org.apache.beam.runners.core.GroupAlsoByWindowsViaOutputBufferDoFn.java Source code

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Here is the source code for org.apache.beam.runners.core.GroupAlsoByWindowsViaOutputBufferDoFn.java

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/*
 * 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 com.google.common.collect.Iterables;
import java.util.ArrayList;
import java.util.List;
import org.apache.beam.runners.core.triggers.ExecutableTriggerStateMachine;
import org.apache.beam.runners.core.triggers.TriggerStateMachines;
import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
import org.apache.beam.sdk.util.SystemDoFnInternal;
import org.apache.beam.sdk.util.TimerInternals;
import org.apache.beam.sdk.util.WindowedValue;
import org.apache.beam.sdk.util.WindowingStrategy;
import org.apache.beam.sdk.util.state.StateInternals;
import org.apache.beam.sdk.util.state.StateInternalsFactory;
import org.joda.time.Instant;

/**
 * The default batch {@link GroupAlsoByWindowsDoFn} implementation, if no specialized "fast path"
 * implementation is applicable.
 */
@SystemDoFnInternal
public class GroupAlsoByWindowsViaOutputBufferDoFn<K, InputT, OutputT, W extends BoundedWindow>
        extends GroupAlsoByWindowsDoFn<K, InputT, OutputT, W> {

    private final WindowingStrategy<?, W> strategy;
    private final StateInternalsFactory<K> stateInternalsFactory;
    private SystemReduceFn<K, InputT, ?, OutputT, W> reduceFn;

    public GroupAlsoByWindowsViaOutputBufferDoFn(WindowingStrategy<?, W> windowingStrategy,
            StateInternalsFactory<K> stateInternalsFactory, SystemReduceFn<K, InputT, ?, OutputT, W> reduceFn) {
        this.strategy = windowingStrategy;
        this.reduceFn = reduceFn;
        this.stateInternalsFactory = stateInternalsFactory;
    }

    @Override
    public void processElement(ProcessContext c) throws Exception {
        K key = c.element().getKey();
        // Used with Batch, we know that all the data is available for this key. We can't use the
        // timer manager from the context because it doesn't exist. So we create one and emulate the
        // watermark, knowing that we have all data and it is in timestamp order.
        InMemoryTimerInternals timerInternals = new InMemoryTimerInternals();
        timerInternals.advanceProcessingTime(Instant.now());
        timerInternals.advanceSynchronizedProcessingTime(Instant.now());
        StateInternals<K> stateInternals = stateInternalsFactory.stateInternalsForKey(key);

        ReduceFnRunner<K, InputT, OutputT, W> reduceFnRunner = new ReduceFnRunner<>(key, strategy,
                ExecutableTriggerStateMachine
                        .create(TriggerStateMachines.stateMachineForTrigger(strategy.getTrigger())),
                stateInternals, timerInternals,
                WindowingInternalsAdapters.outputWindowedValue(c.windowingInternals()),
                WindowingInternalsAdapters.sideInputReader(c.windowingInternals()), droppedDueToClosedWindow,
                reduceFn, c.getPipelineOptions());

        Iterable<List<WindowedValue<InputT>>> chunks = Iterables.partition(c.element().getValue(), 1000);
        for (Iterable<WindowedValue<InputT>> chunk : chunks) {
            // Process the chunk of elements.
            reduceFnRunner.processElements(chunk);

            // Then, since elements are sorted by their timestamp, advance the input watermark
            // to the first element.
            timerInternals.advanceInputWatermark(chunk.iterator().next().getTimestamp());
            // Advance the processing times.
            timerInternals.advanceProcessingTime(Instant.now());
            timerInternals.advanceSynchronizedProcessingTime(Instant.now());

            // Fire all the eligible timers.
            fireEligibleTimers(timerInternals, reduceFnRunner);

            // Leave the output watermark undefined. Since there's no late data in batch mode
            // there's really no need to track it as we do for streaming.
        }

        // Finish any pending windows by advancing the input watermark to infinity.
        timerInternals.advanceInputWatermark(BoundedWindow.TIMESTAMP_MAX_VALUE);

        // Finally, advance the processing time to infinity to fire any timers.
        timerInternals.advanceProcessingTime(BoundedWindow.TIMESTAMP_MAX_VALUE);
        timerInternals.advanceSynchronizedProcessingTime(BoundedWindow.TIMESTAMP_MAX_VALUE);

        fireEligibleTimers(timerInternals, reduceFnRunner);

        reduceFnRunner.persist();
    }

    private void fireEligibleTimers(InMemoryTimerInternals timerInternals,
            ReduceFnRunner<K, InputT, OutputT, W> reduceFnRunner) throws Exception {
        List<TimerInternals.TimerData> timers = new ArrayList<>();
        while (true) {
            TimerInternals.TimerData timer;
            while ((timer = timerInternals.removeNextEventTimer()) != null) {
                timers.add(timer);
            }
            while ((timer = timerInternals.removeNextProcessingTimer()) != null) {
                timers.add(timer);
            }
            while ((timer = timerInternals.removeNextSynchronizedProcessingTimer()) != null) {
                timers.add(timer);
            }
            if (timers.isEmpty()) {
                break;
            }
            reduceFnRunner.onTimers(timers);
            timers.clear();
        }
    }
}