| /** |
| * 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.storm.windowing; |
| |
| import java.util.List; |
| |
| /** |
| * A trigger policy that tracks event counts and sets the context for eviction policy to evict based on latest watermark time. |
| * |
| * @param <T> the type of event tracked by this policy. |
| */ |
| public class WatermarkCountTriggerPolicy<T> implements TriggerPolicy<T, Long> { |
| private final int count; |
| private final TriggerHandler handler; |
| private final EvictionPolicy<T, ?> evictionPolicy; |
| private final WindowManager<T> windowManager; |
| private volatile long lastProcessedTs; |
| private boolean started; |
| |
| public WatermarkCountTriggerPolicy(int count, TriggerHandler handler, |
| EvictionPolicy<T, ?> evictionPolicy, WindowManager<T> windowManager) { |
| this.count = count; |
| this.handler = handler; |
| this.evictionPolicy = evictionPolicy; |
| this.windowManager = windowManager; |
| this.started = false; |
| } |
| |
| @Override |
| public void track(Event<T> event) { |
| if (started && event.isWatermark()) { |
| handleWaterMarkEvent(event); |
| } |
| } |
| |
| @Override |
| public void reset() { |
| // NOOP |
| } |
| |
| @Override |
| public void start() { |
| started = true; |
| } |
| |
| @Override |
| public void shutdown() { |
| // NOOP |
| } |
| |
| /** |
| * Triggers all the pending windows up to the waterMarkEvent timestamp based on the sliding interval count. |
| * |
| * @param waterMarkEvent the watermark event |
| */ |
| private void handleWaterMarkEvent(Event<T> waterMarkEvent) { |
| long watermarkTs = waterMarkEvent.getTimestamp(); |
| List<Long> eventTs = windowManager.getSlidingCountTimestamps(lastProcessedTs, watermarkTs, count); |
| for (long ts : eventTs) { |
| evictionPolicy.setContext(new DefaultEvictionContext(ts, null, Long.valueOf(count))); |
| handler.onTrigger(); |
| lastProcessedTs = ts; |
| } |
| } |
| |
| @Override |
| public Long getState() { |
| return lastProcessedTs; |
| } |
| |
| @Override |
| public void restoreState(Long state) { |
| lastProcessedTs = state; |
| } |
| |
| @Override |
| public String toString() { |
| return "WatermarkCountTriggerPolicy{" + |
| "count=" + count + |
| ", lastProcessedTs=" + lastProcessedTs + |
| ", started=" + started + |
| '}'; |
| } |
| } |