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.util.Objects;
020
021import org.apache.bcel.classfile.LineNumber;
022
023/**
024 * This class represents a line number within a method, i.e., give an instruction a line number corresponding to the
025 * source code line.
026 *
027 * @see LineNumber
028 * @see MethodGen
029 */
030public class LineNumberGen implements InstructionTargeter, Cloneable {
031
032    static final LineNumberGen[] EMPTY_ARRAY = {};
033
034    private InstructionHandle ih;
035    private int srcLine;
036
037    /**
038     * Create a line number.
039     *
040     * @param ih instruction handle to reference
041     */
042    public LineNumberGen(final InstructionHandle ih, final int srcLine) {
043        setInstruction(ih);
044        setSourceLine(srcLine);
045    }
046
047    @Override
048    public Object clone() {
049        try {
050            return super.clone();
051        } catch (final CloneNotSupportedException e) {
052            throw new UnsupportedOperationException("Clone Not Supported", e); // never happens
053        }
054    }
055
056    /**
057     * @return true, if ih is target of this line number
058     */
059    @Override
060    public boolean containsTarget(final InstructionHandle ih) {
061        return this.ih == ih;
062    }
063
064    public InstructionHandle getInstruction() {
065        return ih;
066    }
067
068    /**
069     * Gets LineNumber attribute.
070     *
071     * This relies on that the instruction list has already been dumped to byte code or that the 'setPositions' methods
072     * has been called for the instruction list.
073     */
074    public LineNumber getLineNumber() {
075        return new LineNumber(ih.getPosition(), srcLine);
076    }
077
078    public int getSourceLine() {
079        return srcLine;
080    }
081
082    public void setInstruction(final InstructionHandle instructionHandle) { // TODO could be package-protected?
083        Objects.requireNonNull(instructionHandle, "instructionHandle");
084        BranchInstruction.notifyTarget(this.ih, instructionHandle, this);
085        this.ih = instructionHandle;
086    }
087
088    public void setSourceLine(final int srcLine) { // TODO could be package-protected?
089        this.srcLine = srcLine;
090    }
091
092    /**
093     * @param oldIh old target
094     * @param newIh new target
095     */
096    @Override
097    public void updateTarget(final InstructionHandle oldIh, final InstructionHandle newIh) {
098        if (oldIh != ih) {
099            throw new ClassGenException("Not targeting " + oldIh + ", but " + ih + "}");
100        }
101        setInstruction(newIh);
102    }
103}