001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   https://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.bcel.classfile;
020
021import java.io.DataInput;
022import java.io.DataOutputStream;
023import java.io.IOException;
024
025import org.apache.bcel.Const;
026
027/**
028 * This class is derived from the abstract {@link Constant} and represents a reference to the name and signature of a
029 * field or method.
030 *
031 * @see Constant
032 */
033public final class ConstantNameAndType extends Constant {
034
035    private int nameIndex; // Name of field/method
036    private int signatureIndex; // and its signature.
037
038    /**
039     * Initialize from another object.
040     *
041     * @param c Source to copy.
042     */
043    public ConstantNameAndType(final ConstantNameAndType c) {
044        this(c.getNameIndex(), c.getSignatureIndex());
045    }
046
047    /**
048     * Initialize instance from file data.
049     *
050     * @param file Input stream.
051     * @throws IOException if an I/O error occurs.
052     */
053    ConstantNameAndType(final DataInput file) throws IOException {
054        this(file.readUnsignedShort(), file.readUnsignedShort());
055    }
056
057    /**
058     * Constructs a ConstantNameAndType.
059     *
060     * @param nameIndex Name of field/method.
061     * @param signatureIndex and its signature.
062     */
063    public ConstantNameAndType(final int nameIndex, final int signatureIndex) {
064        super(Const.CONSTANT_NameAndType);
065        this.nameIndex = nameIndex;
066        this.signatureIndex = signatureIndex;
067    }
068
069    /**
070     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
071     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
072     *
073     * @param v Visitor object.
074     */
075    @Override
076    public void accept(final Visitor v) {
077        v.visitConstantNameAndType(this);
078    }
079
080    /**
081     * Dumps name and signature index to file stream in binary format.
082     *
083     * @param file Output file stream.
084     * @throws IOException if an I/O error occurs.
085     */
086    @Override
087    public void dump(final DataOutputStream file) throws IOException {
088        file.writeByte(super.getTag());
089        file.writeShort(nameIndex);
090        file.writeShort(signatureIndex);
091    }
092
093    /**
094     * Gets the name.
095     *
096     * @param cp the constant pool.
097     * @return name.
098     */
099    public String getName(final ConstantPool cp) {
100        return cp.constantToString(getNameIndex(), Const.CONSTANT_Utf8);
101    }
102
103    /**
104     * Gets the name index in constant pool of field/method name.
105     *
106     * @return Name index in constant pool of field/method name.
107     */
108    public int getNameIndex() {
109        return nameIndex;
110    }
111
112    /**
113     * Gets the signature.
114     *
115     * @param cp the constant pool.
116     * @return signature.
117     */
118    public String getSignature(final ConstantPool cp) {
119        return cp.constantToString(getSignatureIndex(), Const.CONSTANT_Utf8);
120    }
121
122    /**
123     * Gets the index in constant pool of field/method signature.
124     *
125     * @return Index in constant pool of field/method signature.
126     */
127    public int getSignatureIndex() {
128        return signatureIndex;
129    }
130
131    /**
132     * Sets the name index.
133     *
134     * @param nameIndex the name index of this constant.
135     */
136    public void setNameIndex(final int nameIndex) {
137        this.nameIndex = nameIndex;
138    }
139
140    /**
141     * Sets the signature index.
142     *
143     * @param signatureIndex the signature index in the constant pool of this type.
144     */
145    public void setSignatureIndex(final int signatureIndex) {
146        this.signatureIndex = signatureIndex;
147    }
148
149    /**
150     * @return String representation.
151     */
152    @Override
153    public String toString() {
154        return super.toString() + "(nameIndex = " + nameIndex + ", signatureIndex = " + signatureIndex + ")";
155    }
156}