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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 the abstract 62 * <A HREF="org.apache.bcel.classfile.Constant.html">Constant</A> class 63 * and represents a reference to a String object. 64 * 65 * @version $Id: ConstantString.java,v 1.2 2002/03/11 16:16:35 mdahm Exp $ 66 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A> 67 * @see Constant 68 */ 69 public final class ConstantString extends Constant implements ConstantObject { 70 private int string_index; // Identical to ConstantClass except for this name 71 72 /*** 73 * Initialize from another object. 74 */ 75 public ConstantString(ConstantString c) { 76 this(c.getStringIndex()); 77 } 78 /*** 79 * Initialize instance from file data. 80 * 81 * @param file Input stream 82 * @throws IOException 83 */ 84 ConstantString(DataInputStream file) throws IOException 85 { 86 this((int)file.readUnsignedShort()); 87 } 88 /*** 89 * @param string_index Index of Constant_Utf8 in constant pool 90 */ 91 public ConstantString(int string_index) 92 { 93 super(Constants.CONSTANT_String); 94 this.string_index = string_index; 95 } 96 /*** 97 * Called by objects that are traversing the nodes of the tree implicitely 98 * defined by the contents of a Java class. I.e., the hierarchy of methods, 99 * fields, attributes, etc. spawns a tree of objects. 100 * 101 * @param v Visitor object 102 */ 103 public void accept(Visitor v) { 104 v.visitConstantString(this); 105 } 106 /*** 107 * Dump constant field reference to file stream in binary format. 108 * 109 * @param file Output file stream 110 * @throws IOException 111 */ 112 public final void dump(DataOutputStream file) throws IOException 113 { 114 file.writeByte(tag); 115 file.writeShort(string_index); 116 } 117 /*** 118 * @return Index in constant pool of the string (ConstantUtf8). 119 */ 120 public final int getStringIndex() { return string_index; } 121 /*** 122 * @param string_index. 123 */ 124 public final void setStringIndex(int string_index) { 125 this.string_index = string_index; 126 } 127 /*** 128 * @return String representation. 129 */ 130 public final String toString() 131 { 132 return super.toString() + "(string_index = " + string_index + ")"; 133 } 134 135 /*** @return String object 136 */ 137 public Object getConstantValue(ConstantPool cp) { 138 Constant c = cp.getConstant(string_index, Constants.CONSTANT_Utf8); 139 return ((ConstantUtf8)c).getBytes(); 140 } 141 142 /*** @return dereferenced string 143 */ 144 public String getBytes(ConstantPool cp) { 145 return (String)getConstantValue(cp); 146 } 147 }

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