1 /*

     2  * reserved comment block

     3  * DO NOT REMOVE OR ALTER!

     4  */

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

     6 

     7 /* ====================================================================

     8  * The Apache Software License, Version 1.1

     9  *

    10  * Copyright (c) 2001 The Apache Software Foundation.  All rights

    11  * reserved.

    12  *

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

    14  * modification, are permitted provided that the following conditions

    15  * are met:

    16  *

    17  * 1. Redistributions of source code must retain the above copyright

    18  *    notice, this list of conditions and the following disclaimer.

    19  *

    20  * 2. Redistributions in binary form must reproduce the above copyright

    21  *    notice, this list of conditions and the following disclaimer in

    22  *    the documentation and/or other materials provided with the

    23  *    distribution.

    24  *

    25  * 3. The end-user documentation included with the redistribution,

    26  *    if any, must include the following acknowledgment:

    27  *       "This product includes software developed by the

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

    29  *    Alternately, this acknowledgment may appear in the software itself,

    30  *    if and wherever such third-party acknowledgments normally appear.

    31  *

    32  * 4. The names "Apache" and "Apache Software Foundation" and

    33  *    "Apache BCEL" must not be used to endorse or promote products

    34  *    derived from this software without prior written permission. For

    35  *    written permission, please contact apache@apache.org.

    36  *

    37  * 5. Products derived from this software may not be called "Apache",

    38  *    "Apache BCEL", nor may "Apache" appear in their name, without

    39  *    prior written permission of the Apache Software Foundation.

    40  *

    41  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED

    42  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

    43  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

    44  * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR

    45  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

    46  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

    47  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF

    48  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

    49  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,

    50  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT

    51  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

    52  * SUCH DAMAGE.

    53  * ====================================================================

    54  *

    55  * This software consists of voluntary contributions made by many

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

    57  * information on the Apache Software Foundation, please see

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

    59  */

    60 

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

    62 import  java.io.*;

    63 

    64 /**

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

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

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

    68  *

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

    70  * @see     Attribute

    71  */

    72 public final class ConstantValue extends Attribute {

    73   private int constantvalue_index;

    74 

    75   /**

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

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

    78    */

    79   public ConstantValue(ConstantValue c) {

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

    81          c.getConstantPool());

    82   }

    83 

    84   /**

    85    * Construct object from file stream.

    86    * @param name_index Name index in constant pool

    87    * @param length Content length in bytes

    88    * @param file Input stream

    89    * @param constant_pool Array of constants

    90    * @throw IOException

    91    */

    92   ConstantValue(int name_index, int length, DataInputStream file,

    93                 ConstantPool constant_pool) throws IOException

    94   {

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

    96   }

    97 

    98   /**

    99    * @param name_index Name index in constant pool

   100    * @param length Content length in bytes

   101    * @param constantvalue_index Index in constant pool

   102    * @param constant_pool Array of constants

   103    */

   104   public ConstantValue(int name_index, int length,

   105                        int constantvalue_index,

   106                        ConstantPool constant_pool)

   107   {

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

   109     this.constantvalue_index = constantvalue_index;

   110   }

   111 

   112   /**

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

   114    * defined by the contents of a Java class. I.e., the hierarchy of methods,

   115    * fields, attributes, etc. spawns a tree of objects.

   116    *

   117    * @param v Visitor object

   118    */

   119   public void accept(Visitor v) {

   120     v.visitConstantValue(this);

   121   }

   122   /**

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

   124    *

   125    * @param file Output file stream

   126    * @throws IOException

   127    */

   128   public final void dump(DataOutputStream file) throws IOException

   129   {

   130     super.dump(file);

   131     file.writeShort(constantvalue_index);

   132   }

   133   /**

   134    * @return Index in constant pool of constant value.

   135    */

   136   public final int getConstantValueIndex() { return constantvalue_index; }

   137 

   138   /**

   139    * @param constantvalue_index.

   140    */

   141   public final void setConstantValueIndex(int constantvalue_index) {

   142     this.constantvalue_index = constantvalue_index;

   143   }

   144 

   145   /**

   146    * @return String representation of constant value.

   147    */

   148   public final String toString() {

   149     Constant c = constant_pool.getConstant(constantvalue_index);

   150 

   151     String   buf;

   152     int    i;

   153 

   154     // Print constant to string depending on its type

   155     switch(c.getTag()) {

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

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

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

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

   160     case Constants.CONSTANT_String:

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

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

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

   164       break;

   165 

   166     default:

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

   168     }

   169 

   170     return buf;

   171   }

   172 

   173   /**

   174    * @return deep copy of this attribute

   175    */

   176   public Attribute copy(ConstantPool constant_pool) {

   177     ConstantValue c = (ConstantValue)clone();

   178     c.constant_pool = constant_pool;

   179     return c;

   180   }

   181 }