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.HashMap;
020import java.util.Timer;
021import java.util.TimerTask;
022
023import org.apache.activemq.util.ServiceStopper;
024import org.apache.activemq.util.ServiceSupport;
025
026/**
027 *
028 */
029public final class Scheduler extends ServiceSupport {
030
031    private final String name;
032    private Timer timer;
033    private final HashMap<Runnable, TimerTask> timerTasks = new HashMap<Runnable, TimerTask>();
034
035    public Scheduler(String name) {
036        this.name = name;
037    }
038
039    public synchronized void executePeriodically(final Runnable task, long period) {
040        TimerTask timerTask = new SchedulerTimerTask(task);
041        timer.schedule(timerTask, period, period);
042        timerTasks.put(task, timerTask);
043    }
044
045    public synchronized void cancel(Runnable task) {
046        TimerTask ticket = timerTasks.remove(task);
047        if (ticket != null) {
048            ticket.cancel();
049            timer.purge(); // remove cancelled TimerTasks
050        }
051    }
052
053    public synchronized void executeAfterDelay(final Runnable task, long redeliveryDelay) {
054        TimerTask timerTask = new SchedulerTimerTask(task);
055        timer.schedule(timerTask, redeliveryDelay);
056    }
057
058    public void shutdown() {
059        timer.cancel();
060    }
061
062    @Override
063    protected synchronized void doStart() throws Exception {
064        this.timer = new Timer(name, true);
065    }
066
067    @Override
068    protected synchronized void doStop(ServiceStopper stopper) throws Exception {
069        if (this.timer != null) {
070            this.timer.cancel();
071        }
072    }
073
074    public String getName() {
075        return name;
076    }
077}