001 /*
002 * $Id: GroovyCategorySupport.java,v 1.7 2005/06/19 19:01:25 spullara Exp $version Apr 26, 2004 4:22:50 PM $user Exp $
003 *
004 * Copyright 2003 (C) Sam Pullara. All Rights Reserved.
005 *
006 * Redistribution and use of this software and associated documentation
007 * ("Software"), with or without modification, are permitted provided that the
008 * following conditions are met: 1. Redistributions of source code must retain
009 * copyright statements and notices. Redistributions must also contain a copy
010 * of this document. 2. Redistributions in binary form must reproduce the above
011 * copyright notice, this list of conditions and the following disclaimer in
012 * the documentation and/or other materials provided with the distribution. 3.
013 * The name "groovy" must not be used to endorse or promote products derived
014 * from this Software without prior written permission of The Codehaus. For
015 * written permission, please contact info@codehaus.org. 4. Products derived
016 * from this Software may not be called "groovy" nor may "groovy" appear in
017 * their names without prior written permission of The Codehaus. "groovy" is a
018 * registered trademark of The Codehaus. 5. Due credit should be given to The
019 * Codehaus - http://groovy.codehaus.org/
020 *
021 * THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS ``AS IS'' AND ANY
022 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
023 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
024 * DISCLAIMED. IN NO EVENT SHALL THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR
025 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
026 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
027 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
028 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
029 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
030 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
031 * DAMAGE.
032 *
033 */
034 package org.codehaus.groovy.runtime;
035
036 import groovy.lang.Closure;
037 import groovy.lang.MetaMethod;
038
039 import java.lang.reflect.Method;
040 import java.lang.reflect.Modifier;
041 import java.util.ArrayList;
042 import java.util.Collections;
043 import java.util.HashMap;
044 import java.util.Iterator;
045 import java.util.List;
046 import java.util.Map;
047 import java.util.WeakHashMap;
048
049
050 /**
051 * @author sam
052 */
053 public class GroovyCategorySupport {
054
055 /**
056 * This method is used to pull all the new methods out of the local thread context with a particular name.
057 *
058 * @param categorizedClass
059 * @param name
060 * @return
061 */
062 public static List getCategoryMethods(Class categorizedClass, String name) {
063 Map properties = getProperties();
064 List methodList = new ArrayList();
065 for (Iterator i = properties.keySet().iterator(); i.hasNext(); ) {
066 Class current = (Class) i.next();
067 if (current.isAssignableFrom(categorizedClass)) {
068 Map metaMethodsMap = (Map) properties.get(current);
069 List newMethodList = (List) metaMethodsMap.get(name);
070 if (newMethodList != null) {
071 methodList.addAll(newMethodList);
072 }
073 }
074 }
075 if (methodList.size() == 0) return null;
076 return methodList;
077 }
078
079 private static class CategoryMethod extends NewInstanceMetaMethod implements Comparable {
080 private Class metaClass;
081
082 public CategoryMethod(MetaMethod metaMethod, Class metaClass) {
083 super(metaMethod);
084 this.metaClass = metaClass;
085 }
086
087 public boolean isCacheable() { return false; }
088
089 /**
090 * Sort by most specific to least specific.
091 * @param o
092 * @return
093 */
094 public int compareTo(Object o) {
095 CategoryMethod thatMethod = (CategoryMethod) o;
096 Class thisClass = metaClass;
097 Class thatClass = thatMethod.metaClass;
098 if (thisClass == thatClass) return 0;
099 Class loop = thisClass;
100 while(loop != Object.class) {
101 loop = thisClass.getSuperclass();
102 if (loop == thatClass) {
103 return -1;
104 }
105 }
106 loop = thatClass;
107 while (loop != Object.class) {
108 loop = thatClass.getSuperclass();
109 if (loop == thisClass) {
110 return 1;
111 }
112 }
113 return 0;
114 }
115 }
116
117 /**
118 * This method is delegated to from the global use(CategoryClass) method. It scans the Category class for static methods
119 * that take 1 or more parameters. The first parameter is the class you are adding the category method to, additional parameters
120 * are those paramteres needed by that method. A use statement cannot be undone and is valid only for the current thread.
121 *
122 * @param categoryClass
123 */
124 private static void use(Class categoryClass) {
125 Map properties = getProperties();
126 Method[] methods = categoryClass.getMethods();
127 for (int i = 0; i < methods.length; i++) {
128 Method method = methods[i];
129 if (Modifier.isStatic(method.getModifiers())) {
130 Class[] paramTypes = method.getParameterTypes();
131 if (paramTypes.length > 0) {
132 Class metaClass = paramTypes[0];
133 Map metaMethodsMap = getMetaMethods(properties, metaClass);
134 List methodList = getMethodList(metaMethodsMap, method.getName());
135 MetaMethod mmethod = new CategoryMethod(new MetaMethod(method), metaClass);
136 methodList.add(mmethod);
137 Collections.sort(methodList);
138 }
139 }
140 }
141 }
142
143 /**
144 * @param clazz
145 * @param closure
146 */
147 public static void use(Class clazz, Closure closure) {
148 newScope();
149 try {
150 use(clazz);
151 closure.call();
152 } finally {
153 endScope();
154 }
155 }
156
157 /**
158 * @param classes
159 * @param closure
160 */
161 public static void use(List classes, Closure closure) {
162 newScope();
163 try {
164 for (Iterator i = classes.iterator(); i.hasNext(); ) {
165 Class clazz = (Class) i.next();
166 use(clazz);
167 }
168 closure.call();
169 } finally {
170 endScope();
171 }
172 }
173
174 private static ThreadLocal local = new ThreadLocal() {
175 protected Object initialValue() {
176 List stack = new ArrayList();
177 stack.add(Collections.EMPTY_MAP);
178 return stack;
179 }
180 };
181
182 private static void newScope() {
183 List stack = (List) local.get();
184 Map properties = new WeakHashMap(getProperties());
185 stack.add(properties);
186 }
187
188 private static void endScope() {
189 List stack = (List) local.get();
190 stack.remove(stack.size() - 1);
191 }
192
193 private static Map getProperties() {
194 List stack = (List) local.get();
195 Map properties = (Map) stack.get(stack.size() - 1);
196 return properties;
197 }
198
199 /**
200 * @param method
201 * @param metaMethodsMap
202 * @return
203 */
204 private static List getMethodList(Map metaMethodsMap, String name) {
205 List methodList = (List) metaMethodsMap.get(name);
206 if (methodList == null) {
207 methodList = new ArrayList(1);
208 metaMethodsMap.put(name, methodList);
209 }
210 return methodList;
211 }
212
213 /**
214 * @param properties
215 * @param metaClass
216 * @return
217 */
218 private static Map getMetaMethods(Map properties, Class metaClass) {
219 Map metaMethodsMap = (Map) properties.get(metaClass);
220 if (metaMethodsMap == null) {
221 metaMethodsMap = new HashMap();
222 properties.put(metaClass, metaMethodsMap);
223 }
224 return metaMethodsMap;
225 }
226
227 }