01: /*
02: * Javassist, a Java-bytecode translator toolkit.
03: * Copyright (C) 1999-2006 Shigeru Chiba. All Rights Reserved.
04: *
05: * The contents of this file are subject to the Mozilla Public License Version
06: * 1.1 (the "License"); you may not use this file except in compliance with
07: * the License. Alternatively, the contents of this file may be used under
08: * the terms of the GNU Lesser General Public License Version 2.1 or later.
09: *
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) throws NotFoundException,
43: 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 classname)
69: throws NotFoundException, CannotCompileException;
70: }
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