001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 *  Unless required by applicable law or agreed to in writing, software
012 *  distributed under the License is distributed on an "AS IS" BASIS,
013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 *  See the License for the specific language governing permissions and
015 *  limitations under the License.
016 *
017 */
018package org.apache.bcel.verifier.structurals;
019
020
021import java.util.HashMap;
022import java.util.HashSet;
023import java.util.Map;
024import java.util.Set;
025
026import org.apache.bcel.generic.CodeExceptionGen;
027import org.apache.bcel.generic.InstructionHandle;
028import org.apache.bcel.generic.MethodGen;
029
030/**
031 * This class allows easy access to ExceptionHandler objects.
032 *
033 */
034public class ExceptionHandlers{
035    /**
036     * The ExceptionHandler instances.
037     * Key: InstructionHandle objects, Values: HashSet<ExceptionHandler> instances.
038     */
039    private final Map<InstructionHandle, Set<ExceptionHandler>> exceptionHandlers;
040
041    /**
042     * Constructor. Creates a new ExceptionHandlers instance.
043     */
044    public ExceptionHandlers(final MethodGen mg) {
045        exceptionHandlers = new HashMap<>();
046        final CodeExceptionGen[] cegs = mg.getExceptionHandlers();
047        for (final CodeExceptionGen ceg : cegs) {
048            final ExceptionHandler eh = new ExceptionHandler(ceg.getCatchType(), ceg.getHandlerPC());
049            for (InstructionHandle ih=ceg.getStartPC(); ih != ceg.getEndPC().getNext(); ih=ih.getNext()) {
050                Set<ExceptionHandler> hs;
051                hs = exceptionHandlers.get(ih);
052                if (hs == null) {
053                    hs = new HashSet<>();
054                    exceptionHandlers.put(ih, hs);
055                }
056                hs.add(eh);
057            }
058        }
059    }
060
061    /**
062     * Returns all the ExceptionHandler instances representing exception
063     * handlers that protect the instruction ih.
064     */
065    public ExceptionHandler[] getExceptionHandlers(final InstructionHandle ih) {
066        final Set<ExceptionHandler> hsSet = exceptionHandlers.get(ih);
067        if (hsSet == null) {
068            return new ExceptionHandler[0];
069        }
070        return hsSet.toArray(new ExceptionHandler[hsSet.size()]);
071    }
072
073}