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.Collections;
020    import java.util.Comparator;
021    import java.util.List;
022    
023    import org.apache.camel.AsyncCallback;
024    import org.apache.camel.AsyncProcessor;
025    import org.apache.camel.Exchange;
026    import org.apache.camel.Expression;
027    import org.apache.camel.Message;
028    import org.apache.camel.support.ServiceSupport;
029    import org.apache.camel.util.AsyncProcessorHelper;
030    
031    /**
032     * A processor that sorts the expression using a comparator
033     */
034    public 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