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.apache.camel.bam; 018 019 import org.apache.camel.bam.model.TimerEvent; 020 import org.apache.camel.impl.ServiceSupport; 021 import org.apache.commons.logging.Log; 022 import org.apache.commons.logging.LogFactory; 023 import org.springframework.orm.jpa.JpaCallback; 024 import org.springframework.orm.jpa.JpaTemplate; 025 026 import javax.persistence.EntityManager; 027 import javax.persistence.LockModeType; 028 import javax.persistence.PersistenceException; 029 import java.util.Date; 030 import java.util.List; 031 import java.util.concurrent.ExecutorService; 032 033 /** 034 * @version $Revision: $ 035 */ 036 public class TimerEngine extends ServiceSupport implements Runnable { 037 private static final Log log = LogFactory.getLog(TimerEngine.class); 038 039 private JpaTemplate template; 040 private ExecutorService executor; 041 private long windowMillis = 1000L; 042 private Thread thread; 043 044 public void run() { 045 while (!isStopped()) { 046 long nextPoll = System.currentTimeMillis() + windowMillis; 047 048 Date window = new Date(nextPoll); 049 List<TimerEvent> list = template.find("select x from " + TimerEvent.class.getName() + " where x.time < ?1 order by x.time", window); 050 for (TimerEvent event : list) { 051 fireEvent(event); 052 } 053 054 long timeToSleep = nextPoll - System.currentTimeMillis(); 055 if (timeToSleep > 0) { 056 log.debug("Sleeping for " + timeToSleep + " millis"); 057 try { 058 Thread.sleep(timeToSleep); 059 } 060 catch (InterruptedException e) { 061 log.debug("Caught: " + e, e); 062 } 063 } 064 } 065 } 066 067 protected void fireEvent(final TimerEvent event) { 068 // lets try lock the object first 069 070 template.execute(new JpaCallback() { 071 public Object doInJpa(EntityManager entityManager) throws PersistenceException { 072 entityManager.lock(event, LockModeType.WRITE); 073 event.fire(); 074 entityManager.remove(event); 075 return null; 076 } 077 }); 078 079 } 080 081 protected void doStart() throws Exception { 082 thread = new Thread(this, "TimerEngine"); 083 thread.start(); 084 } 085 086 protected void doStop() throws Exception { 087 if (thread != null) { 088 thread = null; 089 } 090 } 091 }