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 * @version $Id: Synthetic.java 1806200 2017-08-25 16:33:06Z ggregory $ 036 * @see Attribute 037 */ 038public final class Synthetic extends Attribute { 039 040 private byte[] bytes; 041 042 043 /** 044 * Initialize from another object. Note that both objects use the same 045 * references (shallow copy). Use copy() for a physical copy. 046 */ 047 public Synthetic(final Synthetic c) { 048 this(c.getNameIndex(), c.getLength(), c.getBytes(), c.getConstantPool()); 049 } 050 051 052 /** 053 * @param name_index Index in constant pool to CONSTANT_Utf8, which 054 * should represent the string "Synthetic". 055 * @param length Content length in bytes - should be zero. 056 * @param bytes Attribute contents 057 * @param constant_pool The constant pool this attribute is associated 058 * with. 059 */ 060 public Synthetic(final int name_index, final int length, final byte[] bytes, final ConstantPool constant_pool) { 061 super(Const.ATTR_SYNTHETIC, name_index, length, constant_pool); 062 this.bytes = bytes; 063 } 064 065 066 /** 067 * Construct object from input stream. 068 * 069 * @param name_index Index in constant pool to CONSTANT_Utf8 070 * @param length Content length in bytes 071 * @param input Input stream 072 * @param constant_pool Array of constants 073 * @throws IOException 074 */ 075 Synthetic(final int name_index, final int length, final DataInput input, final ConstantPool constant_pool) 076 throws IOException { 077 this(name_index, length, (byte[]) null, constant_pool); 078 if (length > 0) { 079 bytes = new byte[length]; 080 input.readFully(bytes); 081 System.err.println("Synthetic attribute with length > 0"); 082 } 083 } 084 085 086 /** 087 * Called by objects that are traversing the nodes of the tree implicitely 088 * defined by the contents of a Java class. I.e., the hierarchy of methods, 089 * fields, attributes, etc. spawns a tree of objects. 090 * 091 * @param v Visitor object 092 */ 093 @Override 094 public void accept( final Visitor v ) { 095 v.visitSynthetic(this); 096 } 097 098 099 /** 100 * Dump source file attribute to file stream in binary format. 101 * 102 * @param file Output file stream 103 * @throws IOException 104 */ 105 @Override 106 public final void dump( final DataOutputStream file ) throws IOException { 107 super.dump(file); 108 if (super.getLength() > 0) { 109 file.write(bytes, 0, super.getLength()); 110 } 111 } 112 113 114 /** 115 * @return data bytes. 116 */ 117 public final byte[] getBytes() { 118 return bytes; 119 } 120 121 122 /** 123 * @param bytes 124 */ 125 public final void setBytes( final byte[] bytes ) { 126 this.bytes = bytes; 127 } 128 129 130 /** 131 * @return String representation. 132 */ 133 @Override 134 public final String toString() { 135 final StringBuilder buf = new StringBuilder("Synthetic"); 136 if (super.getLength() > 0) { 137 buf.append(" ").append(Utility.toHexString(bytes)); 138 } 139 return buf.toString(); 140 } 141 142 143 /** 144 * @return deep copy of this attribute 145 */ 146 @Override 147 public Attribute copy( final ConstantPool _constant_pool ) { 148 final Synthetic c = (Synthetic) clone(); 149 if (bytes != null) { 150 c.bytes = new byte[bytes.length]; 151 System.arraycopy(bytes, 0, c.bytes, 0, bytes.length); 152 } 153 c.setConstantPool(_constant_pool); 154 return c; 155 } 156}