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 }