1 package serp.bytecode;
2
3 import java.io.*;
4 import java.util.*;
5
6 import serp.bytecode.lowlevel.*;
7 import serp.bytecode.visitor.*;
8
9 /***
10 * A line number corresponds to a sequence of opcodes that map logically
11 * to a line of source code.
12 *
13 * @author Abe White
14 */
15 public class LineNumber implements Comparable, InstructionPtr, BCEntity,
16 VisitAcceptor {
17 private int _line = 0;
18 private LineNumberTable _owner = null;
19 InstructionPtrStrategy _target = new InstructionPtrStrategy(this);
20
21 LineNumber(LineNumberTable owner) {
22 _owner = owner;
23 }
24
25 LineNumber(LineNumberTable owner, int startPc) {
26 this(owner);
27 setStartPc(startPc);
28 }
29
30 /***
31 * Line numbers are stored in a {@link LineNumberTable}.
32 */
33 public LineNumberTable getTable() {
34 return _owner;
35 }
36
37 void invalidate() {
38 _owner = null;
39 }
40
41 /***
42 * Return source line number.
43 */
44 public int getLine() {
45 return _line;
46 }
47
48 /***
49 * Set the source line number.
50 */
51 public void setLine(int lineNumber) {
52 _line = lineNumber;
53 }
54
55 /***
56 * Return the instruction marking the beginning of this line.
57 */
58 public Instruction getStart() {
59 return _target.getTargetInstruction();
60 }
61
62 /***
63 * Return the index into the code byte array at which this line starts.
64 */
65 public int getStartPc() {
66 return _target.getByteIndex();
67 }
68
69 /***
70 * Set the index into the code byte array at which this line starts.
71 */
72 public void setStartPc(int startPc) {
73 _target.setByteIndex(startPc);
74 }
75
76 /***
77 * Set the {@link Instruction} marking the beginning this line.
78 * The instruction must already be a part of the method.
79 */
80 public void setStart(Instruction instruction) {
81 _target.setTargetInstruction(instruction);
82 }
83
84 public void updateTargets() {
85 _target.updateTargets();
86 }
87
88 public void replaceTarget(Instruction oldTarget, Instruction newTarget) {
89 _target.replaceTarget(oldTarget, newTarget);
90 }
91
92 public Project getProject() {
93 return _owner.getProject();
94 }
95
96 public ConstantPool getPool() {
97 return _owner.getPool();
98 }
99
100 public ClassLoader getClassLoader() {
101 return _owner.getClassLoader();
102 }
103
104 public boolean isValid() {
105 return _owner != null;
106 }
107
108 public void acceptVisit(BCVisitor visit) {
109 visit.enterLineNumber(this);
110 visit.exitLineNumber(this);
111 }
112
113 public int compareTo(Object other) {
114 if (!(other instanceof LineNumber))
115 return -1;
116
117 LineNumber ln = (LineNumber) other;
118 if (getStartPc() == ln.getStartPc())
119 return 0;
120 if (getStartPc() < ln.getStartPc())
121 return -1;
122 return 1;
123 }
124
125 void read(DataInput in) throws IOException {
126 setStartPc(in.readUnsignedShort());
127 setLine(in.readUnsignedShort());
128 }
129
130 void write(DataOutput out) throws IOException {
131 out.writeShort(getStartPc());
132 out.writeShort(getLine());
133 }
134
135 public Code getCode() {
136 return _owner.getCode();
137 }
138 }