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 * @version $Id: LineNumberGen.java 1749603 2016-06-21 20:50:19Z ggregory $
027 * @see     LineNumber
028 * @see     MethodGen
029 */
030public class LineNumberGen implements InstructionTargeter, Cloneable {
031
032    private InstructionHandle ih;
033    private int src_line;
034
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(), src_line);
077    }
078
079
080    public void setInstruction( final InstructionHandle ih ) { // TODO could be package-protected?
081        if (ih == null) {
082            throw new NullPointerException("InstructionHandle may not be null");
083        }
084        BranchInstruction.notifyTarget(this.ih, ih, this);
085        this.ih = ih;
086    }
087
088
089    @Override
090    public Object clone() {
091        try {
092            return super.clone();
093        } catch (final CloneNotSupportedException e) {
094            throw new Error("Clone Not Supported"); // never happens
095        }
096    }
097
098
099    public InstructionHandle getInstruction() {
100        return ih;
101    }
102
103
104    public void setSourceLine( final int src_line ) { // TODO could be package-protected?
105        this.src_line = src_line;
106    }
107
108
109    public int getSourceLine() {
110        return src_line;
111    }
112}