1/*
2 * Javassist, a Java-bytecode translator toolkit.
3 * Copyright (C) 1999-2007 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
16package javassist.convert;
17
18import javassist.CannotCompileException;
19import javassist.CtClass;
20import javassist.bytecode.BadBytecode;
21import javassist.bytecode.CodeAttribute;
22import javassist.bytecode.CodeIterator;
23import javassist.bytecode.ConstPool;
24import javassist.bytecode.MethodInfo;
25import javassist.bytecode.Opcode;
26
27/**
28 * Transformer and its subclasses are used for executing
29 * code transformation specified by CodeConverter.
30 *
31 * @see javassist.CodeConverter
32 */
33public abstract class Transformer implements Opcode {
34    private Transformer next;
35
36    public Transformer(Transformer t) {
37        next = t;
38    }
39
40    public Transformer getNext() { return next; }
41
42    public void initialize(ConstPool cp, CodeAttribute attr) {}
43
44    public void initialize(ConstPool cp, CtClass clazz, MethodInfo minfo) throws CannotCompileException {
45    	initialize(cp, minfo.getCodeAttribute());
46    }
47
48    public void clean() {}
49
50    public abstract int transform(CtClass clazz, int pos, CodeIterator it,
51                ConstPool cp) throws CannotCompileException, BadBytecode;
52
53    public int extraLocals() { return 0; }
54
55    public int extraStack() { return 0; }
56}
57