| /* |
| * 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.nemo.compiler.frontend.beam.transform; |
| |
| import org.apache.beam.sdk.transforms.Materializations; |
| import org.apache.beam.sdk.transforms.ViewFn; |
| import org.apache.beam.sdk.transforms.windowing.BoundedWindow; |
| import org.apache.beam.sdk.transforms.windowing.PaneInfo; |
| import org.apache.beam.sdk.util.WindowedValue; |
| import org.apache.beam.sdk.values.KV; |
| import org.apache.nemo.common.ir.OutputCollector; |
| import org.apache.nemo.common.ir.vertex.transform.Transform; |
| import org.apache.nemo.common.punctuation.Watermark; |
| |
| import javax.annotation.Nullable; |
| import java.io.Serializable; |
| import java.util.*; |
| |
| /** |
| * This transforms emits materialized data for each window. |
| * |
| * @param <I> input type |
| * @param <O> materialized output type |
| */ |
| public final class CreateViewTransform<I, O> implements Transform<WindowedValue<KV<?, I>>, WindowedValue<O>> { |
| private final ViewFn<Materializations.MultimapView<Void, ?>, O> viewFn; |
| private final Map<BoundedWindow, List<I>> windowListMap; |
| |
| private OutputCollector<WindowedValue<O>> outputCollector; |
| |
| private long currentOutputWatermark; |
| |
| /** |
| * Constructor of CreateViewTransform. |
| * |
| * @param viewFn the viewFn that materializes data. |
| */ |
| public CreateViewTransform(final ViewFn<Materializations.MultimapView<Void, ?>, O> viewFn) { |
| this.viewFn = viewFn; |
| this.windowListMap = new HashMap<>(); |
| this.currentOutputWatermark = Long.MIN_VALUE; |
| } |
| |
| @Override |
| public void prepare(final Context context, final OutputCollector<WindowedValue<O>> oc) { |
| this.outputCollector = oc; |
| } |
| |
| @Override |
| public void onData(final WindowedValue<KV<?, I>> element) { |
| // The key of element is always null (beam's semantic) |
| // because view is a globally materialized data regardless of key |
| for (final BoundedWindow window : element.getWindows()) { |
| windowListMap.putIfAbsent(window, new ArrayList<>()); |
| final List<I> list = windowListMap.get(window); |
| list.add(element.getValue().getValue()); |
| } |
| } |
| |
| @Override |
| public void onWatermark(final Watermark inputWatermark) { |
| // If no data, just forwards the watermark |
| if (windowListMap.size() == 0 && currentOutputWatermark < inputWatermark.getTimestamp()) { |
| currentOutputWatermark = inputWatermark.getTimestamp(); |
| outputCollector.emitWatermark(inputWatermark); |
| return; |
| } |
| |
| final Iterator<Map.Entry<BoundedWindow, List<I>>> iterator = windowListMap.entrySet().iterator(); |
| long minOutputTimestampOfEmittedWindows = Long.MAX_VALUE; |
| |
| while (iterator.hasNext()) { |
| final Map.Entry<BoundedWindow, List<I>> entry = iterator.next(); |
| if (entry.getKey().maxTimestamp().getMillis() <= inputWatermark.getTimestamp()) { |
| // emit the windowed data if the watermark timestamp > the window max boundary |
| final O output = viewFn.apply(new MultiView<>(entry.getValue())); |
| outputCollector.emit(WindowedValue.of( |
| output, entry.getKey().maxTimestamp(), entry.getKey(), PaneInfo.ON_TIME_AND_ONLY_FIRING)); |
| iterator.remove(); |
| |
| minOutputTimestampOfEmittedWindows = |
| Math.min(minOutputTimestampOfEmittedWindows, entry.getKey().maxTimestamp().getMillis()); |
| } |
| } |
| |
| if (minOutputTimestampOfEmittedWindows != Long.MAX_VALUE |
| && currentOutputWatermark < minOutputTimestampOfEmittedWindows) { |
| // update current output watermark and emit to next operators |
| currentOutputWatermark = minOutputTimestampOfEmittedWindows; |
| outputCollector.emitWatermark(new Watermark(currentOutputWatermark)); |
| } |
| } |
| |
| @Override |
| public void close() { |
| onWatermark(new Watermark(BoundedWindow.TIMESTAMP_MAX_VALUE.getMillis())); |
| } |
| |
| @Override |
| public String toString() { |
| final StringBuilder sb = new StringBuilder(); |
| sb.append("CreateViewTransform " + viewFn.getClass().getName()); |
| return sb.toString(); |
| } |
| |
| /** |
| * Represents {@code PrimitiveViewT} supplied to the {@link ViewFn}. |
| * |
| * @param <T> primitive view type |
| */ |
| public static final class MultiView<T> implements Materializations.MultimapView<Void, T>, Serializable { |
| private final Iterable<T> iterable; |
| |
| /** |
| * Constructor. |
| * |
| * @param iterable placeholder for side input data. |
| */ |
| public MultiView(final Iterable<T> iterable) { |
| // Create a placeholder for side input data. CreateViewTransform#onData stores data to this list. |
| this.iterable = iterable; |
| } |
| |
| @Override |
| public Iterable<T> get(@Nullable final Void aVoid) { |
| return iterable; |
| } |
| } |
| } |