001 /*
002 $Id: MetaClassRegistry.java,v 1.26 2005/10/21 09:03:03 tug 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 java.beans.IntrospectionException;
049 import java.lang.reflect.Constructor;
050 import java.lang.reflect.Method;
051 import java.security.AccessController;
052 import java.security.PrivilegedAction;
053 import java.util.ArrayList;
054 import java.util.Collections;
055 import java.util.Iterator;
056 import java.util.List;
057 import java.util.Map;
058 import java.util.WeakHashMap;
059
060 import org.codehaus.groovy.runtime.DefaultGroovyMethods;
061 import org.codehaus.groovy.runtime.DefaultGroovyStaticMethods;
062 import org.codehaus.groovy.runtime.MethodHelper;
063
064 /**
065 * A registery of MetaClass instances which caches introspection &
066 * reflection information and allows methods to be dynamically added to
067 * existing classes at runtime
068 *
069 * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
070 * @version $Revision: 1.26 $
071 */
072 /**
073 * @author John Wilson
074 *
075 */
076 public class MetaClassRegistry {
077 private Map metaClasses = Collections.synchronizedMap(new WeakHashMap());
078 private boolean useAccessible;
079 private Map loaderMap = Collections.synchronizedMap(new WeakHashMap());
080 private GroovyClassLoader loader =
081 (GroovyClassLoader) AccessController.doPrivileged(new PrivilegedAction() {
082 public Object run() {
083 return new GroovyClassLoader(getClass().getClassLoader());
084 }
085 });
086
087 public static final int LOAD_DEFAULT = 0;
088 public static final int DONT_LOAD_DEFAULT = 1;
089 private static MetaClassRegistry instanceInclude;
090 private static MetaClassRegistry instanceExclude;
091
092
093 public MetaClassRegistry() {
094 this(LOAD_DEFAULT, true);
095 }
096
097 public MetaClassRegistry(int loadDefault) {
098 this(loadDefault, true);
099 }
100
101 /**
102 * @param useAccessible defines whether or not the {@link java.lang.reflect.AccessibleObject.setAccessible();}
103 * method will be called to enable access to all methods when using reflection
104 */
105 public MetaClassRegistry(boolean useAccessible) {
106 this(LOAD_DEFAULT, useAccessible);
107 }
108
109 public MetaClassRegistry(final int loadDefault, final boolean useAccessible) {
110 this.useAccessible = useAccessible;
111
112 if (loadDefault == LOAD_DEFAULT) {
113 // lets register the default methods
114 lookup(DefaultGroovyMethods.class);
115 registerMethods(DefaultGroovyMethods.class, true);
116 lookup(DefaultGroovyStaticMethods.class);
117 registerMethods(DefaultGroovyStaticMethods.class, false);
118 checkInitialised();
119 }
120 }
121
122 private void registerMethods(final Class theClass, final boolean instanceMethods) {
123 Method[] methods = theClass.getMethods();
124 for (int i = 0; i < methods.length; i++) {
125 Method method = methods[i];
126 if (MethodHelper.isStatic(method)) {
127 Class[] paramTypes = method.getParameterTypes();
128 if (paramTypes.length > 0) {
129 Class owner = paramTypes[0];
130 if (instanceMethods) {
131 lookup(owner).addNewInstanceMethod(method);
132 } else {
133 lookup(owner).addNewStaticMethod(method);
134 }
135 }
136 }
137 }
138 }
139
140 public MetaClass getMetaClass(Class theClass) {
141 synchronized (theClass) {
142 MetaClass answer = (MetaClass) metaClasses.get(theClass);
143 if (answer == null) {
144 answer = getMetaClassFor(theClass);
145 answer.checkInitialised();
146 metaClasses.put(theClass, answer);
147 }
148 return answer;
149 }
150 }
151
152 public void removeMetaClass(Class theClass) {
153 metaClasses.remove(theClass);
154 }
155
156
157 /**
158 * Registers a new MetaClass in the registry to customize the type
159 *
160 * @param theClass
161 * @param theMetaClass
162 */
163 public void setMetaClass(Class theClass, MetaClass theMetaClass) {
164 metaClasses.put(theClass, theMetaClass);
165 }
166
167 public boolean useAccessible() {
168 return useAccessible;
169 }
170
171 /**
172 * A helper class to load meta class bytecode into the class loader
173 */
174 public Class loadClass(final String name, final byte[] bytecode) throws ClassNotFoundException {
175 return (Class) AccessController.doPrivileged(new PrivilegedAction() {
176 public Object run() {
177 return getGroovyLoader(loader).defineClass(name, bytecode, getClass().getProtectionDomain());
178 }
179 });
180 }
181
182 public Class loadClass(final ClassLoader loader, final String name, final byte[] bytecode) throws ClassNotFoundException {
183 return (Class) AccessController.doPrivileged(new PrivilegedAction() {
184 public Object run() {
185 return getGroovyLoader(loader).defineClass(name, bytecode, getClass().getProtectionDomain());
186 }
187 });
188 }
189
190 public Class loadClass(ClassLoader loader, String name) throws ClassNotFoundException {
191 return getGroovyLoader(loader).loadClass(name);
192 }
193
194 public Class loadClass(String name) throws ClassNotFoundException {
195 return getGroovyLoader(loader).loadClass(name);
196 }
197
198 private GroovyClassLoader getGroovyLoader(ClassLoader loader) {
199 if (loader instanceof GroovyClassLoader) {
200 return (GroovyClassLoader) loader;
201 }
202
203 synchronized (loaderMap) {
204 GroovyClassLoader groovyLoader = (GroovyClassLoader) loaderMap.get(loader);
205 if (groovyLoader == null) {
206 if (loader == null || loader == getClass().getClassLoader()) {
207 groovyLoader = this.loader;
208 }
209 else {
210 // lets check that the class loader can see the Groovy classes
211 // if so we'll use that, otherwise lets use the local class loader
212 try {
213 loader.loadClass(getClass().getName());
214
215 // thats fine, lets use the loader
216 groovyLoader = new GroovyClassLoader(loader);
217 }
218 catch (ClassNotFoundException e) {
219
220 // we can't see the groovy classes here
221 // so lets try create a new loader
222 final ClassLoader localLoader = getClass().getClassLoader();
223 groovyLoader = (GroovyClassLoader) AccessController.doPrivileged(new PrivilegedAction() {
224 public Object run() {
225 return new GroovyClassLoader(localLoader);
226 }
227 });
228 }
229 }
230 loaderMap.put(loader, groovyLoader);
231 }
232
233 return groovyLoader;
234 }
235 }
236
237 /**
238 * Ensures that all the registered MetaClass instances are initalized
239 */
240 void checkInitialised() {
241 // lets copy all the classes in the repository right now
242 // to avoid concurrent modification exception
243 List list = new ArrayList(metaClasses.values());
244 for (Iterator iter = list.iterator(); iter.hasNext();) {
245 MetaClass metaClass = (MetaClass) iter.next();
246 metaClass.checkInitialised();
247 }
248 }
249
250 /**
251 * Used by MetaClass when registering new methods which avoids initializing the MetaClass instances on lookup
252 */
253 MetaClass lookup(Class theClass) {
254 MetaClass answer = (MetaClass) metaClasses.get(theClass);
255 if (answer == null) {
256 answer = getMetaClassFor(theClass);
257 metaClasses.put(theClass, answer);
258 }
259 return answer;
260 }
261
262 /**
263 * Find a MetaClass for the class
264 * If there is a custom MetaClass then return an instance of that. Otherwise return an instance of the standard MetaClass
265 *
266 * @param theClass
267 * @return An instace of the MetaClass which will handle this class
268 */
269 private MetaClass getMetaClassFor(final Class theClass) {
270 try {
271 final Class customMetaClass = Class.forName("groovy.runtime.metaclass." + theClass.getName() + "MetaClass");
272 final Constructor customMetaClassConstructor = customMetaClass.getConstructor(new Class[]{MetaClassRegistry.class, Class.class});
273
274 return (MetaClass)customMetaClassConstructor.newInstance(new Object[]{this, theClass});
275 } catch (final ClassNotFoundException e) {
276 try {
277 return new MetaClassImpl(this, theClass);
278 } catch (final IntrospectionException e1) {
279 throw new GroovyRuntimeException("Could not introspect class: " + theClass.getName() + ". Reason: " + e1, e1);
280 }
281 } catch (final Exception e) {
282 throw new GroovyRuntimeException("Could not instantiate custom Metaclass for class: " + theClass.getName() + ". Reason: " + e, e);
283 }
284 }
285
286 public MetaMethod getDefinedMethod(Class theClass, String methodName, Class[] args, boolean isStatic) {
287 MetaClass metaclass = this.getMetaClass(theClass);
288 if (metaclass == null) {
289 return null;
290 }
291 else {
292 if (isStatic) {
293 return metaclass.retrieveStaticMethod(methodName, args);
294 }
295 else {
296 return metaclass.retrieveMethod(methodName, args);
297 }
298 }
299 }
300
301 public Constructor getDefinedConstructor(Class theClass, Class[] args) {
302 MetaClass metaclass = this.getMetaClass(theClass);
303 if (metaclass == null) {
304 return null;
305 }
306 else {
307 return metaclass.retrieveConstructor(args);
308 }
309 }
310
311 /**
312 * Singleton of MetaClassRegistry. Shall we use threadlocal to store the instance?
313 *
314 * @param includeExtension
315 * @return
316 */
317 public static MetaClassRegistry getIntance(int includeExtension) {
318 if (includeExtension != DONT_LOAD_DEFAULT) {
319 if (instanceInclude == null) {
320 instanceInclude = new MetaClassRegistry();
321 }
322 return instanceInclude;
323 }
324 else {
325 if (instanceExclude == null) {
326 instanceExclude = new MetaClassRegistry(DONT_LOAD_DEFAULT);
327 }
328 return instanceExclude;
329 }
330 }
331 }