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: 788621 $ 031 */ 032 public class CatchProcessor extends DelegateProcessor implements Traceable { 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 public String getTraceLabel() { 050 return "Catch"; 051 } 052 053 /** 054 * Whether this catch processor catch the given thrown exception 055 * 056 * @param exchange the current exchange 057 * @param exception the thrown exception 058 * @return <tt>true</tt> if this processor catches it, <tt>false</tt> otherwise. 059 */ 060 public boolean catches(Exchange exchange, Throwable exception) { 061 // use the exception iterator to walk the caused by hierachy 062 Iterator<Throwable> it = ObjectHelper.createExceptionIterator(exception); 063 while (it.hasNext()) { 064 Throwable e = it.next(); 065 // see if we catch this type 066 for (Class type : exceptions) { 067 if (type.isInstance(e) && matchesWhen(exchange)) { 068 return true; 069 } 070 } 071 } 072 073 // not found 074 return false; 075 } 076 077 078 /** 079 * Whether this catch processor handles the exception it have caught 080 * 081 * @param exchange the current exchange 082 * @return <tt>true</tt> if this processor handles it, <tt>false</tt> otherwise. 083 */ 084 public boolean handles(Exchange exchange) { 085 if (handled == null) { 086 // handle by default 087 return true; 088 } 089 090 return handled.matches(exchange); 091 } 092 093 public List<Class> getExceptions() { 094 return exceptions; 095 } 096 097 /** 098 * Strategy method for matching the exception type with the current exchange. 099 * <p/> 100 * This default implementation will match as: 101 * <ul> 102 * <li>Always true if no when predicate on the exception type 103 * <li>Otherwise the when predicate is matches against the current exchange 104 * </ul> 105 * 106 * @param exchange the current {@link org.apache.camel.Exchange} 107 * @return <tt>true</tt> if matched, <tt>false</tt> otherwise. 108 */ 109 protected boolean matchesWhen(Exchange exchange) { 110 if (onWhen == null) { 111 // if no predicate then it's always a match 112 return true; 113 } 114 return onWhen.matches(exchange); 115 } 116 117 }