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 
16 package javassist.bytecode;
17 
18 import java.io.DataInputStream;
19 import java.util.Map;
20 import java.io.IOException;
21 
22 /**
23  * <code>ConstantValue_attribute</code>.
24  */
25 public class ConstantAttribute extends AttributeInfo {
26     /**
27      * The name of this attribute <code>"ConstantValue"</code>.
28      */
29     public static final String tag = "ConstantValue";
30 
ConstantAttribute(ConstPool cp, int n, DataInputStream in)31     ConstantAttribute(ConstPool cp, int n, DataInputStream in)
32         throws IOException
33     {
34         super(cp, n, in);
35     }
36 
37     /**
38      * Constructs a ConstantValue attribute.
39      *
40      * @param cp                a constant pool table.
41      * @param index             <code>constantvalue_index</code>
42      *                          of <code>ConstantValue_attribute</code>.
43      */
ConstantAttribute(ConstPool cp, int index)44     public ConstantAttribute(ConstPool cp, int index) {
45         super(cp, tag);
46         byte[] bvalue = new byte[2];
47         bvalue[0] = (byte)(index >>> 8);
48         bvalue[1] = (byte)index;
49         set(bvalue);
50     }
51 
52     /**
53      * Returns <code>constantvalue_index</code>.
54      */
getConstantValue()55     public int getConstantValue() {
56         return ByteArray.readU16bit(get(), 0);
57     }
58 
59     /**
60      * Makes a copy.  Class names are replaced according to the
61      * given <code>Map</code> object.
62      *
63      * @param newCp     the constant pool table used by the new copy.
64      * @param classnames        pairs of replaced and substituted
65      *                          class names.
66      */
copy(ConstPool newCp, Map classnames)67     public AttributeInfo copy(ConstPool newCp, Map classnames) {
68         int index = getConstPool().copy(getConstantValue(), newCp,
69                                         classnames);
70         return new ConstantAttribute(newCp, index);
71     }
72 }
73