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Java > Open Source Codes > org > openejb > util > proxy > Jdk13InvocationHandler


1 /**
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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
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28  * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
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40  *
41  * Copyright 1999 (C) Exoffice Technologies Inc. All Rights Reserved.
42  *
43  * $Id: Jdk13InvocationHandler.java 1096 2004-03-26 21:41:16Z dblevins $
44  */

45 package org.openejb.util.proxy;
46
47 import java.io.Serializable JavaDoc;
48 import java.lang.reflect.Method JavaDoc;
49
50 /**
51  * Implementation of JDK 1.3 InvocationHandler for JDK 1.3 Proxies.
52  * This only compiles on JDK 1.3 or better. This is the interface
53  * between the OpenEJB InvocationHandler and the JDK 1.3 proxy. It
54  * allows the OpenEJB InvocationHandler to be null or changed after
55  * proxy instantiation, which is not normally allowed for JDK 1.3
56  * proxies.
57  *
58  * @author Aaron Mulder (ammulder@alumni.princeton.edu)
59  * @version $Revision: 1096 $
60  */

61 public class Jdk13InvocationHandler implements java.lang.reflect.InvocationHandler JavaDoc, Serializable JavaDoc {
62     private org.openejb.util.proxy.InvocationHandler delegate;
63
64     public Jdk13InvocationHandler() {
65     }
66
67     public Jdk13InvocationHandler(org.openejb.util.proxy.InvocationHandler delegate) {
68         setInvocationHandler(delegate);
69     }
70
71     public org.openejb.util.proxy.InvocationHandler getInvocationHandler() {
72         return delegate;
73     }
74
75     public org.openejb.util.proxy.InvocationHandler setInvocationHandler(org.openejb.util.proxy.InvocationHandler handler) {
76         org.openejb.util.proxy.InvocationHandler old = delegate;
77         delegate = handler;
78         return old;
79     }
80
81     public Object JavaDoc invoke(Object JavaDoc proxy, Method JavaDoc method, Object JavaDoc[] args) throws Throwable JavaDoc {
82         if(delegate != null) {
83             if(args == null) {
84                 args = new Object JavaDoc[0];
85                 // A bug in the proxy call?
86
}
87             return delegate.invoke(proxy, method, args);
88         } else {
89             throw new NullPointerException JavaDoc("No invocation handler for proxy "+proxy);
90         }
91     }
92 }
93
94
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