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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 the abstract
66   * <A HREF="com.sun.org.apache.bcel.internal.classfile.Constant.html">Constant</A> class
67   * and represents a reference to a (external) class.
68   *
69   * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
70   * @see     Constant
71   */
72  public final class ConstantClass extends Constant implements ConstantObject {
73    private int name_index; // Identical to ConstantString except for the name
74  
75    /**
76     * Initialize from another object.
77     */
78    public ConstantClass(ConstantClass c) {
79      this(c.getNameIndex());
80    }
81  
82    /**
83     * Initialize instance from file data.
84     *
85     * @param file Input stream
86     * @throws IOException
87     */
88    ConstantClass(DataInputStream file) throws IOException
89    {
90      this(file.readUnsignedShort());
91    }
92  
93    /**
94     * @param name_index Name index in constant pool.  Should refer to a
95     * ConstantUtf8.
96     */
97    public ConstantClass(int name_index) {
98      super(Constants.CONSTANT_Class);
99      this.name_index = name_index;
100   }
101 
102   /**
103    * Called by objects that are traversing the nodes of the tree implicitely
104    * defined by the contents of a Java class. I.e., the hierarchy of methods,
105    * fields, attributes, etc. spawns a tree of objects.
106    *
107    * @param v Visitor object
108    */
109   public void accept(Visitor v) {
110     v.visitConstantClass(this);
111   }
112 
113   /**
114    * Dump constant class to file stream in binary format.
115    *
116    * @param file Output file stream
117    * @throws IOException
118    */
119   public final void dump(DataOutputStream file) throws IOException
120   {
121     file.writeByte(tag);
122     file.writeShort(name_index);
123   }
124 
125   /**
126    * @return Name index in constant pool of class name.
127    */
128   public final int getNameIndex() { return name_index; }
129 
130   /**
131    * @param name_index.
132    */
133   public final void setNameIndex(int name_index) {
134     this.name_index = name_index;
135   }
136 
137 
138   /** @return String object
139    */
140   public Object getConstantValue(ConstantPool cp) {
141     Constant c = cp.getConstant(name_index, Constants.CONSTANT_Utf8);
142     return ((ConstantUtf8)c).getBytes();
143   }
144 
145   /** @return dereferenced string
146    */
147   public String getBytes(ConstantPool cp) {
148     return (String)getConstantValue(cp);
149   }
150 
151   /**
152    * @return String representation.
153    */
154   public final String toString() {
155     return super.toString() + "(name_index = " + name_index + ")";
156   }
157 }