| /** |
| * 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.concurrent.atomic.AtomicInteger; |
| |
| /** |
| * A trigger that tracks event counts and calls back {@link TriggerHandler#onTrigger()} when the count threshold is hit. |
| * |
| * @param <T> the type of event tracked by this policy. |
| */ |
| public class CountTriggerPolicy<T> implements TriggerPolicy<T, Integer> { |
| private final int count; |
| private final AtomicInteger currentCount; |
| private final TriggerHandler handler; |
| private final EvictionPolicy<T, ?> evictionPolicy; |
| private boolean started; |
| |
| public CountTriggerPolicy(int count, TriggerHandler handler, EvictionPolicy<T, ?> evictionPolicy) { |
| this.count = count; |
| this.currentCount = new AtomicInteger(); |
| this.handler = handler; |
| this.evictionPolicy = evictionPolicy; |
| this.started = false; |
| } |
| |
| @Override |
| public void track(Event<T> event) { |
| if (started && !event.isWatermark()) { |
| if (currentCount.incrementAndGet() >= count) { |
| evictionPolicy.setContext(new DefaultEvictionContext(System.currentTimeMillis())); |
| handler.onTrigger(); |
| } |
| } |
| } |
| |
| @Override |
| public void reset() { |
| currentCount.set(0); |
| } |
| |
| @Override |
| public void start() { |
| started = true; |
| } |
| |
| @Override |
| public void shutdown() { |
| // NOOP |
| } |
| |
| @Override |
| public Integer getState() { |
| return currentCount.get(); |
| } |
| |
| @Override |
| public void restoreState(Integer state) { |
| currentCount.set(state); |
| } |
| |
| @Override |
| public String toString() { |
| return "CountTriggerPolicy{" |
| + "count=" + count |
| + ", currentCount=" + currentCount |
| + ", started=" + started |
| + '}'; |
| } |
| } |