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