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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   * This class is derived from the abstract 
26   * <A HREF="org.apache.bcel.classfile.Constant.html">Constant</A> class 
27   * and represents a reference to the name and signature
28   * of a field or method.
29   *
30   * @version $Id: ConstantNameAndType.java 386056 2006-03-15 11:31:56Z tcurdt $
31   * @author  <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
32   * @see     Constant
33   */
34  public final class ConstantNameAndType extends Constant {
35  
36      private int name_index; // Name of field/method
37      private int signature_index; // and its signature.
38  
39  
40      /***
41       * Initialize from another object.
42       */
43      public ConstantNameAndType(ConstantNameAndType c) {
44          this(c.getNameIndex(), c.getSignatureIndex());
45      }
46  
47  
48      /***
49       * Initialize instance from file data.
50       *
51       * @param file Input stream
52       * @throws IOException
53       */
54      ConstantNameAndType(DataInputStream file) throws IOException {
55          this(file.readUnsignedShort(), file.readUnsignedShort());
56      }
57  
58  
59      /***
60       * @param name_index Name of field/method
61       * @param signature_index and its signature
62       */
63      public ConstantNameAndType(int name_index, int signature_index) {
64          super(Constants.CONSTANT_NameAndType);
65          this.name_index = name_index;
66          this.signature_index = signature_index;
67      }
68  
69  
70      /***
71       * Called by objects that are traversing the nodes of the tree implicitely
72       * defined by the contents of a Java class. I.e., the hierarchy of methods,
73       * fields, attributes, etc. spawns a tree of objects.
74       *
75       * @param v Visitor object
76       */
77      public void accept( Visitor v ) {
78          v.visitConstantNameAndType(this);
79      }
80  
81  
82      /***
83       * Dump name and signature index to file stream in binary format.
84       *
85       * @param file Output file stream
86       * @throws IOException
87       */
88      public final void dump( DataOutputStream file ) throws IOException {
89          file.writeByte(tag);
90          file.writeShort(name_index);
91          file.writeShort(signature_index);
92      }
93  
94  
95      /***
96       * @return Name index in constant pool of field/method name.
97       */
98      public final int getNameIndex() {
99          return name_index;
100     }
101 
102 
103     /*** @return name
104      */
105     public final String getName( ConstantPool cp ) {
106         return cp.constantToString(getNameIndex(), Constants.CONSTANT_Utf8);
107     }
108 
109 
110     /***
111      * @return Index in constant pool of field/method signature.
112      */
113     public final int getSignatureIndex() {
114         return signature_index;
115     }
116 
117 
118     /*** @return signature
119      */
120     public final String getSignature( ConstantPool cp ) {
121         return cp.constantToString(getSignatureIndex(), Constants.CONSTANT_Utf8);
122     }
123 
124 
125     /***
126      * @param name_index the name index of this constant
127      */
128     public final void setNameIndex( int name_index ) {
129         this.name_index = name_index;
130     }
131 
132 
133     /***
134      * @param signature_index the signature index in the constant pool of this type
135      */
136     public final void setSignatureIndex( int signature_index ) {
137         this.signature_index = signature_index;
138     }
139 
140 
141     /***
142      * @return String representation
143      */
144     public final String toString() {
145         return super.toString() + "(name_index = " + name_index + ", signature_index = "
146                 + signature_index + ")";
147     }
148 }