| /** |
| * 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.ambari.server.utils; |
| |
| import java.util.concurrent.BlockingQueue; |
| import java.util.concurrent.Executors; |
| import java.util.concurrent.ThreadPoolExecutor; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.locks.Condition; |
| import java.util.concurrent.locks.ReentrantLock; |
| |
| /** |
| * ThreadPoolExecutor extension which is stopped by default and can be started & stopped. |
| */ |
| public class ManagedThreadPoolExecutor extends ThreadPoolExecutor { |
| |
| private volatile boolean isStopped; |
| private final ReentrantLock pauseLock = new ReentrantLock(); |
| private final Condition unpaused = pauseLock.newCondition(); |
| |
| public ManagedThreadPoolExecutor(int corePoolSize, int maximumPoolSize, |
| long keepAliveTime, TimeUnit unit, |
| BlockingQueue<Runnable> workQueue) { |
| super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, |
| Executors.defaultThreadFactory()); |
| isStopped = true; |
| } |
| |
| protected void beforeExecute(Thread t, Runnable r) { |
| super.beforeExecute(t, r); |
| pauseLock.lock(); |
| try { |
| while (isStopped) { |
| unpaused.await(); |
| } |
| } catch (InterruptedException ie) { |
| t.interrupt(); |
| } finally { |
| pauseLock.unlock(); |
| } |
| } |
| |
| public void start() { |
| pauseLock.lock(); |
| try { |
| isStopped = false; |
| unpaused.signalAll(); |
| } finally { |
| pauseLock.unlock(); |
| } |
| } |
| |
| public void stop() { |
| pauseLock.lock(); |
| try { |
| isStopped = true; |
| } finally { |
| pauseLock.unlock(); |
| } |
| } |
| |
| public boolean isRunning() { |
| return !isStopped; |
| } |
| |
| } |