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1   /*
2    * Copyright (c) MuleSoft, Inc.  All rights reserved.  http://www.mulesoft.com
3    * The software in this package is published under the terms of the CPAL v1.0
4    * license, a copy of which has been included with this distribution in the
5    * LICENSE.txt file.
6    */
7   package org.mule.util.concurrent;
8   
9   import edu.emory.mathcs.backport.java.util.concurrent.RejectedExecutionException;
10  import edu.emory.mathcs.backport.java.util.concurrent.RejectedExecutionHandler;
11  import edu.emory.mathcs.backport.java.util.concurrent.ThreadPoolExecutor;
12  import edu.emory.mathcs.backport.java.util.concurrent.TimeUnit;
13  
14  /**
15   * A handler for unexecutable tasks that waits until the task can be submitted for
16   * execution or times out. Generously snipped from the jsr166 repository at: <a
17   * href="http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/main/java/util/concurrent/ThreadPoolExecutor.java"></a>.
18   */
19  // @Immutable
20  public class WaitPolicy implements RejectedExecutionHandler
21  {
22      private final long time;
23      private final TimeUnit timeUnit;
24  
25      /**
26       * Constructs a <tt>WaitPolicy</tt> which waits (almost) forever.
27       */
28      public WaitPolicy()
29      {
30          // effectively waits forever
31          this(Long.MAX_VALUE, TimeUnit.SECONDS);
32      }
33  
34      /**
35       * Constructs a <tt>WaitPolicy</tt> with timeout. A negative <code>time</code>
36       * value is interpreted as <code>Long.MAX_VALUE</code>.
37       */
38      public WaitPolicy(long time, TimeUnit timeUnit)
39      {
40          super();
41          this.time = (time < 0 ? Long.MAX_VALUE : time);
42          this.timeUnit = timeUnit;
43      }
44  
45      @SuppressWarnings("boxing")
46      public void rejectedExecution(Runnable r, ThreadPoolExecutor e)
47      {
48          try
49          {
50              if (e.isShutdown())
51              {
52                  throw new RejectedExecutionException("ThreadPoolExecutor is already shut down");
53              }
54              else if (!e.getQueue().offer(r, time, timeUnit))
55              {
56                  String message = String.format("ThreadPoolExecutor did not accept within %1d %2s", 
57                      time, timeUnit);
58                  throw new RejectedExecutionException(message);
59              }
60          }
61          catch (InterruptedException ie)
62          {
63              Thread.currentThread().interrupt();
64              throw new RejectedExecutionException(ie);
65          }
66      }
67  
68  }