001 /* ====================================================================
002 * The Apache Software License, Version 1.1
003 *
004 * Copyright (c) 2003 The Apache Software Foundation. All rights
005 * reserved.
006 *
007 * Redistribution and use in source and binary forms, with or without
008 * modification, are permitted provided that the following conditions
009 * are met:
010 *
011 * 1. Redistributions of source code must retain the above copyright
012 * notice, this list of conditions and the following disclaimer.
013 *
014 * 2. Redistributions in binary form must reproduce the above copyright
015 * notice, this list of conditions and the following disclaimer in
016 * the documentation and/or other materials provided with the
017 * distribution.
018 *
019 * 3. The end-user documentation included with the redistribution,
020 * if any, must include the following acknowledgment:
021 * "This product includes software developed by the
022 * Apache Software Foundation (http://www.apache.org/)."
023 * Alternately, this acknowledgment may appear in the software itself,
024 * if and wherever such third-party acknowledgments normally appear.
025 *
026 * 4. The names "The Jakarta Project", "Commons", and "Apache Software
027 * Foundation" must not be used to endorse or promote products derived
028 * from this software without prior written permission. For written
029 * permission, please contact apache@apache.org.
030 *
031 * 5. Products derived from this software may not be called "Apache",
032 * nor may "Apache" appear in their name, without prior written
033 * permission of the Apache Software Foundation.
034 *
035 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
036 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
037 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
038 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
039 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
040 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
041 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
042 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
043 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
044 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
045 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
046 * SUCH DAMAGE.
047 * ====================================================================
048 *
049 * This software consists of voluntary contributions made by many
050 * individuals on behalf of the Apache Software Foundation. For more
051 * information on the Apache Software Foundation, please see
052 * <http://www.apache.org/>.
053 *
054 */
055 package org.jpu.patterns.proxy;
056
057 import java.lang.reflect.Method;
058 import java.util.ArrayList;
059 import java.util.Iterator;
060 import java.util.List;
061
062 /**
063 * Experimental class; do not use.
064 */
065 public class DelegatingProxy extends JPUInvocationHandler {
066
067 protected boolean doInvoke(Object proxy, Method method, Object[] args, Object[] result) throws Throwable {
068 boolean handled = false;
069 List mappings = new ArrayList();
070 addDelegateMappings(mappings);
071 Iterator it = mappings.iterator();
072 while ( it.hasNext() ) {
073 Mapping mapping = (Mapping)it.next();
074 if ( mapping.declaringClass.equals( method.getDeclaringClass() ) ) {
075 if ( mapping.delegate instanceof Delegator ) {
076 Delegator delegator = (Delegator)mapping.delegate;
077 result[0] = delegator.delegate(proxy, method, args);
078 }
079 else {
080 result[0] = method.invoke( mapping.delegate, args );
081 }
082 handled = true;
083 break;
084 }
085 }
086 return handled;
087 }
088
089 protected static interface Delegator {
090 public Object delegate(Object proxy, Method method, Object[] args) throws Throwable;
091 }
092
093 protected static class Mapping {
094 public Mapping(Class c, Object d) {
095 declaringClass = c;
096 delegate = d;
097 }
098 public Class declaringClass = null;
099 public Object delegate = null;
100 }
101
102 protected void addDelegateMappings(List dest) {
103 dest.add( new Mapping(Object.class, this) );
104 }
105 }
106