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.verifier.structurals;
18
19 import java.util.HashMap;
20 import java.util.HashSet;
21 import java.util.Map;
22 import java.util.Set;
23
24 import org.apache.bcel.generic.CodeExceptionGen;
25 import org.apache.bcel.generic.InstructionHandle;
26 import org.apache.bcel.generic.MethodGen;
27
28 /**
29 * This class allows easy access to ExceptionHandler objects.
30 */
31 public class ExceptionHandlers {
32
33 /**
34 * Empty array.
35 */
36 private static final ExceptionHandler[] EMPTY_ARRAY = {};
37
38 /**
39 * The ExceptionHandler instances. Key: InstructionHandle objects, Values: HashSet<ExceptionHandler> instances.
40 */
41 private final Map<InstructionHandle, Set<ExceptionHandler>> exceptionHandlers;
42
43 /**
44 * Constructs a new ExceptionHandlers instance.
45 */
46 public ExceptionHandlers(final MethodGen mg) {
47 exceptionHandlers = new HashMap<>();
48 final CodeExceptionGen[] cegs = mg.getExceptionHandlers();
49 for (final CodeExceptionGen ceg : cegs) {
50 final ExceptionHandler eh = new ExceptionHandler(ceg.getCatchType(), ceg.getHandlerPC());
51 for (InstructionHandle ih = ceg.getStartPC(); ih != ceg.getEndPC().getNext(); ih = ih.getNext()) {
52 exceptionHandlers.computeIfAbsent(ih, k -> new HashSet<>()).add(eh);
53 }
54 }
55 }
56
57 /**
58 * Returns all the ExceptionHandler instances representing exception handlers that protect the instruction ih.
59 */
60 public ExceptionHandler[] getExceptionHandlers(final InstructionHandle ih) {
61 final Set<ExceptionHandler> hsSet = exceptionHandlers.get(ih);
62 if (hsSet == null) {
63 return EMPTY_ARRAY;
64 }
65 return hsSet.toArray(ExceptionHandler.EMPTY_ARRAY);
66 }
67
68 }