001 /*
002 $Id: MetaClassRegistry.java,v 1.20 2005/04/13 14:15:26 jstrachan Exp $
003
004 Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
005
006 Redistribution and use of this software and associated documentation
007 ("Software"), with or without modification, are permitted provided
008 that the following conditions are met:
009
010 1. Redistributions of source code must retain copyright
011 statements and notices. Redistributions must also contain a
012 copy of this document.
013
014 2. Redistributions in binary form must reproduce the
015 above copyright notice, this list of conditions and the
016 following disclaimer in the documentation and/or other
017 materials provided with the distribution.
018
019 3. The name "groovy" must not be used to endorse or promote
020 products derived from this Software without prior written
021 permission of The Codehaus. For written permission,
022 please contact info@codehaus.org.
023
024 4. Products derived from this Software may not be called "groovy"
025 nor may "groovy" appear in their names without prior written
026 permission of The Codehaus. "groovy" is a registered
027 trademark of The Codehaus.
028
029 5. Due credit should be given to The Codehaus -
030 http://groovy.codehaus.org/
031
032 THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS
033 ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
034 NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
035 FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
036 THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
037 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
038 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
039 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
040 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
041 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
042 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
043 OF THE POSSIBILITY OF SUCH DAMAGE.
044
045 */
046 package groovy.lang;
047
048 import org.codehaus.groovy.runtime.DefaultGroovyMethods;
049 import org.codehaus.groovy.runtime.DefaultGroovyStaticMethods;
050
051 import java.beans.IntrospectionException;
052 import java.lang.reflect.Constructor;
053 import java.security.AccessController;
054 import java.security.PrivilegedAction;
055 import java.util.ArrayList;
056 import java.util.Collections;
057 import java.util.Iterator;
058 import java.util.List;
059 import java.util.Map;
060 import java.util.WeakHashMap;
061
062 /**
063 * A registery of MetaClass instances which caches introspection &
064 * reflection information and allows methods to be dynamically added to
065 * existing classes at runtime
066 *
067 * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
068 * @version $Revision: 1.20 $
069 */
070 public class MetaClassRegistry {
071 private Map metaClasses = Collections.synchronizedMap(new WeakHashMap());
072 private boolean useAccessible;
073 private Map loaderMap = Collections.synchronizedMap(new WeakHashMap());
074 private GroovyClassLoader loader =
075 (GroovyClassLoader) AccessController.doPrivileged(new PrivilegedAction() {
076 public Object run() {
077 return new GroovyClassLoader(getClass().getClassLoader());
078 }
079 });
080
081 public static final int LOAD_DEFAULT = 0;
082 public static final int DONT_LOAD_DEFAULT = 1;
083 private static MetaClassRegistry instanceInclude;
084 private static MetaClassRegistry instanceExclude;
085
086
087 public MetaClassRegistry() {
088 this(true);
089 }
090
091 public MetaClassRegistry(int loadDefault) {
092 if (loadDefault == LOAD_DEFAULT) {
093 this.useAccessible = true;
094 // lets register the default methods
095 lookup(DefaultGroovyMethods.class).registerInstanceMethods();
096 lookup(DefaultGroovyStaticMethods.class).registerStaticMethods();
097 checkInitialised();
098 }
099 else {
100 this.useAccessible = true;
101 // do nothing to avoid loading DefaultGroovyMethod
102 }
103 }
104
105 /**
106 * @param useAccessible defines whether or not the {@link java.lang.reflect.AccessibleObject.setAccessible();}
107 * method will be called to enable access to all methods when using reflection
108 */
109 public MetaClassRegistry(boolean useAccessible) {
110 this.useAccessible = useAccessible;
111
112 // lets register the default methods
113 lookup(DefaultGroovyMethods.class).registerInstanceMethods();
114 lookup(DefaultGroovyStaticMethods.class).registerStaticMethods();
115 checkInitialised();
116 }
117
118 public MetaClass getMetaClass(Class theClass) {
119 synchronized (theClass) {
120 MetaClass answer = (MetaClass) metaClasses.get(theClass);
121 if (answer == null) {
122 try {
123 answer = new MetaClass(this, theClass);
124 answer.checkInitialised();
125 }
126 catch (IntrospectionException e) {
127 throw new GroovyRuntimeException("Could not introspect class: " + theClass.getName() + ". Reason: " + e,
128 e);
129 }
130 metaClasses.put(theClass, answer);
131 }
132 return answer;
133 }
134 }
135
136 public void removeMetaClass(Class theClass) {
137 metaClasses.remove(theClass);
138 }
139
140
141 /**
142 * Registers a new MetaClass in the registry to customize the type
143 *
144 * @param theClass
145 * @param theMetaClass
146 */
147 public void setMetaClass(Class theClass, MetaClass theMetaClass) {
148 metaClasses.put(theClass, theMetaClass);
149 }
150
151 public boolean useAccessible() {
152 return useAccessible;
153 }
154
155 /**
156 * A helper class to load meta class bytecode into the class loader
157 */
158 public Class loadClass(final String name, final byte[] bytecode) throws ClassNotFoundException {
159 return (Class) AccessController.doPrivileged(new PrivilegedAction() {
160 public Object run() {
161 return getGroovyLoader(loader).defineClass(name, bytecode, getClass().getProtectionDomain());
162 }
163 });
164 }
165
166 public Class loadClass(final ClassLoader loader, final String name, final byte[] bytecode) throws ClassNotFoundException {
167 return (Class) AccessController.doPrivileged(new PrivilegedAction() {
168 public Object run() {
169 return getGroovyLoader(loader).defineClass(name, bytecode, getClass().getProtectionDomain());
170 }
171 });
172 }
173
174 public Class loadClass(ClassLoader loader, String name) throws ClassNotFoundException {
175 return getGroovyLoader(loader).loadClass(name);
176 }
177
178 public Class loadClass(String name) throws ClassNotFoundException {
179 return getGroovyLoader(loader).loadClass(name);
180 }
181
182 private GroovyClassLoader getGroovyLoader(ClassLoader loader) {
183 if (loader instanceof GroovyClassLoader) {
184 return (GroovyClassLoader) loader;
185 }
186
187 synchronized (loaderMap) {
188 GroovyClassLoader groovyLoader = (GroovyClassLoader) loaderMap.get(loader);
189 if (groovyLoader == null) {
190 if (loader == null || loader == getClass().getClassLoader()) {
191 groovyLoader = this.loader;
192 }
193 else {
194 // lets check that the class loader can see the Groovy classes
195 // if so we'll use that, otherwise lets use the local class loader
196 try {
197 loader.loadClass(getClass().getName());
198
199 // thats fine, lets use the loader
200 groovyLoader = new GroovyClassLoader(loader);
201 }
202 catch (ClassNotFoundException e) {
203
204 // we can't see the groovy classes here
205 // so lets try create a new loader
206 ClassLoader localLoader = getClass().getClassLoader();
207 groovyLoader = new GroovyClassLoader(localLoader);
208 }
209 }
210 loaderMap.put(loader, groovyLoader);
211 }
212
213 return groovyLoader;
214 }
215 }
216
217 /**
218 * Ensures that all the registered MetaClass instances are initalized
219 */
220 void checkInitialised() {
221 // lets copy all the classes in the repository right now
222 // to avoid concurrent modification exception
223 List list = new ArrayList(metaClasses.values());
224 for (Iterator iter = list.iterator(); iter.hasNext();) {
225 MetaClass metaClass = (MetaClass) iter.next();
226 metaClass.checkInitialised();
227 }
228 }
229
230 /**
231 * Used by MetaClass when registering new methods which avoids initializing the MetaClass instances on lookup
232 */
233 MetaClass lookup(Class theClass) {
234 MetaClass answer = (MetaClass) metaClasses.get(theClass);
235 if (answer == null) {
236 try {
237 answer = new MetaClass(this, theClass);
238 }
239 catch (IntrospectionException e) {
240 throw new GroovyRuntimeException("Could not introspect class: " + theClass.getName() + ". Reason: " + e,
241 e);
242 }
243 metaClasses.put(theClass, answer);
244 }
245 return answer;
246 }
247
248
249 public MetaMethod getDefinedMethod(Class theClass, String methodName, Class[] args, boolean isStatic) {
250 MetaClass metaclass = this.getMetaClass(theClass);
251 if (metaclass == null) {
252 return null;
253 }
254 else {
255 if (isStatic) {
256 return metaclass.retrieveStaticMethod(methodName, args);
257 }
258 else {
259 return metaclass.retrieveMethod(methodName, args);
260 }
261 }
262 }
263
264 public Constructor getDefinedConstructor(Class theClass, Class[] args) {
265 MetaClass metaclass = this.getMetaClass(theClass);
266 if (metaclass == null) {
267 return null;
268 }
269 else {
270 return metaclass.retrieveConstructor(args);
271 }
272 }
273
274 /**
275 * Singleton of MetaClassRegistry. Shall we use threadlocal to store the instance?
276 *
277 * @param includeExtension
278 * @return
279 */
280 public static MetaClassRegistry getIntance(int includeExtension) {
281 if (includeExtension != DONT_LOAD_DEFAULT) {
282 if (instanceInclude == null) {
283 instanceInclude = new MetaClassRegistry();
284 }
285 return instanceInclude;
286 }
287 else {
288 if (instanceExclude == null) {
289 instanceExclude = new MetaClassRegistry(DONT_LOAD_DEFAULT);
290 }
291 return instanceExclude;
292 }
293 }
294 }