregateSupplier<K1, KeyValue<K, V>, V1> aggregateSupplier, KeyValueMapper<K, V, K1> selector, String name);
+    <K1, V1, V2> KTable<K1, V2> aggregate(AggregateSupplier<K1, V1, V2> aggregateSupplier, KeyValueMapper<K, V, KeyValue<K1, V1>> selector, String name);
+
+    /**
+     * Sum values of this table by the selected key on a window basis.
+     */
+    <K1, V1> KTable<K1, V1>sum(KeyValueMapper<K, V, KeyValue<K1, V1>> selector, String name);
+
+    /**
+     * Count number of records of this table by the selected key on a window basis.
+     */
+    <K1> KTable<K1, Long> count(KeyValueMapper<K, V, KeyValue<K1, Long>> selector, String name);
+
+    /**
+     * Get the top-k records of this table by the selected key on a window basis.
+     */
+    <K1, V1> KTable<K1, Collection<V1>> topK(int k, KeyValueMapper<K, V, KeyValue<K1, V1>> selector, String name);
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
index 3a9508a92b70a..16a490d1f3085 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
@@ -30,6 +30,7 @@
 import org.apache.kafka.streams.kstream.ValueMapper;
 import org.apache.kafka.streams.processor.StateStoreSupplier;
 
+import java.util.Collection;
 import java.util.Set;
 
 /**
@@ -237,8 +238,26 @@ public <V1, R> KTable<K, R> leftJoin(KTable<K, V1> other, ValueJoiner<V, V1, R>
     }
 
     @Override
-    public <K1, V1> KTable<K1, V1> aggregate(AggregateSupplier<K1, KeyValue<K, V>, V1> aggregateSupplier, KeyValueMapper<K, V, K1> selector) {
+    public <K1, V1, V2> KTable<K1, V2> aggregate(AggregateSupplier<K1, V1, V2> aggregateSupplier, KeyValueMapper<K, V, KeyValue<K1, V1>> selector, String name) {
         // TODO
         return null;
     }
+
+    @Override
+    public <K1, V1> KTable<K1, V1>sum(KeyValueMapper<K, V, KeyValue<K1, V1>> selector, String name) {
+
+        return this.aggregate(new SumSupplier<>(), selector, name);
+    }
+
+    @Override
+    public <K1> KTable<K1, Long> count(KeyValueMapper<K, V, KeyValue<K1, Long>> selector, String name) {
+
+        return this.aggregate(new CountSupplier<>(), selector, name);
+    }
+
+    @Override
+    public <K1, V1> KTable<K1, Collection<V1>> topK(int k, KeyValueMapper<K, V, KeyValue<K1, V1>> selector, String name) {
+
+        return this.aggregate(new TopKSupplier<>(k), selector, name);
+    }
 }

From 1f360a25022d0286f6ebbf1a6735201ba8fdab53 Mon Sep 17 00:00:00 2001
From: Guozhang Wang <wangguoz@gmail.com>
Date: Tue, 15 Dec 2015 11:43:53 -0800
Subject: [PATCH 08/14] address Yasu's comments

---
 .../kafka/streams/kstream/HoppingWindow.java  | 10 ++++++++++
 .../kafka/streams/kstream/HoppingWindows.java |  4 ++++
 .../kafka/streams/kstream/SlidingWindow.java  | 10 ++++++++++
 .../kafka/streams/kstream/SlidingWindows.java |  6 ++++++
 .../streams/kstream/UnlimitedWindow.java      | 10 ++++++++++
 .../streams/kstream/UnlimitedWindows.java     |  4 ++++
 .../apache/kafka/streams/kstream/Window.java  | 16 +++++++--------
 .../apache/kafka/streams/kstream/Windows.java | 20 +++++++++++++++++++
 8 files changed, 71 insertions(+), 9 deletions(-)

diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindow.java b/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindow.java
index fcfe017db36cd..795d58188225e 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindow.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindow.java
@@ -22,4 +22,14 @@ public class HoppingWindow extends Window {
     public HoppingWindow(long start, long end) {
         super(start, end);
     }
+
+    @Override
+    public boolean overlap(Window other) {
+        return super.overlap(other) && other.getClass().equals(HoppingWindow.class);
+    }
+
+    @Override
+    public boolean equalsTo(Window other) {
+        return super.equalsTo(other) && other.getClass().equals(HoppingWindow.class);
+    }
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindows.java b/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindows.java
index 671289794f0c7..6a60e405b3e51 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindows.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindows.java
@@ -22,6 +22,8 @@
 
 public class HoppingWindows extends Windows<HoppingWindow> {
 
+    private static final String NAME = "HOPPING-WINDOWS-";
+
     private long size;
 
     private long period;
@@ -29,6 +31,8 @@ public class HoppingWindows extends Windows<HoppingWindow> {
     private HoppingWindows(long size) {
         super();
 
+        setName(newName(NAME));
+
         this.size = size;
         this.period = size;
     }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindow.java b/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindow.java
index e0a79040ac74a..1f38ad84b4b0d 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindow.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindow.java
@@ -23,4 +23,14 @@ public class SlidingWindow extends Window {
     public SlidingWindow(long start, long end) {
         super(start, end);
     }
+
+    @Override
+    public boolean overlap(Window other) {
+        return super.overlap(other) && other.getClass().equals(SlidingWindow.class);
+    }
+
+    @Override
+    public boolean equalsTo(Window other) {
+        return super.equalsTo(other) && other.getClass().equals(SlidingWindow.class);
+    }
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindows.java b/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindows.java
index e19ee4fd66ab8..f07c908efb8a9 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindows.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindows.java
@@ -23,9 +23,15 @@
 
 public class SlidingWindows extends Windows<SlidingWindow> {
 
+    private static final String NAME = "SLIDING-WINDOWS-";
+
     private long size;
 
     private SlidingWindows(long size) {
+        super();
+
+        setName(newName(NAME));
+
         this.size = size;
     }
 
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindow.java b/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindow.java
index 5e2bb07871147..b2638fedbab00 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindow.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindow.java
@@ -22,4 +22,14 @@ public class UnlimitedWindow extends Window {
     public UnlimitedWindow(long start) {
         super(start, Long.MAX_VALUE);
     }
+
+    @Override
+    public boolean overlap(Window other) {
+        return super.overlap(other) && other.getClass().equals(UnlimitedWindow.class);
+    }
+
+    @Override
+    public boolean equalsTo(Window other) {
+        return super.equalsTo(other) && other.getClass().equals(UnlimitedWindow.class);
+    }
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindows.java b/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindows.java
index 5d35a7eeea0dc..1d347c2d77b5d 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindows.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindows.java
@@ -22,11 +22,15 @@
 
 public class UnlimitedWindows extends Windows<UnlimitedWindow> {
 
+    private static final String NAME = "UNLIMITED-WINDOWS-";
+
     private long start;
 
     private UnlimitedWindows(long start) {
         super();
 
+        setName(newName(NAME));
+
         this.start = start;
     }
 
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/Window.java b/streams/src/main/java/org/apache/kafka/streams/kstream/Window.java
index 5ebe6ab7b595e..63e0a35725f6f 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/Window.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/Window.java
@@ -17,7 +17,7 @@
 
 package org.apache.kafka.streams.kstream;
 
-public abstract class Window implements Comparable<Window> {
+public abstract class Window {
 
     private long start;
     private long end;
@@ -41,13 +41,11 @@ public long end() {
         return end;
     }
 
-    @Override
-    public int compareTo(Window other) {
-        if (this.start() > other.start())
-            return 1;
-        else if (this.start() < other.start())
-            return -1;
-        else
-            return 0;
+    public boolean overlap(Window other) {
+        return this.start() < other.end() || other.start() < this.end();
+    }
+
+    public boolean equalsTo(Window other) {
+        return this.start() == other.start() && this.end() == other.end();
     }
 }
\ No newline at end of file
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/Windows.java b/streams/src/main/java/org/apache/kafka/streams/kstream/Windows.java
index 3c1ed367ce111..ff504e89e9b09 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/Windows.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/Windows.java
@@ -18,6 +18,7 @@
 package org.apache.kafka.streams.kstream;
 
 import java.util.Collection;
+import java.util.concurrent.atomic.AtomicInteger;
 
 public abstract class Windows<W extends Window> {
 
@@ -25,15 +26,30 @@ public abstract class Windows<W extends Window> {
 
     private static final long DEFAULT_MAINTAIN_DURATION = 24 * 60 * 60 * 1000L;   // one day
 
+    private static final AtomicInteger NAME_INDEX = new AtomicInteger(0);
+
     private long emitDuration;
 
     private long maintainDuration;
 
+    private String name;
+
     protected Windows() {
         this.emitDuration = DEFAULT_EMIT_DURATION;
         this.maintainDuration = DEFAULT_MAINTAIN_DURATION;
     }
 
+    public String name() {
+        return name;
+    }
+
+    /**
+     * Set the window name
+     */
+    protected void setName(String name) {
+        this.name = name;
+    }
+
     /**
      * Set the window emit duration in milliseconds of system time
      */
@@ -60,6 +76,10 @@ public long maintainMs() {
         return this.maintainDuration;
     }
 
+    protected String newName(String prefix) {
+        return prefix + String.format("%010d", NAME_INDEX.getAndIncrement());
+    }
+
     abstract boolean equalTo(Windows other);
 
     abstract Collection<Window> windowsFor(long timestamp);

From 2b027bf8614026cbec05404dffd5e9c2598db6f4 Mon Sep 17 00:00:00 2001
From: Guozhang Wang <wangguoz@gmail.com>
Date: Tue, 15 Dec 2015 12:58:11 -0800
Subject: [PATCH 09/14] add missing files

---
 .../kstream/internals/CountSupplier.java      |  51 +++++
 .../kstream/internals/SumSupplier.java        | 190 ++++++++++++++++++
 .../kstream/internals/TopKSupplier.java       | 102 ++++++++++
 3 files changed, 343 insertions(+)
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/internals/CountSupplier.java
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/internals/SumSupplier.java
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java

diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CountSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CountSupplier.java
new file mode 100644
index 0000000000000..b28cf1eee96c6
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CountSupplier.java
@@ -0,0 +1,51 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.kstream.internals;
+
+import org.apache.kafka.streams.kstream.AggregateSupplier;
+import org.apache.kafka.streams.kstream.Aggregator;
+
+public class CountSupplier<K, V> implements AggregateSupplier<K, V, Long> {
+
+    private class Count implements Aggregator<K, V, Long> {
+        @Override
+        public Long initialValue(){
+            return 0L;
+        }
+
+        public @Override
+        Long add(K aggKey, V value, Long aggregate) {
+            return aggregate + 1L;
+        }
+
+        public @Override
+        Long remove(K aggKey, V value, Long aggregate) {
+            return aggregate - 1L;
+        }
+
+        public @Override
+        Long merge(Long aggr1, Long aggr2) {
+            return aggr1 + aggr2;
+        }
+    }
+
+    @Override
+    public Aggregator<K, V, Long> get(Class<K> keyClass, Class<V> valueClass, Class<Long> aggClass) {
+        return new Count();
+    }
+}
\ No newline at end of file
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/SumSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/SumSupplier.java
new file mode 100644
index 0000000000000..886516b8adfb3
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/SumSupplier.java
@@ -0,0 +1,190 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.kstream.internals;
+
+import org.apache.kafka.common.KafkaException;
+import org.apache.kafka.streams.kstream.AggregateSupplier;
+import org.apache.kafka.streams.kstream.Aggregator;
+
+public class SumSupplier<K, V> implements AggregateSupplier<K, V, V> {
+
+    private class LongSum<K> implements Aggregator<K, Long, Long> {
+
+        @Override
+        public Long initialValue(){
+            return 0L;
+        }
+
+        @Override
+        public Long add(K aggKey, Long value, Long aggregate) {
+            return aggregate + value;
+        }
+
+        @Override
+        public Long remove(K aggKey, Long value, Long aggregate) {
+            return aggregate - value;
+        }
+
+        @Override
+        public Long merge(Long aggr1, Long aggr2) {
+            return aggr1 + aggr2;
+        }
+    }
+
+    private class IntSum<K> implements Aggregator<K, Integer, Integer> {
+
+        @Override
+        public Integer initialValue(){
+            return 0;
+        }
+
+        @Override
+        public Integer add(K aggKey, Integer value, Integer aggregate) {
+            return aggregate + value;
+        }
+
+        @Override
+        public Integer remove(K aggKey, Integer value, Integer aggregate) {
+            return aggregate - value;
+        }
+
+        @Override
+        public Integer merge(Integer aggr1, Integer aggr2) {
+            return aggr1 + aggr2;
+        }
+    }
+
+    private class ShortSum<K> implements Aggregator<K, Short, Short> {
+
+        @Override
+        public Short initialValue(){
+            return (short) 0;
+        }
+
+        @Override
+        public Short add(K aggKey, Short value, Short aggregate) {
+            return (short) (aggregate + value);
+        }
+
+        @Override
+        public Short remove(K aggKey, Short value, Short aggregate) {
+            return (short) (aggregate - value);
+        }
+
+        @Override
+        public Short merge(Short aggr1, Short aggr2) {
+            return (short) (aggr1 + aggr2);
+        }
+    }
+
+    private class DoubleSum<K> implements Aggregator<K, Double, Double> {
+
+        @Override
+        public Double initialValue(){
+            return 0.0d;
+        }
+
+        @Override
+        public Double add(K aggKey, Double value, Double aggregate) {
+            return aggregate + value;
+        }
+
+        @Override
+        public Double remove(K aggKey, Double value, Double aggregate) {
+            return aggregate - value;
+        }
+
+        @Override
+        public Double merge(Double aggr1, Double aggr2) {
+            return aggr1 + aggr2;
+        }
+    }
+
+    private class FloatSum<K> implements Aggregator<K, Float, Float> {
+
+        @Override
+        public Float initialValue(){
+            return 0.0f;
+        }
+
+        @Override
+        public Float add(K aggKey, Float value, Float aggregate) {
+            return aggregate + value;
+        }
+
+        @Override
+        public Float remove(K aggKey, Float value, Float aggregate) {
+            return aggregate - value;
+        }
+
+        @Override
+        public Float merge(Float aggr1, Float aggr2) {
+            return aggr1 + aggr2;
+        }
+    }
+
+    private class ByteSum<K> implements Aggregator<K, Byte, Byte> {
+
+        @Override
+        public Byte initialValue(){
+            return (byte) 0L;
+        }
+
+        @Override
+        public Byte add(K aggKey, Byte value, Byte aggregate) {
+            long aggValue = aggregate;
+
+            return (byte) (aggValue + value);
+        }
+
+        @Override
+        public Byte remove(K aggKey, Byte value, Byte aggregate) {
+            long aggValue = aggregate;
+
+            return (byte) (aggValue - value);
+        }
+
+        @Override
+        public Byte merge(Byte aggr1, Byte aggr2) {
+            long aggValue1 = aggr1;
+
+            return (byte) (aggValue1 + aggr2);
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public Aggregator<K, V, V> get(Class<K> keyClass, Class<V> valueClass, Class<V> aggClass) {
+        if (valueClass == Long.class) {
+            return (Aggregator<K, V, V>) new LongSum<K>();
+        } else if (valueClass == Integer.class) {
+            return (Aggregator<K, V, V>) new IntSum<K>();
+        } else if (valueClass == Short.class) {
+            return (Aggregator<K, V, V>) new ShortSum<K>();
+        } else if (valueClass == Double.class) {
+            return (Aggregator<K, V, V>) new DoubleSum<K>();
+        } else if (valueClass == Float.class) {
+            return (Aggregator<K, V, V>) new FloatSum<K>();
+        } else if (valueClass == Byte.class) {
+            return (Aggregator<K, V, V>) new ByteSum<K>();
+        } else {
+            throw new KafkaException("The value type " + valueClass.getName() +
+                    " is not supported for built-in sum aggregations.");
+        }
+    }
+}
\ No newline at end of file
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java
new file mode 100644
index 0000000000000..d35096476bf70
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java
@@ -0,0 +1,102 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.kstream.internals;
+
+import org.apache.kafka.streams.kstream.AggregateSupplier;
+import org.apache.kafka.streams.kstream.Aggregator;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.PriorityQueue;
+import java.util.Set;
+
+public class TopKSupplier<K, V> implements AggregateSupplier<K, V, Collection<V>> {
+
+    private final int k;
+
+    public TopKSupplier(int k) {
+        this.k = k;
+    }
+
+    private class TopK<K, V> implements Aggregator<K, V, Collection<V>> {
+
+        private final Map<K, PriorityQueue<V>> sorted = new HashMap<>();
+
+        @Override
+        public Collection<V> initialValue(){
+            return Collections.<V>emptySet();
+        }
+
+        @Override
+        public Collection<V> add(K aggKey, V value, Collection<V> aggregate) {
+            PriorityQueue<V> queue = sorted.get(aggKey);
+            if (queue == null) {
+                queue = new PriorityQueue<>();
+                sorted.put(aggKey, queue);
+            }
+
+            queue.add(value);
+
+            PriorityQueue<V> copy = new PriorityQueue<>(queue);
+
+            Set<V> ret = new HashSet<>();
+            for (int i = 1; i <= k; i++)
+                ret.add(copy.poll());
+
+            return ret;
+        }
+
+        @Override
+        public Collection<V> remove(K aggKey, V value, Collection<V> aggregate) {
+            PriorityQueue<V> queue = sorted.get(aggKey);
+
+            if (queue == null)
+                throw new IllegalStateException("This should not happen.");
+
+            queue.remove(value);
+
+            PriorityQueue<V> copy = new PriorityQueue<>(queue);
+
+            Set<V> ret = new HashSet<>();
+            for (int i = 1; i <= k; i++)
+                ret.add(copy.poll());
+
+            return ret;
+        }
+
+        @Override
+        public Collection<V> merge(Collection<V> aggr1, Collection<V> aggr2) {
+            PriorityQueue<V> copy = new PriorityQueue<>(aggr1);
+            copy.addAll(aggr2);
+
+            Set<V> ret = new HashSet<>();
+            for (int i = 1; i <= k; i++)
+                ret.add(copy.poll());
+
+            return ret;
+        }
+    }
+
+    @Override
+    public Aggregator<K, V, Collection<V>> get(Class<K> keyClass, Class<V> valueClass, Class<Collection<V>> aggClass) {
+        return new TopK<>();
+    }
+}
\ No newline at end of file

From 5214b12fcd66eb4cfa9af4258ca2146c11aa2e89 Mon Sep 17 00:00:00 2001
From: Guozhang Wang <wangguoz@gmail.com>
Date: Tue, 15 Dec 2015 15:11:27 -0800
Subject: [PATCH 10/14] address Yasu's comments

---
 .../kafka/streams/examples/KTableJob.java     |  34 ++--
 .../streams/kstream/AggregateSupplier.java    |   2 +-
 .../apache/kafka/streams/kstream/KStream.java |   2 +-
 .../apache/kafka/streams/kstream/KTable.java  |   2 +-
 .../kstream/internals/CountSupplier.java      |   2 +-
 .../kstream/internals/KStreamImpl.java        |   4 +-
 .../streams/kstream/internals/KTableImpl.java |   4 +-
 .../kstream/internals/SumSupplier.java        | 160 ++----------------
 .../kstream/internals/TopKSupplier.java       |   6 +-
 9 files changed, 49 insertions(+), 167 deletions(-)

diff --git a/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java b/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
index a68bbe216897c..a60263675b69b 100644
--- a/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
+++ b/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
@@ -33,6 +33,7 @@
 import org.apache.kafka.streams.kstream.KeyValue;
 import org.apache.kafka.streams.kstream.KeyValueMapper;
 import org.apache.kafka.streams.kstream.ValueJoiner;
+import org.apache.kafka.streams.kstream.ValueMapper;
 import org.apache.kafka.streams.kstream.Window;
 import org.apache.kafka.streams.kstream.WindowMapper;
 
@@ -56,33 +57,44 @@ public static void main(String[] args) throws Exception {
         // stream aggregate
         KStream<String, Integer> stream1 = builder.stream("topic1");
 
-        KWindowedTable<String, Integer, HoppingWindow> wtable1 = stream1.sumByKey(HoppingWindows.of(1000).every(500).emit(1000).until(1000 * 60 * 60 * 24 /* one day */));
+        @SuppressWarnings("unchecked")
+        KWindowedTable<String, Long, HoppingWindow> wtable1 = stream1.sumByKey(new ValueMapper<Integer, Long>() {
+            @Override
+            public Long apply(Integer value) {
+                return (long) value;
+            }
+        }, HoppingWindows.of(1000).every(500).emit(1000).until(1000 * 60 * 60 * 24 /* one day */));
 
         // table aggregation
         KTable<String, String> table1 = builder.table("topic2");
 
-        KTable<String, Integer> table2 = table1.sum(new KeyValueMapper<String, String, KeyValue<String, Integer>>() {
+        KTable<String, Long> table2 = table1.sum(new KeyValueMapper<String, String, KeyValue<String, Integer>>() {
             @Override
             public KeyValue<String, Integer> apply(String key, String value) {
                 return new KeyValue<>(value, new Integer(key));
             }
+        }, new ValueMapper<Integer, Long>() {
+            @Override
+            public Long apply(Integer value) {
+                return (long) value;
+            }
         }, "table2");
 
         // stream-table join
-        KStream<String, Integer> stream2 = stream1.leftJoin(table2, new ValueJoiner<Integer, Integer, Integer>() {
+        KStream<String, Long> stream2 = stream1.leftJoin(table2, new ValueJoiner<Integer, Long, Long>() {
             @Override
-            public Integer apply(Integer value1, Integer value2) {
+            public Long apply(Integer value1, Long value2) {
                 if (value2 == null)
-                    return 0;
+                    return 0L;
                 else
                     return value1 * value2;
             }
         });
 
         // table-table join
-        KTable<String, String> table3 = table1.outerJoin(table2, new ValueJoiner<String, Integer, String>() {
+        KTable<String, String> table3 = table1.outerJoin(table2, new ValueJoiner<String, Long, String>() {
             @Override
-            public String apply(String value1, Integer value2) {
+            public String apply(String value1, Long value2) {
                 if (value2 == null)
                     return value1 + "-null";
                 else if (value1 == null)
@@ -93,9 +105,9 @@ else if (value1 == null)
         });
 
         // windowed table self join
-        KWindowedTable<String, Integer, HoppingWindow> wtable2 = wtable1.leftJoin(wtable1, 1000 * 60 * 60 * 24 * 7 /* a week ago*/, new ValueJoiner<Integer, Integer, Integer>() {
+        KWindowedTable<String, Long, HoppingWindow> wtable2 = wtable1.leftJoin(wtable1, 1000 * 60 * 60 * 24 * 7 /* a week ago*/, new ValueJoiner<Long, Long, Long>() {
             @Override
-            public Integer apply(Integer value1, Integer value2) {
+            public Long apply(Long value1, Long value2) {
                 if (value2 == null)
                     return value1;
                 else
@@ -103,9 +115,9 @@ public Integer apply(Integer value1, Integer value2) {
             }
         });
 
-        KStream<String, String> stream3 = wtable2.toStream(new WindowMapper<String, Integer, HoppingWindow, String, String>() {
+        KStream<String, String> stream3 = wtable2.toStream(new WindowMapper<String, Long, HoppingWindow, String, String>() {
             @Override
-            public KeyValue<String, String> apply(String key, Integer value, HoppingWindow window) {
+            public KeyValue<String, String> apply(String key, Long value, HoppingWindow window) {
                 return new KeyValue<>(key + window.start(), value.toString());
             }
         });
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/AggregateSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/AggregateSupplier.java
index cd6d317c99acc..3ee80756adbb4 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/AggregateSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/AggregateSupplier.java
@@ -19,5 +19,5 @@
 
 public interface AggregateSupplier<K, V, T> {
 
-    Aggregator<K, V, T> get(Class<K> keyClass, Class<V> valueClass, Class<T> aggClass);
+    Aggregator<K, V, T> get();
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
index caa5fc5c46b08..32a0ceec0af23 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
@@ -199,7 +199,7 @@ public interface KStream<K, V> {
     /**
      * Sum values of this stream by key on a window basis.
      */
-    <W extends Window> KWindowedTable<K, V, W> sumByKey(Windows<W> windows);
+    <W extends Window> KWindowedTable<K, Long, W> sumByKey(ValueMapper<V, Long> valueMapper, Windows<W> windows);
 
     /**
      * Count number of records of this stream by key on a window basis.
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
index d08e547746257..6ac0064986613 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
@@ -154,7 +154,7 @@ public interface KTable<K, V> {
     /**
      * Sum values of this table by the selected key on a window basis.
      */
-    <K1, V1> KTable<K1, V1>sum(KeyValueMapper<K, V, KeyValue<K1, V1>> selector, String name);
+    <K1, V1> KTable<K1, Long>sum(KeyValueMapper<K, V, KeyValue<K1, V1>> selector, ValueMapper<V1, Long> valueMapper, String name);
 
     /**
      * Count number of records of this table by the selected key on a window basis.
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CountSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CountSupplier.java
index b28cf1eee96c6..39e4188d4913d 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CountSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CountSupplier.java
@@ -45,7 +45,7 @@ Long merge(Long aggr1, Long aggr2) {
     }
 
     @Override
-    public Aggregator<K, V, Long> get(Class<K> keyClass, Class<V> valueClass, Class<Long> aggClass) {
+    public Aggregator<K, V, Long> get() {
         return new Count();
     }
 }
\ No newline at end of file
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
index 266280c1b0248..72651c2819f38 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
@@ -268,9 +268,9 @@ public <T, W extends Window> KWindowedTable<K, T, W> aggregateByKey(AggregateSup
     }
 
     @Override
-    public <W extends Window> KWindowedTable<K, V, W> sumByKey(Windows<W> windows) {
+    public <W extends Window> KWindowedTable<K, Long, W> sumByKey(ValueMapper<V, Long> valueMapper, Windows<W> windows) {
 
-        return this.aggregateByKey(new SumSupplier<>(), windows);
+        return this.aggregateByKey(new SumSupplier<>(valueMapper), windows);
     }
 
     @Override
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
index 1495f7f735d8b..646e0d6757b0d 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
@@ -254,9 +254,9 @@ public <K1, V1, V2> KTable<K1, V2> aggregate(AggregateSupplier<K1, V1, V2> aggre
     }
 
     @Override
-    public <K1, V1> KTable<K1, V1>sum(KeyValueMapper<K, V, KeyValue<K1, V1>> selector, String name) {
+    public <K1, V1> KTable<K1, Long> sum(KeyValueMapper<K, V, KeyValue<K1, V1>> selector, ValueMapper<V1, Long> valueMapper, String name) {
 
-        return this.aggregate(new SumSupplier<>(), selector, name);
+        return this.aggregate(new SumSupplier<>(valueMapper), selector, name);
     }
 
     @Override
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/SumSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/SumSupplier.java
index 886516b8adfb3..bd2b99e8365f7 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/SumSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/SumSupplier.java
@@ -17,174 +17,44 @@
 
 package org.apache.kafka.streams.kstream.internals;
 
-import org.apache.kafka.common.KafkaException;
 import org.apache.kafka.streams.kstream.AggregateSupplier;
 import org.apache.kafka.streams.kstream.Aggregator;
+import org.apache.kafka.streams.kstream.ValueMapper;
 
-public class SumSupplier<K, V> implements AggregateSupplier<K, V, V> {
+public class SumSupplier<K, V> implements AggregateSupplier<K, V, Long> {
 
-    private class LongSum<K> implements Aggregator<K, Long, Long> {
+    private final ValueMapper<V, Long> valueMapper;
 
-        @Override
-        public Long initialValue(){
-            return 0L;
-        }
-
-        @Override
-        public Long add(K aggKey, Long value, Long aggregate) {
-            return aggregate + value;
-        }
-
-        @Override
-        public Long remove(K aggKey, Long value, Long aggregate) {
-            return aggregate - value;
-        }
-
-        @Override
-        public Long merge(Long aggr1, Long aggr2) {
-            return aggr1 + aggr2;
-        }
-    }
-
-    private class IntSum<K> implements Aggregator<K, Integer, Integer> {
-
-        @Override
-        public Integer initialValue(){
-            return 0;
-        }
-
-        @Override
-        public Integer add(K aggKey, Integer value, Integer aggregate) {
-            return aggregate + value;
-        }
-
-        @Override
-        public Integer remove(K aggKey, Integer value, Integer aggregate) {
-            return aggregate - value;
-        }
-
-        @Override
-        public Integer merge(Integer aggr1, Integer aggr2) {
-            return aggr1 + aggr2;
-        }
-    }
-
-    private class ShortSum<K> implements Aggregator<K, Short, Short> {
-
-        @Override
-        public Short initialValue(){
-            return (short) 0;
-        }
-
-        @Override
-        public Short add(K aggKey, Short value, Short aggregate) {
-            return (short) (aggregate + value);
-        }
-
-        @Override
-        public Short remove(K aggKey, Short value, Short aggregate) {
-            return (short) (aggregate - value);
-        }
-
-        @Override
-        public Short merge(Short aggr1, Short aggr2) {
-            return (short) (aggr1 + aggr2);
-        }
-    }
-
-    private class DoubleSum<K> implements Aggregator<K, Double, Double> {
-
-        @Override
-        public Double initialValue(){
-            return 0.0d;
-        }
-
-        @Override
-        public Double add(K aggKey, Double value, Double aggregate) {
-            return aggregate + value;
-        }
-
-        @Override
-        public Double remove(K aggKey, Double value, Double aggregate) {
-            return aggregate - value;
-        }
-
-        @Override
-        public Double merge(Double aggr1, Double aggr2) {
-            return aggr1 + aggr2;
-        }
+    public SumSupplier(ValueMapper<V, Long> valueMapper) {
+        this.valueMapper = valueMapper;
     }
 
-    private class FloatSum<K> implements Aggregator<K, Float, Float> {
+    private class LongSum implements Aggregator<K, V, Long> {
 
         @Override
-        public Float initialValue(){
-            return 0.0f;
+        public Long initialValue(){
+            return 0L;
         }
 
         @Override
-        public Float add(K aggKey, Float value, Float aggregate) {
-            return aggregate + value;
+        public Long add(K aggKey, V value, Long aggregate) {
+            return aggregate + valueMapper.apply(value);
         }
 
         @Override
-        public Float remove(K aggKey, Float value, Float aggregate) {
-            return aggregate - value;
+        public Long remove(K aggKey, V value, Long aggregate) {
+            return aggregate - valueMapper.apply(value);
         }
 
         @Override
-        public Float merge(Float aggr1, Float aggr2) {
+        public Long merge(Long aggr1, Long aggr2) {
             return aggr1 + aggr2;
         }
     }
 
-    private class ByteSum<K> implements Aggregator<K, Byte, Byte> {
-
-        @Override
-        public Byte initialValue(){
-            return (byte) 0L;
-        }
-
-        @Override
-        public Byte add(K aggKey, Byte value, Byte aggregate) {
-            long aggValue = aggregate;
-
-            return (byte) (aggValue + value);
-        }
-
-        @Override
-        public Byte remove(K aggKey, Byte value, Byte aggregate) {
-            long aggValue = aggregate;
-
-            return (byte) (aggValue - value);
-        }
-
-        @Override
-        public Byte merge(Byte aggr1, Byte aggr2) {
-            long aggValue1 = aggr1;
-
-            return (byte) (aggValue1 + aggr2);
-        }
-    }
-
     @SuppressWarnings("unchecked")
     @Override
-    public Aggregator<K, V, V> get(Class<K> keyClass, Class<V> valueClass, Class<V> aggClass) {
-        if (valueClass == Long.class) {
-            return (Aggregator<K, V, V>) new LongSum<K>();
-        } else if (valueClass == Integer.class) {
-            return (Aggregator<K, V, V>) new IntSum<K>();
-        } else if (valueClass == Short.class) {
-            return (Aggregator<K, V, V>) new ShortSum<K>();
-        } else if (valueClass == Double.class) {
-            return (Aggregator<K, V, V>) new DoubleSum<K>();
-        } else if (valueClass == Float.class) {
-            return (Aggregator<K, V, V>) new FloatSum<K>();
-        } else if (valueClass == Byte.class) {
-            return (Aggregator<K, V, V>) new ByteSum<K>();
-        } else {
-            throw new KafkaException("The value type " + valueClass.getName() +
-                    " is not supported for built-in sum aggregations.");
-        }
+    public Aggregator<K, V, Long> get() {
+        return new LongSum();
     }
 }
\ No newline at end of file
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java
index d35096476bf70..e09ddbe2004f4 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java
@@ -36,7 +36,7 @@ public TopKSupplier(int k) {
         this.k = k;
     }
 
-    private class TopK<K, V> implements Aggregator<K, V, Collection<V>> {
+    private class TopK implements Aggregator<K, V, Collection<V>> {
 
         private final Map<K, PriorityQueue<V>> sorted = new HashMap<>();
 
@@ -96,7 +96,7 @@ public Collection<V> merge(Collection<V> aggr1, Collection<V> aggr2) {
     }
 
     @Override
-    public Aggregator<K, V, Collection<V>> get(Class<K> keyClass, Class<V> valueClass, Class<Collection<V>> aggClass) {
-        return new TopK<>();
+    public Aggregator<K, V, Collection<V>> get() {
+        return new TopK();
     }
 }
\ No newline at end of file

From a603a9afde8a86906d085b6cf942df67d2082fb9 Mon Sep 17 00:00:00 2001
From: Guozhang Wang <wangguoz@gmail.com>
Date: Tue, 15 Dec 2015 15:15:29 -0800
Subject: [PATCH 11/14] rename aggregateSupplier to aggregatorSupplier

---
 .../java/org/apache/kafka/streams/examples/KTableJob.java     | 3 ---
 .../{AggregateSupplier.java => AggregatorSupplier.java}       | 2 +-
 .../main/java/org/apache/kafka/streams/kstream/KStream.java   | 4 ++--
 .../main/java/org/apache/kafka/streams/kstream/KTable.java    | 4 ++--
 .../apache/kafka/streams/kstream/internals/CountSupplier.java | 4 ++--
 .../apache/kafka/streams/kstream/internals/KStreamImpl.java   | 4 ++--
 .../apache/kafka/streams/kstream/internals/KTableImpl.java    | 4 ++--
 .../apache/kafka/streams/kstream/internals/SumSupplier.java   | 4 ++--
 .../apache/kafka/streams/kstream/internals/TopKSupplier.java  | 4 ++--
 9 files changed, 15 insertions(+), 18 deletions(-)
 rename streams/src/main/java/org/apache/kafka/streams/kstream/{AggregateSupplier.java => AggregatorSupplier.java} (94%)

diff --git a/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java b/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
index a60263675b69b..e296f01a5bc6e 100644
--- a/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
+++ b/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
@@ -20,8 +20,6 @@
 import org.apache.kafka.common.serialization.IntegerSerializer;
 import org.apache.kafka.common.serialization.StringSerializer;
 import org.apache.kafka.common.serialization.StringDeserializer;
-import org.apache.kafka.streams.kstream.AggregateSupplier;
-import org.apache.kafka.streams.kstream.Aggregator;
 import org.apache.kafka.streams.kstream.HoppingWindow;
 import org.apache.kafka.streams.kstream.HoppingWindows;
 import org.apache.kafka.streams.kstream.KStreamBuilder;
@@ -34,7 +32,6 @@
 import org.apache.kafka.streams.kstream.KeyValueMapper;
 import org.apache.kafka.streams.kstream.ValueJoiner;
 import org.apache.kafka.streams.kstream.ValueMapper;
-import org.apache.kafka.streams.kstream.Window;
 import org.apache.kafka.streams.kstream.WindowMapper;
 
 import java.util.Properties;
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/AggregateSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/AggregatorSupplier.java
similarity index 94%
rename from streams/src/main/java/org/apache/kafka/streams/kstream/AggregateSupplier.java
rename to streams/src/main/java/org/apache/kafka/streams/kstream/AggregatorSupplier.java
index 3ee80756adbb4..6ed9125a888bf 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/AggregateSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/AggregatorSupplier.java
@@ -17,7 +17,7 @@
 
 package org.apache.kafka.streams.kstream;
 
-public interface AggregateSupplier<K, V, T> {
+public interface AggregatorSupplier<K, V, T> {
 
     Aggregator<K, V, T> get();
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
index 32a0ceec0af23..b4cf253576ffa 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
@@ -190,11 +190,11 @@ public interface KStream<K, V> {
     /**
      * Aggregate values of this stream by key on a window basis.
      *
-     * @param aggregateSupplier the class of aggregateSupplier
+     * @param aggregatorSupplier the class of aggregatorSupplier
      * @param windows the window definition
      * @param <T>   the value type of the aggregated table
      */
-    <T, W extends Window> KWindowedTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, Windows<W> windows);
+    <T, W extends Window> KWindowedTable<K, T, W> aggregateByKey(AggregatorSupplier<K, V, T> aggregatorSupplier, Windows<W> windows);
 
     /**
      * Sum values of this stream by key on a window basis.
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
index 6ac0064986613..010881ed0cfeb 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
@@ -143,13 +143,13 @@ public interface KTable<K, V> {
     /**
      * Aggregate values of this table by the selected key.
      *
-     * @param aggregateSupplier the class of aggregateSupplier
+     * @param aggregatorSupplier the class of aggregatorSupplier
      * @param selector the KeyValue mapper that select the aggregate key
      * @param name the name of the resulted table
      * @param <K1>   the key type of the aggregated table
      * @param <V1>   the value type of the aggregated table
      */
-    <K1, V1, V2> KTable<K1, V2> aggregate(AggregateSupplier<K1, V1, V2> aggregateSupplier, KeyValueMapper<K, V, KeyValue<K1, V1>> selector, String name);
+    <K1, V1, V2> KTable<K1, V2> aggregate(AggregatorSupplier<K1, V1, V2> aggregatorSupplier, KeyValueMapper<K, V, KeyValue<K1, V1>> selector, String name);
 
     /**
      * Sum values of this table by the selected key on a window basis.
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CountSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CountSupplier.java
index 39e4188d4913d..6203afa2305c2 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CountSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CountSupplier.java
@@ -17,10 +17,10 @@
 
 package org.apache.kafka.streams.kstream.internals;
 
-import org.apache.kafka.streams.kstream.AggregateSupplier;
+import org.apache.kafka.streams.kstream.AggregatorSupplier;
 import org.apache.kafka.streams.kstream.Aggregator;
 
-public class CountSupplier<K, V> implements AggregateSupplier<K, V, Long> {
+public class CountSupplier<K, V> implements AggregatorSupplier<K, V, Long> {
 
     private class Count implements Aggregator<K, V, Long> {
         @Override
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
index 72651c2819f38..ac090b8d81338 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
@@ -19,7 +19,7 @@
 
 import org.apache.kafka.common.serialization.Deserializer;
 import org.apache.kafka.common.serialization.Serializer;
-import org.apache.kafka.streams.kstream.AggregateSupplier;
+import org.apache.kafka.streams.kstream.AggregatorSupplier;
 import org.apache.kafka.streams.kstream.KStreamBuilder;
 import org.apache.kafka.streams.kstream.KTable;
 import org.apache.kafka.streams.kstream.KWindowedTable;
@@ -262,7 +262,7 @@ public Processor get() {
     }
 
     @Override
-    public <T, W extends Window> KWindowedTable<K, T, W> aggregateByKey(AggregateSupplier<K, V, T> aggregateSupplier, Windows<W> windows) {
+    public <T, W extends Window> KWindowedTable<K, T, W> aggregateByKey(AggregatorSupplier<K, V, T> aggregatorSupplier, Windows<W> windows) {
         // TODO
         return null;
     }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
index 646e0d6757b0d..a8208e877df0c 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
@@ -19,7 +19,7 @@
 
 import org.apache.kafka.common.serialization.Deserializer;
 import org.apache.kafka.common.serialization.Serializer;
-import org.apache.kafka.streams.kstream.AggregateSupplier;
+import org.apache.kafka.streams.kstream.AggregatorSupplier;
 import org.apache.kafka.streams.kstream.KStream;
 import org.apache.kafka.streams.kstream.KStreamBuilder;
 import org.apache.kafka.streams.kstream.KTable;
@@ -248,7 +248,7 @@ public <V1, R> KTable<K, R> leftJoin(KTable<K, V1> other, ValueJoiner<V, V1, R>
     }
 
     @Override
-    public <K1, V1, V2> KTable<K1, V2> aggregate(AggregateSupplier<K1, V1, V2> aggregateSupplier, KeyValueMapper<K, V, KeyValue<K1, V1>> selector, String name) {
+    public <K1, V1, V2> KTable<K1, V2> aggregate(AggregatorSupplier<K1, V1, V2> aggregatorSupplier, KeyValueMapper<K, V, KeyValue<K1, V1>> selector, String name) {
         // TODO
         return null;
     }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/SumSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/SumSupplier.java
index bd2b99e8365f7..fd31802327fe4 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/SumSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/SumSupplier.java
@@ -17,11 +17,11 @@
 
 package org.apache.kafka.streams.kstream.internals;
 
-import org.apache.kafka.streams.kstream.AggregateSupplier;
+import org.apache.kafka.streams.kstream.AggregatorSupplier;
 import org.apache.kafka.streams.kstream.Aggregator;
 import org.apache.kafka.streams.kstream.ValueMapper;
 
-public class SumSupplier<K, V> implements AggregateSupplier<K, V, Long> {
+public class SumSupplier<K, V> implements AggregatorSupplier<K, V, Long> {
 
     private final ValueMapper<V, Long> valueMapper;
 
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java
index e09ddbe2004f4..5e5b7781bb0cc 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java
@@ -17,7 +17,7 @@
 
 package org.apache.kafka.streams.kstream.internals;
 
-import org.apache.kafka.streams.kstream.AggregateSupplier;
+import org.apache.kafka.streams.kstream.AggregatorSupplier;
 import org.apache.kafka.streams.kstream.Aggregator;
 
 import java.util.Collection;
@@ -28,7 +28,7 @@
 import java.util.PriorityQueue;
 import java.util.Set;
 
-public class TopKSupplier<K, V> implements AggregateSupplier<K, V, Collection<V>> {
+public class TopKSupplier<K, V> implements AggregatorSupplier<K, V, Collection<V>> {
 
     private final int k;
 

From e186710bc3b66e88148ab81087276cedffa2bad3 Mon Sep 17 00:00:00 2001
From: Guozhang Wang <wangguoz@gmail.com>
Date: Wed, 16 Dec 2015 14:20:59 -0800
Subject: [PATCH 12/14] modify built-in aggregates

---
 .../kafka/streams/examples/KTableJob.java     | 25 ++++++++--------
 .../apache/kafka/streams/kstream/KStream.java |  8 +++--
 .../apache/kafka/streams/kstream/KTable.java  | 10 +++++--
 .../streams/kstream/KeyValueToIntMapper.java  | 23 +++++++++++++++
 .../kstream/internals/KStreamImpl.java        | 27 ++++++++++++-----
 .../streams/kstream/internals/KTableImpl.java | 29 ++++++++++++++-----
 .../kstream/internals/TopKSupplier.java       |  2 +-
 7 files changed, 92 insertions(+), 32 deletions(-)
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/KeyValueToIntMapper.java

diff --git a/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java b/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
index e296f01a5bc6e..a4a004137db24 100644
--- a/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
+++ b/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
@@ -30,6 +30,7 @@
 import org.apache.kafka.streams.kstream.KWindowedTable;
 import org.apache.kafka.streams.kstream.KeyValue;
 import org.apache.kafka.streams.kstream.KeyValueMapper;
+import org.apache.kafka.streams.kstream.KeyValueToLongMapper;
 import org.apache.kafka.streams.kstream.ValueJoiner;
 import org.apache.kafka.streams.kstream.ValueMapper;
 import org.apache.kafka.streams.kstream.WindowMapper;
@@ -52,35 +53,35 @@ public static void main(String[] args) throws Exception {
         KStreamBuilder builder = new KStreamBuilder();
 
         // stream aggregate
-        KStream<String, Integer> stream1 = builder.stream("topic1");
+        KStream<String, Long> stream1 = builder.stream("topic1");
 
         @SuppressWarnings("unchecked")
-        KWindowedTable<String, Long, HoppingWindow> wtable1 = stream1.sumByKey(new ValueMapper<Integer, Long>() {
+        KWindowedTable<String, Long, HoppingWindow> wtable1 = stream1.sumByKey(new KeyValueToLongMapper<String, Long>() {
             @Override
-            public Long apply(Integer value) {
-                return (long) value;
+            public long apply(String key, Long value) {
+                return value;
             }
         }, HoppingWindows.of(1000).every(500).emit(1000).until(1000 * 60 * 60 * 24 /* one day */));
 
         // table aggregation
         KTable<String, String> table1 = builder.table("topic2");
 
-        KTable<String, Long> table2 = table1.sum(new KeyValueMapper<String, String, KeyValue<String, Integer>>() {
+        KTable<String, Long> table2 = table1.sum(new KeyValueMapper<String, String, String>() {
             @Override
-            public KeyValue<String, Integer> apply(String key, String value) {
-                return new KeyValue<>(value, new Integer(key));
+            public String apply(String key, String value) {
+                return value;
             }
-        }, new ValueMapper<Integer, Long>() {
+        }, new KeyValueToLongMapper<String, String>() {
             @Override
-            public Long apply(Integer value) {
-                return (long) value;
+            public long apply(String key, String value) {
+                return Long.parseLong(value);
             }
         }, "table2");
 
         // stream-table join
-        KStream<String, Long> stream2 = stream1.leftJoin(table2, new ValueJoiner<Integer, Long, Long>() {
+        KStream<String, Long> stream2 = stream1.leftJoin(table2, new ValueJoiner<Long, Long, Long>() {
             @Override
-            public Long apply(Integer value1, Long value2) {
+            public Long apply(Long value1, Long value2) {
                 if (value2 == null)
                     return 0L;
                 else
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
index b4cf253576ffa..b8dd9b5d71d37 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
@@ -199,7 +199,11 @@ public interface KStream<K, V> {
     /**
      * Sum values of this stream by key on a window basis.
      */
-    <W extends Window> KWindowedTable<K, Long, W> sumByKey(ValueMapper<V, Long> valueMapper, Windows<W> windows);
+    <W extends Window> KWindowedTable<K, Long, W> sumByKey(KeyValueToLongMapper<K, V> valueSelector, Windows<W> windows);
+
+    <W extends Window> KWindowedTable<K, Integer, W> sumByKey(KeyValueToIntMapper<K, V> valueSelector, Windows<W> windows);
+
+    <W extends Window> KWindowedTable<K, Double, W> sumByKey(KeyValueToDoubleMapper<K, V> valueSelector, Windows<W> windows);
 
     /**
      * Count number of records of this stream by key on a window basis.
@@ -209,5 +213,5 @@ public interface KStream<K, V> {
     /**
      * Get the top-k records of this stream by key on a window basis.
      */
-    <W extends Window> KWindowedTable<K, Collection<V>, W> topKByKey(int k, Windows<W> windows);
+    <W extends Window, V1 extends Comparable<V1>> KWindowedTable<K, Collection<V1>, W> topKByKey(int k, KeyValueMapper<K, V, V1> valueSelector, Windows<W> windows);
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
index 010881ed0cfeb..7f70fbd096230 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
@@ -154,15 +154,19 @@ public interface KTable<K, V> {
     /**
      * Sum values of this table by the selected key on a window basis.
      */
-    <K1, V1> KTable<K1, Long>sum(KeyValueMapper<K, V, KeyValue<K1, V1>> selector, ValueMapper<V1, Long> valueMapper, String name);
+    <K1> KTable<K1, Long> sum(KeyValueMapper<K, V, K1> keySelector, KeyValueToLongMapper<K, V> valueSelector, String name);
+
+    <K1> KTable<K1, Integer> sum(KeyValueMapper<K, V, K1> keySelector, KeyValueToIntMapper<K, V> valueSelector, String name);
+
+    <K1> KTable<K1, Double> sum(KeyValueMapper<K, V, K1> keySelector, KeyValueToDoubleMapper<K, V> valueSelector, String name);
 
     /**
      * Count number of records of this table by the selected key on a window basis.
      */
-    <K1> KTable<K1, Long> count(KeyValueMapper<K, V, KeyValue<K1, Long>> selector, String name);
+    <K1> KTable<K1, Long> count(KeyValueMapper<K, V, K1> keySelector, String name);
 
     /**
      * Get the top-k records of this table by the selected key on a window basis.
      */
-    <K1, V1> KTable<K1, Collection<V1>> topK(int k, KeyValueMapper<K, V, KeyValue<K1, V1>> selector, String name);
+    <K1, V1 extends Comparable<V1>> KTable<K1, Collection<V1>> topK(int k, KeyValueMapper<K, V, K1> selector, String name);
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KeyValueToIntMapper.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KeyValueToIntMapper.java
new file mode 100644
index 0000000000000..72e5ee935a1c2
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KeyValueToIntMapper.java
@@ -0,0 +1,23 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.kstream;
+
+public interface KeyValueToIntMapper<K, V> {
+
+    int apply(K key, V value);
+}
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
index ac090b8d81338..5956d2872f8c8 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamImpl.java
@@ -24,6 +24,9 @@
 import org.apache.kafka.streams.kstream.KTable;
 import org.apache.kafka.streams.kstream.KWindowedTable;
 import org.apache.kafka.streams.kstream.KeyValue;
+import org.apache.kafka.streams.kstream.KeyValueToDoubleMapper;
+import org.apache.kafka.streams.kstream.KeyValueToIntMapper;
+import org.apache.kafka.streams.kstream.KeyValueToLongMapper;
 import org.apache.kafka.streams.kstream.TransformerSupplier;
 import org.apache.kafka.streams.kstream.ValueJoiner;
 import org.apache.kafka.streams.kstream.ValueTransformerSupplier;
@@ -268,20 +271,30 @@ public <T, W extends Window> KWindowedTable<K, T, W> aggregateByKey(AggregatorSu
     }
 
     @Override
-    public <W extends Window> KWindowedTable<K, Long, W> sumByKey(ValueMapper<V, Long> valueMapper, Windows<W> windows) {
+    public <W extends Window> KWindowedTable<K, Long, W> sumByKey(KeyValueToLongMapper<K, V> valueSelector, Windows<W> windows) {
+        // TODO
+        return null;
+    }
 
-        return this.aggregateByKey(new SumSupplier<>(valueMapper), windows);
+    public <W extends Window> KWindowedTable<K, Integer, W> sumByKey(KeyValueToIntMapper<K, V> valueSelector, Windows<W> windows) {
+        // TODO
+        return null;
+    }
+
+    public <W extends Window> KWindowedTable<K, Double, W> sumByKey(KeyValueToDoubleMapper<K, V> valueSelector, Windows<W> windows) {
+        // TODO
+        return null;
     }
 
     @Override
     public <W extends Window> KWindowedTable<K, Long, W> countByKey(Windows<W> windows) {
-
-        return this.aggregateByKey(new CountSupplier<>(), windows);
+        // TODO
+        return null;
     }
 
     @Override
-    public <W extends Window> KWindowedTable<K, Collection<V>, W> topKByKey(int k, Windows<W> windows) {
-
-        return this.aggregateByKey(new TopKSupplier<>(k), windows);
+    public <W extends Window, V1 extends Comparable<V1>> KWindowedTable<K, Collection<V1>, W> topKByKey(int k, KeyValueMapper<K, V, V1> valueSelector, Windows<W> windows) {
+        // TODO
+        return null;
     }
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
index a8208e877df0c..08301e630a970 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
@@ -25,6 +25,9 @@
 import org.apache.kafka.streams.kstream.KTable;
 import org.apache.kafka.streams.kstream.KeyValue;
 import org.apache.kafka.streams.kstream.KeyValueMapper;
+import org.apache.kafka.streams.kstream.KeyValueToDoubleMapper;
+import org.apache.kafka.streams.kstream.KeyValueToIntMapper;
+import org.apache.kafka.streams.kstream.KeyValueToLongMapper;
 import org.apache.kafka.streams.kstream.Predicate;
 import org.apache.kafka.streams.kstream.ValueJoiner;
 import org.apache.kafka.streams.kstream.ValueMapper;
@@ -254,20 +257,32 @@ public <K1, V1, V2> KTable<K1, V2> aggregate(AggregatorSupplier<K1, V1, V2> aggr
     }
 
     @Override
-    public <K1, V1> KTable<K1, Long> sum(KeyValueMapper<K, V, KeyValue<K1, V1>> selector, ValueMapper<V1, Long> valueMapper, String name) {
-
-        return this.aggregate(new SumSupplier<>(valueMapper), selector, name);
+    public <K1> KTable<K1, Long> sum(KeyValueMapper<K, V, K1> keySelector, KeyValueToLongMapper<K, V> valueSelector, String name) {
+        // TODO
+        return null;
     }
 
     @Override
-    public <K1> KTable<K1, Long> count(KeyValueMapper<K, V, KeyValue<K1, Long>> selector, String name) {
+    public <K1> KTable<K1, Integer> sum(KeyValueMapper<K, V, K1> keySelector, KeyValueToIntMapper<K, V> valueSelector, String name) {
+        // TODO
+        return null;
+    }
 
-        return this.aggregate(new CountSupplier<>(), selector, name);
+    @Override
+    public <K1> KTable<K1, Double> sum(KeyValueMapper<K, V, K1> keySelector, KeyValueToDoubleMapper<K, V> valueSelector, String name) {
+        // TODO
+        return null;
     }
 
     @Override
-    public <K1, V1> KTable<K1, Collection<V1>> topK(int k, KeyValueMapper<K, V, KeyValue<K1, V1>> selector, String name) {
+    public <K1> KTable<K1, Long> count(KeyValueMapper<K, V, K1> keySelector, String name) {
+        // TODO
+        return null;
+    }
 
-        return this.aggregate(new TopKSupplier<>(k), selector, name);
+    @Override
+    public <K1, V1 extends Comparable<V1>> KTable<K1, Collection<V1>> topK(int k, KeyValueMapper<K, V, K1> selector, String name) {
+        // TODO
+        return null;
     }
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java
index 5e5b7781bb0cc..becdeceba7d07 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java
@@ -28,7 +28,7 @@
 import java.util.PriorityQueue;
 import java.util.Set;
 
-public class TopKSupplier<K, V> implements AggregatorSupplier<K, V, Collection<V>> {
+public class TopKSupplier<K, V extends Comparable<V>> implements AggregatorSupplier<K, V, Collection<V>> {
 
     private final int k;
 

From 5bb1e8c95e0c1ab131d5212d1a7d793ce8b49414 Mon Sep 17 00:00:00 2001
From: Guozhang Wang <wangguoz@gmail.com>
Date: Wed, 16 Dec 2015 14:24:10 -0800
Subject: [PATCH 13/14] add missing files

---
 .../kstream/KeyValueToDoubleMapper.java       | 23 +++++++++++++++++++
 .../streams/kstream/KeyValueToLongMapper.java | 23 +++++++++++++++++++
 2 files changed, 46 insertions(+)
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/KeyValueToDoubleMapper.java
 create mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/KeyValueToLongMapper.java

diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KeyValueToDoubleMapper.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KeyValueToDoubleMapper.java
new file mode 100644
index 0000000000000..ae3b85817f9fe
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KeyValueToDoubleMapper.java
@@ -0,0 +1,23 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.kstream;
+
+public interface KeyValueToDoubleMapper<K, V> {
+
+    double apply(K key, V value);
+}
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KeyValueToLongMapper.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KeyValueToLongMapper.java
new file mode 100644
index 0000000000000..3a8d8a89d1814
--- /dev/null
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KeyValueToLongMapper.java
@@ -0,0 +1,23 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.kafka.streams.kstream;
+
+public interface KeyValueToLongMapper<K, V> {
+
+    long apply(K key, V value);
+}

From 4570dd0d98526f8388c13ef5fe4af12d372f73c6 Mon Sep 17 00:00:00 2001
From: Guozhang Wang <wangguoz@gmail.com>
Date: Wed, 16 Dec 2015 16:01:58 -0800
Subject: [PATCH 14/14] further comments addressed

---
 .../kafka/streams/examples/KTableJob.java     |  2 +-
 .../kafka/streams/kstream/HoppingWindows.java | 28 +++++----
 .../apache/kafka/streams/kstream/KStream.java | 25 +++++++-
 .../apache/kafka/streams/kstream/KTable.java  | 42 ++++++++++---
 .../kafka/streams/kstream/SlidingWindows.java | 21 ++++---
 .../streams/kstream/UnlimitedWindows.java     | 20 ++++---
 .../apache/kafka/streams/kstream/Windows.java |  9 +--
 .../kstream/internals/CountSupplier.java      | 51 ----------------
 .../streams/kstream/internals/KTableImpl.java |  2 +-
 .../kstream/internals/SumSupplier.java        | 60 -------------------
 .../kstream/internals/TopKSupplier.java       |  4 ++
 11 files changed, 108 insertions(+), 156 deletions(-)
 delete mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/internals/CountSupplier.java
 delete mode 100644 streams/src/main/java/org/apache/kafka/streams/kstream/internals/SumSupplier.java

diff --git a/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java b/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
index a4a004137db24..c58f3b3f4f62c 100644
--- a/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
+++ b/streams/src/main/java/org/apache/kafka/streams/examples/KTableJob.java
@@ -61,7 +61,7 @@ public static void main(String[] args) throws Exception {
             public long apply(String key, Long value) {
                 return value;
             }
-        }, HoppingWindows.of(1000).every(500).emit(1000).until(1000 * 60 * 60 * 24 /* one day */));
+        }, HoppingWindows.of("window1").with(500L).every(500L).emit(1000L).until(1000L * 60 * 60 * 24 /* one day */));
 
         // table aggregation
         KTable<String, String> table1 = builder.table("topic2");
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindows.java b/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindows.java
index 6a60e405b3e51..289d054c32855 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindows.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/HoppingWindows.java
@@ -22,27 +22,35 @@
 
 public class HoppingWindows extends Windows<HoppingWindow> {
 
-    private static final String NAME = "HOPPING-WINDOWS-";
+    private static final long DEFAULT_SIZE_MS = 1000L;
 
     private long size;
 
     private long period;
 
-    private HoppingWindows(long size) {
-        super();
+    private HoppingWindows(String name) {
+        super(name);
 
-        setName(newName(NAME));
-
-        this.size = size;
-        this.period = size;
+        this.size = DEFAULT_SIZE_MS;
+        this.period = this.size;
     }
 
     /**
      * Returns a half-interval hopping window definition with the window size in milliseconds
-     * of the form &#91; N &#42; size, N &#42; size + size &#41;
+     * of the form &#91; N &#42; default_size, N &#42; default_size + default_size &#41;
      */
-    public static HoppingWindows of(long size) {
-        return new HoppingWindows(size);
+    public static HoppingWindows of(String name) {
+        return new HoppingWindows(name);
+    }
+
+    /**
+     * Returns a new hopping window definition with the original size but reassign the window
+     * period in milliseconds of the form &#91; N &#42; period, N &#42; period + size &#41;
+     */
+    public HoppingWindows with(long size) {
+        this.size = size;
+
+        return this;
     }
 
     /**
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
index b8dd9b5d71d37..3ffb69bef3c96 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KStream.java
@@ -197,21 +197,42 @@ public interface KStream<K, V> {
     <T, W extends Window> KWindowedTable<K, T, W> aggregateByKey(AggregatorSupplier<K, V, T> aggregatorSupplier, Windows<W> windows);
 
     /**
-     * Sum values of this stream by key on a window basis.
+     * Sum extracted long integer values of this stream by key on a window basis.
+     *
+     * @param valueSelector the class of KeyValueToLongMapper to extract the long integer from value
+     * @param windows the window definition
      */
     <W extends Window> KWindowedTable<K, Long, W> sumByKey(KeyValueToLongMapper<K, V> valueSelector, Windows<W> windows);
 
+    /**
+     * Sum extracted integer values of this stream by key on a window basis.
+     *
+     * @param valueSelector the class of KeyValueToIntMapper to extract the long integer from value
+     * @param windows the window definition
+     */
     <W extends Window> KWindowedTable<K, Integer, W> sumByKey(KeyValueToIntMapper<K, V> valueSelector, Windows<W> windows);
 
+    /**
+     * Sum extracted double decimal values of this stream by key on a window basis.
+     *
+     * @param valueSelector the class of KeyValueToDoubleMapper to extract the long integer from value
+     * @param windows the window definition
+     */
     <W extends Window> KWindowedTable<K, Double, W> sumByKey(KeyValueToDoubleMapper<K, V> valueSelector, Windows<W> windows);
 
     /**
      * Count number of records of this stream by key on a window basis.
+     *
+     * @param windows the window definition
      */
     <W extends Window> KWindowedTable<K, Long, W> countByKey(Windows<W> windows);
 
     /**
-     * Get the top-k records of this stream by key on a window basis.
+     * Get the top-k values of this stream by key on a window basis.
+     *
+     * @param k parameter of the top-k computation
+     * @param valueSelector the class of KeyValueMapper to extract the comparable value
+     * @param windows the window definition
      */
     <W extends Window, V1 extends Comparable<V1>> KWindowedTable<K, Collection<V1>, W> topKByKey(int k, KeyValueMapper<K, V, V1> valueSelector, Windows<W> windows);
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java b/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
index 7f70fbd096230..71a3486fd4dd0 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/KTable.java
@@ -114,7 +114,7 @@ public interface KTable<K, V> {
      * @param joiner ValueJoiner
      * @param <V1>   the value type of the other stream
      * @param <V2>   the value type of the new stream
-     * @return the instance of KStream
+     * @return the instance of KTable
      */
     <V1, V2> KTable<K, V2> join(KTable<K, V1> other, ValueJoiner<V, V1, V2> joiner);
 
@@ -125,7 +125,7 @@ public interface KTable<K, V> {
      * @param joiner ValueJoiner
      * @param <V1>   the value type of the other stream
      * @param <V2>   the value type of the new stream
-     * @return the instance of KStream
+     * @return the instance of KTable
      */
     <V1, V2> KTable<K, V2> outerJoin(KTable<K, V1> other, ValueJoiner<V, V1, V2> joiner);
 
@@ -136,37 +136,63 @@ public interface KTable<K, V> {
      * @param joiner ValueJoiner
      * @param <V1>   the value type of the other stream
      * @param <V2>   the value type of the new stream
-     * @return the instance of KStream
+     * @return the instance of KTable
      */
     <V1, V2> KTable<K, V2> leftJoin(KTable<K, V1> other, ValueJoiner<V, V1, V2> joiner);
 
     /**
      * Aggregate values of this table by the selected key.
      *
-     * @param aggregatorSupplier the class of aggregatorSupplier
+     * @param aggregatorSupplier the class of AggregatorSupplier
      * @param selector the KeyValue mapper that select the aggregate key
      * @param name the name of the resulted table
      * @param <K1>   the key type of the aggregated table
      * @param <V1>   the value type of the aggregated table
+     * @return the instance of KTable
      */
     <K1, V1, V2> KTable<K1, V2> aggregate(AggregatorSupplier<K1, V1, V2> aggregatorSupplier, KeyValueMapper<K, V, KeyValue<K1, V1>> selector, String name);
 
     /**
-     * Sum values of this table by the selected key on a window basis.
+     * Sum extracted long integer values of this table by the selected aggregation key
+     *
+     * @param keySelector the class of KeyValueMapper to select the aggregation key
+     * @param valueSelector the class of KeyValueToLongMapper to extract the long integer from value
+     * @param name the name of the resulted table
      */
     <K1> KTable<K1, Long> sum(KeyValueMapper<K, V, K1> keySelector, KeyValueToLongMapper<K, V> valueSelector, String name);
 
+    /**
+     * Sum extracted integer values of this table by the selected aggregation key
+     *
+     * @param keySelector the class of KeyValueMapper to select the aggregation key
+     * @param valueSelector the class of KeyValueToIntMapper to extract the long integer from value
+     * @param name the name of the resulted table
+     */
     <K1> KTable<K1, Integer> sum(KeyValueMapper<K, V, K1> keySelector, KeyValueToIntMapper<K, V> valueSelector, String name);
 
+    /**
+     * Sum extracted double decimal values of this table by the selected aggregation key
+     *
+     * @param keySelector the class of KeyValueMapper to select the aggregation key
+     * @param valueSelector the class of KeyValueToDoubleMapper to extract the long integer from value
+     * @param name the name of the resulted table
+     */
     <K1> KTable<K1, Double> sum(KeyValueMapper<K, V, K1> keySelector, KeyValueToDoubleMapper<K, V> valueSelector, String name);
 
     /**
-     * Count number of records of this table by the selected key on a window basis.
+     * Count number of records of this table by the selected aggregation key
+     *
+     * @param keySelector the class of KeyValueMapper to select the aggregation key
+     * @param name the name of the resulted table
      */
     <K1> KTable<K1, Long> count(KeyValueMapper<K, V, K1> keySelector, String name);
 
     /**
-     * Get the top-k records of this table by the selected key on a window basis.
+     * Get the top-k values of this table by the selected aggregation key
+     *
+     * @param k parameter of the top-k computation
+     * @param keySelector the class of KeyValueMapper to select the aggregation key
+     * @param name the name of the resulted table
      */
-    <K1, V1 extends Comparable<V1>> KTable<K1, Collection<V1>> topK(int k, KeyValueMapper<K, V, K1> selector, String name);
+    <K1, V1 extends Comparable<V1>> KTable<K1, Collection<V1>> topK(int k, KeyValueMapper<K, V, K1> keySelector, String name);
 }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindows.java b/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindows.java
index f07c908efb8a9..eb98dfdfbfb7b 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindows.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/SlidingWindows.java
@@ -23,23 +23,30 @@
 
 public class SlidingWindows extends Windows<SlidingWindow> {
 
-    private static final String NAME = "SLIDING-WINDOWS-";
+    private static final long DEFAULT_SIZE_MS = 1000L;
 
     private long size;
 
-    private SlidingWindows(long size) {
-        super();
+    private SlidingWindows(String name) {
+        super(name);
 
-        setName(newName(NAME));
+        this.size = DEFAULT_SIZE_MS;
+    }
 
-        this.size = size;
+    /**
+     * Returns a half-interval sliding window definition with the default window size
+     */
+    public static SlidingWindows of(String name) {
+        return new SlidingWindows(name);
     }
 
     /**
      * Returns a half-interval sliding window definition with the window size in milliseconds
      */
-    public static SlidingWindows of(long size) {
-        return new SlidingWindows(size);
+    public SlidingWindows with(long size) {
+        this.size = size;
+
+        return this;
     }
 
     @Override
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindows.java b/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindows.java
index 1d347c2d77b5d..c4dff697b06ef 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindows.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/UnlimitedWindows.java
@@ -22,23 +22,27 @@
 
 public class UnlimitedWindows extends Windows<UnlimitedWindow> {
 
-    private static final String NAME = "UNLIMITED-WINDOWS-";
+    private static final long DEFAULT_START_TIMESTAMP = 0L;
 
     private long start;
 
-    private UnlimitedWindows(long start) {
-        super();
+    private UnlimitedWindows(String name) {
+        super(name);
 
-        setName(newName(NAME));
-
-        this.start = start;
+        this.start = DEFAULT_START_TIMESTAMP;
     }
 
     /**
      * Returns an unlimited window definition
      */
-    public static UnlimitedWindows on(long start) {
-        return new UnlimitedWindows(start);
+    public static UnlimitedWindows of(String name) {
+        return new UnlimitedWindows(name);
+    }
+
+    public UnlimitedWindows startOn(long start) {
+        this.start = start;
+
+        return this;
     }
 
     @Override
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/Windows.java b/streams/src/main/java/org/apache/kafka/streams/kstream/Windows.java
index ff504e89e9b09..9a4a6ed45f084 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/Windows.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/Windows.java
@@ -34,7 +34,7 @@ public abstract class Windows<W extends Window> {
 
     private String name;
 
-    protected Windows() {
+    protected Windows(String name) {
         this.emitDuration = DEFAULT_EMIT_DURATION;
         this.maintainDuration = DEFAULT_MAINTAIN_DURATION;
     }
@@ -43,13 +43,6 @@ public String name() {
         return name;
     }
 
-    /**
-     * Set the window name
-     */
-    protected void setName(String name) {
-        this.name = name;
-    }
-
     /**
      * Set the window emit duration in milliseconds of system time
      */
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CountSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CountSupplier.java
deleted file mode 100644
index 6203afa2305c2..0000000000000
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/CountSupplier.java
+++ /dev/null
@@ -1,51 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.kafka.streams.kstream.internals;
-
-import org.apache.kafka.streams.kstream.AggregatorSupplier;
-import org.apache.kafka.streams.kstream.Aggregator;
-
-public class CountSupplier<K, V> implements AggregatorSupplier<K, V, Long> {
-
-    private class Count implements Aggregator<K, V, Long> {
-        @Override
-        public Long initialValue(){
-            return 0L;
-        }
-
-        public @Override
-        Long add(K aggKey, V value, Long aggregate) {
-            return aggregate + 1L;
-        }
-
-        public @Override
-        Long remove(K aggKey, V value, Long aggregate) {
-            return aggregate - 1L;
-        }
-
-        public @Override
-        Long merge(Long aggr1, Long aggr2) {
-            return aggr1 + aggr2;
-        }
-    }
-
-    @Override
-    public Aggregator<K, V, Long> get() {
-        return new Count();
-    }
-}
\ No newline at end of file
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
index 08301e630a970..8e5ec8054ea4d 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableImpl.java
@@ -281,7 +281,7 @@ public <K1> KTable<K1, Long> count(KeyValueMapper<K, V, K1> keySelector, String
     }
 
     @Override
-    public <K1, V1 extends Comparable<V1>> KTable<K1, Collection<V1>> topK(int k, KeyValueMapper<K, V, K1> selector, String name) {
+    public <K1, V1 extends Comparable<V1>> KTable<K1, Collection<V1>> topK(int k, KeyValueMapper<K, V, K1> keySelector, String name) {
         // TODO
         return null;
     }
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/SumSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/SumSupplier.java
deleted file mode 100644
index fd31802327fe4..0000000000000
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/SumSupplier.java
+++ /dev/null
@@ -1,60 +0,0 @@
-/**
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.kafka.streams.kstream.internals;
-
-import org.apache.kafka.streams.kstream.AggregatorSupplier;
-import org.apache.kafka.streams.kstream.Aggregator;
-import org.apache.kafka.streams.kstream.ValueMapper;
-
-public class SumSupplier<K, V> implements AggregatorSupplier<K, V, Long> {
-
-    private final ValueMapper<V, Long> valueMapper;
-
-    public SumSupplier(ValueMapper<V, Long> valueMapper) {
-        this.valueMapper = valueMapper;
-    }
-
-    private class LongSum implements Aggregator<K, V, Long> {
-
-        @Override
-        public Long initialValue(){
-            return 0L;
-        }
-
-        @Override
-        public Long add(K aggKey, V value, Long aggregate) {
-            return aggregate + valueMapper.apply(value);
-        }
-
-        @Override
-        public Long remove(K aggKey, V value, Long aggregate) {
-            return aggregate - valueMapper.apply(value);
-        }
-
-        @Override
-        public Long merge(Long aggr1, Long aggr2) {
-            return aggr1 + aggr2;
-        }
-    }
-
-    @SuppressWarnings("unchecked")
-    @Override
-    public Aggregator<K, V, Long> get() {
-        return new LongSum();
-    }
-}
\ No newline at end of file
diff --git a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java
index becdeceba7d07..2d765cb74b96a 100644
--- a/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java
+++ b/streams/src/main/java/org/apache/kafka/streams/kstream/internals/TopKSupplier.java
@@ -28,6 +28,10 @@
 import java.util.PriorityQueue;
 import java.util.Set;
 
+/**
+ * NOTE: This is just a demo aggregate supplier that can be implemented by users to add their own built-in aggregates.
+ * It is highly in-efficient and is not supposed to be merged in.
+ */
 public class TopKSupplier<K, V extends Comparable<V>> implements AggregatorSupplier<K, V, Collection<V>> {
 
     private final int k;