    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one
    003 * or more contributor license agreements.  See the NOTICE file
    004 * distributed with this work for additional information
    005 * regarding copyright ownership.  The ASF licenses this file
    006 * to you under the Apache License, Version 2.0 (the
    007 * "License"); you may not use this file except in compliance
    008 * with the License.  You may obtain a copy of the License at
    009 *
    010 *   https://www.apache.org/licenses/LICENSE-2.0
    011 *
    012 * Unless required by applicable law or agreed to in writing,
    013 * software distributed under the License is distributed on an
    014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015 * KIND, either express or implied.  See the License for the
    016 * specific language governing permissions and limitations
    017 * under the License.
    018 */
    019package org.apache.bcel.generic;
    020
    021import java.util.Objects;
    022
    023import org.apache.bcel.classfile.LineNumber;
    024
    025/**
    026 * This class represents a line number within a method, that is, give an instruction a line number corresponding to the
    027 * source code line.
    028 *
    029 * @see LineNumber
    030 * @see MethodGen
    031 */
    032public class LineNumberGen implements InstructionTargeter, Cloneable {
    033
    034    static final LineNumberGen[] EMPTY_ARRAY = {};
    035
    036    private InstructionHandle ih;
    037    private int srcLine;
    038
    039    /**
    040     * Create a line number.
    041     *
    042     * @param ih instruction handle to reference.
    043     */
    044    public LineNumberGen(final InstructionHandle ih, final int srcLine) {
    045        setInstruction(ih);
    046        setSourceLine(srcLine);
    047    }
    048
    049    @Override
    050    public Object clone() {
    051        try {
    052            return super.clone();
    053        } catch (final CloneNotSupportedException e) {
    054            throw new UnsupportedOperationException("Clone Not Supported", e); // never happens
    055        }
    056    }
    057
    058    /**
    059     * @return true, if ih is target of this line number.
    060     */
    061    @Override
    062    public boolean containsTarget(final InstructionHandle ih) {
    063        return this.ih == ih;
    064    }
    065
    066    public InstructionHandle getInstruction() {
    067        return ih;
    068    }
    069
    070    /**
    071     * Gets LineNumber attribute.
    072     *
    073     * This relies on that the instruction list has already been dumped to byte code or that the 'setPositions' methods
    074     * has been called for the instruction list.
    075     */
    076    public LineNumber getLineNumber() {
    077        return new LineNumber(ih.getPosition(), srcLine);
    078    }
    079
    080    public int getSourceLine() {
    081        return srcLine;
    082    }
    083
    084    public void setInstruction(final InstructionHandle instructionHandle) { // TODO could be package-protected?
    085        Objects.requireNonNull(instructionHandle, "instructionHandle");
    086        BranchInstruction.notifyTarget(this.ih, instructionHandle, this);
    087        this.ih = instructionHandle;
    088    }
    089
    090    public void setSourceLine(final int srcLine) { // TODO could be package-protected?
    091        this.srcLine = srcLine;
    092    }
    093
    094    /**
    095     * @param oldIh old target.
    096     * @param newIh new target.
    097     */
    098    @Override
    099    public void updateTarget(final InstructionHandle oldIh, final InstructionHandle newIh) {
    100        if (oldIh != ih) {
    101            throw new ClassGenException("Not targeting " + oldIh + ", but " + ih + "}");
    102        }
    103        setInstruction(newIh);
    104    }
    105}