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 * reserved comment block

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 */

package com.sun.org.apache.bcel.internal.classfile;

/* ====================================================================

 * The Apache Software License, Version 1.1

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 * reserved.

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 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

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 *        Apache Software Foundation (http://www.apache.org/)."

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 * ====================================================================

 *

 * This software consists of voluntary contributions made by many

 * individuals on behalf of the Apache Software Foundation.  For more

 * information on the Apache Software Foundation, please see

 * <http://www.apache.org/>.

 */

import  com.sun.org.apache.bcel.internal.Constants;

import  java.io.*;

/**

 * This class is derived from <em>Attribute</em> and represents a constant

 * value, i.e., a default value for initializing a class field.

 * This class is instantiated by the <em>Attribute.readAttribute()</em> method.

 *

 * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>

 * @see     Attribute

 */

public final class ConstantValue extends Attribute {

  private int constantvalue_index;

  /**

   * Initialize from another object. Note that both objects use the same

   * references (shallow copy). Use clone() for a physical copy.

   */

  public ConstantValue(ConstantValue c) {

    this(c.getNameIndex(), c.getLength(), c.getConstantValueIndex(),

         c.getConstantPool());

  }

  /**

   * Construct object from file stream.

   * @param name_index Name index in constant pool

   * @param length Content length in bytes

   * @param file Input stream

   * @param constant_pool Array of constants

   * @throw IOException

   */

  ConstantValue(int name_index, int length, DataInputStream file,

                ConstantPool constant_pool) throws IOException

  {

    this(name_index, length, (int)file.readUnsignedShort(), constant_pool);

  }

  /**

   * @param name_index Name index in constant pool

   * @param length Content length in bytes

   * @param constantvalue_index Index in constant pool

   * @param constant_pool Array of constants

   */

  public ConstantValue(int name_index, int length,

                       int constantvalue_index,

                       ConstantPool constant_pool)

  {

    super(Constants.ATTR_CONSTANT_VALUE, name_index, length, constant_pool);

    this.constantvalue_index = constantvalue_index;

  }

  /**

   * Called by objects that are traversing the nodes of the tree implicitely

   * 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

   */

  public void accept(Visitor v) {

    v.visitConstantValue(this);

  }

  /**

   * Dump constant value attribute to file stream on binary format.

   *

   * @param file Output file stream

   * @throws IOException

   */

  public final void dump(DataOutputStream file) throws IOException

  {

    super.dump(file);

    file.writeShort(constantvalue_index);

  }

  /**

   * @return Index in constant pool of constant value.

   */

  public final int getConstantValueIndex() { return constantvalue_index; }

  /**

   * @param constantvalue_index.

   */

  public final void setConstantValueIndex(int constantvalue_index) {

    this.constantvalue_index = constantvalue_index;

  }

  /**

   * @return String representation of constant value.

   */

  public final String toString() {

    Constant c = constant_pool.getConstant(constantvalue_index);

    String   buf;

    int    i;

    // Print constant to string depending on its type

    switch(c.getTag()) {

    case Constants.CONSTANT_Long:    buf = "" + ((ConstantLong)c).getBytes();    break;

    case Constants.CONSTANT_Float:   buf = "" + ((ConstantFloat)c).getBytes();   break;

    case Constants.CONSTANT_Double:  buf = "" + ((ConstantDouble)c).getBytes();  break;

    case Constants.CONSTANT_Integer: buf = "" + ((ConstantInteger)c).getBytes(); break;

    case Constants.CONSTANT_String:

      i   = ((ConstantString)c).getStringIndex();

      c   = constant_pool.getConstant(i, Constants.CONSTANT_Utf8);

      buf = "\"" + Utility.convertString(((ConstantUtf8)c).getBytes()) + "\"";

      break;

    default:

      throw new IllegalStateException("Type of ConstValue invalid: " + c);

    }

    return buf;

  }

  /**

   * @return deep copy of this attribute

   */

  public Attribute copy(ConstantPool constant_pool) {

    ConstantValue c = (ConstantValue)clone();

    c.constant_pool = constant_pool;

    return c;

  }

}