1 /*
2  * Licensed to the Apache Software Foundation (ASF) under one or more
3  * contributor license agreements.  See the NOTICE file distributed with
4  * this work for additional information regarding copyright ownership.
5  * The ASF licenses this file to You under the Apache License, Version 2.0
6  * (the "License"); you may not use this file except in compliance with
7  * the License.  You may obtain a copy of the License at
8  *
9  *      http://www.apache.org/licenses/LICENSE-2.0
10  *
11  *  Unless required by applicable law or agreed to in writing, software
12  *  distributed under the License is distributed on an "AS IS" BASIS,
13  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  *  See the License for the specific language governing permissions and
15  *  limitations under the License.
16  *
17  */
18 package org.apache.bcel.classfile;
19 
20 import java.io.DataInput;
21 import java.io.DataOutputStream;
22 import java.io.IOException;
23 
24 import org.apache.bcel.Const;
25 
26 /**
27  * This class is derived from the abstract {@link Constant}
28  * and represents a reference to the name and signature
29  * of a field or method.
30  *
31  * @version $Id$
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      */
ConstantNameAndType(final ConstantNameAndType c)43     public ConstantNameAndType(final 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      */
ConstantNameAndType(final DataInput file)54     ConstantNameAndType(final DataInput 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      */
ConstantNameAndType(final int name_index, final int signature_index)63     public ConstantNameAndType(final int name_index, final int signature_index) {
64         super(Const.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     @Override
accept( final Visitor v )78     public void accept( final Visitor v ) {
79         v.visitConstantNameAndType(this);
80     }
81 
82 
83     /**
84      * Dump name and signature index to file stream in binary format.
85      *
86      * @param file Output file stream
87      * @throws IOException
88      */
89     @Override
dump( final DataOutputStream file )90     public final void dump( final DataOutputStream file ) throws IOException {
91         file.writeByte(super.getTag());
92         file.writeShort(name_index);
93         file.writeShort(signature_index);
94     }
95 
96 
97     /**
98      * @return Name index in constant pool of field/method name.
99      */
getNameIndex()100     public final int getNameIndex() {
101         return name_index;
102     }
103 
104 
105     /** @return name
106      */
getName( final ConstantPool cp )107     public final String getName( final ConstantPool cp ) {
108         return cp.constantToString(getNameIndex(), Const.CONSTANT_Utf8);
109     }
110 
111 
112     /**
113      * @return Index in constant pool of field/method signature.
114      */
getSignatureIndex()115     public final int getSignatureIndex() {
116         return signature_index;
117     }
118 
119 
120     /** @return signature
121      */
getSignature( final ConstantPool cp )122     public final String getSignature( final ConstantPool cp ) {
123         return cp.constantToString(getSignatureIndex(), Const.CONSTANT_Utf8);
124     }
125 
126 
127     /**
128      * @param name_index the name index of this constant
129      */
setNameIndex( final int name_index )130     public final void setNameIndex( final int name_index ) {
131         this.name_index = name_index;
132     }
133 
134 
135     /**
136      * @param signature_index the signature index in the constant pool of this type
137      */
setSignatureIndex( final int signature_index )138     public final void setSignatureIndex( final int signature_index ) {
139         this.signature_index = signature_index;
140     }
141 
142 
143     /**
144      * @return String representation
145      */
146     @Override
toString()147     public final String toString() {
148         return super.toString() + "(name_index = " + name_index + ", signature_index = "
149                 + signature_index + ")";
150     }
151 }
152