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.Comparator;
020 import java.util.Set;
021 import java.util.TreeSet;
022
023 import org.apache.camel.CamelContext;
024 import org.apache.camel.Exchange;
025 import org.apache.camel.Expression;
026 import org.apache.camel.Processor;
027 import org.apache.camel.Traceable;
028 import org.apache.camel.util.ExpressionComparator;
029
030 /**
031 * An implementation of the <a href="http://camel.apache.org/resequencer.html">Resequencer</a>
032 * which can reorder messages within a batch.
033 *
034 * @version
035 */
036 @SuppressWarnings("deprecation")
037 public class Resequencer extends BatchProcessor implements Traceable {
038
039 // TODO: Rework to avoid using BatchProcessor
040
041 public Resequencer(CamelContext camelContext, Processor processor, Expression expression) {
042 this(camelContext, processor, createSet(expression, false, false), expression);
043 }
044
045 public Resequencer(CamelContext camelContext, Processor processor, Expression expression,
046 boolean allowDuplicates, boolean reverse) {
047 this(camelContext, processor, createSet(expression, allowDuplicates, reverse), expression);
048 }
049
050 public Resequencer(CamelContext camelContext, Processor processor, Set<Exchange> collection, Expression expression) {
051 super(camelContext, processor, collection, expression);
052 }
053
054 @Override
055 public String toString() {
056 return "Resequencer[to: " + getProcessor() + "]";
057 }
058
059 public String getTraceLabel() {
060 return "resequencer";
061 }
062
063 // Implementation methods
064 //-------------------------------------------------------------------------
065
066 protected static Set<Exchange> createSet(Expression expression, boolean allowDuplicates, boolean reverse) {
067 return createSet(new ExpressionComparator(expression), allowDuplicates, reverse);
068 }
069
070 protected static Set<Exchange> createSet(final Comparator<? super Exchange> comparator, boolean allowDuplicates, boolean reverse) {
071 Comparator<? super Exchange> answer = comparator;
072
073 if (reverse) {
074 answer = new Comparator<Exchange>() {
075 public int compare(Exchange o1, Exchange o2) {
076 int answer = comparator.compare(o1, o2);
077 // reverse it
078 return answer * -1;
079 }
080 };
081 }
082
083 // if we allow duplicates then we need to cater for that in the comparator
084 final Comparator<? super Exchange> forAllowDuplicates = answer;
085 if (allowDuplicates) {
086 answer = new Comparator<Exchange>() {
087 public int compare(Exchange o1, Exchange o2) {
088 int answer = forAllowDuplicates.compare(o1, o2);
089 if (answer == 0) {
090 // they are equal but we should allow duplicates so say that o2 is higher
091 // so it will come next
092 return 1;
093 }
094 return answer;
095 }
096 };
097 }
098
099 return new TreeSet<Exchange>(answer);
100 }
101
102 }