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Java > Open Source Codes > org > objectweb > dream > synchro > LockPullUnlockImpl


1 /**
2  * Dream
3  * Copyright (C) 2003-2004 INRIA Rhone-Alpes
4  *
5  * This library is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation; either
8  * version 2 of the License, or (at your option) any later version.
9  *
10  * This library is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  * Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public
16  * License along with this library; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18  *
19  * Contact : dream@objectweb.org
20  *
21  * Initial developer(s): Vivien Quema
22  * Contributor(s):
23  */
24
25 package org.objectweb.dream.synchro;
26
27 import java.util.Map JavaDoc;
28
29 import org.objectweb.dream.AbstractComponent;
30 import org.objectweb.dream.InterruptedPullException;
31 import org.objectweb.dream.Pull;
32 import org.objectweb.dream.PullException;
33 import org.objectweb.dream.message.Message;
34 import org.objectweb.fractal.api.NoSuchInterfaceException;
35 import org.objectweb.fractal.api.control.IllegalBindingException;
36 import org.objectweb.fractal.api.control.IllegalLifeCycleException;
37
38 /**
39  * This component has a Pull output. When its pull method is called, it locks a
40  * mutex (to which it is bound), calls pulls a message on its input, and then
41  * unlocks the mutex.
42  */
43 public class LockPullUnlockImpl extends AbstractComponent implements Pull
44 {
45
46   protected Pull inPullItf;
47   protected Mutex mutexItf;
48
49   // ---------------------------------------------------------------------------
50 // Implementation of the Push interface.
51 // ---------------------------------------------------------------------------
52
53   /**
54    * @see org.objectweb.dream.Pull#pull(java.util.Map)
55    */
56   public Message pull(Map JavaDoc context) throws PullException
57   {
58     Message msg = null;
59     try
60     {
61       mutexItf.lock();
62     }
63     catch (InterruptedException JavaDoc e)
64     {
65       throw new InterruptedPullException(e);
66     }
67     try
68     {
69       msg = inPullItf.pull(context);
70     }
71     finally
72     {
73       mutexItf.unlock();
74     }
75     return msg;
76   }
77
78   // ---------------------------------------------------------------------------
79 // Implementation of the BindingController interface.
80 // ---------------------------------------------------------------------------
81
82   /**
83    * @see org.objectweb.fractal.api.control.BindingController#bindFc(String,
84    * Object)
85    */
86   public synchronized void bindFc(String JavaDoc clientItfName, Object JavaDoc serverItf)
87       throws NoSuchInterfaceException, IllegalBindingException,
88       IllegalLifeCycleException
89   {
90     super.bindFc(clientItfName, serverItf);
91     if (clientItfName.equals(Pull.IN_PULL_ITF_NAME))
92     {
93       inPullItf = (Pull) serverItf;
94     }
95     else if (clientItfName.equals(Mutex.MUTEX_ITF_NAME))
96     {
97       mutexItf = (Mutex) serverItf;
98     }
99   }
100
101   /**
102    * @see org.objectweb.fractal.api.control.BindingController#listFc()
103    */
104   public String JavaDoc[] listFc()
105   {
106     return new String JavaDoc[]{Pull.IN_PULL_ITF_NAME, Mutex.MUTEX_ITF_NAME};
107   }
108
109 }
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