1 /*
2 * reserved comment block
3 * DO NOT REMOVE OR ALTER!
4 */
5 package com.sun.org.apache.bcel.internal.classfile;
6
7 /* ====================================================================
8 * The Apache Software License, Version 1.1
9 *
10 * Copyright (c) 2001 The Apache Software Foundation. All rights
11 * reserved.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 *
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 *
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in
22 * the documentation and/or other materials provided with the
23 * distribution.
24 *
25 * 3. The end-user documentation included with the redistribution,
26 * if any, must include the following acknowledgment:
27 * "This product includes software developed by the
28 * Apache Software Foundation (http://www.apache.org/)."
29 * Alternately, this acknowledgment may appear in the software itself,
30 * if and wherever such third-party acknowledgments normally appear.
31 *
32 * 4. The names "Apache" and "Apache Software Foundation" and
33 * "Apache BCEL" must not be used to endorse or promote products
34 * derived from this software without prior written permission. For
35 * written permission, please contact apache@apache.org.
36 *
37 * 5. Products derived from this software may not be called "Apache",
38 * "Apache BCEL", nor may "Apache" appear in their name, without
39 * prior written permission of the Apache Software Foundation.
40 *
41 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
42 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
43 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
44 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
45 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
46 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
47 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
48 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
49 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
50 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
51 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
52 * SUCH DAMAGE.
53 * ====================================================================
54 *
55 * This software consists of voluntary contributions made by many
56 * individuals on behalf of the Apache Software Foundation. For more
57 * information on the Apache Software Foundation, please see
58 * <http://www.apache.org/>.
59 */
60
61 import com.sun.org.apache.bcel.internal.Constants;
62 import java.io.*;
63
64 /**
65 * This class is derived from <em>Attribute</em> and represents a constant
66 * value, i.e., a default value for initializing a class field.
67 * This class is instantiated by the <em>Attribute.readAttribute()</em> method.
68 *
69 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
70 * @see Attribute
71 */
72 public final class ConstantValue extends Attribute {
73 private int constantvalue_index;
74
75 /**
76 * Initialize from another object. Note that both objects use the same
77 * references (shallow copy). Use clone() for a physical copy.
78 */
79 public ConstantValue(ConstantValue c) {
80 this(c.getNameIndex(), c.getLength(), c.getConstantValueIndex(),
81 c.getConstantPool());
82 }
83
84 /**
85 * Construct object from file stream.
86 * @param name_index Name index in constant pool
87 * @param length Content length in bytes
88 * @param file Input stream
89 * @param constant_pool Array of constants
90 * @throw IOException
91 */
92 ConstantValue(int name_index, int length, DataInputStream file,
93 ConstantPool constant_pool) throws IOException
94 {
95 this(name_index, length, (int)file.readUnsignedShort(), constant_pool);
96 }
97
98 /**
99 * @param name_index Name index in constant pool
100 * @param length Content length in bytes
101 * @param constantvalue_index Index in constant pool
102 * @param constant_pool Array of constants
103 */
104 public ConstantValue(int name_index, int length,
105 int constantvalue_index,
106 ConstantPool constant_pool)
107 {
108 super(Constants.ATTR_CONSTANT_VALUE, name_index, length, constant_pool);
109 this.constantvalue_index = constantvalue_index;
110 }
111
112 /**
113 * Called by objects that are traversing the nodes of the tree implicitely
114 * defined by the contents of a Java class. I.e., the hierarchy of methods,
115 * fields, attributes, etc. spawns a tree of objects.
116 *
117 * @param v Visitor object
118 */
119 public void accept(Visitor v) {
120 v.visitConstantValue(this);
121 }
122 /**
123 * Dump constant value attribute to file stream on binary format.
124 *
125 * @param file Output file stream
126 * @throws IOException
127 */
128 public final void dump(DataOutputStream file) throws IOException
129 {
130 super.dump(file);
131 file.writeShort(constantvalue_index);
132 }
133 /**
134 * @return Index in constant pool of constant value.
135 */
136 public final int getConstantValueIndex() { return constantvalue_index; }
137
138 /**
139 * @param constantvalue_index.
140 */
141 public final void setConstantValueIndex(int constantvalue_index) {
142 this.constantvalue_index = constantvalue_index;
143 }
144
145 /**
146 * @return String representation of constant value.
147 */
148 public final String toString() {
149 Constant c = constant_pool.getConstant(constantvalue_index);
150
151 String buf;
152 int i;
153
154 // Print constant to string depending on its type
155 switch(c.getTag()) {
156 case Constants.CONSTANT_Long: buf = "" + ((ConstantLong)c).getBytes(); break;
157 case Constants.CONSTANT_Float: buf = "" + ((ConstantFloat)c).getBytes(); break;
158 case Constants.CONSTANT_Double: buf = "" + ((ConstantDouble)c).getBytes(); break;
159 case Constants.CONSTANT_Integer: buf = "" + ((ConstantInteger)c).getBytes(); break;
160 case Constants.CONSTANT_String:
161 i = ((ConstantString)c).getStringIndex();
162 c = constant_pool.getConstant(i, Constants.CONSTANT_Utf8);
163 buf = "\"" + Utility.convertString(((ConstantUtf8)c).getBytes()) + "\"";
164 break;
165
166 default:
167 throw new IllegalStateException("Type of ConstValue invalid: " + c);
168 }
169
170 return buf;
171 }
172
173 /**
174 * @return deep copy of this attribute
175 */
176 public Attribute copy(ConstantPool constant_pool) {
177 ConstantValue c = (ConstantValue)clone();
178 c.constant_pool = constant_pool;
179 return c;
180 }
181 }