1 /*
2 * Copyright (c) 2005 The University of Reading
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University of Reading, nor the names of the
14 * authors or contributors may be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 package uk.ac.rdg.resc.jstyx.client;
30
31 import uk.ac.rdg.resc.jstyx.messages.StyxMessage;
32 import uk.ac.rdg.resc.jstyx.messages.RerrorMessage;
33 import uk.ac.rdg.resc.jstyx.StyxException;
34
35 /***
36 * Class that implements a method that waits until a reply arrives, then
37 * returns the reply.
38 *
39 * @author Jon Blower
40 * $Revision: 302 $
41 * $Date: 2005-06-27 18:17:16 +0100 (Mon, 27 Jun 2005) $
42 * $Log$
43 * Revision 1.3 2005/06/27 17:17:16 jonblower
44 * Changed MessageCallback to pass Tmessage as parameter, rather than storing in the instance
45 *
46 * Revision 1.2 2005/02/21 18:09:43 jonblower
47 * *** empty log message ***
48 *
49 * Revision 1.1.1.1 2005/02/16 18:58:20 jonblower
50 * Initial import
51 *
52 */
53 class StyxReplyCallback extends MessageCallback
54 {
55 private StyxMessage reply; // The reply from a Styx server (i.e. an RMessage)
56 private String errorMsg; // Non-null if an error has occurred
57
58 /***
59 * Creates a new instance of StyxReplyCallback
60 */
61 public StyxReplyCallback()
62 {
63 this.reply = null;
64 this.errorMsg = null;
65 }
66
67 /***
68 * Waits for the reply to arrive, then returns it
69 * @return the RMessage corresponding to the TMessage that was sent
70 * @throws StyxException if an error is returned from the server
71 */
72 public synchronized StyxMessage getReply() throws StyxException
73 {
74 while (reply == null && errorMsg == null)
75 {
76 try
77 {
78 // wait for Producer to put value
79 wait();
80 }
81 catch (InterruptedException e)
82 {
83 }
84 }
85 if (errorMsg != null)
86 {
87 throw new StyxException(errorMsg);
88 }
89 return reply;
90 }
91
92 /***
93 * Called when a valid reply (i.e. not an Rerror message) arrives from
94 * the server.
95 */
96 public synchronized void replyArrived(StyxMessage rMessage, StyxMessage tMessage)
97 {
98 reply = rMessage;
99 notifyAll();
100 }
101
102 /***
103 * Called when an error occurs (either an Rerror message was returned by
104 * the server, the reply was of an unexpected type, or something else -
105 * see MessageCallback).
106 */
107 public synchronized void error(String message, StyxMessage tMessage)
108 {
109 errorMsg = message;
110 notifyAll();
111 }
112
113 }