001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * https://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 */ 019package org.apache.bcel.verifier.structurals; 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 */ 033public class ExceptionHandlers { 034 035 /** 036 * Empty array. 037 */ 038 private static final ExceptionHandler[] EMPTY_ARRAY = {}; 039 040 /** 041 * The ExceptionHandler instances. Key: InstructionHandle objects, Values: HashSet<ExceptionHandler> instances. 042 */ 043 private final Map<InstructionHandle, Set<ExceptionHandler>> exceptionHandlers; 044 045 /** 046 * Constructs a new ExceptionHandlers instance. 047 */ 048 public ExceptionHandlers(final MethodGen mg) { 049 exceptionHandlers = new HashMap<>(); 050 final CodeExceptionGen[] cegs = mg.getExceptionHandlers(); 051 for (final CodeExceptionGen ceg : cegs) { 052 final ExceptionHandler eh = new ExceptionHandler(ceg.getCatchType(), ceg.getHandlerPC()); 053 for (InstructionHandle ih = ceg.getStartPC(); ih != ceg.getEndPC().getNext(); ih = ih.getNext()) { 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}