1 /*
2  * Licensed to the Apache Software Foundation (ASF) under one or more
3  * contributor license agreements.  See the NOTICE file distributed with
4  * this work for additional information regarding copyright ownership.
5  * The ASF licenses this file to You under the Apache License, Version 2.0
6  * (the "License"); you may not use this file except in compliance with
7  * the License.  You may obtain a copy of the License at
8  *
9  *      http://www.apache.org/licenses/LICENSE-2.0
10  *
11  *  Unless required by applicable law or agreed to in writing, software
12  *  distributed under the License is distributed on an "AS IS" BASIS,
13  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  *  See the License for the specific language governing permissions and
15  *  limitations under the License.
16  *
17  */
18 package org.apache.bcel.generic;
19 
20 import org.apache.bcel.classfile.LineNumber;
21 
22 /**
23  * This class represents a line number within a method, i.e., give an instruction
24  * a line number corresponding to the source code line.
25  *
26  * @version $Id$
27  * @see     LineNumber
28  * @see     MethodGen
29  */
30 public class LineNumberGen implements InstructionTargeter, Cloneable {
31 
32     private InstructionHandle ih;
33     private int src_line;
34 
35 
36     /**
37      * Create a line number.
38      *
39      * @param ih instruction handle to reference
40      */
LineNumberGen(final InstructionHandle ih, final int src_line)41     public LineNumberGen(final InstructionHandle ih, final int src_line) {
42         setInstruction(ih);
43         setSourceLine(src_line);
44     }
45 
46 
47     /**
48      * @return true, if ih is target of this line number
49      */
50     @Override
containsTarget( final InstructionHandle ih )51     public boolean containsTarget( final InstructionHandle ih ) {
52         return this.ih == ih;
53     }
54 
55 
56     /**
57      * @param old_ih old target
58      * @param new_ih new target
59      */
60     @Override
updateTarget( final InstructionHandle old_ih, final InstructionHandle new_ih )61     public void updateTarget( final InstructionHandle old_ih, final InstructionHandle new_ih ) {
62         if (old_ih != ih) {
63             throw new ClassGenException("Not targeting " + old_ih + ", but " + ih + "}");
64         }
65         setInstruction(new_ih);
66     }
67 
68 
69     /**
70      * Get LineNumber attribute .
71      *
72      * This relies on that the instruction list has already been dumped to byte code or
73      * or that the `setPositions' methods has been called for the instruction list.
74      */
getLineNumber()75     public LineNumber getLineNumber() {
76         return new LineNumber(ih.getPosition(), src_line);
77     }
78 
79 
setInstruction( final InstructionHandle ih )80     public void setInstruction( final InstructionHandle ih ) { // TODO could be package-protected?
81         if (ih == null) {
82             throw new NullPointerException("InstructionHandle may not be null");
83         }
84         BranchInstruction.notifyTarget(this.ih, ih, this);
85         this.ih = ih;
86     }
87 
88 
89     @Override
clone()90     public Object clone() {
91         try {
92             return super.clone();
93         } catch (final CloneNotSupportedException e) {
94             throw new Error("Clone Not Supported"); // never happens
95         }
96     }
97 
98 
getInstruction()99     public InstructionHandle getInstruction() {
100         return ih;
101     }
102 
103 
setSourceLine( final int src_line )104     public void setSourceLine( final int src_line ) { // TODO could be package-protected?
105         this.src_line = src_line;
106     }
107 
108 
getSourceLine()109     public int getSourceLine() {
110         return src_line;
111     }
112 }
113