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 */
017package org.apache.bcel.classfile;
018
019import java.io.DataInput;
020import java.io.DataOutputStream;
021import java.io.IOException;
022
023import org.apache.bcel.Const;
024
025/**
026 * This class is derived from the abstract {@link Constant} and represents a reference to the name and signature of a
027 * field or method.
028 *
029 * @see Constant
030 */
031public final class ConstantNameAndType extends Constant {
032
033    private int nameIndex; // Name of field/method
034    private int signatureIndex; // and its signature.
035
036    /**
037     * Initialize from another object.
038     *
039     * @param c Source to copy.
040     */
041    public ConstantNameAndType(final ConstantNameAndType c) {
042        this(c.getNameIndex(), c.getSignatureIndex());
043    }
044
045    /**
046     * Initialize instance from file data.
047     *
048     * @param file Input stream
049     * @throws IOException if an I/O error occurs.
050     */
051    ConstantNameAndType(final DataInput file) throws IOException {
052        this(file.readUnsignedShort(), file.readUnsignedShort());
053    }
054
055    /**
056     * @param nameIndex Name of field/method
057     * @param signatureIndex and its signature
058     */
059    public ConstantNameAndType(final int nameIndex, final int signatureIndex) {
060        super(Const.CONSTANT_NameAndType);
061        this.nameIndex = nameIndex;
062        this.signatureIndex = signatureIndex;
063    }
064
065    /**
066     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
067     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
068     *
069     * @param v Visitor object
070     */
071    @Override
072    public void accept(final Visitor v) {
073        v.visitConstantNameAndType(this);
074    }
075
076    /**
077     * Dump name and signature index to file stream in binary format.
078     *
079     * @param file Output file stream
080     * @throws IOException if an I/O error occurs.
081     */
082    @Override
083    public void dump(final DataOutputStream file) throws IOException {
084        file.writeByte(super.getTag());
085        file.writeShort(nameIndex);
086        file.writeShort(signatureIndex);
087    }
088
089    /**
090     * @return name
091     */
092    public String getName(final ConstantPool cp) {
093        return cp.constantToString(getNameIndex(), Const.CONSTANT_Utf8);
094    }
095
096    /**
097     * @return Name index in constant pool of field/method name.
098     */
099    public int getNameIndex() {
100        return nameIndex;
101    }
102
103    /**
104     * @return signature
105     */
106    public String getSignature(final ConstantPool cp) {
107        return cp.constantToString(getSignatureIndex(), Const.CONSTANT_Utf8);
108    }
109
110    /**
111     * @return Index in constant pool of field/method signature.
112     */
113    public int getSignatureIndex() {
114        return signatureIndex;
115    }
116
117    /**
118     * @param nameIndex the name index of this constant
119     */
120    public void setNameIndex(final int nameIndex) {
121        this.nameIndex = nameIndex;
122    }
123
124    /**
125     * @param signatureIndex the signature index in the constant pool of this type
126     */
127    public void setSignatureIndex(final int signatureIndex) {
128        this.signatureIndex = signatureIndex;
129    }
130
131    /**
132     * @return String representation
133     */
134    @Override
135    public String toString() {
136        return super.toString() + "(nameIndex = " + nameIndex + ", signatureIndex = " + signatureIndex + ")";
137    }
138}