001 /** 002 * 003 * Licensed to the Apache Software Foundation (ASF) under one or more 004 * contributor license agreements. See the NOTICE file distributed with 005 * this work for additional information regarding copyright ownership. 006 * The ASF licenses this file to You under the Apache License, Version 2.0 007 * (the "License"); you may not use this file except in compliance with 008 * the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018 package org.apache.camel.util; 019 020 import org.apache.camel.Exchange; 021 import org.apache.camel.Expression; 022 023 import java.util.Comparator; 024 025 /** 026 * An implementation of {@link Comparator} which takes an {@link Expression} which is evaluated 027 * on each exchange to compare 028 * 029 * @version $Revision: 1.1 $ 030 */ 031 public class ExpressionComparator<E extends Exchange> implements Comparator<E> { 032 private final Expression<E> expression; 033 034 public ExpressionComparator(Expression<E> expression) { 035 this.expression = expression; 036 } 037 038 public int compare(E e1, E e2) { 039 Object o1 = expression.evaluate(e1); 040 Object o2 = expression.evaluate(e2); 041 return ObjectHelper.compare(o1, o2); 042 } 043 }