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 * @version $Id$
35 * @see MethodGen
36 * @see CodeException
37 * @see InstructionHandle
38 */
39 public final class CodeExceptionGen implements InstructionTargeter, Cloneable {
40
41 private InstructionHandle start_pc;
42 private InstructionHandle end_pc;
43 private InstructionHandle handler_pc;
44 private ObjectType catch_type;
45
46
47 /**
48 * Add an exception handler, i.e., specify region where a handler is active and an
49 * instruction where the actual handling is done.
50 *
51 * @param start_pc Start of handled region (inclusive)
52 * @param end_pc End of handled region (inclusive)
53 * @param handler_pc Where handling is done
54 * @param catch_type which exception is handled, null for ANY
55 */
56 public CodeExceptionGen(final InstructionHandle start_pc, final InstructionHandle end_pc,
57 final InstructionHandle handler_pc, final ObjectType catch_type) {
58 setStartPC(start_pc);
59 setEndPC(end_pc);
60 setHandlerPC(handler_pc);
61 this.catch_type = catch_type;
62 }
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( final ConstantPoolGen cp ) {
75 return new CodeException(start_pc.getPosition(), end_pc.getPosition()
76 + end_pc.getInstruction().getLength(), handler_pc.getPosition(),
77 (catch_type == null) ? 0 : cp.addClass(catch_type));
78 }
79
80
81 /* Set start of handler
82 * @param start_pc Start of handled region (inclusive)
83 */
84 public void setStartPC( final InstructionHandle start_pc ) { // TODO could be package-protected?
85 BranchInstruction.notifyTarget(this.start_pc, start_pc, this);
86 this.start_pc = start_pc;
87 }
88
89
90 /* Set end of handler
91 * @param end_pc End of handled region (inclusive)
92 */
93 public void setEndPC( final InstructionHandle end_pc ) { // TODO could be package-protected?
94 BranchInstruction.notifyTarget(this.end_pc, end_pc, this);
95 this.end_pc = end_pc;
96 }
97
98
99 /* Set handler code
100 * @param handler_pc Start of handler
101 */
102 public void setHandlerPC( final InstructionHandle handler_pc ) { // TODO could be package-protected?
103 BranchInstruction.notifyTarget(this.handler_pc, handler_pc, this);
104 this.handler_pc = handler_pc;
105 }
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( final InstructionHandle old_ih, final InstructionHandle new_ih ) {
114 boolean targeted = false;
115 if (start_pc == old_ih) {
116 targeted = true;
117 setStartPC(new_ih);
118 }
119 if (end_pc == old_ih) {
120 targeted = true;
121 setEndPC(new_ih);
122 }
123 if (handler_pc == old_ih) {
124 targeted = true;
125 setHandlerPC(new_ih);
126 }
127 if (!targeted) {
128 throw new ClassGenException("Not targeting " + old_ih + ", but {" + start_pc + ", "
129 + end_pc + ", " + handler_pc + "}");
130 }
131 }
132
133
134 /**
135 * @return true, if ih is target of this handler
136 */
137 @Override
138 public boolean containsTarget( final InstructionHandle ih ) {
139 return (start_pc == ih) || (end_pc == ih) || (handler_pc == ih);
140 }
141
142
143 /** Sets the type of the Exception to catch. Set 'null' for ANY. */
144 public void setCatchType( final ObjectType catch_type ) {
145 this.catch_type = catch_type;
146 }
147
148
149 /** Gets the type of the Exception to catch, 'null' for ANY. */
150 public ObjectType getCatchType() {
151 return catch_type;
152 }
153
154
155 /** @return start of handled region (inclusive)
156 */
157 public InstructionHandle getStartPC() {
158 return start_pc;
159 }
160
161
162 /** @return end of handled region (inclusive)
163 */
164 public InstructionHandle getEndPC() {
165 return end_pc;
166 }
167
168
169 /** @return start of handler
170 */
171 public InstructionHandle getHandlerPC() {
172 return handler_pc;
173 }
174
175
176 @Override
177 public String toString() {
178 return "CodeExceptionGen(" + start_pc + ", " + end_pc + ", " + handler_pc + ")";
179 }
180
181
182 @Override
183 public Object clone() {
184 try {
185 return super.clone();
186 } catch (final CloneNotSupportedException e) {
187 throw new Error("Clone Not Supported"); // never happens
188 }
189 }
190 }