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1   /***
2    * 
3    * Copyright 2005 LogicBlaze, Inc. http://www.logicblaze.com
4    * 
5    * Licensed under the Apache License, Version 2.0 (the "License"); 
6    * you may not use this file except in compliance with the License. 
7    * You may obtain a copy of the License at 
8    * 
9    * http://www.apache.org/licenses/LICENSE-2.0
10   * 
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS, 
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
14   * See the License for the specific language governing permissions and 
15   * limitations under the License. 
16   * 
17   **/
18  package org.logicblaze.lingo.util;
19  
20  import edu.emory.mathcs.backport.java.util.concurrent.ScheduledExecutorService;
21  import edu.emory.mathcs.backport.java.util.concurrent.TimeUnit;
22  
23  import org.apache.commons.logging.Log;
24  import org.apache.commons.logging.LogFactory;
25  
26  /***
27   * A simple POJO which is useful for wiring together tasks in an IoC type way.
28   * 
29   * @version $Revision$
30   */
31  public class ScheduledTask implements Runnable {
32  
33      private static final Log log = LogFactory.getLog(ScheduledTask.class);
34  
35      private ScheduledExecutorService executor;
36      private Runnable task;
37      private long timeoutMillis;
38  
39      public ScheduledTask(Runnable task, ScheduledExecutorService executor, long millis) {
40          this.task = task;
41          this.executor = executor;
42          this.timeoutMillis = millis;
43          scheduleTask();
44      }
45  
46      /***
47       * Performs the task and then schedules another execution of the task.
48       */
49      public void run() {
50          try {
51              task.run();
52          }
53          catch (RuntimeException e) {
54              log.warn("Caught exception while running task: " + task + ". Detail: " + e, e);
55          }
56          scheduleTask();
57      }
58  
59      public void stop() {
60          executor = null;
61      }
62  
63      // Properties
64      // -------------------------------------------------------------------------
65      public long getTimeoutMillis() {
66          return timeoutMillis;
67      }
68  
69      public void setTimeoutMillis(long timeoutMillis) {
70          this.timeoutMillis = timeoutMillis;
71      }
72  
73      // Implemetation methods
74      // -------------------------------------------------------------------------
75      protected void scheduleTask() {
76          if (executor != null) {
77              executor.schedule(this, timeoutMillis, TimeUnit.MILLISECONDS);
78          }
79      }
80  
81  }