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.impl;
018
019import java.util.concurrent.ScheduledExecutorService;
020
021import org.apache.camel.Endpoint;
022import org.apache.camel.Exchange;
023import org.apache.camel.PollingConsumer;
024import org.apache.camel.Processor;
025import org.apache.camel.util.ServiceHelper;
026
027/**
028 * A default implementation of an event driven {@link org.apache.camel.Consumer} which uses the
029 * {@link PollingConsumer}
030 *
031 * @version 
032 */
033public class DefaultScheduledPollConsumer extends ScheduledPollConsumer {
034    private PollingConsumer pollingConsumer;
035
036    public DefaultScheduledPollConsumer(DefaultEndpoint defaultEndpoint, Processor processor) {
037        super(defaultEndpoint, processor);
038    }
039
040    public DefaultScheduledPollConsumer(Endpoint endpoint, Processor processor, ScheduledExecutorService executor) {
041        super(endpoint, processor, executor);
042    }
043
044    protected int poll() throws Exception {
045        int messagesPolled = 0;
046
047        while (isPollAllowed()) {
048            Exchange exchange = pollingConsumer.receiveNoWait();
049            if (exchange == null) {
050                break;
051            }
052
053            messagesPolled++;
054            log.trace("Polled {} {}", messagesPolled, exchange);
055
056            // if the result of the polled exchange has output we should create a new exchange and
057            // use the output as input to the next processor
058            if (exchange.hasOut()) {
059                // lets create a new exchange
060                Exchange newExchange = getEndpoint().createExchange();
061                newExchange.getIn().copyFrom(exchange.getOut());
062                exchange = newExchange;
063            }
064            getProcessor().process(exchange);
065        }
066
067        return messagesPolled;
068    }
069
070    @Override
071    protected void doStart() throws Exception {
072        pollingConsumer = getEndpoint().createPollingConsumer();
073        ServiceHelper.startService(pollingConsumer);
074        super.doStart();
075    }
076
077    @Override
078    protected void doStop() throws Exception {
079        ServiceHelper.stopService(pollingConsumer);
080        super.doStop();
081    }
082}