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Java > Open Source Codes > org > apache > bcel > classfile > ConstantNameAndType


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 JavaDoc;
20 import java.io.DataOutputStream JavaDoc;
21 import java.io.IOException JavaDoc;
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 JavaDoc file) throws IOException JavaDoc {
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 JavaDoc file ) throws IOException JavaDoc {
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 JavaDoc 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 JavaDoc 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 JavaDoc toString() {
145         return super.toString() + "(name_index = " + name_index + ", signature_index = "
146                 + signature_index + ")";
147     }
148 }
149
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