[BEAM-2314] Add ValidatesRunner test for merging custom windows

sdks/java/core/src/test/java/org/apache/beam/sdk/transforms/windowing/MergingCustomWindowsTest.java

@@ -0,0 +1,178 @@
+/*
+ * 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.beam.sdk.transforms.windowing;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+import org.apache.beam.sdk.coders.Coder;
+import org.apache.beam.sdk.coders.CustomCoder;
+import org.apache.beam.sdk.coders.VarIntCoder;
+import org.apache.beam.sdk.testing.PAssert;
+import org.apache.beam.sdk.testing.TestPipeline;
+import org.apache.beam.sdk.testing.ValidatesRunner;
+import org.apache.beam.sdk.transforms.Combine;
+import org.apache.beam.sdk.transforms.Count;
+import org.apache.beam.sdk.transforms.Create;
+import org.apache.beam.sdk.values.PCollection;
+import org.apache.beam.sdk.values.TimestampedValue;
+import org.joda.time.Duration;
+import org.joda.time.Instant;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/**
+ * Tests merging of custom windows.
+ */
+@RunWith(JUnit4.class)
+public class MergingCustomWindowsTest {
+
+  @Rule
+  public TestPipeline pipeline = TestPipeline.create();
+
+  @Test
+  @Category(ValidatesRunner.class)
+  public void testMergingCustomWindows() {
+    Instant startInstant = new Instant(0L);
+    List<TimestampedValue<String>> input = new ArrayList<>();
+    input.add(TimestampedValue.of("big", startInstant.plus(Duration.standardSeconds(10))));
+    input.add(TimestampedValue.of("small", startInstant.plus(Duration.standardSeconds(20))));
+    input.add(TimestampedValue.of("small", startInstant.plus(Duration.standardSeconds(30))));
+    PCollection<String> inputCollection = pipeline.apply(Create.timestamped(input));
+    PCollection<String> windowedCollection = inputCollection
+        .apply(Window.into(new CustomWindowFn()));
+    PCollection<Long> count = windowedCollection
+        .apply(Combine.globally(Count.<String>combineFn()).withoutDefaults());
+    PAssert.thatSingleton("Wrong number of elements in output collection", count).isEqualTo(3L);
+    pipeline.run();
+  }
+
+  private static class CustomWindow extends IntervalWindow {
+
+    private boolean isBig;
+
+    private CustomWindow(Instant start, Instant end, boolean isBig) {
+      super(start, end);
+      this.isBig = isBig;
+    }
+
+    @Override public boolean equals(Object o) {
+      if (this == o) {
+        return true;
+      }
+      if (o == null || getClass() != o.getClass()) {
+        return false;
+      }
+      if (!super.equals(o)) {
+        return false;
+      }
+      CustomWindow that = (CustomWindow) o;
+      return isBig == that.isBig;
+    }
+
+    @Override public int hashCode() {
+      return Objects.hash(super.hashCode(), isBig);
+    }
+  }
+
+  private static class CustomWindowCoder extends CustomCoder<CustomWindow> {
+
+    private static final CustomWindowCoder INSTANCE = new CustomWindowCoder();
+    private static final Coder<IntervalWindow> INTERVAL_WINDOW_CODER = IntervalWindow.getCoder();
+    private static final VarIntCoder VAR_INT_CODER = VarIntCoder.of();
+
+    public static CustomWindowCoder of() {
+      return INSTANCE;
+    }
+
+    @Override
+    public void encode(CustomWindow window, OutputStream outStream)
+        throws IOException {
+      INTERVAL_WINDOW_CODER.encode(window, outStream);
+      VAR_INT_CODER.encode(window.isBig ? 1 : 0, outStream);
+    }
+
+    @Override
+    public CustomWindow decode(InputStream inStream) throws IOException {
+      IntervalWindow superWindow = INTERVAL_WINDOW_CODER.decode(inStream);
+      boolean isBig = VAR_INT_CODER.decode(inStream) != 0;
+      return new CustomWindow(superWindow.start(), superWindow.end(), isBig);
+    }
+
+    @Override
+    public void verifyDeterministic() throws NonDeterministicException {
+      INTERVAL_WINDOW_CODER.verifyDeterministic();
+      VAR_INT_CODER.verifyDeterministic();
+    }
+  }
+
+  private static class CustomWindowFn extends WindowFn<String, CustomWindow> {
+
+    @Override
+    public Collection<CustomWindow> assignWindows(AssignContext c) throws Exception {
+      String element = c.element();
+      CustomWindow customWindow;
+      // put big elements in windows of 30s and small ones in windows of 5s
+      if ("big".equals(element)) {
+        customWindow =
+            new CustomWindow(c.timestamp(), c.timestamp().plus(Duration.standardSeconds(30)), true);
+      } else {
+        customWindow =
+            new CustomWindow(c.timestamp(), c.timestamp().plus(Duration.standardSeconds(5)), false);
+      }
+      return Collections.singletonList(customWindow);
+    }
+
+    @Override
+    public void mergeWindows(MergeContext c) throws Exception {
+      List<CustomWindow> toBeMerged = new ArrayList<>();
+      CustomWindow bigWindow = null;
+      for (CustomWindow customWindow : c.windows()) {
+        toBeMerged.add(customWindow);
+        if (customWindow.isBig) {
+          bigWindow = customWindow;
+        }
+      }
+      // merge small windows into big windows
+      c.merge(toBeMerged, bigWindow);
+    }
+
+    @Override
+    public boolean isCompatible(WindowFn<?, ?> other) {
+      return other instanceof CustomWindowFn;
+    }
+
+    @Override
+    public Coder<CustomWindow> windowCoder() {
+      return CustomWindowCoder.of();
+    }
+
+    @Override
+    public WindowMappingFn<CustomWindow> getDefaultWindowMappingFn() {
+      throw new UnsupportedOperationException("side inputs not supported");
+    }
+  }
+}