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.processor;
018
019import java.util.Collections;
020import java.util.Comparator;
021import java.util.List;
022
023import org.apache.camel.AsyncCallback;
024import org.apache.camel.AsyncProcessor;
025import org.apache.camel.Exchange;
026import org.apache.camel.Expression;
027import org.apache.camel.Message;
028import org.apache.camel.support.ServiceSupport;
029import org.apache.camel.util.AsyncProcessorHelper;
030
031/**
032 * A processor that sorts the expression using a comparator
033 */
034public class SortProcessor<T> extends ServiceSupport implements AsyncProcessor {
035
036    private final Expression expression;
037    private final Comparator<? super T> comparator;
038
039    public SortProcessor(Expression expression, Comparator<? super T> comparator) {
040        this.expression = expression;
041        this.comparator = comparator;
042    }
043
044    public void process(Exchange exchange) throws Exception {
045        AsyncProcessorHelper.process(this, exchange);
046    }
047
048    @Override
049    public boolean process(Exchange exchange, AsyncCallback callback) {
050        try {
051            Message in = exchange.getIn();
052
053            @SuppressWarnings("unchecked")
054            List<T> list = expression.evaluate(exchange, List.class);
055            Collections.sort(list, comparator);
056
057            if (exchange.getPattern().isOutCapable()) {
058                Message out = exchange.getOut();
059                out.copyFrom(in);
060                out.setBody(list);
061            } else {
062                in.setBody(list);
063            }
064        } catch (Exception e) {
065            exchange.setException(e);
066        }
067
068        callback.done(true);
069        return true;
070    }
071
072    public String toString() {
073        return "Sort[" + expression + "]";
074    }
075
076    @Override
077    protected void doStart() throws Exception {
078        // noop
079    }
080
081    @Override
082    protected void doStop() throws Exception {
083        // noop
084    }
085}
086
087