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.resequencer; 018 019 import java.util.List; 020 021 import org.apache.camel.Exchange; 022 import org.apache.camel.Expression; 023 024 /** 025 * Compares elements of an {@link Exchange} sequence by comparing 026 * <code>long</code> values returned by this comaprator's 027 * <code>expression</code>. The expression is set during route definition 028 * e.g. 029 * 030 * <pre> 031 * ...resequencer(header("seqnum")).stream()... 032 * </pre> 033 * 034 * @version $Revision: 792319 $ 035 */ 036 public class DefaultExchangeComparator implements ExpressionResultComparator { 037 038 private Expression expression; 039 040 public Expression getExpression() { 041 return expression; 042 } 043 044 public void setExpression(Expression expression) { 045 this.expression = expression; 046 } 047 048 @SuppressWarnings("unchecked") 049 public void setExpressions(List<Expression> expressions) { 050 if (expressions.isEmpty()) { 051 throw new IllegalArgumentException("Expression required to resolve sequence number"); 052 } else if (expressions.size() > 1) { 053 throw new IllegalArgumentException("More than one expression currently not supported"); 054 } 055 expression = expressions.get(0); 056 } 057 058 public boolean predecessor(Exchange o1, Exchange o2) { 059 long n1 = getSequenceNumber(o1); 060 long n2 = getSequenceNumber(o2); 061 return n1 == (n2 - 1L); 062 } 063 064 public boolean successor(Exchange o1, Exchange o2) { 065 long n1 = getSequenceNumber(o1); 066 long n2 = getSequenceNumber(o2); 067 return n2 == (n1 - 1L); 068 } 069 070 public int compare(Exchange o1, Exchange o2) { 071 Long n1 = getSequenceNumber(o1); 072 Long n2 = getSequenceNumber(o2); 073 return n1.compareTo(n2); 074 } 075 076 private long getSequenceNumber(Exchange exchange) { 077 return expression.evaluate(exchange, Long.class); 078 } 079 080 }