1 /*
2 * reserved comment block
3 * DO NOT REMOVE OR ALTER!
4 */
5 /*
6 * Licensed to the Apache Software Foundation (ASF) under one or more
7 * contributor license agreements. See the NOTICE file distributed with
8 * this work for additional information regarding copyright ownership.
9 * The ASF licenses this file to You under the Apache License, Version 2.0
10 * (the "License"); you may not use this file except in compliance with
11 * the License. You may obtain a copy of the License at
12 *
13 * http://www.apache.org/licenses/LICENSE-2.0
14 *
15 * Unless required by applicable law or agreed to in writing, software
16 * distributed under the License is distributed on an "AS IS" BASIS,
17 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
18 * See the License for the specific language governing permissions and
19 * limitations under the License.
20 */
21
22 package com.sun.org.apache.bcel.internal.generic;
23
24
25 import com.sun.org.apache.bcel.internal.classfile.*;
26
27 /**
28 * This class represents an exception handler, i.e., specifies the region where
29 * a handler is active and an instruction where the actual handling is done.
30 * pool as parameters. Opposed to the JVM specification the end of the handled
31 * region is set to be inclusive, i.e. all instructions between start and end
32 * are protected including the start and end instructions (handles) themselves.
33 * The end of the region is automatically mapped to be exclusive when calling
34 * getCodeException(), i.e., there is no difference semantically.
35 *
36 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
37 * @see MethodGen
38 * @see CodeException
39 * @see InstructionHandle
40 */
41 public final class CodeExceptionGen
42 implements InstructionTargeter, Cloneable, java.io.Serializable {
43 private InstructionHandle start_pc;
44 private InstructionHandle end_pc;
45 private InstructionHandle handler_pc;
46 private ObjectType catch_type;
47
48 /**
49 * Add an exception handler, i.e., specify region where a handler is active and an
50 * instruction where the actual handling is done.
51 *
52 * @param start_pc Start of handled region (inclusive)
53 * @param end_pc End of handled region (inclusive)
54 * @param handler_pc Where handling is done
55 * @param catch_type which exception is handled, null for ANY
56 */
57 public CodeExceptionGen(InstructionHandle start_pc, InstructionHandle end_pc,
58 InstructionHandle handler_pc, ObjectType catch_type) {
59 setStartPC(start_pc);
60 setEndPC(end_pc);
61 setHandlerPC(handler_pc);
62 this.catch_type = catch_type;
63 }
64
65 /**
66 * Get CodeException object.<BR>
67 *
68 * This relies on that the instruction list has already been dumped
69 * to byte code or or that the `setPositions' methods has been
70 * called for the instruction list.
71 *
72 * @param cp constant pool
73 */
74 public CodeException getCodeException(ConstantPoolGen cp) {
75 return new CodeException(start_pc.getPosition(),
76 end_pc.getPosition() + end_pc.getInstruction().getLength(),
77 handler_pc.getPosition(),
78 (catch_type == null)? 0 : cp.addClass(catch_type));
79 }
80
81 /* Set start of handler
82 * @param start_pc Start of handled region (inclusive)
83 */
84 public final void setStartPC(InstructionHandle start_pc) {
85 BranchInstruction.notifyTargetChanging(this.start_pc, this);
86 this.start_pc = start_pc;
87 BranchInstruction.notifyTargetChanged(this.start_pc, this);
88 }
89
90 /* Set end of handler
91 * @param end_pc End of handled region (inclusive)
92 */
93 public final void setEndPC(InstructionHandle end_pc) {
94 BranchInstruction.notifyTargetChanging(this.end_pc, this);
95 this.end_pc = end_pc;
96 BranchInstruction.notifyTargetChanged(this.end_pc, this);
97 }
98
99 /* Set handler code
100 * @param handler_pc Start of handler
101 */
102 public final void setHandlerPC(InstructionHandle handler_pc) {
103 BranchInstruction.notifyTargetChanging(this.handler_pc, this);
104 this.handler_pc = handler_pc;
105 BranchInstruction.notifyTargetChanged(this.handler_pc, this);
106 }
107
108 /**
109 * @param old_ih old target, either start or end
110 * @param new_ih new target
111 */
112 @Override
113 public void updateTarget(InstructionHandle old_ih, InstructionHandle new_ih) {
114 boolean targeted = false;
115
116 if(start_pc == old_ih) {
117 targeted = true;
118 setStartPC(new_ih);
119 }
120
121 if(end_pc == old_ih) {
122 targeted = true;
123 setEndPC(new_ih);
124 }
125
126 if(handler_pc == old_ih) {
127 targeted = true;
128 setHandlerPC(new_ih);
129 }
130
131 if(!targeted)
132 throw new ClassGenException("Not targeting " + old_ih + ", but {" + start_pc + ", " +
133 end_pc + ", " + handler_pc + "}");
134 }
135
136 /**
137 * @return true, if ih is target of this handler
138 */
139 @Override
140 public boolean containsTarget(InstructionHandle ih) {
141 return (start_pc == ih) || (end_pc == ih) || (handler_pc == ih);
142 }
143
144 /** Sets the type of the Exception to catch. Set 'null' for ANY. */
145 public void setCatchType(ObjectType catch_type) { this.catch_type = catch_type; }
146 /** Gets the type of the Exception to catch, 'null' for ANY. */
147 public ObjectType getCatchType() { return catch_type; }
148
149 /** @return start of handled region (inclusive)
150 */
151 public InstructionHandle getStartPC() { return start_pc; }
152
153 /** @return end of handled region (inclusive)
154 */
155 public InstructionHandle getEndPC() { return end_pc; }
156
157 /** @return start of handler
158 */
159 public InstructionHandle getHandlerPC() { return handler_pc; }
160
161 @Override
162 public String toString() {
163 return "CodeExceptionGen(" + start_pc + ", " + end_pc + ", " + handler_pc + ")";
164 }
165
166 @Override
167 public Object clone() {
168 try {
169 return super.clone();
170 } catch(CloneNotSupportedException e) {
171 System.err.println(e);
172 return null;
173 }
174 }
175 }