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 * @version $Id: ExceptionHandlers.java 1749603 2016-06-21 20:50:19Z ggregory $
034 */
035public class ExceptionHandlers{
036    /**
037     * The ExceptionHandler instances.
038     * Key: InstructionHandle objects, Values: HashSet<ExceptionHandler> instances.
039     */
040    private final Map<InstructionHandle, Set<ExceptionHandler>> exceptionhandlers;
041
042    /**
043     * Constructor. Creates a new ExceptionHandlers instance.
044     */
045    public ExceptionHandlers(final MethodGen mg) {
046        exceptionhandlers = new HashMap<>();
047        final CodeExceptionGen[] cegs = mg.getExceptionHandlers();
048        for (final CodeExceptionGen ceg : cegs) {
049            final ExceptionHandler eh = new ExceptionHandler(ceg.getCatchType(), ceg.getHandlerPC());
050            for (InstructionHandle ih=ceg.getStartPC(); ih != ceg.getEndPC().getNext(); ih=ih.getNext()) {
051                Set<ExceptionHandler> hs;
052                hs = exceptionhandlers.get(ih);
053                if (hs == null) {
054                    hs = new HashSet<>();
055                    exceptionhandlers.put(ih, hs);
056                }
057                hs.add(eh);
058            }
059        }
060    }
061
062    /**
063     * Returns all the ExceptionHandler instances representing exception
064     * handlers that protect the instruction ih.
065     */
066    public ExceptionHandler[] getExceptionHandlers(final InstructionHandle ih) {
067        final Set<ExceptionHandler> hsSet = exceptionhandlers.get(ih);
068        if (hsSet == null) {
069            return new ExceptionHandler[0];
070        }
071        return hsSet.toArray(new ExceptionHandler[hsSet.size()]);
072    }
073
074}