1 /* 2 * reserved comment block 3 * DO NOT REMOVE OR ALTER! 4 */ 5 /* 6 * Licensed to the Apache Software Foundation (ASF) under one or more 7 * contributor license agreements. See the NOTICE file distributed with 8 * this work for additional information regarding copyright ownership. 9 * The ASF licenses this file to You under the Apache License, Version 2.0 10 * (the "License"); you may not use this file except in compliance with 11 * the License. You may obtain a copy of the License at 12 * 13 * http://www.apache.org/licenses/LICENSE-2.0 14 * 15 * Unless required by applicable law or agreed to in writing, software 16 * distributed under the License is distributed on an "AS IS" BASIS, 17 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 18 * See the License for the specific language governing permissions and 19 * limitations under the License. 20 */ 21 22 package com.sun.org.apache.bcel.internal.classfile; 23 24 import java.io.DataInput; 25 import java.io.DataOutputStream; 26 import java.io.IOException; 27 28 import com.sun.org.apache.bcel.internal.Const; 29 30 /** 31 * This class is derived from the abstract {@link Constant} 32 * and represents a reference to a String object. 33 * 34 * @version $Id$ 35 * @see Constant 36 */ 37 public final class ConstantString extends Constant implements ConstantObject { 38 39 private int string_index; // Identical to ConstantClass except for this name 40 41 42 /** 43 * Initialize from another object. 44 */ 45 public ConstantString(final ConstantString c) { 46 this(c.getStringIndex()); 47 } 48 49 50 /** 51 * Initialize instance from file data. 52 * 53 * @param file Input stream 54 * @throws IOException 55 */ 56 ConstantString(final DataInput file) throws IOException { 57 this(file.readUnsignedShort()); 58 } 59 60 61 /** 62 * @param string_index Index of Constant_Utf8 in constant pool 63 */ 64 public ConstantString(final int string_index) { 65 super(Const.CONSTANT_String); 66 this.string_index = string_index; 67 } 68 69 70 /** 71 * Called by objects that are traversing the nodes of the tree implicitely 72 * defined by the contents of a Java class. I.e., the hierarchy of methods, 73 * fields, attributes, etc. spawns a tree of objects. 74 * 75 * @param v Visitor object 76 */ 77 @Override 78 public void accept( final Visitor v ) { 79 v.visitConstantString(this); 80 } 81 82 83 /** 84 * Dump constant field reference to file stream in binary format. 85 * 86 * @param file Output file stream 87 * @throws IOException 88 */ 89 @Override 90 public final void dump( final DataOutputStream file ) throws IOException { 91 file.writeByte(super.getTag()); 92 file.writeShort(string_index); 93 } 94 95 96 /** 97 * @return Index in constant pool of the string (ConstantUtf8). 98 */ 99 public final int getStringIndex() { 100 return string_index; 101 } 102 103 104 /** 105 * @param string_index the index into the constant of the string value 106 */ 107 public final void setStringIndex( final int string_index ) { 108 this.string_index = string_index; 109 } 110 111 112 /** 113 * @return String representation. 114 */ 115 @Override 116 public final String toString() { 117 return super.toString() + "(string_index = " + string_index + ")"; 118 } 119 120 121 /** @return String object 122 */ 123 @Override 124 public Object getConstantValue( final ConstantPool cp ) { 125 final Constant c = cp.getConstant(string_index, Const.CONSTANT_Utf8); 126 return ((ConstantUtf8) c).getBytes(); 127 } 128 129 130 /** @return dereferenced string 131 */ 132 public String getBytes( final ConstantPool cp ) { 133 return (String) getConstantValue(cp); 134 } 135 }