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 package org.apache.bcel.generic;
18
19 import java.util.Objects;
20
21 import org.apache.bcel.classfile.LineNumber;
22
23 /**
24 * This class represents a line number within a method, i.e., give an instruction a line number corresponding to the
25 * source code line.
26 *
27 * @see LineNumber
28 * @see MethodGen
29 */
30 public class LineNumberGen implements InstructionTargeter, Cloneable {
31
32 static final LineNumberGen[] EMPTY_ARRAY = {};
33
34 private InstructionHandle ih;
35 private int srcLine;
36
37 /**
38 * Create a line number.
39 *
40 * @param ih instruction handle to reference
41 */
42 public LineNumberGen(final InstructionHandle ih, final int srcLine) {
43 setInstruction(ih);
44 setSourceLine(srcLine);
45 }
46
47 @Override
48 public Object clone() {
49 try {
50 return super.clone();
51 } catch (final CloneNotSupportedException e) {
52 throw new UnsupportedOperationException("Clone Not Supported", e); // never happens
53 }
54 }
55
56 /**
57 * @return true, if ih is target of this line number
58 */
59 @Override
60 public boolean containsTarget(final InstructionHandle ih) {
61 return this.ih == ih;
62 }
63
64 public InstructionHandle getInstruction() {
65 return ih;
66 }
67
68 /**
69 * Gets LineNumber attribute.
70 *
71 * This relies on that the instruction list has already been dumped to byte code or that the 'setPositions' methods
72 * has been called for the instruction list.
73 */
74 public LineNumber getLineNumber() {
75 return new LineNumber(ih.getPosition(), srcLine);
76 }
77
78 public int getSourceLine() {
79 return srcLine;
80 }
81
82 public void setInstruction(final InstructionHandle instructionHandle) { // TODO could be package-protected?
83 Objects.requireNonNull(instructionHandle, "instructionHandle");
84 BranchInstruction.notifyTarget(this.ih, instructionHandle, this);
85 this.ih = instructionHandle;
86 }
87
88 public void setSourceLine(final int srcLine) { // TODO could be package-protected?
89 this.srcLine = srcLine;
90 }
91
92 /**
93 * @param oldIh old target
94 * @param newIh new target
95 */
96 @Override
97 public void updateTarget(final InstructionHandle oldIh, final InstructionHandle newIh) {
98 if (oldIh != ih) {
99 throw new ClassGenException("Not targeting " + oldIh + ", but " + ih + "}");
100 }
101 setInstruction(newIh);
102 }
103 }