1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
|
/**
*
* Copyright 2005 The Apache Software Foundation or its licensors, as applicable.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.tuscany.common.resource.impl;
import java.io.IOException;
import java.lang.ref.WeakReference;
import java.net.URL;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import org.apache.tuscany.common.resource.ResourceLoader;
/**
* Default implementation of the ResourceLoader interface.
*
* @version $Rev: 369102 $ $Date: 2006-01-14 13:48:56 -0800 (Sat, 14 Jan 2006) $
*/
public class ResourceLoaderImpl implements ResourceLoader {
private final WeakReference<ClassLoader> classLoaderReference;
private WeakReference<GeneratedClassLoader> generatedClassLoaderReference;
private final List<ResourceLoader> parents;
/**
* A class loader that allows new classes to be defined from an array of bytes
*/
private class GeneratedClassLoader extends ClassLoader {
/**
* Constructs a new ResourceLoaderImpl.GeneratedClassLoader.
*/
public GeneratedClassLoader(ClassLoader classLoader) {
super(classLoader);
}
/**
* Converts an array of bytes into a Class.
* @param bytes
* @return
*/
private Class<?> addClass(byte[] bytes) {
return defineClass(null, bytes, 0, bytes.length);
}
}
/**
* Constructs a new ResourceLoaderImpl.
* @param classLoader
*/
public ResourceLoaderImpl(ClassLoader classLoader) {
classLoaderReference = new WeakReference(classLoader);
generatedClassLoaderReference = new WeakReference(new GeneratedClassLoader(classLoader));
ClassLoader parentCL = classLoader.getParent();
parents = parentCL == null ? Collections.EMPTY_LIST : Collections.singletonList(new ResourceLoaderImpl(parentCL));
}
/**
* Return the classloader backing this resource loader.
*
* @return the classloader that backs this resource loader
* @throws IllegalStateException if the classloader has been garbage collected
*/
//FIXME Temporary used to set the classloader on the thread context, need to changed to private
public ClassLoader getClassLoader() throws IllegalStateException {
ClassLoader cl = classLoaderReference.get();
if (cl == null) {
throw new IllegalStateException("Referenced ClassLoader has been garbage collected");
}
return cl;
}
public List<ResourceLoader> getParents() {
return parents;
}
public Class loadClass(String name) throws ClassNotFoundException {
GeneratedClassLoader cl = generatedClassLoaderReference.get();
if (cl != null) {
return Class.forName(name, true, cl);
} else {
return Class.forName(name, true, getClassLoader());
}
}
public Class<?> addClass(byte[] bytes) {
GeneratedClassLoader cl = generatedClassLoaderReference.get();
if (cl == null) {
cl=new GeneratedClassLoader(getClassLoader());
generatedClassLoaderReference = new WeakReference(cl);
}
return cl.addClass(bytes);
}
public Iterator<URL> getResources(String name) throws IOException {
// This implementation used to cache but users are not likely
// to ask for the same resource multiple times.
// Create a new set, add all the resources visible from the current ClassLoader
Set<URL> set = new HashSet();
ClassLoader classLoader = getClassLoader();
for (Enumeration<URL> e = classLoader.getResources(name); e.hasMoreElements();) {
set.add(e.nextElement());
}
// Remove the resources visible from the parent ClassLoaders
for (ResourceLoader parent : getParents()) {
for (Iterator<URL> i = parent.getAllResources(name); i.hasNext();) {
set.remove(i.next());
}
}
return set.iterator();
}
public Iterator<URL> getAllResources(String name) throws IOException {
return new EnumerationIterator(getClassLoader().getResources(name));
}
public URL getResource(String name) throws IOException {
return getClassLoader().getResource(name);
}
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof ResourceLoaderImpl)) {
return false;
}
final ResourceLoaderImpl other = (ResourceLoaderImpl) obj;
return getClassLoader() == other.getClassLoader();
}
public int hashCode() {
return getClassLoader().hashCode();
}
private static class EnumerationIterator<E> implements Iterator<E> {
private final Enumeration<E> e;
public EnumerationIterator(Enumeration<E> e) {
this.e = e;
}
public boolean hasNext() {
return e.hasMoreElements();
}
public E next() {
return e.nextElement();
}
public void remove() {
throw new UnsupportedOperationException();
}
}
}
|
