001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 * 017 */ 018package org.apache.bcel.classfile; 019 020import java.io.DataInput; 021import java.io.DataOutputStream; 022import java.io.IOException; 023 024import org.apache.bcel.Const; 025 026/** 027 * This class is derived from <em>Attribute</em> and declares this class as 028 * `synthetic', i.e., it needs special handling. The JVM specification 029 * states "A class member that does not appear in the source code must be 030 * marked using a Synthetic attribute." It may appear in the ClassFile 031 * attribute table, a field_info table or a method_info table. This class 032 * is intended to be instantiated from the 033 * <em>Attribute.readAttribute()</em> method. 034 * 035 * @see Attribute 036 */ 037public final class Synthetic extends Attribute { 038 039 private byte[] bytes; 040 041 042 /** 043 * Initialize from another object. Note that both objects use the same 044 * references (shallow copy). Use copy() for a physical copy. 045 */ 046 public Synthetic(final Synthetic c) { 047 this(c.getNameIndex(), c.getLength(), c.getBytes(), c.getConstantPool()); 048 } 049 050 051 /** 052 * @param name_index Index in constant pool to CONSTANT_Utf8, which 053 * should represent the string "Synthetic". 054 * @param length Content length in bytes - should be zero. 055 * @param bytes Attribute contents 056 * @param constant_pool The constant pool this attribute is associated 057 * with. 058 */ 059 public Synthetic(final int name_index, final int length, final byte[] bytes, final ConstantPool constant_pool) { 060 super(Const.ATTR_SYNTHETIC, name_index, length, constant_pool); 061 this.bytes = bytes; 062 } 063 064 065 /** 066 * Construct object from input stream. 067 * 068 * @param name_index Index in constant pool to CONSTANT_Utf8 069 * @param length Content length in bytes 070 * @param input Input stream 071 * @param constant_pool Array of constants 072 * @throws IOException 073 */ 074 Synthetic(final int name_index, final int length, final DataInput input, final ConstantPool constant_pool) 075 throws IOException { 076 this(name_index, length, (byte[]) null, constant_pool); 077 if (length > 0) { 078 bytes = new byte[length]; 079 input.readFully(bytes); 080 println("Synthetic attribute with length > 0"); 081 } 082 } 083 084 085 /** 086 * Called by objects that are traversing the nodes of the tree implicitely 087 * defined by the contents of a Java class. I.e., the hierarchy of methods, 088 * fields, attributes, etc. spawns a tree of objects. 089 * 090 * @param v Visitor object 091 */ 092 @Override 093 public void accept( final Visitor v ) { 094 v.visitSynthetic(this); 095 } 096 097 098 /** 099 * Dump source file attribute to file stream in binary format. 100 * 101 * @param file Output file stream 102 * @throws IOException 103 */ 104 @Override 105 public void dump( final DataOutputStream file ) throws IOException { 106 super.dump(file); 107 if (super.getLength() > 0) { 108 file.write(bytes, 0, super.getLength()); 109 } 110 } 111 112 113 /** 114 * @return data bytes. 115 */ 116 public byte[] getBytes() { 117 return bytes; 118 } 119 120 121 /** 122 * @param bytes 123 */ 124 public void setBytes( final byte[] bytes ) { 125 this.bytes = bytes; 126 } 127 128 129 /** 130 * @return String representation. 131 */ 132 @Override 133 public String toString() { 134 final StringBuilder buf = new StringBuilder("Synthetic"); 135 if (super.getLength() > 0) { 136 buf.append(" ").append(Utility.toHexString(bytes)); 137 } 138 return buf.toString(); 139 } 140 141 142 /** 143 * @return deep copy of this attribute 144 */ 145 @Override 146 public Attribute copy( final ConstantPool _constant_pool ) { 147 final Synthetic c = (Synthetic) clone(); 148 if (bytes != null) { 149 c.bytes = new byte[bytes.length]; 150 System.arraycopy(bytes, 0, c.bytes, 0, bytes.length); 151 } 152 c.setConstantPool(_constant_pool); 153 return c; 154 } 155}