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