/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   */
  package org.apache.bcel.classfile;
  
  import java.io.DataInput;
  import java.io.DataOutputStream;
  import java.io.IOException;
  
  import org.apache.bcel.Const;
  import org.apache.bcel.util.Args;
  
  /**
   * This class is derived from <em>Attribute</em> and declares this class as 'synthetic', i.e., it needs special
   * handling. The JVM specification states "A class member that does not appear in the source code must be marked using a
   * Synthetic attribute." It may appear in the ClassFile attribute table, a field_info table or a method_info table. This
   * class is intended to be instantiated from the <em>Attribute.readAttribute()</em> method.
   *
   * @see Attribute
   */
  public final class Synthetic extends Attribute {
  
      private byte[] bytes;
  
      /**
       * @param nameIndex Index in constant pool to CONSTANT_Utf8, which should represent the string "Synthetic".
       * @param length Content length in bytes - should be zero.
       * @param bytes Attribute contents
       * @param constantPool The constant pool this attribute is associated with.
       */
      public Synthetic(final int nameIndex, final int length, final byte[] bytes, final ConstantPool constantPool) {
          super(Const.ATTR_SYNTHETIC, nameIndex, Args.require0(length, "Synthetic attribute length"), constantPool);
          this.bytes = bytes;
      }
  
      /**
       * Constructs object from input stream.
       *
       * @param nameIndex Index in constant pool to CONSTANT_Utf8
       * @param length Content length in bytes
       * @param input Input stream
       * @param constantPool Array of constants
       * @throws IOException if an I/O error occurs.
       */
      Synthetic(final int nameIndex, final int length, final DataInput input, final ConstantPool constantPool) throws IOException {
          this(nameIndex, length, (byte[]) null, constantPool);
          if (length > 0) {
              bytes = new byte[length];
              input.readFully(bytes);
              println("Synthetic attribute with length > 0");
          }
      }
  
      /**
       * Initialize from another object. Note that both objects use the same references (shallow copy). Use copy() for a
       * physical copy.
       *
       * @param c Source to copy.
       */
      public Synthetic(final Synthetic c) {
          this(c.getNameIndex(), c.getLength(), c.getBytes(), c.getConstantPool());
      }
  
      /**
       * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
       * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
       *
       * @param v Visitor object
       */
      @Override
      public void accept(final Visitor v) {
          v.visitSynthetic(this);
      }
  
      /**
       * @return deep copy of this attribute
       */
      @Override
      public Attribute copy(final ConstantPool constantPool) {
          final Synthetic c = (Synthetic) clone();
          if (bytes != null) {
              c.bytes = bytes.clone();
          }
          c.setConstantPool(constantPool);
          return c;
      }
 
     /**
      * Dump source file attribute to file stream in binary format.
      *
      * @param file Output file stream
      * @throws IOException if an I/O error occurs.
      */
     @Override
     public void dump(final DataOutputStream file) throws IOException {
         super.dump(file);
         if (super.getLength() > 0) {
             file.write(bytes, 0, super.getLength());
         }
     }
 
     /**
      * @return data bytes.
      */
     public byte[] getBytes() {
         return bytes;
     }
 
     /**
      * @param bytes
      */
     public void setBytes(final byte[] bytes) {
         this.bytes = bytes;
     }
 
     /**
      * @return String representation.
      */
     @Override
     public String toString() {
         final StringBuilder buf = new StringBuilder("Synthetic");
         if (super.getLength() > 0) {
             buf.append(" ").append(Utility.toHexString(bytes));
         }
         return buf.toString();
     }
 }