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