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 
  25 import  com.sun.org.apache.bcel.internal.Constants;
  26 import  java.io.*;
  27 
  28 /**
  29  * This class is derived from <em>Attribute</em> and declares this class as
  30  * `synthetic', i.e., it needs special handling.  The JVM specification
  31  * states "A class member that does not appear in the source code must be
  32  * marked using a Synthetic attribute."  It may appear in the ClassFile
  33  * attribute table, a field_info table or a method_info table.  This class
  34  * is intended to be instantiated from the
  35  * <em>Attribute.readAttribute()</em> method.
  36  *
  37  * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
  38  * @see     Attribute
  39  */
  40 public final class Synthetic extends Attribute {
  41   private byte[] bytes;
  42 
  43   /**
  44    * Initialize from another object. Note that both objects use the same
  45    * references (shallow copy). Use copy() for a physical copy.
  46    */
  47   public Synthetic(Synthetic c) {
  48     this(c.getNameIndex(), c.getLength(), c.getBytes(), c.getConstantPool());
  49   }
  50 
  51   /**
  52    * @param name_index Index in constant pool to CONSTANT_Utf8, which
  53    * should represent the string "Synthetic".
  54    * @param length Content length in bytes - should be zero.
  55    * @param bytes Attribute contents
  56    * @param constant_pool The constant pool this attribute is associated
  57    * with.
  58    */
  59   public Synthetic(int name_index, int length, byte[] bytes,
  60                    ConstantPool constant_pool)
  61   {
  62     super(Constants.ATTR_SYNTHETIC, name_index, length, constant_pool);
  63     this.bytes         = bytes;
  64   }
  65 
  66   /**
  67    * Construct object from file stream.
  68    * @param name_index Index in constant pool to CONSTANT_Utf8
  69    * @param length Content length in bytes
  70    * @param file Input stream
  71    * @param constant_pool Array of constants
  72    * @throws IOException
  73    */
  74   Synthetic(int name_index, int length, DataInputStream file,
  75             ConstantPool constant_pool) throws IOException
  76   {
  77     this(name_index, length, (byte [])null, constant_pool);
  78 
  79     if(length > 0) {
  80       bytes = new byte[length];
  81       file.readFully(bytes);
  82       System.err.println("Synthetic attribute with length > 0");
  83     }
  84   }
  85   /**
  86    * Called by objects that are traversing the nodes of the tree implicitely
  87    * defined by the contents of a Java class. I.e., the hierarchy of methods,
  88    * fields, attributes, etc. spawns a tree of objects.
  89    *
  90    * @param v Visitor object
  91    */
  92   public void accept(Visitor v) {
  93     v.visitSynthetic(this);
  94   }
  95   /**
  96    * Dump source file attribute to file stream in binary format.
  97    *
  98    * @param file Output file stream
  99    * @throws IOException
 100    */
 101   public final void dump(DataOutputStream file) throws IOException
 102   {
 103     super.dump(file);
 104     if(length > 0)
 105       file.write(bytes, 0, length);
 106   }
 107   /**
 108    * @return data bytes.
 109    */
 110   public final byte[] getBytes() { return bytes; }
 111 
 112   /**
 113    * @param bytes.
 114    */
 115   public final void setBytes(byte[] bytes) {
 116     this.bytes = bytes;
 117   }
 118 
 119   /**
 120    * @return String representation.
 121    */
 122   public final String toString() {
 123     StringBuffer buf = new StringBuffer("Synthetic");
 124 
 125     if(length > 0)
 126       buf.append(" " + Utility.toHexString(bytes));
 127 
 128     return buf.toString();
 129   }
 130 
 131   /**
 132    * @return deep copy of this attribute
 133    */
 134   public Attribute copy(ConstantPool constant_pool) {
 135     Synthetic c = (Synthetic)clone();
 136 
 137     if(bytes != null)
 138       c.bytes = (byte[])bytes.clone();
 139 
 140     c.constant_pool = constant_pool;
 141     return c;
 142   }
 143 }