    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.generic;
    019
    020import java.io.DataOutputStream;
    021import java.io.IOException;
    022
    023import org.apache.bcel.classfile.Constant;
    024import org.apache.bcel.classfile.ConstantClass;
    025import org.apache.bcel.classfile.ConstantPool;
    026import org.apache.bcel.util.ByteSequence;
    027
    028/**
    029 * Abstract super class for instructions that use an index into the
    030 * constant pool such as LDC, INVOKEVIRTUAL, etc.
    031 *
    032 * @see ConstantPoolGen
    033 * @see LDC
    034 * @see INVOKEVIRTUAL
    035 *
    036 * @version $Id$
    037 */
    038public abstract class CPInstruction extends Instruction implements TypedInstruction,
    039        IndexedInstruction {
    040
    041    /**
    042     * @deprecated (since 6.0) will be made private; do not access directly, use getter/setter
    043     */
    044    @Deprecated
    045    protected int index; // index to constant pool
    046
    047
    048    /**
    049     * Empty constructor needed for Instruction.readInstruction.
    050     * Not to be used otherwise.
    051     */
    052    CPInstruction() {
    053    }
    054
    055
    056    /**
    057     * @param index to constant pool
    058     */
    059    protected CPInstruction(final short opcode, final int index) {
    060        super(opcode, (short) 3);
    061        setIndex(index);
    062    }
    063
    064
    065    /**
    066     * Dump instruction as byte code to stream out.
    067     * @param out Output stream
    068     */
    069    @Override
    070    public void dump( final DataOutputStream out ) throws IOException {
    071        out.writeByte(super.getOpcode());
    072        out.writeShort(index);
    073    }
    074
    075
    076    /**
    077     * Long output format:
    078     *
    079     * &lt;name of opcode&gt; "["&lt;opcode number&gt;"]"
    080     * "("&lt;length of instruction&gt;")" "&lt;"&lt; constant pool index&gt;"&gt;"
    081     *
    082     * @param verbose long/short format switch
    083     * @return mnemonic for instruction
    084     */
    085    @Override
    086    public String toString( final boolean verbose ) {
    087        return super.toString(verbose) + " " + index;
    088    }
    089
    090
    091    /**
    092     * @return mnemonic for instruction with symbolic references resolved
    093     */
    094    @Override
    095    public String toString( final ConstantPool cp ) {
    096        final Constant c = cp.getConstant(index);
    097        String str = cp.constantToString(c);
    098        if (c instanceof ConstantClass) {
    099            str = str.replace('.', '/');
    100        }
    101        return org.apache.bcel.Const.getOpcodeName(super.getOpcode()) + " " + str;
    102    }
    103
    104
    105    /**
    106     * Read needed data (i.e., index) from file.
    107     * @param bytes input stream
    108     * @param wide wide prefix?
    109     */
    110    @Override
    111    protected void initFromFile( final ByteSequence bytes, final boolean wide ) throws IOException {
    112        setIndex(bytes.readUnsignedShort());
    113        super.setLength(3);
    114    }
    115
    116
    117    /**
    118     * @return index in constant pool referred by this instruction.
    119     */
    120    @Override
    121    public final int getIndex() {
    122        return index;
    123    }
    124
    125
    126    /**
    127     * Set the index to constant pool.
    128     * @param index in  constant pool.
    129     */
    130    @Override
    131    public void setIndex( final int index ) { // TODO could be package-protected?
    132        if (index < 0) {
    133            throw new ClassGenException("Negative index value: " + index);
    134        }
    135        this.index = index;
    136    }
    137
    138
    139    /** @return type related with this instruction.
    140     */
    141    @Override
    142    public Type getType( final ConstantPoolGen cpg ) {
    143        final ConstantPool cp = cpg.getConstantPool();
    144        String name = cp.getConstantString(index, org.apache.bcel.Const.CONSTANT_Class);
    145        if (!name.startsWith("[")) {
    146            name = "L" + name + ";";
    147        }
    148        return Type.getType(name);
    149    }
    150}