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Java > Open Source Codes > javassist > ClassClassPath


1 /*
2  * Javassist, a Java-bytecode translator toolkit.
3  * Copyright (C) 1999-2005 Shigeru Chiba. All Rights Reserved.
4  *
5  * The contents of this file are subject to the Mozilla Public License Version
6  * 1.1 (the "License"); you may not use this file except in compliance with
7  * the License. Alternatively, the contents of this file may be used under
8  * the terms of the GNU Lesser General Public License Version 2.1 or later.
9  *
10  * Software distributed under the License is distributed on an "AS IS" basis,
11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12  * for the specific language governing rights and limitations under the
13  * License.
14  */
15
16 package javassist;
17
18 import java.io.InputStream JavaDoc;
19 import java.net.URL JavaDoc;
20
21 /**
22  * A search-path for obtaining a class file
23  * by <code>getResourceAsStream()</code> in <code>java.lang.Class</code>.
24  *
25  * <p>Try adding a <code>ClassClassPath</code> when a program is running
26  * with a user-defined class loader and any class files are not found with
27  * the default <code>ClassPool</code>. For example,
28  *
29  * <ul><pre>
30  * ClassPool cp = ClassPool.getDefault();
31  * cp.insertClassPath(new ClassClassPath(this.getClass()));
32  * </pre></ul>
33  *
34  * This code snippet permanently adds a <code>ClassClassPath</code>
35  * to the default <code>ClassPool</code>. Note that the default
36  * <code>ClassPool</code> is a singleton. The added
37  * <code>ClassClassPath</code> uses a class object representing
38  * the class including the code snippet above.
39  *
40  * @see ClassPool#insertClassPath(ClassPath)
41  * @see ClassPool#appendClassPath(ClassPath)
42  * @see LoaderClassPath
43  */
44 public class ClassClassPath implements ClassPath {
45     private Class JavaDoc thisClass;
46
47     /** Creates a search path.
48      *
49      * @param c the <code>Class</code> object used to obtain a class
50      * file. <code>getResourceAsStream()</code> is called on
51      * this object.
52      */
53     public ClassClassPath(Class JavaDoc c) {
54         thisClass = c;
55     }
56
57     ClassClassPath() {
58         /* The value of thisClass was this.getClass() in early versions:
59          *
60          * thisClass = this.getClass();
61          *
62          * However, this made openClassfile() not search all the system
63          * class paths if javassist.jar is put in jre/lib/ext/
64          * (with JDK1.4).
65          */
66         this(java.lang.Object JavaDoc.class);
67     }
68
69     /**
70      * Obtains a class file by <code>getResourceAsStream()</code>.
71      */
72     public InputStream JavaDoc openClassfile(String JavaDoc classname) {
73         String JavaDoc jarname = "/" + classname.replace('.', '/') + ".class";
74         return thisClass.getResourceAsStream(jarname);
75     }
76
77     /**
78      * Obtains the URL of the specified class file.
79      *
80      * @return null if the class file could not be found.
81      */
82     public URL JavaDoc find(String JavaDoc classname) {
83         String JavaDoc jarname = "/" + classname.replace('.', '/') + ".class";
84         return thisClass.getResource(jarname);
85     }
86
87     /**
88      * Does nothing.
89      */
90     public void close() {
91     }
92
93     public String JavaDoc toString() {
94         return thisClass.getName() + ".class";
95     }
96 }
97
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