| /* |
| * 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.runners.core; |
| |
| import org.apache.beam.sdk.coders.VarLongCoder; |
| import org.apache.beam.sdk.state.CombiningState; |
| import org.apache.beam.sdk.state.ReadableState; |
| import org.apache.beam.sdk.transforms.Sum; |
| import org.apache.beam.sdk.transforms.windowing.BoundedWindow; |
| import org.apache.beam.sdk.values.WindowingStrategy; |
| import org.apache.beam.sdk.values.WindowingStrategy.AccumulationMode; |
| |
| /** |
| * Tracks which windows have non-empty panes. Specifically, which windows have new elements since |
| * their last triggering. |
| * |
| * @param <W> The kind of windows being tracked. |
| */ |
| public abstract class NonEmptyPanes<K, W extends BoundedWindow> { |
| |
| static <K, W extends BoundedWindow> NonEmptyPanes<K, W> create( |
| WindowingStrategy<?, W> strategy, ReduceFn<K, ?, ?, W> reduceFn) { |
| if (strategy.getMode() == AccumulationMode.DISCARDING_FIRED_PANES) { |
| return new DiscardingModeNonEmptyPanes<>(reduceFn); |
| } else { |
| return new GeneralNonEmptyPanes<>(); |
| } |
| } |
| |
| /** |
| * Record that some content has been added to the window in {@code context}, and therefore the |
| * current pane is not empty. |
| */ |
| public abstract void recordContent(StateAccessor<K> context); |
| |
| /** Record that the given pane is empty. */ |
| public abstract void clearPane(StateAccessor<K> state); |
| |
| /** Return true if the current pane for the window in {@code context} is empty. */ |
| public abstract ReadableState<Boolean> isEmpty(StateAccessor<K> context); |
| |
| /** Prefetch in preparation for merging. */ |
| public abstract void prefetchOnMerge(MergingStateAccessor<K, W> state); |
| |
| /** Eagerly merge backing state. */ |
| public abstract void onMerge(MergingStateAccessor<K, W> context); |
| |
| /** |
| * An implementation of {@code NonEmptyPanes} optimized for use with discarding mode. Uses the |
| * presence of data in the accumulation buffer to record non-empty panes. |
| */ |
| private static class DiscardingModeNonEmptyPanes<K, W extends BoundedWindow> |
| extends NonEmptyPanes<K, W> { |
| |
| private ReduceFn<K, ?, ?, W> reduceFn; |
| |
| private DiscardingModeNonEmptyPanes(ReduceFn<K, ?, ?, W> reduceFn) { |
| this.reduceFn = reduceFn; |
| } |
| |
| @Override |
| public ReadableState<Boolean> isEmpty(StateAccessor<K> state) { |
| return reduceFn.isEmpty(state); |
| } |
| |
| @Override |
| public void recordContent(StateAccessor<K> state) { |
| // Nothing to do -- the reduceFn is tracking contents |
| } |
| |
| @Override |
| public void clearPane(StateAccessor<K> state) { |
| // Nothing to do -- the reduceFn is tracking contents |
| } |
| |
| @Override |
| public void prefetchOnMerge(MergingStateAccessor<K, W> state) { |
| // Nothing to do -- the reduceFn is tracking contents |
| } |
| |
| @Override |
| public void onMerge(MergingStateAccessor<K, W> context) { |
| // Nothing to do -- the reduceFn is tracking contents |
| } |
| } |
| |
| /** An implementation of {@code NonEmptyPanes} for general use. */ |
| private static class GeneralNonEmptyPanes<K, W extends BoundedWindow> |
| extends NonEmptyPanes<K, W> { |
| |
| private static final StateTag<CombiningState<Long, long[], Long>> PANE_ADDITIONS_TAG = |
| StateTags.makeSystemTagInternal( |
| StateTags.combiningValueFromInputInternal("count", VarLongCoder.of(), Sum.ofLongs())); |
| |
| @Override |
| public void recordContent(StateAccessor<K> state) { |
| state.access(PANE_ADDITIONS_TAG).add(1L); |
| } |
| |
| @Override |
| public void clearPane(StateAccessor<K> state) { |
| state.access(PANE_ADDITIONS_TAG).clear(); |
| } |
| |
| @Override |
| public ReadableState<Boolean> isEmpty(StateAccessor<K> state) { |
| return state.access(PANE_ADDITIONS_TAG).isEmpty(); |
| } |
| |
| @Override |
| public void prefetchOnMerge(MergingStateAccessor<K, W> state) { |
| StateMerging.prefetchCombiningValues(state, PANE_ADDITIONS_TAG); |
| } |
| |
| @Override |
| public void onMerge(MergingStateAccessor<K, W> context) { |
| StateMerging.mergeCombiningValues(context, PANE_ADDITIONS_TAG); |
| } |
| } |
| } |