001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 *  Unless required by applicable law or agreed to in writing, software
012 *  distributed under the License is distributed on an "AS IS" BASIS,
013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 *  See the License for the specific language governing permissions and
015 *  limitations under the License.
016 *
017 */
018package org.apache.bcel.classfile;
019
020import java.io.DataInput;
021import java.io.DataOutputStream;
022import java.io.IOException;
023
024import org.apache.bcel.Const;
025
026/**
027 * This class is derived from the abstract {@link Constant}
028 * and represents a reference to the name and signature
029 * of a field or method.
030 *
031 * @version $Id: ConstantNameAndType.java 1806200 2017-08-25 16:33:06Z ggregory $
032 * @see     Constant
033 */
034public final class ConstantNameAndType extends Constant {
035
036    private int name_index; // Name of field/method
037    private int signature_index; // and its signature.
038
039
040    /**
041     * Initialize from another object.
042     */
043    public ConstantNameAndType(final ConstantNameAndType c) {
044        this(c.getNameIndex(), c.getSignatureIndex());
045    }
046
047
048    /**
049     * Initialize instance from file data.
050     *
051     * @param file Input stream
052     * @throws IOException
053     */
054    ConstantNameAndType(final DataInput file) throws IOException {
055        this(file.readUnsignedShort(), file.readUnsignedShort());
056    }
057
058
059    /**
060     * @param name_index Name of field/method
061     * @param signature_index and its signature
062     */
063    public ConstantNameAndType(final int name_index, final int signature_index) {
064        super(Const.CONSTANT_NameAndType);
065        this.name_index = name_index;
066        this.signature_index = signature_index;
067    }
068
069
070    /**
071     * Called by objects that are traversing the nodes of the tree implicitely
072     * defined by the contents of a Java class. I.e., the hierarchy of methods,
073     * fields, attributes, etc. spawns a tree of objects.
074     *
075     * @param v Visitor object
076     */
077    @Override
078    public void accept( final Visitor v ) {
079        v.visitConstantNameAndType(this);
080    }
081
082
083    /**
084     * Dump name and signature index to file stream in binary format.
085     *
086     * @param file Output file stream
087     * @throws IOException
088     */
089    @Override
090    public final void dump( final DataOutputStream file ) throws IOException {
091        file.writeByte(super.getTag());
092        file.writeShort(name_index);
093        file.writeShort(signature_index);
094    }
095
096
097    /**
098     * @return Name index in constant pool of field/method name.
099     */
100    public final int getNameIndex() {
101        return name_index;
102    }
103
104
105    /** @return name
106     */
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     */
115    public final int getSignatureIndex() {
116        return signature_index;
117    }
118
119
120    /** @return signature
121     */
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     */
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     */
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
147    public final String toString() {
148        return super.toString() + "(name_index = " + name_index + ", signature_index = "
149                + signature_index + ")";
150    }
151}