    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.generic;
    018
    019import java.io.DataOutputStream;
    020import java.io.IOException;
    021
    022import org.apache.bcel.classfile.Constant;
    023import org.apache.bcel.classfile.ConstantClass;
    024import org.apache.bcel.classfile.ConstantPool;
    025import org.apache.bcel.classfile.Utility;
    026import org.apache.bcel.util.ByteSequence;
    027
    028/**
    029 * Abstract super class for instructions that use an index into the constant pool such as LDC, INVOKEVIRTUAL, etc.
    030 *
    031 * @see ConstantPoolGen
    032 * @see LDC
    033 * @see INVOKEVIRTUAL
    034 */
    035public abstract class CPInstruction extends Instruction implements TypedInstruction, IndexedInstruction {
    036
    037    /**
    038     * @deprecated (since 6.0) will be made private; do not access directly, use getter/setter
    039     */
    040    @Deprecated
    041    protected int index; // index to constant pool
    042
    043    /**
    044     * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
    045     */
    046    CPInstruction() {
    047    }
    048
    049    /**
    050     * @param index to constant pool
    051     */
    052    protected CPInstruction(final short opcode, final int index) {
    053        super(opcode, (short) 3);
    054        setIndex(index);
    055    }
    056
    057    /**
    058     * Dump instruction as byte code to stream out.
    059     *
    060     * @param out Output stream
    061     */
    062    @Override
    063    public void dump(final DataOutputStream out) throws IOException {
    064        out.writeByte(super.getOpcode());
    065        out.writeShort(index);
    066    }
    067
    068    /**
    069     * @return index in constant pool referred by this instruction.
    070     */
    071    @Override
    072    public final int getIndex() {
    073        return index;
    074    }
    075
    076    /**
    077     * @return type related with this instruction.
    078     */
    079    @Override
    080    public Type getType(final ConstantPoolGen cpg) {
    081        final ConstantPool cp = cpg.getConstantPool();
    082        String name = cp.getConstantString(index, org.apache.bcel.Const.CONSTANT_Class);
    083        if (!name.startsWith("[")) {
    084            name = "L" + name + ";";
    085        }
    086        return Type.getType(name);
    087    }
    088
    089    /**
    090     * Read needed data (i.e., index) from file.
    091     *
    092     * @param bytes input stream
    093     * @param wide wide prefix?
    094     */
    095    @Override
    096    protected void initFromFile(final ByteSequence bytes, final boolean wide) throws IOException {
    097        setIndex(bytes.readUnsignedShort());
    098        super.setLength(3);
    099    }
    100
    101    /**
    102     * Set the index to constant pool.
    103     *
    104     * @param index in constant pool.
    105     */
    106    @Override
    107    public void setIndex(final int index) { // TODO could be package-protected?
    108        if (index < 0) {
    109            throw new ClassGenException("Negative index value: " + index);
    110        }
    111        this.index = index;
    112    }
    113
    114    /**
    115     * Long output format:
    116     *
    117     * &lt;name of opcode&gt; "["&lt;opcode number&gt;"]" "("&lt;length of instruction&gt;")" "&lt;"&lt; constant pool
    118     * index&gt;"&gt;"
    119     *
    120     * @param verbose long/short format switch
    121     * @return mnemonic for instruction
    122     */
    123    @Override
    124    public String toString(final boolean verbose) {
    125        return super.toString(verbose) + " " + index;
    126    }
    127
    128    /**
    129     * @return mnemonic for instruction with symbolic references resolved
    130     */
    131    @Override
    132    public String toString(final ConstantPool cp) {
    133        final Constant c = cp.getConstant(index);
    134        String str = cp.constantToString(c);
    135        if (c instanceof ConstantClass) {
    136            str = Utility.packageToPath(str);
    137        }
    138        return org.apache.bcel.Const.getOpcodeName(super.getOpcode()) + " " + str;
    139    }
    140}