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 */ 017 package org.fusesource.hawtdb.util; 018 019 import java.util.HashMap; 020 import java.util.Timer; 021 import java.util.TimerTask; 022 023 /** 024 */ 025 public final class Scheduler { 026 027 028 029 public static final Timer CLOCK_DAEMON = new Timer("ActiveMQ Scheduler", true); 030 private static final HashMap<Runnable, TimerTask> TIMER_TASKS = new HashMap<Runnable, TimerTask>(); 031 032 private Scheduler() { 033 } 034 035 public static synchronized void executePeriodically(final Runnable task, long period) { 036 TimerTask timerTask = new SchedulerTimerTask(task); 037 CLOCK_DAEMON.scheduleAtFixedRate(timerTask, period, period); 038 TIMER_TASKS.put(task, timerTask); 039 } 040 041 public static synchronized void cancel(Runnable task) { 042 TimerTask ticket = TIMER_TASKS.remove(task); 043 if (ticket != null) { 044 ticket.cancel(); 045 CLOCK_DAEMON.purge();//remove cancelled TimerTasks 046 } 047 } 048 049 public static void executeAfterDelay(final Runnable task, long redeliveryDelay) { 050 TimerTask timerTask = new SchedulerTimerTask(task); 051 CLOCK_DAEMON.schedule(timerTask, redeliveryDelay); 052 } 053 054 public static void shutdown() { 055 CLOCK_DAEMON.cancel(); 056 } 057 058 }