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    }