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1   //******************************************************************************
2   //
3   // File:    Proxy.java
4   // Package: edu.rit.pj.cluster
5   // Unit:    Class edu.rit.pj.cluster.Proxy
6   //
7   // This Java source file is copyright (C) 2006 by Alan Kaminsky. All rights
8   // reserved. For further information, contact the author, Alan Kaminsky, at
9   // ark@cs.rit.edu.
10  //
11  // This Java source file is part of the Parallel Java Library ("PJ"). PJ is free
12  // software; you can redistribute it and/or modify it under the terms of the GNU
13  // General Public License as published by the Free Software Foundation; either
14  // version 3 of the License, or (at your option) any later version.
15  //
16  // PJ is distributed in the hope that it will be useful, but WITHOUT ANY
17  // WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
18  // A PARTICULAR PURPOSE. See the GNU General Public License for more details.
19  //
20  // Linking this library statically or dynamically with other modules is making a
21  // combined work based on this library. Thus, the terms and conditions of the GNU
22  // General Public License cover the whole combination.
23  //
24  // As a special exception, the copyright holders of this library give you
25  // permission to link this library with independent modules to produce an
26  // executable, regardless of the license terms of these independent modules, and
27  // to copy and distribute the resulting executable under terms of your choice,
28  // provided that you also meet, for each linked independent module, the terms
29  // and conditions of the license of that module. An independent module is a module
30  // which is not derived from or based on this library. If you modify this library,
31  // you may extend this exception to your version of the library, but you are not
32  // obligated to do so. If you do not wish to do so, delete this exception
33  // statement from your version.
34  //
35  // A copy of the GNU General Public License is provided in the file gpl.txt. You
36  // may also obtain a copy of the GNU General Public License on the World Wide
37  // Web at http://www.gnu.org/licenses/gpl.html.
38  //
39  //******************************************************************************
40  package edu.rit.pj.cluster;
41  
42  import java.io.IOException;
43  
44  import edu.rit.mp.Buf;
45  import edu.rit.mp.Channel;
46  import edu.rit.mp.ChannelGroup;
47  import edu.rit.mp.ObjectBuf;
48  import edu.rit.mp.Status;
49  
50  /**
51   * Class Proxy is the abstract base class for a proxy object for sending
52   * messages to a PJ process.
53   *
54   * @author Alan Kaminsky
55   * @version 20-Nov-2006
56   */
57  public abstract class Proxy {
58  
59  // Hidden data members.
60      private ChannelGroup myChannelGroup;
61      private Channel myChannel;
62  
63  // Exported constructors.
64      /**
65       * Construct a new proxy. The proxy will use the given channel in the given
66       * channel group to send messages to the far end process.
67       *
68       * @param theChannelGroup Channel group.
69       * @param theChannel Channel.
70       */
71      public Proxy(ChannelGroup theChannelGroup,
72              Channel theChannel) {
73          myChannelGroup = theChannelGroup;
74          myChannel = theChannel;
75      }
76  
77  // Exported operations.
78      /**
79       * Send the given message to this proxy's far end process.
80       *
81       * @param theMessage Message.
82       * @exception IOException Thrown if an I/O error occurred.
83       * @throws java.io.IOException if any.
84       */
85      public void send(Message theMessage)
86              throws IOException {
87          myChannelGroup.send(myChannel,
88                  theMessage.getTag(),
89                  ObjectBuf.buffer(theMessage));
90      }
91  
92      /**
93       * Send a message with the given tag and items to this proxy's far end
94       * process.
95       *
96       * @param theTag Message tag.
97       * @param theSrc Item source buffer.
98       * @exception IOException Thrown if an I/O error occurred.
99       * @throws java.io.IOException if any.
100      */
101     public void send(int theTag,
102             Buf theSrc)
103             throws IOException {
104         myChannelGroup.send(myChannel, theTag, theSrc);
105     }
106 
107     /**
108      * Receive a message from this proxy's far end process. A message will be
109      * received from this proxy's channel in this proxy's channel group. The
110      * message must have a tag of 0. The message items are stored in the given
111      * item destination buffer.
112      * <P>
113      * The <code>receive()</code> method does not return until the message has been
114      * fully received.
115      *
116      * @param theDst Item destination buffer.
117      * @return Status object giving the outcome of the message reception.
118      * @exception IOException Thrown if an I/O error occurred.
119      * @throws java.io.IOException if any.
120      */
121     public Status receive(Buf theDst)
122             throws IOException {
123         return myChannelGroup.receive(myChannel, theDst);
124     }
125 
126     /**
127      * Receive a message with the given tag from this proxy's far end process. A
128      * message will be received from this proxy's channel in this proxy's
129      * channel group. If <code>theTag</code> is null, a message will be received
130      * with any tag. The message items are stored in the given item destination
131      * buffer.
132      * <P>
133      * The <code>receive()</code> method does not return until the message has been
134      * fully received.
135      *
136      * @param theTag Message tag, or null to receive any tag.
137      * @param theDst Item destination buffer.
138      * @return Status object giving the outcome of the message reception.
139      * @exception IOException Thrown if an I/O error occurred.
140      * @throws java.io.IOException if any.
141      */
142     public Status receive(Integer theTag,
143             Buf theDst)
144             throws IOException {
145         return myChannelGroup.receive(myChannel, theTag, theDst);
146     }
147 
148     /**
149      * Close communication with this proxy's far end process.
150      */
151     public void close() {
152         myChannel.close();
153     }
154 
155 }