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.util.Objects;
021
022import org.apache.bcel.classfile.LineNumber;
023
024/**
025 * This class represents a line number within a method, i.e., give an instruction a line number corresponding to the
026 * source code line.
027 *
028 * @see LineNumber
029 * @see MethodGen
030 */
031public class LineNumberGen implements InstructionTargeter, Cloneable {
032
033    static final LineNumberGen[] EMPTY_ARRAY = {};
034
035    private InstructionHandle ih;
036    private int srcLine;
037
038    /**
039     * Create a line number.
040     *
041     * @param ih instruction handle to reference
042     */
043    public LineNumberGen(final InstructionHandle ih, final int src_line) {
044        setInstruction(ih);
045        setSourceLine(src_line);
046    }
047
048    @Override
049    public Object clone() {
050        try {
051            return super.clone();
052        } catch (final CloneNotSupportedException e) {
053            throw new Error("Clone Not Supported"); // never happens
054        }
055    }
056
057    /**
058     * @return true, if ih is target of this line number
059     */
060    @Override
061    public boolean containsTarget(final InstructionHandle ih) {
062        return this.ih == ih;
063    }
064
065    public InstructionHandle getInstruction() {
066        return ih;
067    }
068
069    /**
070     * Get LineNumber attribute .
071     *
072     * This relies on that the instruction list has already been dumped to byte code or that the `setPositions' methods
073     * has been called for the instruction list.
074     */
075    public LineNumber getLineNumber() {
076        return new LineNumber(ih.getPosition(), srcLine);
077    }
078
079    public int getSourceLine() {
080        return srcLine;
081    }
082
083    public void setInstruction(final InstructionHandle instructionHandle) { // TODO could be package-protected?
084        Objects.requireNonNull(instructionHandle, "instructionHandle");
085        BranchInstruction.notifyTarget(this.ih, instructionHandle, this);
086        this.ih = instructionHandle;
087    }
088
089    public void setSourceLine(final int src_line) { // TODO could be package-protected?
090        this.srcLine = src_line;
091    }
092
093    /**
094     * @param old_ih old target
095     * @param new_ih new target
096     */
097    @Override
098    public void updateTarget(final InstructionHandle old_ih, final InstructionHandle new_ih) {
099        if (old_ih != ih) {
100            throw new ClassGenException("Not targeting " + old_ih + ", but " + ih + "}");
101        }
102        setInstruction(new_ih);
103    }
104}