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1 package org.apache.bcel.classfile; 2 3 /* ==================================================================== 4 * The Apache Software License, Version 1.1 5 * 6 * Copyright (c) 2001 The Apache Software Foundation. All rights 7 * reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * 21 * 3. The end-user documentation included with the redistribution, 22 * if any, must include the following acknowledgment: 23 * "This product includes software developed by the 24 * Apache Software Foundation (http://www.apache.org/)." 25 * Alternately, this acknowledgment may appear in the software itself, 26 * if and wherever such third-party acknowledgments normally appear. 27 * 28 * 4. The names "Apache" and "Apache Software Foundation" and 29 * "Apache BCEL" must not be used to endorse or promote products 30 * derived from this software without prior written permission. For 31 * written permission, please contact apache@apache.org. 32 * 33 * 5. Products derived from this software may not be called "Apache", 34 * "Apache BCEL", nor may "Apache" appear in their name, without 35 * prior written permission of the Apache Software Foundation. 36 * 37 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED 38 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 39 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 40 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR 41 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 42 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 43 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 44 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 45 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 46 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 47 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 48 * SUCH DAMAGE. 49 * ==================================================================== 50 * 51 * This software consists of voluntary contributions made by many 52 * individuals on behalf of the Apache Software Foundation. For more 53 * information on the Apache Software Foundation, please see 54 * <http://www.apache.org/>;. 55 */ 56 57 import org.apache.bcel.Constants; 58 import java.io.*; 59 60 /*** 61 * This class is derived from <em>Attribute</em> and represents a constant 62 * value, i.e., a default value for initializing a class field. 63 * This class is instantiated by the <em>Attribute.readAttribute()</em> method. 64 * 65 * @version $Id: ConstantValue.java,v 1.5 2003/02/13 11:18:23 enver Exp $ 66 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A> 67 * @see Attribute 68 */ 69 public final class ConstantValue extends Attribute { 70 private int constantvalue_index; 71 72 /*** 73 * Initialize from another object. Note that both objects use the same 74 * references (shallow copy). Use clone() for a physical copy. 75 */ 76 public ConstantValue(ConstantValue c) { 77 this(c.getNameIndex(), c.getLength(), c.getConstantValueIndex(), 78 c.getConstantPool()); 79 } 80 81 /*** 82 * Construct object from file stream. 83 * @param name_index Name index in constant pool 84 * @param length Content length in bytes 85 * @param file Input stream 86 * @param constant_pool Array of constants 87 * @throw IOException 88 */ 89 ConstantValue(int name_index, int length, DataInputStream file, 90 ConstantPool constant_pool) throws IOException 91 { 92 this(name_index, length, (int)file.readUnsignedShort(), constant_pool); 93 } 94 95 /*** 96 * @param name_index Name index in constant pool 97 * @param length Content length in bytes 98 * @param constantvalue_index Index in constant pool 99 * @param constant_pool Array of constants 100 */ 101 public ConstantValue(int name_index, int length, 102 int constantvalue_index, 103 ConstantPool constant_pool) 104 { 105 super(Constants.ATTR_CONSTANT_VALUE, name_index, length, constant_pool); 106 this.constantvalue_index = constantvalue_index; 107 } 108 109 /*** 110 * Called by objects that are traversing the nodes of the tree implicitely 111 * defined by the contents of a Java class. I.e., the hierarchy of methods, 112 * fields, attributes, etc. spawns a tree of objects. 113 * 114 * @param v Visitor object 115 */ 116 public void accept(Visitor v) { 117 v.visitConstantValue(this); 118 } 119 /*** 120 * Dump constant value attribute to file stream on binary format. 121 * 122 * @param file Output file stream 123 * @throws IOException 124 */ 125 public final void dump(DataOutputStream file) throws IOException 126 { 127 super.dump(file); 128 file.writeShort(constantvalue_index); 129 } 130 /*** 131 * @return Index in constant pool of constant value. 132 */ 133 public final int getConstantValueIndex() { return constantvalue_index; } 134 135 /*** 136 * @param constantvalue_index. 137 */ 138 public final void setConstantValueIndex(int constantvalue_index) { 139 this.constantvalue_index = constantvalue_index; 140 } 141 142 /*** 143 * @return String representation of constant value. 144 */ 145 public final String toString() { 146 Constant c = constant_pool.getConstant(constantvalue_index); 147 148 String buf; 149 int i; 150 151 // Print constant to string depending on its type 152 switch(c.getTag()) { 153 case Constants.CONSTANT_Long: buf = "" + ((ConstantLong)c).getBytes(); break; 154 case Constants.CONSTANT_Float: buf = "" + ((ConstantFloat)c).getBytes(); break; 155 case Constants.CONSTANT_Double: buf = "" + ((ConstantDouble)c).getBytes(); break; 156 case Constants.CONSTANT_Integer: buf = "" + ((ConstantInteger)c).getBytes(); break; 157 case Constants.CONSTANT_String: 158 i = ((ConstantString)c).getStringIndex(); 159 c = constant_pool.getConstant(i, Constants.CONSTANT_Utf8); 160 buf = "\"" + Utility.convertString(((ConstantUtf8)c).getBytes()) + "\""; 161 break; 162 163 default: 164 throw new IllegalStateException("Type of ConstValue invalid: " + c); 165 } 166 167 return buf; 168 } 169 170 /*** 171 * @return deep copy of this attribute 172 */ 173 public Attribute copy(ConstantPool constant_pool) { 174 ConstantValue c = (ConstantValue)clone(); 175 c.constant_pool = constant_pool; 176 return c; 177 } 178 }

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