    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 org.apache.bcel.classfile.LineNumber;
    021
    022/**
    023 * This class represents a line number within a method, i.e., give an instruction
    024 * a line number corresponding to the source code line.
    025 *
    026 * @see     LineNumber
    027 * @see     MethodGen
    028 */
    029public class LineNumberGen implements InstructionTargeter, Cloneable {
    030
    031    private InstructionHandle ih;
    032    private int src_line;
    033
    034
    035    /**
    036     * Create a line number.
    037     *
    038     * @param ih instruction handle to reference
    039     */
    040    public LineNumberGen(final InstructionHandle ih, final int src_line) {
    041        setInstruction(ih);
    042        setSourceLine(src_line);
    043    }
    044
    045
    046    /**
    047     * @return true, if ih is target of this line number
    048     */
    049    @Override
    050    public boolean containsTarget( final InstructionHandle ih ) {
    051        return this.ih == ih;
    052    }
    053
    054
    055    /**
    056     * @param old_ih old target
    057     * @param new_ih new target
    058     */
    059    @Override
    060    public void updateTarget( final InstructionHandle old_ih, final InstructionHandle new_ih ) {
    061        if (old_ih != ih) {
    062            throw new ClassGenException("Not targeting " + old_ih + ", but " + ih + "}");
    063        }
    064        setInstruction(new_ih);
    065    }
    066
    067
    068    /**
    069     * Get LineNumber attribute .
    070     *
    071     * This relies on that the instruction list has already been dumped to byte code or
    072     * or that the `setPositions' methods has been called for the instruction list.
    073     */
    074    public LineNumber getLineNumber() {
    075        return new LineNumber(ih.getPosition(), src_line);
    076    }
    077
    078
    079    public void setInstruction( final InstructionHandle ih ) { // TODO could be package-protected?
    080        if (ih == null) {
    081            throw new NullPointerException("InstructionHandle may not be null");
    082        }
    083        BranchInstruction.notifyTarget(this.ih, ih, this);
    084        this.ih = ih;
    085    }
    086
    087
    088    @Override
    089    public Object clone() {
    090        try {
    091            return super.clone();
    092        } catch (final CloneNotSupportedException e) {
    093            throw new Error("Clone Not Supported"); // never happens
    094        }
    095    }
    096
    097
    098    public InstructionHandle getInstruction() {
    099        return ih;
    100    }
    101
    102
    103    public void setSourceLine( final int src_line ) { // TODO could be package-protected?
    104        this.src_line = src_line;
    105    }
    106
    107
    108    public int getSourceLine() {
    109        return src_line;
    110    }
    111}