KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > javassist > convert > TransformWriteField


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.convert;
17
18 import javassist.CtClass;
19 import javassist.CtField;
20 import javassist.bytecode.*;
21
22 final public class TransformWriteField extends TransformReadField {
23     public TransformWriteField(Transformer next, CtField field,
24                                String JavaDoc methodClassname, String JavaDoc methodName)
25     {
26         super(next, field, methodClassname, methodName);
27     }
28
29     public int transform(CtClass tclazz, int pos, CodeIterator iterator,
30                          ConstPool cp) throws BadBytecode
31     {
32         int c = iterator.byteAt(pos);
33         if (c == PUTFIELD || c == PUTSTATIC) {
34             int index = iterator.u16bitAt(pos + 1);
35             String JavaDoc typedesc = isField(tclazz.getClassPool(), cp,
36                                 fieldClass, fieldname, isPrivate, index);
37             if (typedesc != null) {
38                 if (c == PUTSTATIC) {
39                     CodeAttribute ca = iterator.get();
40                     iterator.move(pos);
41                     char c0 = typedesc.charAt(0);
42                     if (c0 == 'J' || c0 == 'D') { // long or double
43 // insertGap() may insert 4 bytes.
44 iterator.insertGap(3);
45                         iterator.writeByte(ACONST_NULL, pos);
46                         iterator.writeByte(DUP_X2, pos + 1);
47                         iterator.writeByte(POP, pos + 2);
48                         ca.setMaxStack(ca.getMaxStack() + 2);
49                     }
50                     else {
51                         // insertGap() may insert 4 bytes.
52 iterator.insertGap(2);
53                         iterator.writeByte(ACONST_NULL, pos);
54                         iterator.writeByte(SWAP, pos + 1);
55                         ca.setMaxStack(ca.getMaxStack() + 1);
56                     }
57
58                     pos = iterator.next();
59                 }
60
61                 int mi = cp.addClassInfo(methodClassname);
62                 String JavaDoc type = "(Ljava/lang/Object;" + typedesc + ")V";
63                 int methodref = cp.addMethodrefInfo(mi, methodName, type);
64                 iterator.writeByte(INVOKESTATIC, pos);
65                 iterator.write16bit(methodref, pos + 1);
66             }
67         }
68
69         return pos;
70     }
71 }
72
Popular Tags