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 org.apache.bcel.classfile.CodeException;
20
21 /**
22 * This class represents an exception handler, i.e., specifies the region where a handler is active and an instruction
23 * where the actual handling is done. pool as parameters. Opposed to the JVM specification the end of the handled region
24 * is set to be inclusive, i.e. all instructions between start and end are protected including the start and end
25 * instructions (handles) themselves. The end of the region is automatically mapped to be exclusive when calling
26 * getCodeException(), i.e., there is no difference semantically.
27 *
28 * @see MethodGen
29 * @see CodeException
30 * @see InstructionHandle
31 */
32 public final class CodeExceptionGen implements InstructionTargeter, Cloneable {
33
34 static final CodeExceptionGen[] EMPTY_ARRAY = {};
35
36 private InstructionHandle startPc;
37 private InstructionHandle endPc;
38 private InstructionHandle handlerPc;
39 private ObjectType catchType;
40
41 /**
42 * Add an exception handler, i.e., specify region where a handler is active and an instruction where the actual handling
43 * is done.
44 *
45 * @param startPc Start of handled region (inclusive)
46 * @param endPc End of handled region (inclusive)
47 * @param handlerPc Where handling is done
48 * @param catchType which exception is handled, null for ANY
49 */
50 public CodeExceptionGen(final InstructionHandle startPc, final InstructionHandle endPc, final InstructionHandle handlerPc, final ObjectType catchType) {
51 setStartPC(startPc);
52 setEndPC(endPc);
53 setHandlerPC(handlerPc);
54 this.catchType = catchType;
55 }
56
57 @Override
58 public Object clone() {
59 try {
60 return super.clone();
61 } catch (final CloneNotSupportedException e) {
62 throw new UnsupportedOperationException("Clone Not Supported", e); // never happens
63 }
64 }
65
66 /**
67 * @return true, if ih is target of this handler
68 */
69 @Override
70 public boolean containsTarget(final InstructionHandle ih) {
71 return startPc == ih || endPc == ih || handlerPc == ih;
72 }
73
74 /** Gets the type of the Exception to catch, 'null' for ANY. */
75 public ObjectType getCatchType() {
76 return catchType;
77 }
78
79 /**
80 * Gets CodeException object.<BR>
81 *
82 * This relies on that the instruction list has already been dumped to byte code or that the 'setPositions' methods
83 * has been called for the instruction list.
84 *
85 * @param cp constant pool
86 */
87 public CodeException getCodeException(final ConstantPoolGen cp) {
88 return new CodeException(startPc.getPosition(), endPc.getPosition() + endPc.getInstruction().getLength(), handlerPc.getPosition(),
89 catchType == null ? 0 : cp.addClass(catchType));
90 }
91
92 /**
93 * @return end of handled region (inclusive)
94 */
95 public InstructionHandle getEndPC() {
96 return endPc;
97 }
98
99 /**
100 * @return start of handler
101 */
102 public InstructionHandle getHandlerPC() {
103 return handlerPc;
104 }
105
106 /**
107 * @return start of handled region (inclusive)
108 */
109 public InstructionHandle getStartPC() {
110 return startPc;
111 }
112
113 /** Sets the type of the Exception to catch. Set 'null' for ANY. */
114 public void setCatchType(final ObjectType catchType) {
115 this.catchType = catchType;
116 }
117
118 /*
119 * Sets end of handler
120 *
121 * @param endPc End of handled region (inclusive)
122 */
123 public void setEndPC(final InstructionHandle endPc) { // TODO could be package-protected?
124 BranchInstruction.notifyTarget(this.endPc, endPc, this);
125 this.endPc = endPc;
126 }
127
128 /*
129 * Sets handler code
130 *
131 * @param handlerPc Start of handler
132 */
133 public void setHandlerPC(final InstructionHandle handlerPc) { // TODO could be package-protected?
134 BranchInstruction.notifyTarget(this.handlerPc, handlerPc, this);
135 this.handlerPc = handlerPc;
136 }
137
138 /*
139 * Sets start of handler
140 *
141 * @param startPc Start of handled region (inclusive)
142 */
143 public void setStartPC(final InstructionHandle startPc) { // TODO could be package-protected?
144 BranchInstruction.notifyTarget(this.startPc, startPc, this);
145 this.startPc = startPc;
146 }
147
148 @Override
149 public String toString() {
150 return "CodeExceptionGen(" + startPc + ", " + endPc + ", " + handlerPc + ")";
151 }
152
153 /**
154 * @param oldIh old target, either start or end
155 * @param newIh new target
156 */
157 @Override
158 public void updateTarget(final InstructionHandle oldIh, final InstructionHandle newIh) {
159 boolean targeted = false;
160 if (startPc == oldIh) {
161 targeted = true;
162 setStartPC(newIh);
163 }
164 if (endPc == oldIh) {
165 targeted = true;
166 setEndPC(newIh);
167 }
168 if (handlerPc == oldIh) {
169 targeted = true;
170 setHandlerPC(newIh);
171 }
172 if (!targeted) {
173 throw new ClassGenException("Not targeting " + oldIh + ", but {" + startPc + ", " + endPc + ", " + handlerPc + "}");
174 }
175 }
176 }