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Java > Open Source Codes > org > springframework > instrument > classloading > glassfish > GlassFishLoadTimeWeaver


1 /*
2  * Copyright 2002-2006 the original author or authors.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16
17 package org.springframework.instrument.classloading.glassfish;
18
19 import java.lang.instrument.ClassFileTransformer JavaDoc;
20
21 import com.sun.enterprise.loader.InstrumentableClassLoader;
22
23 import org.springframework.instrument.classloading.LoadTimeWeaver;
24 import org.springframework.util.Assert;
25 import org.springframework.util.ClassUtils;
26
27 /**
28  * {@link LoadTimeWeaver} implementation for GlassFish's instrumentable ClassLoader.
29  *
30  * @author Costin Leau
31  * @author Juergen Hoeller
32  * @since 2.0.1
33  * @see com.sun.enterprise.loader.InstrumentableClassLoader
34  */
35 public class GlassFishLoadTimeWeaver implements LoadTimeWeaver {
36
37     private final InstrumentableClassLoader classLoader;
38
39
40     public GlassFishLoadTimeWeaver() {
41         this(ClassUtils.getDefaultClassLoader());
42     }
43
44     public GlassFishLoadTimeWeaver(ClassLoader JavaDoc classLoader) {
45         Assert.notNull(classLoader, "ClassLoader must not be null");
46         InstrumentableClassLoader icl = determineClassLoader(classLoader);
47         if (icl == null) {
48             throw new IllegalArgumentException JavaDoc(classLoader + " and its parents are not suitable ClassLoaders: " +
49                     "An [" + InstrumentableClassLoader.class.getName() + "] implementation is required.");
50         }
51         this.classLoader = icl;
52     }
53
54     /**
55      * Determine the GlassFish InstrumentableClassLoader for the given ClassLoader.
56      * @param classLoader the ClassLoader to check
57      * @return the InstrumentableClassLoader, or <code>null</code> if none found
58      */
59     protected InstrumentableClassLoader determineClassLoader(ClassLoader JavaDoc classLoader) {
60         // Detect transformation-aware ClassLoader by traversing the hierarchy
61 // (as in GlassFish, Spring can be loaded by the WebappClassLoader).
62 for (ClassLoader JavaDoc cl = classLoader; cl != null; cl = cl.getParent()) {
63             if (cl instanceof InstrumentableClassLoader) {
64                 return (InstrumentableClassLoader) cl;
65             }
66         }
67         return null;
68     }
69
70
71     public void addTransformer(ClassFileTransformer JavaDoc transformer) {
72         this.classLoader.addTransformer(new ClassTransformerAdapter(transformer));
73     }
74
75     public ClassLoader JavaDoc getInstrumentableClassLoader() {
76         return (ClassLoader JavaDoc) this.classLoader;
77     }
78
79     public ClassLoader JavaDoc getThrowawayClassLoader() {
80         return this.classLoader.copy();
81     }
82
83 }
84
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