001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.activemq.thread;
018
019import java.util.concurrent.Executor;
020
021/**
022 * 
023 */
024public class DeterministicTaskRunner implements TaskRunner {
025
026    private final Executor executor;
027    private final Task task;
028    private final Runnable runable;
029    private boolean shutdown;    
030    
031    /**Constructor
032     * @param executor
033     * @param task
034     */
035    public DeterministicTaskRunner(Executor executor, Task task) {
036        this.executor = executor;
037        this.task = task;
038        this.runable = new Runnable() {
039            public void run() {
040                Thread.currentThread();
041                runTask();
042            }
043        };
044    }
045
046    /**
047     * We Expect MANY wakeup calls on the same TaskRunner - but each
048     * needs to run
049     */
050    public void wakeup() throws InterruptedException {
051        synchronized (runable) {
052
053            if (shutdown) {
054                return;
055            }
056            executor.execute(runable);
057
058        }
059    }
060
061    /**
062     * shut down the task
063     * 
064     * @throws InterruptedException
065     */
066    public void shutdown(long timeout) throws InterruptedException {
067        synchronized (runable) {
068            shutdown = true;
069        }
070    }
071
072    public void shutdown() throws InterruptedException {
073        shutdown(0);
074    }
075
076    final void runTask() {
077
078        synchronized (runable) {
079            if (shutdown) {
080                runable.notifyAll();
081                return;
082            }
083        }
084        task.iterate();
085    }
086}