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 */
017package org.apache.camel.util;
018
019import java.util.Comparator;
020import java.util.List;
021
022import org.apache.camel.Exchange;
023import org.apache.camel.Expression;
024
025/**
026 * An implementation of {@link java.util.Comparator} which takes a list of
027 * {@link org.apache.camel.Expression} objects which is evaluated
028 * on each exchange to compare them
029 *
030 * @version 
031 */
032public class ExpressionListComparator implements Comparator<Exchange> {
033    private final List<Expression> expressions;
034
035    public ExpressionListComparator(List<Expression> expressions) {
036        this.expressions = expressions;
037    }
038
039    public int compare(Exchange e1, Exchange e2) {
040        for (Expression expression : expressions) {
041            Object o1 = expression.evaluate(e1, Object.class);
042            Object o2 = expression.evaluate(e2, Object.class);
043            int answer = ObjectHelper.compare(o1, o2);
044            if (answer != 0) {
045                return answer;
046            }
047        }
048        return 0;
049    }
050}