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.store.kahadb.disk.util; 018 019import java.util.HashMap; 020import java.util.Timer; 021import java.util.TimerTask; 022 023/** 024 * 025 */ 026public final class Scheduler { 027 028 029 030 public static final Timer CLOCK_DAEMON = new Timer("KahaDB Scheduler", true); 031 private static final HashMap<Runnable, TimerTask> TIMER_TASKS = new HashMap<Runnable, TimerTask>(); 032 033 private Scheduler() { 034 } 035 036 public static synchronized void executePeriodically(final Runnable task, long period) { 037 TimerTask timerTask = new SchedulerTimerTask(task); 038 CLOCK_DAEMON.schedule(timerTask, period, period); 039 TIMER_TASKS.put(task, timerTask); 040 } 041 042 public static synchronized void cancel(Runnable task) { 043 TimerTask ticket = TIMER_TASKS.remove(task); 044 if (ticket != null) { 045 ticket.cancel(); 046 CLOCK_DAEMON.purge();//remove cancelled TimerTasks 047 } 048 } 049 050 public static void executeAfterDelay(final Runnable task, long redeliveryDelay) { 051 TimerTask timerTask = new SchedulerTimerTask(task); 052 CLOCK_DAEMON.schedule(timerTask, redeliveryDelay); 053 } 054 055 public static void shutdown() { 056 CLOCK_DAEMON.cancel(); 057 } 058 059}