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 package org.apache.camel.processor; 018 019 import java.util.Iterator; 020 import java.util.List; 021 022 import org.apache.camel.Exchange; 023 import org.apache.camel.Predicate; 024 import org.apache.camel.Processor; 025 import org.apache.camel.util.ObjectHelper; 026 027 /** 028 * A processor which catches exceptions. 029 * 030 * @version $Revision: 766610 $ 031 */ 032 public class CatchProcessor extends DelegateProcessor { 033 private final List<Class> exceptions; 034 private final Predicate onWhen; 035 private final Predicate handled; 036 037 public CatchProcessor(List<Class> exceptions, Processor processor, Predicate onWhen, Predicate handled) { 038 super(processor); 039 this.exceptions = exceptions; 040 this.onWhen = onWhen; 041 this.handled = handled; 042 } 043 044 @Override 045 public String toString() { 046 return "Catch[" + exceptions + " -> " + getProcessor() + "]"; 047 } 048 049 /** 050 * Whether this catch processor catch the given thrown exception 051 * 052 * @param exchange the current exchange 053 * @param exception the thrown exception 054 * @return <tt>true</tt> if this processor catches it, <tt>false</tt> otherwise. 055 */ 056 public boolean catches(Exchange exchange, Throwable exception) { 057 // use the exception iterator to walk the caused by hierachy 058 Iterator<Throwable> it = ObjectHelper.createExceptionIterator(exception); 059 while (it.hasNext()) { 060 Throwable e = it.next(); 061 // see if we catch this type 062 for (Class type : exceptions) { 063 if (type.isInstance(e) && matchesWhen(exchange)) { 064 return true; 065 } 066 } 067 } 068 069 // not found 070 return false; 071 } 072 073 074 /** 075 * Whether this catch processor handles the exception it have caught 076 * 077 * @param exchange the current exchange 078 * @return <tt>true</tt> if this processor handles it, <tt>false</tt> otherwise. 079 */ 080 public boolean handles(Exchange exchange) { 081 if (handled == null) { 082 // handle by default 083 return true; 084 } 085 086 return handled.matches(exchange); 087 } 088 089 public List<Class> getExceptions() { 090 return exceptions; 091 } 092 093 /** 094 * Strategy method for matching the exception type with the current exchange. 095 * <p/> 096 * This default implementation will match as: 097 * <ul> 098 * <li>Always true if no when predicate on the exception type 099 * <li>Otherwise the when predicate is matches against the current exchange 100 * </ul> 101 * 102 * @param exchange the current {@link org.apache.camel.Exchange} 103 * @return <tt>true</tt> if matched, <tt>false</tt> otherwise. 104 */ 105 protected boolean matchesWhen(Exchange exchange) { 106 if (onWhen == null) { 107 // if no predicate then it's always a match 108 return true; 109 } 110 return onWhen.matches(exchange); 111 } 112 113 }