Fix Theta bug wrt SingleItemSketch merge from Memory.

src/main/java/org/apache/datasketches/theta/DirectQuickSelectSketchR.java

@@ -262,8 +262,8 @@ UpdateReturnState hashUpdate(final long hash) {
    * @return the hash table threshold
    */
   static final int setHashTableThreshold(final int lgNomLongs, final int lgArrLongs) {
-    //FindBugs may complain if DQS_RESIZE_THRESHOLD == REBUILD_THRESHOLD, but this allows us
-    // to tune these constants for different sketches.
+    //FindBugs may complain (DB_DUPLICATE_BRANCHES) if DQS_RESIZE_THRESHOLD == REBUILD_THRESHOLD,
+    //but this allows us to tune these constants for different sketches.
     final double fraction = (lgArrLongs <= lgNomLongs) ? DQS_RESIZE_THRESHOLD : REBUILD_THRESHOLD;
     return (int) Math.floor(fraction * (1 << lgArrLongs));
   }

src/main/java/org/apache/datasketches/theta/UnionImpl.java

@@ -369,7 +369,8 @@ private void processVer3(final Memory skMem) {
       // OR the above and the SI bit is set
       if (SingleItemSketch.testPre0SeedHash(skMem.getLong(0), seedHash_)) {
         final long hash = skMem.getLong(8);
-        update(hash); //a hash < 1 will be rejected later
+        //backdoor update, hash function is bypassed. A hash < 1 will be rejected later
+        gadget_.hashUpdate(hash);
         return;
       }
       return; //empty

src/main/java/org/apache/datasketches/tuple/Sketch.java

@@ -116,10 +116,14 @@ public double getTheta() {
    * @return a SketchIterator
    */
   public SketchIterator<S> iterator() {
-    return new SketchIterator<S>(keys_, summaries_);
+    return new SketchIterator<>(keys_, summaries_);
   }
 
-  long getThetaLong() {
+  /**
+   * Returns Theta as a long
+   * @return Theta as a long
+   */
+  public long getThetaLong() {
     return theta_;
   }
 

src/main/java/org/apache/datasketches/tuple/UpdatableSummary.java

@@ -26,7 +26,8 @@
 public interface UpdatableSummary<U> extends Summary {
 
   /**
-   * This is to provide a method of updating summaries
+   * This is to provide a method of updating summaries.
+   * This should not be called by the user.
    * @param value update value
    */
   public void update(U value);

src/main/java/org/apache/datasketches/tuple/adouble/DoubleSketch.java

@@ -0,0 +1,60 @@
+/*
+ * 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.datasketches.tuple.adouble;
+
+import org.apache.datasketches.ResizeFactor;
+import org.apache.datasketches.memory.Memory;
+import org.apache.datasketches.tuple.UpdatableSketch;
+
+/**
+ * @author Lee Rhodes
+ */
+public class DoubleSketch extends UpdatableSketch<Double, DoubleSummary> {
+
+  /**
+   * Constructs this sketch with given <i>lgK</i>.
+   * @param lgK Log_base2 of <i>Nominal Entries</i>.
+   * <a href="{@docRoot}/resources/dictionary.html#nomEntries">See Nominal Entries</a>
+   * @param mode The DoubleSummary mode to be used
+   */
+  public DoubleSketch(final int lgK, final DoubleSummary.Mode mode) {
+    super(1 << lgK, ResizeFactor.X8.ordinal(), 1.0F, new DoubleSummaryFactory(mode));
+  }
+
+  /**
+   * Constructs this sketch from a Memory image, which must be from an DoubleSketch, and
+   * usually with data.
+   * @param mem the given Memory
+   * @param mode The DoubleSummary mode to be used
+   */
+  public DoubleSketch(final Memory mem, final DoubleSummary.Mode mode) {
+    super(mem, new DoubleSummaryDeserializer(), new DoubleSummaryFactory(mode));
+  }
+
+  @Override
+  public void update(final String key, final Double value) {
+    super.update(key, value);
+  }
+
+  @Override
+  public void update(final long key, final Double value) {
+    super.update(key, value);
+  }
+}

src/main/java/org/apache/datasketches/tuple/adouble/DoubleSummary.java

@@ -31,6 +31,8 @@
  * Supported modes: Sum, Min, Max, AlwaysOne, Increment. The default mode is Sum.
  */
 public final class DoubleSummary implements UpdatableSummary<Double> {
+  private double value_;
+  private final Mode mode_;
 
   /**
    * The aggregation modes for this Summary
@@ -48,6 +50,7 @@ public static enum Mode {
      * <p>New retained value = min(previous retained value, incoming value)</p>
      */
     Min,
+
     /**
      * The aggregation mode is the maximum function.
      * <p>New retained value = max(previous retained value, incoming value)</p>
@@ -58,27 +61,21 @@ public static enum Mode {
      * The aggregation mode is always one.
      * <p>New retained value = 1.0</p>
      */
-    AlwaysOne,
-
-    /**
-     * The aggregation mode is increment by one.
-     * <p>New retained value = previous retained value + 1.0</p>
-     */
-    Increment
+    AlwaysOne
   }
 
-  private double value_;
-  private final Mode mode_;
-
   /**
-   * Creates an instance of DoubleSummary with zero starting value and default mode (Sum)
+   * Creates an instance of DoubleSummary with a given starting value and mode
+   * @param value starting value
+   * @param mode update mode
    */
-  public DoubleSummary() {
-    this(0, Mode.Sum);
+  private DoubleSummary(final double value, final Mode mode) {
+    value_ = value;
+    mode_ = mode;
   }
 
   /**
-   * Creates an instance of DoubleSummary with a starting value and a given mode (Sum)
+   * Creates an instance of DoubleSummary with a given mode.
    * @param mode update mode
    */
   public DoubleSummary(final Mode mode) {
@@ -96,21 +93,9 @@ public DoubleSummary(final Mode mode) {
       case AlwaysOne:
         value_ = 1.0;
         break;
-      case Increment:
-        value_ = 0;
     }
   }
 
-  /**
-   * Creates an instance of DoubleSummary with a given starting value and mode
-   * @param value starting value
-   * @param mode update mode
-   */
-  public DoubleSummary(final double value, final Mode mode) {
-    value_ = value;
-    mode_ = mode;
-  }
-
   @Override
   public void update(final Double value) {
     switch (mode_) {
@@ -126,8 +111,6 @@ public void update(final Double value) {
     case AlwaysOne:
       value_ = 1.0;
       break;
-    case Increment:
-      value_++;
     }
   }
 

src/main/java/org/apache/datasketches/tuple/adouble/DoubleSummaryFactory.java

@@ -31,6 +31,7 @@ public final class DoubleSummaryFactory implements SummaryFactory<DoubleSummary>
   /**
    * Creates an instance of DoubleSummaryFactory with default mode
    */
+  @Deprecated
   public DoubleSummaryFactory() {
     summaryMode_ = DoubleSummary.Mode.Sum;
   }

src/main/java/org/apache/datasketches/tuple/adouble/DoubleSummarySetOperations.java

@@ -30,9 +30,12 @@ public final class DoubleSummarySetOperations implements SummarySetOperations<Do
 
   private final Mode summaryMode_;
 
+  //TODO see IntegerSummarySetOperations for better model
+
   /**
    * Creates an instance with default mode.
    */
+  @Deprecated
   public DoubleSummarySetOperations() {
     summaryMode_ = DoubleSummary.Mode.Sum;
   }
@@ -53,13 +56,14 @@ public DoubleSummary union(final DoubleSummary a, final DoubleSummary b) {
     return result;
   }
 
-  @Override
+
   /**
    * Intersection is not well defined or even meaningful between numeric values.
    * Nevertheless, this can be defined to be just a different type of aggregation.
    * In this case it is defined to be the same as union. It can be overridden to
    * be a more meaningful operation.
    */
+  @Override
   public DoubleSummary intersection(final DoubleSummary a, final DoubleSummary b) {
     return union(a, b);
   }

src/main/java/org/apache/datasketches/tuple/aninteger/IntegerSketch.java

@@ -0,0 +1,61 @@
+/*
+ * 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.datasketches.tuple.aninteger;
+
+import org.apache.datasketches.ResizeFactor;
+import org.apache.datasketches.memory.Memory;
+import org.apache.datasketches.tuple.UpdatableSketch;
+
+/**
+ * @author Lee Rhodes
+ */
+public class IntegerSketch extends UpdatableSketch<Integer, IntegerSummary> {
+
+  /**
+   * Constructs this sketch with given <i>lgK</i>.
+   * @param lgK Log_base2 of <i>Nominal Entries</i>.
+   * <a href="{@docRoot}/resources/dictionary.html#nomEntries">See Nominal Entries</a>
+   * @param mode The IntegerSummary mode to be used
+   */
+  public IntegerSketch(final int lgK, final IntegerSummary.Mode mode) {
+    super(1 << lgK, ResizeFactor.X8.ordinal(), 1.0F, new IntegerSummaryFactory(mode));
+  }
+
+  /**
+   * Constructs this sketch from a Memory image, which must be from an IntegerSketch, and
+   * usually with data.
+   * @param mem the given Memory
+   * @param mode The IntegerSummary mode to be used
+   */
+  public IntegerSketch(final Memory mem, final IntegerSummary.Mode mode) {
+    super(mem, new IntegerSummaryDeserializer(), new IntegerSummaryFactory(mode));
+  }
+
+  @Override
+  public void update(final String key, final Integer value) {
+    super.update(key, value);
+  }
+
+  @Override
+  public void update(final long key, final Integer value) {
+    super.update(key, value);
+  }
+
+}