1 /*
2 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package com.sun.xml.internal.bind.v2;
27
28 import java.lang.reflect.Constructor;
29 import java.lang.reflect.InvocationTargetException;
30 import java.lang.reflect.Method;
31 import java.lang.reflect.Modifier;
32 import java.lang.ref.WeakReference;
33 import java.security.AccessController;
34 import java.security.PrivilegedAction;
35 import java.util.Map;
36 import java.util.WeakHashMap;
37 import java.util.logging.Level;
38 import java.util.logging.Logger;
39
40 import com.sun.xml.internal.bind.Util;
41
42 /**
43 * Creates new instances of classes.
44 *
45 * <p>
46 * This code handles the case where the class is not public or the constructor is
47 * not public.
48 *
49 * @since 2.0
50 * @author Kohsuke Kawaguchi
51 */
52 public final class ClassFactory {
53 private static final Class[] emptyClass = new Class[0];
54 private static final Object[] emptyObject = new Object[0];
55
56 private static final Logger logger = Util.getClassLogger();
57
58 /**
59 * Cache from a class to its default constructor.
60 *
61 * To avoid synchronization among threads, we use {@link ThreadLocal}.
62 */
63 private static final ThreadLocal<Map<Class, WeakReference<Constructor>>> tls = new ThreadLocal<Map<Class,WeakReference<Constructor>>>() {
64 @Override
65 public Map<Class,WeakReference<Constructor>> initialValue() {
66 return new WeakHashMap<Class,WeakReference<Constructor>>();
67 }
68 };
69
70 public static void cleanCache() {
71 if (tls != null) {
72 try {
73 tls.remove();
74 } catch (Exception e) {
75 logger.log(Level.WARNING, "Unable to clean Thread Local cache of classes used in Unmarshaller: {0}", e.getLocalizedMessage());
76 }
77 }
78 }
79
80 /**
81 * Creates a new instance of the class but throw exceptions without catching it.
82 */
83 public static <T> T create0( final Class<T> clazz ) throws IllegalAccessException, InvocationTargetException, InstantiationException {
84 Map<Class,WeakReference<Constructor>> m = tls.get();
85 Constructor<T> cons = null;
86 WeakReference<Constructor> consRef = m.get(clazz);
87 if(consRef!=null)
88 cons = consRef.get();
89 if(cons==null) {
90 if (System.getSecurityManager() == null) {
91 cons = tryGetDeclaredConstructor(clazz);
92 } else {
93 cons = AccessController.doPrivileged(new PrivilegedAction<Constructor<T>>() {
94 @Override
95 public Constructor<T> run() {
96 return tryGetDeclaredConstructor(clazz);
97 }
98 });
99 }
100
101 int classMod = clazz.getModifiers();
102
103 if(!Modifier.isPublic(classMod) || !Modifier.isPublic(cons.getModifiers())) {
104 // attempt to make it work even if the constructor is not accessible
105 try {
106 cons.setAccessible(true);
107 } catch(SecurityException e) {
108 // but if we don't have a permission to do so, work gracefully.
109 logger.log(Level.FINE,"Unable to make the constructor of "+clazz+" accessible",e);
110 throw e;
111 }
112 }
113
114 m.put(clazz,new WeakReference<Constructor>(cons));
115 }
116
117 return cons.newInstance(emptyObject);
118 }
119
120 private static <T> Constructor<T> tryGetDeclaredConstructor(Class<T> clazz) {
121 try {
122 return clazz.getDeclaredConstructor((Class<T>[])emptyClass);
123 } catch (NoSuchMethodException e) {
124 logger.log(Level.INFO,"No default constructor found on "+clazz,e);
125 NoSuchMethodError exp;
126 if(clazz.getDeclaringClass()!=null && !Modifier.isStatic(clazz.getModifiers())) {
127 exp = new NoSuchMethodError(Messages.NO_DEFAULT_CONSTRUCTOR_IN_INNER_CLASS
128 .format(clazz.getName()));
129 } else {
130 exp = new NoSuchMethodError(e.getMessage());
131 }
132 exp.initCause(e);
133 throw exp;
134 }
135 }
136
137 /**
138 * The same as {@link #create0} but with an error handling to make
139 * the instantiation error fatal.
140 */
141 public static <T> T create( Class<T> clazz ) {
142 try {
143 return create0(clazz);
144 } catch (InstantiationException e) {
145 logger.log(Level.INFO,"failed to create a new instance of "+clazz,e);
146 throw new InstantiationError(e.toString());
147 } catch (IllegalAccessException e) {
148 logger.log(Level.INFO,"failed to create a new instance of "+clazz,e);
149 throw new IllegalAccessError(e.toString());
150 } catch (InvocationTargetException e) {
151 Throwable target = e.getTargetException();
152
153 // most likely an error on the user's code.
154 // just let it through for the ease of debugging
155 if(target instanceof RuntimeException)
156 throw (RuntimeException)target;
157
158 // error. just forward it for the ease of debugging
159 if(target instanceof Error)
160 throw (Error)target;
161
162 // a checked exception.
163 // not sure how we should report this error,
164 // but for now we just forward it by wrapping it into a runtime exception
165 throw new IllegalStateException(target);
166 }
167 }
168
169 /**
170 * Call a method in the factory class to get the object.
171 */
172 public static Object create(Method method) {
173 Throwable errorMsg;
174 try {
175 return method.invoke(null, emptyObject);
176 } catch (InvocationTargetException ive) {
177 Throwable target = ive.getTargetException();
178
179 if(target instanceof RuntimeException)
180 throw (RuntimeException)target;
181
182 if(target instanceof Error)
183 throw (Error)target;
184
185 throw new IllegalStateException(target);
186 } catch (IllegalAccessException e) {
187 logger.log(Level.INFO,"failed to create a new instance of "+method.getReturnType().getName(),e);
188 throw new IllegalAccessError(e.toString());
189 } catch (IllegalArgumentException iae){
190 logger.log(Level.INFO,"failed to create a new instance of "+method.getReturnType().getName(),iae);
191 errorMsg = iae;
192 } catch (NullPointerException npe){
193 logger.log(Level.INFO,"failed to create a new instance of "+method.getReturnType().getName(),npe);
194 errorMsg = npe;
195 } catch (ExceptionInInitializerError eie){
196 logger.log(Level.INFO,"failed to create a new instance of "+method.getReturnType().getName(),eie);
197 errorMsg = eie;
198 }
199
200 NoSuchMethodError exp;
201 exp = new NoSuchMethodError(errorMsg.getMessage());
202 exp.initCause(errorMsg);
203 throw exp;
204 }
205
206 /**
207 * Infers the instanciable implementation class that can be assigned to the given field type.
208 *
209 * @return null
210 * if inference fails.
211 */
212 public static <T> Class<? extends T> inferImplClass(Class<T> fieldType, Class[] knownImplClasses) {
213 if(!fieldType.isInterface())
214 return fieldType;
215
216 for( Class<?> impl : knownImplClasses ) {
217 if(fieldType.isAssignableFrom(impl))
218 return impl.asSubclass(fieldType);
219 }
220
221 // if we can't find an implementation class,
222 // let's just hope that we will never need to create a new object,
223 // and returns null
224 return null;
225 }
226 }