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 package com.sun.org.apache.bcel.internal.generic;
22
23 import com.sun.org.apache.bcel.internal.classfile.CodeException;
24
25 /**
26 * This class represents an exception handler, i.e., specifies the region where
27 * a handler is active and an instruction where the actual handling is done.
28 * pool as parameters. Opposed to the JVM specification the end of the handled
29 * region is set to be inclusive, i.e. all instructions between start and end
30 * are protected including the start and end instructions (handles) themselves.
31 * The end of the region is automatically mapped to be exclusive when calling
32 * getCodeException(), i.e., there is no difference semantically.
33 *
34 * @see MethodGen
35 * @see CodeException
36 * @see InstructionHandle
37 */
38 public final class CodeExceptionGen implements InstructionTargeter, Cloneable {
39
40 private InstructionHandle start_pc;
41 private InstructionHandle end_pc;
42 private InstructionHandle handler_pc;
43 private ObjectType catch_type;
44
45
46 /**
47 * Add an exception handler, i.e., specify region where a handler is active and an
48 * instruction where the actual handling is done.
49 *
50 * @param start_pc Start of handled region (inclusive)
51 * @param end_pc End of handled region (inclusive)
52 * @param handler_pc Where handling is done
53 * @param catch_type which exception is handled, null for ANY
54 */
55 public CodeExceptionGen(final InstructionHandle start_pc, final InstructionHandle end_pc,
56 final InstructionHandle handler_pc, final ObjectType catch_type) {
57 setStartPC(start_pc);
58 setEndPC(end_pc);
59 setHandlerPC(handler_pc);
60 this.catch_type = catch_type;
61 }
62
63
64 /**
65 * Get CodeException object.<BR>
66 *
67 * This relies on that the instruction list has already been dumped
68 * to byte code or or that the `setPositions' methods has been
69 * called for the instruction list.
70 *
71 * @param cp constant pool
72 */
73 public CodeException getCodeException( final ConstantPoolGen cp ) {
74 return new CodeException(start_pc.getPosition(), end_pc.getPosition()
75 + end_pc.getInstruction().getLength(), handler_pc.getPosition(),
76 (catch_type == null) ? 0 : cp.addClass(catch_type));
77 }
78
79
80 /* Set start of handler
81 * @param start_pc Start of handled region (inclusive)
82 */
83 public void setStartPC( final InstructionHandle start_pc ) { // TODO could be package-protected?
84 BranchInstruction.notifyTarget(this.start_pc, start_pc, this);
85 this.start_pc = start_pc;
86 }
87
88
89 /* Set end of handler
90 * @param end_pc End of handled region (inclusive)
91 */
92 public void setEndPC( final InstructionHandle end_pc ) { // TODO could be package-protected?
93 BranchInstruction.notifyTarget(this.end_pc, end_pc, this);
94 this.end_pc = end_pc;
95 }
96
97
98 /* Set handler code
99 * @param handler_pc Start of handler
100 */
101 public void setHandlerPC( final InstructionHandle handler_pc ) { // TODO could be package-protected?
102 BranchInstruction.notifyTarget(this.handler_pc, handler_pc, this);
103 this.handler_pc = handler_pc;
104 }
105
106
107 /**
108 * @param old_ih old target, either start or end
109 * @param new_ih new target
110 */
111 @Override
112 public void updateTarget( final InstructionHandle old_ih, final InstructionHandle new_ih ) {
113 boolean targeted = false;
114 if (start_pc == old_ih) {
115 targeted = true;
116 setStartPC(new_ih);
117 }
118 if (end_pc == old_ih) {
119 targeted = true;
120 setEndPC(new_ih);
121 }
122 if (handler_pc == old_ih) {
123 targeted = true;
124 setHandlerPC(new_ih);
125 }
126 if (!targeted) {
127 throw new ClassGenException("Not targeting " + old_ih + ", but {" + start_pc + ", "
128 + end_pc + ", " + handler_pc + "}");
129 }
130 }
131
132
133 /**
134 * @return true, if ih is target of this handler
135 */
136 @Override
137 public boolean containsTarget( final InstructionHandle ih ) {
138 return (start_pc == ih) || (end_pc == ih) || (handler_pc == ih);
139 }
140
141
142 /** Sets the type of the Exception to catch. Set 'null' for ANY. */
143 public void setCatchType( final ObjectType catch_type ) {
144 this.catch_type = catch_type;
145 }
146
147
148 /** Gets the type of the Exception to catch, 'null' for ANY. */
149 public ObjectType getCatchType() {
150 return catch_type;
151 }
152
153
154 /** @return start of handled region (inclusive)
155 */
156 public InstructionHandle getStartPC() {
157 return start_pc;
158 }
159
160
161 /** @return end of handled region (inclusive)
162 */
163 public InstructionHandle getEndPC() {
164 return end_pc;
165 }
166
167
168 /** @return start of handler
169 */
170 public InstructionHandle getHandlerPC() {
171 return handler_pc;
172 }
173
174
175 @Override
176 public String toString() {
177 return "CodeExceptionGen(" + start_pc + ", " + end_pc + ", " + handler_pc + ")";
178 }
179
180
181 @Override
182 public Object clone() {
183 try {
184 return super.clone();
185 } catch (final CloneNotSupportedException e) {
186 throw new Error("Clone Not Supported"); // never happens
187 }
188 }
189 }