1 /*
2 * The Apache Software License, Version 1.1
3 *
4 * Copyright (c) 2002 The Apache Software Foundation. All rights
5 * reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 *
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in
16 * the documentation and/or other materials provided with the
17 * distribution.
18 *
19 * 3. The end-user documentation included with the redistribution,
20 * if any, must include the following acknowledgment:
21 * "This product includes software developed by the
22 * Apache Software Foundation (http://www.apache.org/)."
23 * Alternately, this acknowledgment may appear in the software itself,
24 * if and wherever such third-party acknowledgments normally appear.
25 *
26 * 4. The names "Apache" and "Apache Software Foundation" must
27 * not be used to endorse or promote products derived from this
28 * software without prior written permission. For written
29 * permission, please contact apache@apache.org.
30 *
31 * 5. Products derived from this software may not be called "Apache",
32 * nor may "Apache" appear in their name, without prior written
33 * permission of the Apache Software Foundation.
34 *
35 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
36 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
37 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
38 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
39 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
41 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
42 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
43 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
44 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
45 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46 * SUCH DAMAGE.
47 * ====================================================================
48 *
49 * This software consists of voluntary contributions made by many
50 * individuals on behalf of the Apache Software Foundation. For more
51 * information on the Apache Software Foundation, please see
52 * <http://www.apache.org/>;.
53 */
54 package net.sf.cglib.proxy;
55
56 import java.lang.reflect.Constructor;
57 import java.lang.reflect.Modifier;
58 import java.util.*;
59 import net.sf.cglib.core.*;
60 import org.objectweb.asm.ClassVisitor;
61
62 /***
63 * <code>Mixin</code> allows
64 * multiple objects to be combined into a single larger object. The
65 * methods in the generated object simply call the original methods in the
66 * underlying "delegate" objects.
67 * @author Chris Nokleberg
68 * @version $Id: Mixin.java,v 1.4 2004/01/25 22:28:02 herbyderby Exp $
69 */
70 abstract public class Mixin {
71 private static final MixinKey KEY_FACTORY =
72 (MixinKey)KeyFactory.create(MixinKey.class, KeyFactory.CLASS_BY_NAME);
73 private static final Map ROUTE_CACHE = Collections.synchronizedMap(new HashMap());
74
75 public static final int STYLE_INTERFACES = 0;
76 public static final int STYLE_BEANS = 1;
77 public static final int STYLE_EVERYTHING = 2;
78
79 interface MixinKey {
80 public Object newInstance(int style, Class[] classes, int[] route);
81 }
82
83 abstract public Mixin newInstance(Object[] delegates);
84
85 /***
86 * Helper method to create an interface mixin. For finer control over the
87 * generated instance, use a new instance of <code>Mixin</code>
88 * instead of this static method.
89 * TODO
90 */
91 public static Mixin create(Object[] delegates) {
92 Generator gen = new Generator();
93 gen.setDelegates(delegates);
94 return gen.create();
95 }
96
97 /***
98 * Helper method to create an interface mixin. For finer control over the
99 * generated instance, use a new instance of <code>Mixin</code>
100 * instead of this static method.
101 * TODO
102 */
103 public static Mixin create(Class[] interfaces, Object[] delegates) {
104 Generator gen = new Generator();
105 gen.setClasses(interfaces);
106 gen.setDelegates(delegates);
107 return gen.create();
108 }
109
110 /***
111 * Helper method to create a bean mixin. For finer control over the
112 * generated instance, use a new instance of <code>Mixin</code>
113 * instead of this static method.
114 * TODO
115 */
116 public static Mixin createBean(Object[] beans) {
117 Generator gen = new Generator();
118 gen.setStyle(STYLE_BEANS);
119 gen.setDelegates(beans);
120 return gen.create();
121 }
122
123 public static class Generator extends AbstractClassGenerator {
124 private static final Source SOURCE = new Source(Mixin.class.getName());
125
126 private Class[] classes;
127 private Object[] delegates;
128 private int style = STYLE_INTERFACES;
129
130 private int[] route;
131
132 public Generator() {
133 super(SOURCE);
134 }
135
136 protected ClassLoader getDefaultClassLoader() {
137 return classes[0].getClassLoader(); // is this right?
138 }
139
140 public void setStyle(int style) {
141 switch (style) {
142 case STYLE_INTERFACES:
143 case STYLE_BEANS:
144 case STYLE_EVERYTHING:
145 this.style = style;
146 break;
147 default:
148 throw new IllegalArgumentException("Unknown mixin style: " + style);
149 }
150 }
151
152 public void setClasses(Class[] classes) {
153 this.classes = classes;
154 }
155
156 public void setDelegates(Object[] delegates) {
157 this.delegates = delegates;
158 }
159
160 public Mixin create() {
161 if (classes == null && delegates == null) {
162 throw new IllegalStateException("Either classes or delegates must be set");
163 }
164 switch (style) {
165 case STYLE_INTERFACES:
166 if (classes == null) {
167 Route r = route(delegates);
168 classes = r.classes;
169 route = r.route;
170 }
171 break;
172 case STYLE_BEANS:
173 // fall-through
174 case STYLE_EVERYTHING:
175 if (classes == null) {
176 classes = ReflectUtils.getClasses(delegates);
177 } else {
178 if (delegates != null) {
179 Class[] temp = ReflectUtils.getClasses(delegates);
180 if (classes.length != temp.length) {
181 throw new IllegalStateException("Specified classes are incompatible with delegates");
182 }
183 for (int i = 0; i < classes.length; i++) {
184 if (!classes[i].isAssignableFrom(temp[i])) {
185 throw new IllegalStateException("Specified class " + classes[i] + " is incompatible with delegate class " + temp[i] + " (index " + i + ")");
186 }
187 }
188 }
189 }
190 }
191 setNamePrefix(classes[ReflectUtils.findPackageProtected(classes)].getName());
192 return (Mixin)super.create(KEY_FACTORY.newInstance(style, classes, route));
193 }
194
195 public void generateClass(ClassVisitor v) {
196 switch (style) {
197 case STYLE_INTERFACES:
198 new MixinEmitter(v, getClassName(), classes, route);
199 break;
200 case STYLE_BEANS:
201 new MixinBeanEmitter(v, getClassName(), classes);
202 break;
203 case STYLE_EVERYTHING:
204 new MixinEverythingEmitter(v, getClassName(), classes);
205 break;
206 }
207 }
208
209 protected Object firstInstance(Class type) {
210 return ((Mixin)ReflectUtils.newInstance(type)).newInstance(delegates);
211 }
212
213 protected Object nextInstance(Object instance) {
214 return ((Mixin)instance).newInstance(delegates);
215 }
216 }
217
218 public static Class[] getClasses(Object[] delegates) {
219 return (Class[])route(delegates).classes.clone();
220 }
221
222 // public static int[] getRoute(Object[] delegates) {
223 // return (int[])route(delegates).route.clone();
224 // }
225
226 private static Route route(Object[] delegates) {
227 Object key = ClassesKey.create(delegates);
228 Route route = (Route)ROUTE_CACHE.get(key);
229 if (route == null) {
230 ROUTE_CACHE.put(key, route = new Route(delegates));
231 }
232 return route;
233 }
234
235 private static class Route
236 {
237 private Class[] classes;
238 private int[] route;
239
240 Route(Object[] delegates) {
241 Map map = new HashMap();
242 ArrayList collect = new ArrayList();
243 for (int i = 0; i < delegates.length; i++) {
244 Class delegate = delegates[i].getClass();
245 collect.clear();
246 ReflectUtils.addAllInterfaces(delegate, collect);
247 for (Iterator it = collect.iterator(); it.hasNext();) {
248 Class iface = (Class)it.next();
249 if (!map.containsKey(iface)) {
250 map.put(iface, new Integer(i));
251 }
252 }
253 }
254 classes = new Class[map.size()];
255 route = new int[map.size()];
256 int index = 0;
257 for (Iterator it = map.keySet().iterator(); it.hasNext();) {
258 Class key = (Class)it.next();
259 classes[index] = key;
260 route[index] = ((Integer)map.get(key)).intValue();
261 index++;
262 }
263 }
264 }
265 }
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