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1   /*
2    * Copyright  2000-2004 The Apache Software Foundation
3    *
4    *  Licensed under the Apache License, Version 2.0 (the "License");
5    *  you may not use this file except in compliance with the License.
6    *  You may obtain a copy of the License at
7    *
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    *
10   *  Unless required by applicable law or agreed to in writing, software
11   *  distributed under the License is distributed on an "AS IS" BASIS,
12   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   *  See the License for the specific language governing permissions and
14   *  limitations under the License.
15   *
16   */
17  package org.apache.bcel.classfile;
18  
19  import java.io.DataInputStream;
20  import java.io.DataOutputStream;
21  import java.io.IOException;
22  import org.apache.bcel.Constants;
23  
24  /*** 
25   * Abstract super class for Fieldref and Methodref constants.
26   *
27   * @version $Id: ConstantCP.java 386056 2006-03-15 11:31:56Z tcurdt $
28   * @author  <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
29   * @see     ConstantFieldref
30   * @see     ConstantMethodref
31   * @see     ConstantInterfaceMethodref
32   */
33  public abstract class ConstantCP extends Constant {
34  
35      /*** References to the constants containing the class and the field signature
36       */
37      protected int class_index, name_and_type_index;
38  
39  
40      /***
41       * Initialize from another object.
42       */
43      public ConstantCP(ConstantCP c) {
44          this(c.getTag(), c.getClassIndex(), c.getNameAndTypeIndex());
45      }
46  
47  
48      /***
49       * Initialize instance from file data.
50       *
51       * @param tag  Constant type tag
52       * @param file Input stream
53       * @throws IOException
54       */
55      ConstantCP(byte tag, DataInputStream file) throws IOException {
56          this(tag, file.readUnsignedShort(), file.readUnsignedShort());
57      }
58  
59  
60      /***
61       * @param class_index Reference to the class containing the field
62       * @param name_and_type_index and the field signature
63       */
64      protected ConstantCP(byte tag, int class_index, int name_and_type_index) {
65          super(tag);
66          this.class_index = class_index;
67          this.name_and_type_index = name_and_type_index;
68      }
69  
70  
71      /*** 
72       * Dump constant field reference to file stream in binary format.
73       *
74       * @param file Output file stream
75       * @throws IOException
76       */
77      public final void dump( DataOutputStream file ) throws IOException {
78          file.writeByte(tag);
79          file.writeShort(class_index);
80          file.writeShort(name_and_type_index);
81      }
82  
83  
84      /***
85       * @return Reference (index) to class this field or method belongs to.
86       */
87      public final int getClassIndex() {
88          return class_index;
89      }
90  
91  
92      /***
93       * @return Reference (index) to signature of the field.
94       */
95      public final int getNameAndTypeIndex() {
96          return name_and_type_index;
97      }
98  
99  
100     /***
101      * @param class_index points to Constant_class 
102      */
103     public final void setClassIndex( int class_index ) {
104         this.class_index = class_index;
105     }
106 
107 
108     /***
109      * @return Class this field belongs to.
110      */
111     public String getClass( ConstantPool cp ) {
112         return cp.constantToString(class_index, Constants.CONSTANT_Class);
113     }
114 
115 
116     /***
117      * @param name_and_type_index points to Constant_NameAndType
118      */
119     public final void setNameAndTypeIndex( int name_and_type_index ) {
120         this.name_and_type_index = name_and_type_index;
121     }
122 
123 
124     /***
125      * @return String representation.
126      */
127     public final String toString() {
128         return super.toString() + "(class_index = " + class_index + ", name_and_type_index = "
129                 + name_and_type_index + ")";
130     }
131 }