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Java > Open Source Codes > org > exolab > jms > net > connector > Response


1 /**
2  * Redistribution and use of this software and associated documentation
3  * ("Software"), with or without modification, are permitted provided
4  * that the following conditions are met:
5  *
6  * 1. Redistributions of source code must retain copyright
7  * statements and notices. Redistributions must also contain a
8  * copy of this document.
9  *
10  * 2. Redistributions in binary form must reproduce the
11  * above copyright notice, this list of conditions and the
12  * following disclaimer in the documentation and/or other
13  * materials provided with the distribution.
14  *
15  * 3. The name "Exolab" must not be used to endorse or promote
16  * products derived from this Software without prior written
17  * permission of Exoffice Technologies. For written permission,
18  * please contact info@exolab.org.
19  *
20  * 4. Products derived from this Software may not be called "Exolab"
21  * nor may "Exolab" appear in their names without prior written
22  * permission of Exoffice Technologies. Exolab is a registered
23  * trademark of Exoffice Technologies.
24  *
25  * 5. Due credit should be given to the Exolab Project
26  * (http://www.exolab.org/).
27  *
28  * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
29  * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
30  * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
31  * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
32  * EXOFFICE TECHNOLOGIES OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
33  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
34  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
35  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
37  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
38  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
39  * OF THE POSSIBILITY OF SUCH DAMAGE.
40  *
41  * Copyright 2003-2004 (C) Exoffice Technologies Inc. All Rights Reserved.
42  *
43  * $Id: Response.java,v 1.1 2004/11/26 01:51:03 tanderson Exp $
44  */
45 package org.exolab.jms.net.connector;
46
47 import java.io.IOException JavaDoc;
48 import java.io.ObjectInput JavaDoc;
49 import java.io.ObjectOutput JavaDoc;
50 import java.io.Serializable JavaDoc;
51 import java.lang.reflect.Method JavaDoc;
52
53 import org.exolab.jms.net.util.SerializationHelper;
54
55
56 /**
57  * A <code>Response</code> wraps the result of a remote method invocation
58  *
59  * @author <a HREF="mailto:tma@netspace.net.au">Tim Anderson</a>
60  * @version $Revision: 1.1 $ $Date: 2004/11/26 01:51:03 $
61  * @see Request
62  * @see Connection
63  */
64 public class Response implements Serializable JavaDoc {
65
66     /**
67      * The invocation result. May be <code>null</code>
68      */
69     private Object JavaDoc _object;
70
71     /**
72      * An exception generated by the invocation. May be <code>null</code>
73      */
74     private Throwable JavaDoc _exception;
75
76     /**
77      * The invoked method
78      */
79     private transient Method JavaDoc _method;
80
81     /**
82      * Construct a new <code>Response</code> for a successful invocation
83      *
84      * @param object the result of the invocation
85      * @param method the invoked method
86      */
87     public Response(Object JavaDoc object, Method JavaDoc method) {
88         _object = object;
89         _method = method;
90     }
91
92     /**
93      * Construct a new <code>Response</code> for a failed invocation
94      *
95      * @param exception the exception generated by the invocation
96      */
97     public Response(Throwable JavaDoc exception) {
98         _exception = exception;
99     }
100
101     /**
102      * Returns the result of the invocation
103      *
104      * @return the result of the invocation
105      */
106     public Object JavaDoc getObject() {
107         return _object;
108     }
109
110     /**
111      * Returns the exception generated by the invocation
112      *
113      * @return the exception, or <code>null</code> if no exception was thrown
114      */
115     public Throwable JavaDoc getException() {
116         return _exception;
117     }
118
119     /**
120      * Determines if the response is a successful return
121      *
122      * @return <code>true</code> if the response is a successful return
123      */
124     public boolean isReturn() {
125         return (_exception == null);
126     }
127
128     /**
129      * Determines if the response is an exception
130      *
131      * @return <code>true</code> if the response is an exception
132      */
133     public boolean isException() {
134         return !isReturn();
135     }
136
137     /**
138      * Writes this to a stream
139      *
140      * @param out the stream to write to
141      * @throws IOException if an I/O error occurs
142      */
143     public void write(ObjectOutput JavaDoc out) throws IOException JavaDoc {
144         boolean normal = isReturn();
145         out.writeBoolean(normal);
146         if (normal) {
147             Class JavaDoc type = _method.getReturnType();
148             if (type != void.class) {
149                 SerializationHelper.write(type, _object, out);
150             }
151         } else {
152             out.writeObject(_exception);
153         }
154     }
155
156     /**
157      * Read a response from a stream
158      *
159      * @param in the stream to read from
160      * @param method the method that the response relates to
161      * @return the read response
162      * @throws ClassNotFoundException if the response contains a class which
163      * can't be found
164      * @throws IOException if an I/O error occurs
165      */
166     public static Response read(ObjectInput JavaDoc in, Method JavaDoc method)
167             throws ClassNotFoundException JavaDoc, IOException JavaDoc {
168         Response response = null;
169         boolean returnResponse = in.readBoolean();
170         if (returnResponse) {
171             Class JavaDoc type = method.getReturnType();
172             Object JavaDoc object = null;
173             if (type != void.class) {
174                 object = SerializationHelper.read(type, in);
175             }
176             response = new Response(object, method);
177         } else {
178             Object JavaDoc object = in.readObject();
179             response = new Response((Throwable JavaDoc) object);
180         }
181         return response;
182     }
183
184 }
185
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