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
026 * a line number corresponding to the source code line.
027 *
028 * @see     LineNumber
029 * @see     MethodGen
030 */
031public class LineNumberGen implements InstructionTargeter, Cloneable {
032
033    private InstructionHandle ih;
034    private int srcLine;
035
036    /**
037     * Create a line number.
038     *
039     * @param ih instruction handle to reference
040     */
041    public LineNumberGen(final InstructionHandle ih, final int src_line) {
042        setInstruction(ih);
043        setSourceLine(src_line);
044    }
045
046
047    /**
048     * @return true, if ih is target of this line number
049     */
050    @Override
051    public boolean containsTarget( final InstructionHandle ih ) {
052        return this.ih == ih;
053    }
054
055
056    /**
057     * @param old_ih old target
058     * @param new_ih new target
059     */
060    @Override
061    public void updateTarget( final InstructionHandle old_ih, final InstructionHandle new_ih ) {
062        if (old_ih != ih) {
063            throw new ClassGenException("Not targeting " + old_ih + ", but " + ih + "}");
064        }
065        setInstruction(new_ih);
066    }
067
068
069    /**
070     * Get LineNumber attribute .
071     *
072     * This relies on that the instruction list has already been dumped to byte code or
073     * or that the `setPositions' methods has been called for the instruction list.
074     */
075    public LineNumber getLineNumber() {
076        return new LineNumber(ih.getPosition(), srcLine);
077    }
078
079
080    public void setInstruction( final InstructionHandle instructionHandle ) { // TODO could be package-protected?
081        Objects.requireNonNull(instructionHandle, "instructionHandle");
082        BranchInstruction.notifyTarget(this.ih, instructionHandle, this);
083        this.ih = instructionHandle;
084    }
085
086
087    @Override
088    public Object clone() {
089        try {
090            return super.clone();
091        } catch (final CloneNotSupportedException e) {
092            throw new Error("Clone Not Supported"); // never happens
093        }
094    }
095
096
097    public InstructionHandle getInstruction() {
098        return ih;
099    }
100
101
102    public void setSourceLine( final int src_line ) { // TODO could be package-protected?
103        this.srcLine = src_line;
104    }
105
106
107    public int getSourceLine() {
108        return srcLine;
109    }
110}