1 /*
2 * Copyright (c) 1998, 2005 Gargoyle Software Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are met:
6 *
7 * 1. Redistributions of source code must retain the above copyright notice,
8 * this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright notice,
10 * this list of conditions and the following disclaimer in the documentation
11 * and/or other materials provided with the distribution.
12 * 3. The end-user documentation included with the redistribution, if any, must
13 * include the following acknowledgment:
14 *
15 * "This product includes software developed by Gargoyle Software Inc.
16 * (http://www.GargoyleSoftware.com/)."
17 *
18 * Alternately, this acknowledgment may appear in the software itself, if
19 * and wherever such third-party acknowledgments normally appear.
20 * 4. The name "Gargoyle Software" must not be used to endorse or promote
21 * products derived from this software without prior written permission.
22 * For written permission, please contact info@GargoyleSoftware.com.
23 * 5. Products derived from this software may not be called "GSBase", nor may
24 * "GSBase" appear in their name, without prior written permission of
25 * Gargoyle Software Inc.
26 *
27 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
28 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
29 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GARGOYLE
30 * SOFTWARE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
32 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
33 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
36 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37 */
38 package com.gargoylesoftware.base.util;
39
40 import java.lang.reflect.InvocationHandler;
41 import java.lang.reflect.Method;
42 import java.lang.reflect.Proxy;
43
44 /***
45 * A collection of utility methods dealing with proxy objects
46 *
47 * @version $Revision: 1.4 $
48 * @author <a href="mailto:mbowler@GargoyleSoftware.com">Mike Bowler</a>
49 */
50 public final class ProxyUtil {
51 // Private constructor to prevent instantiation
52 private ProxyUtil() {
53 }
54
55 /***
56 * Create a proxy object that implements the interface specified by 'clazz'.
57 * All methods invoked on this object will return null.
58 *
59 * @param clazz The interface that the proxy will support
60 * @return The new proxy object.
61 */
62 public static Object createProxy( final Class clazz ) {
63 return createProxy( clazz, new Object[0][] );
64 }
65
66
67 /***
68 * Create a proxy object that implements the interface specified by 'clazz'.
69 * Any methods specified in args will return the given result, any methods
70 * not specified here will return null.
71 * <pre>
72 * final Object args[][] = {
73 * {"getAutoCommit", Boolean.TRUE},
74 * {"getCatalog", "foobar"}
75 * };
76 * final Connection connection = ProxyUtil.createProxy(Connection.class, args);
77 * </pre>
78 * Calling getAutoCommit() on this object will return true. Calling getCatalog()
79 * on this object will return "foobar". Calling any other method will return null.
80 *
81 * @param clazz The interface that will be supported by the generated proxy
82 * @param args methodname/object pairs
83 * @return The new proxy object
84 */
85 public static Object createProxy( final Class clazz, final Object args[][] ) {
86 if( clazz == null ) {
87 throw new NullPointerException("clazz");
88 }
89 if( args == null ) {
90 throw new NullPointerException("args");
91 }
92
93 final InvocationHandler handler = new InvocationHandler() {
94 public Object invoke(Object proxy, Method method, Object[] methodArgs) {
95 final String methodName = method.getName();
96
97 int i;
98 for( i=0; i<args.length; i++ ) {
99 if( methodName.equals(args[i][0]) ) {
100 return args[i][1];
101 }
102 }
103
104 if( methodName.equals("toString") ) {
105 return "Proxy["+clazz.getName()+"]";
106 }
107
108 return null;
109 }
110 };
111 return Proxy.newProxyInstance(
112 clazz.getClassLoader(),
113 new Class[] { clazz },
114 handler);
115 }
116 }