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Java > Open Source Codes > org > mr > core > util > StageExecutionThread


1 /*
2  * Copyright 2002 by
3  * <a HREF="http://www.coridan.com">Coridan</a>
4  * <a HREF="mailto: support@coridan.com ">support@coridan.com</a>
5  *
6  * The contents of this file are subject to the Mozilla Public License Version
7  * 1.1 (the "License"); you may not use this file except in compliance with the
8  * License. You may obtain a copy of the License at
9  * http://www.mozilla.org/MPL/
10  *
11  * Software distributed under the License is distributed on an "AS IS" basis,
12  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
13  * for the specific language governing rights and limitations under the
14  * License.
15  *
16  * The Original Code is "MantaRay" (TM).
17  *
18  * The Initial Developer of the Original Code is Amir Shevat.
19  * Portions created by the Initial Developer are Copyright (C) 2006
20  * Coridan Inc. All Rights Reserved.
21  *
22  * Contributor(s): all the names of the contributors are added in the source
23  * code where applicable.
24  *
25  * Alternatively, the contents of this file may be used under the terms of the
26  * LGPL license (the "GNU LESSER GENERAL PUBLIC LICENSE"), in which case the
27  * provisions of LGPL are applicable instead of those above. If you wish to
28  * allow use of your version of this file only under the terms of the LGPL
29  * License and not to allow others to use your version of this file under
30  * the MPL, indicate your decision by deleting the provisions above and
31  * replace them with the notice and other provisions required by the LGPL.
32  * If you do not delete the provisions above, a recipient may use your version
33  * of this file under either the MPL or the GNU LESSER GENERAL PUBLIC LICENSE.
34  
35  *
36  * This library is free software; you can redistribute it and/or modify it
37  * under the terms of the MPL as stated above or under the terms of the GNU
38  * Lesser General Public License as published by the Free Software Foundation;
39  * either version 2.1 of the License, or any later version.
40  *
41  * This library is distributed in the hope that it will be useful, but WITHOUT
42  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
43  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
44  * License for more details.
45  */
46 /*
47  * Created on Dec 14, 2003
48  *
49  */
50 package org.mr.core.util;
51
52 import org.apache.commons.logging.Log;
53 import org.apache.commons.logging.LogFactory;
54
55 /**
56  * The worker of a stage. This thread Dequeue an event and pass it along to the handler.
57  * @author Amir Shevat
58  *
59  */
60 public class StageExecutionThread extends Thread JavaDoc{
61     private boolean up = true;
62     private AbstractStage stage;
63     private static Log log;
64     
65     protected Object JavaDoc stopEvent = new Object JavaDoc();
66     
67     /**
68      * Constructs a StageExecutionThread.
69      * @param stage The stage this execution thread belongs to.
70      */
71     StageExecutionThread(AbstractStage stage){
72         this.stage = stage;
73         log = LogFactory.getLog("StageExecutionThread");
74     }
75     
76     
77     public void run(){
78             while (up) {
79                 try {
80                     Object JavaDoc e = stage.dequeue();
81                     if(e == this.stopEvent || !this.up){
82                         // this thread has been told to die
83 return;
84                     }
85                     boolean cont = stage.sendToHandler(e);
86                     if(!cont){
87                         up = cont;
88                     }
89                     //yield();
90 } //try
91 catch (ThreadDeath JavaDoc e) {
92                     // every body must die at some point
93 setUp(false);
94                     throw e;
95                 } //catch
96 catch (Throwable JavaDoc ex) {
97                     if(log.isFatalEnabled())
98                         log.fatal("Stage thread error. ",ex);
99                 } //catch
100 } //while
101 if(log.isDebugEnabled()){
102                 log.debug("Handler returned false. Exiting stage execution thread.");
103             }
104             
105     }
106
107     /**
108      * @return True if the execution thread is up, else false.
109      */
110     public boolean isUp() {
111         return up;
112     }
113
114     /**
115      * @param up The boolean up to set.
116      */
117     public void setUp(boolean up) {
118         this.up = up;
119     }
120
121
122     
123 }
124
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