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Java > Open Source Codes > javassist > Translator


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 /**
19  * An observer of <code>Loader</code>.
20  * The users can define a class implementing this
21  * interface and attach an instance of that class to a
22  * <code>Loader</code> object so that it can translate a class file
23  * when the class file is loaded into the JVM.
24  *
25  * @see Loader#addTranslator(ClassPool, Translator)
26  */
27 public interface Translator {
28     /**
29      * Is invoked by a <code>Loader</code> for initialization
30      * when the object is attached to the <code>Loader</code> object.
31      * This method can be used for getting (for caching) some
32      * <code>CtClass</code> objects that will be accessed
33      * in <code>onLoad()</code> in <code>Translator</code>.
34      *
35      * @param pool the <code>ClassPool</code> that this translator
36      * should use.
37      * @see Loader
38      * @throws NotFoundException if a <code>CtClass</code> cannot be found.
39      * @throws CannotCompileException if the initialization by this method
40      * fails.
41      */
42     void start(ClassPool pool)
43         throws NotFoundException, CannotCompileException;
44
45     /**
46      * Is invoked by a <code>Loader</code> for notifying that
47      * a class is loaded. The <code>Loader</code> calls
48      *
49      * <ul><pre>
50      * pool.get(classname).toBytecode()</pre></ul>
51      *
52      * to read the class file after <code>onLoad()</code> returns.
53      *
54      * <p><code>classname</code> may be the name of a class
55      * that has not been created yet.
56      * If so, <code>onLoad()</code> must create that class so that
57      * the <code>Loader</code> can read it after <code>onLoad()</code>
58      * returns.
59      *
60      * @param pool the <code>ClassPool</code> that this translator
61      * should use.
62      * @param classname the name of the class being loaded.
63      * @see Loader
64      * @throws NotFoundException if a <code>CtClass</code> cannot be found.
65      * @throws CannotCompileException if the code transformation
66      * by this method fails.
67      */
68     void onLoad(ClassPool pool, String JavaDoc classname)
69         throws NotFoundException, CannotCompileException;
70 }
71
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