    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 * @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    /**
    040     * Initialize from another object.
    041     */
    042    public ConstantNameAndType(final ConstantNameAndType c) {
    043        this(c.getNameIndex(), c.getSignatureIndex());
    044    }
    045
    046
    047    /**
    048     * Initialize instance from file data.
    049     *
    050     * @param file Input stream
    051     * @throws IOException
    052     */
    053    ConstantNameAndType(final DataInput file) throws IOException {
    054        this(file.readUnsignedShort(), file.readUnsignedShort());
    055    }
    056
    057
    058    /**
    059     * @param nameIndex Name of field/method
    060     * @param signatureIndex and its signature
    061     */
    062    public ConstantNameAndType(final int nameIndex, final int signatureIndex) {
    063        super(Const.CONSTANT_NameAndType);
    064        this.nameIndex = nameIndex;
    065        this.signatureIndex = signatureIndex;
    066    }
    067
    068
    069    /**
    070     * Called by objects that are traversing the nodes of the tree implicitely
    071     * defined by the contents of a Java class. I.e., the hierarchy of methods,
    072     * fields, attributes, etc. spawns a tree of objects.
    073     *
    074     * @param v Visitor object
    075     */
    076    @Override
    077    public void accept( final Visitor v ) {
    078        v.visitConstantNameAndType(this);
    079    }
    080
    081
    082    /**
    083     * Dump name and signature index to file stream in binary format.
    084     *
    085     * @param file Output file stream
    086     * @throws IOException
    087     */
    088    @Override
    089    public void dump( final DataOutputStream file ) throws IOException {
    090        file.writeByte(super.getTag());
    091        file.writeShort(nameIndex);
    092        file.writeShort(signatureIndex);
    093    }
    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 name
    105     */
    106    public String getName( final ConstantPool cp ) {
    107        return cp.constantToString(getNameIndex(), Const.CONSTANT_Utf8);
    108    }
    109
    110
    111    /**
    112     * @return Index in constant pool of field/method signature.
    113     */
    114    public int getSignatureIndex() {
    115        return signatureIndex;
    116    }
    117
    118
    119    /** @return signature
    120     */
    121    public String getSignature( final ConstantPool cp ) {
    122        return cp.constantToString(getSignatureIndex(), Const.CONSTANT_Utf8);
    123    }
    124
    125
    126    /**
    127     * @param nameIndex the name index of this constant
    128     */
    129    public void setNameIndex( final int nameIndex ) {
    130        this.nameIndex = nameIndex;
    131    }
    132
    133
    134    /**
    135     * @param signatureIndex the signature index in the constant pool of this type
    136     */
    137    public void setSignatureIndex( final int signatureIndex ) {
    138        this.signatureIndex = signatureIndex;
    139    }
    140
    141
    142    /**
    143     * @return String representation
    144     */
    145    @Override
    146    public String toString() {
    147        return super.toString() + "(nameIndex = " + nameIndex + ", signatureIndex = "
    148                + signatureIndex + ")";
    149    }
    150}