| /* |
| * 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.policy; |
| |
| import java.util.Map; |
| import java.util.concurrent.locks.LockSupport; |
| import org.apache.storm.Config; |
| import org.apache.storm.utils.ObjectReader; |
| |
| /** |
| * A Progressive Wait Strategy. |
| * |
| * <p>Has three levels of idling. Stays in each level for a configured number of iterations before entering the next level. |
| * Level 1 - No idling. Returns immediately. Stays in this level for `level1Count` iterations. Level 2 - Calls LockSupport.parkNanos(1). |
| * Stays in this level for `level2Count` iterations Level 3 - Calls Thread.sleep(). Stays in this level until wait situation changes. |
| * |
| * <p>The initial spin can be useful to prevent downstream bolt from repeatedly sleeping/parking when the upstream component is a bit |
| * relatively slower. Allows downstream bolt can enter deeper wait states only if the traffic to it appears to have reduced. |
| */ |
| public class WaitStrategyProgressive implements IWaitStrategy { |
| private int level1Count; |
| private int level2Count; |
| private long level3SleepMs; |
| |
| @Override |
| public void prepare(Map<String, Object> conf, WaitSituation waitSituation) { |
| if (waitSituation == WaitSituation.SPOUT_WAIT) { |
| level1Count = ObjectReader.getInt(conf.get(Config.TOPOLOGY_SPOUT_WAIT_PROGRESSIVE_LEVEL1_COUNT)); |
| level2Count = ObjectReader.getInt(conf.get(Config.TOPOLOGY_SPOUT_WAIT_PROGRESSIVE_LEVEL2_COUNT)); |
| level3SleepMs = ObjectReader.getLong(conf.get(Config.TOPOLOGY_SPOUT_WAIT_PROGRESSIVE_LEVEL3_SLEEP_MILLIS)); |
| } else if (waitSituation == WaitSituation.BOLT_WAIT) { |
| level1Count = ObjectReader.getInt(conf.get(Config.TOPOLOGY_BOLT_WAIT_PROGRESSIVE_LEVEL1_COUNT)); |
| level2Count = ObjectReader.getInt(conf.get(Config.TOPOLOGY_BOLT_WAIT_PROGRESSIVE_LEVEL2_COUNT)); |
| level3SleepMs = ObjectReader.getLong(conf.get(Config.TOPOLOGY_BOLT_WAIT_PROGRESSIVE_LEVEL3_SLEEP_MILLIS)); |
| } else if (waitSituation == WaitSituation.BACK_PRESSURE_WAIT) { |
| level1Count = ObjectReader.getInt(conf.get(Config.TOPOLOGY_BACKPRESSURE_WAIT_PROGRESSIVE_LEVEL1_COUNT)); |
| level2Count = ObjectReader.getInt(conf.get(Config.TOPOLOGY_BACKPRESSURE_WAIT_PROGRESSIVE_LEVEL2_COUNT)); |
| level3SleepMs = ObjectReader.getLong(conf.get(Config.TOPOLOGY_BACKPRESSURE_WAIT_PROGRESSIVE_LEVEL3_SLEEP_MILLIS)); |
| } else { |
| throw new IllegalArgumentException("Unknown wait situation : " + waitSituation); |
| } |
| } |
| |
| @Override |
| public int idle(int idleCounter) throws InterruptedException { |
| if (idleCounter < level1Count) { // level 1 - no waiting |
| ++idleCounter; |
| } else if (idleCounter < level1Count + level2Count) { // level 2 - parkNanos(1L) |
| ++idleCounter; |
| LockSupport.parkNanos(1L); |
| } else { // level 3 - longer idling with Thread.sleep() |
| Thread.sleep(level3SleepMs); |
| } |
| return idleCounter; |
| } |
| } |