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 020import java.util.HashMap; 021import java.util.HashSet; 022import java.util.Map; 023import java.util.Set; 024 025import org.apache.bcel.generic.CodeExceptionGen; 026import org.apache.bcel.generic.InstructionHandle; 027import org.apache.bcel.generic.MethodGen; 028 029/** 030 * This class allows easy access to ExceptionHandler objects. 031 */ 032public class ExceptionHandlers { 033 034 /** 035 * Empty array. 036 */ 037 private static final ExceptionHandler[] EMPTY_ARRAY = {}; 038 039 /** 040 * The ExceptionHandler instances. Key: InstructionHandle objects, Values: HashSet<ExceptionHandler> instances. 041 */ 042 private final Map<InstructionHandle, Set<ExceptionHandler>> exceptionHandlers; 043 044 /** 045 * Constructor. Creates a new ExceptionHandlers instance. 046 */ 047 public ExceptionHandlers(final MethodGen mg) { 048 exceptionHandlers = new HashMap<>(); 049 final CodeExceptionGen[] cegs = mg.getExceptionHandlers(); 050 for (final CodeExceptionGen ceg : cegs) { 051 final ExceptionHandler eh = new ExceptionHandler(ceg.getCatchType(), ceg.getHandlerPC()); 052 for (InstructionHandle ih = ceg.getStartPC(); ih != ceg.getEndPC().getNext(); ih = ih.getNext()) { 053 exceptionHandlers.computeIfAbsent(ih, k -> new HashSet<>()).add(eh); 054 exceptionHandlers.computeIfAbsent(ih, k -> new HashSet<>()).add(eh); 055 } 056 } 057 } 058 059 /** 060 * Returns all the ExceptionHandler instances representing exception handlers that protect the instruction ih. 061 */ 062 public ExceptionHandler[] getExceptionHandlers(final InstructionHandle ih) { 063 final Set<ExceptionHandler> hsSet = exceptionHandlers.get(ih); 064 if (hsSet == null) { 065 return EMPTY_ARRAY; 066 } 067 return hsSet.toArray(ExceptionHandler.EMPTY_ARRAY); 068 } 069 070}