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.component.browse;
018    
019    import java.util.List;
020    import java.util.concurrent.CopyOnWriteArrayList;
021    
022    import org.apache.camel.Component;
023    import org.apache.camel.Consumer;
024    import org.apache.camel.Exchange;
025    import org.apache.camel.Processor;
026    import org.apache.camel.Producer;
027    import org.apache.camel.Service;
028    import org.apache.camel.impl.DefaultEndpoint;
029    import org.apache.camel.impl.DefaultProducer;
030    import org.apache.camel.processor.loadbalancer.LoadBalancer;
031    import org.apache.camel.processor.loadbalancer.LoadBalancerConsumer;
032    import org.apache.camel.processor.loadbalancer.TopicLoadBalancer;
033    import org.apache.camel.spi.BrowsableEndpoint;
034    
035    /**
036     * An endpoint which maintains a {@link List} of {@link Exchange} instances
037     * which can be useful for tooling, debugging and visualising routes.
038     *
039     * @version 
040     */
041    public class BrowseEndpoint extends DefaultEndpoint implements BrowsableEndpoint, Service {
042        private List<Exchange> exchanges;
043        private final LoadBalancer loadBalancer = new TopicLoadBalancer();
044    
045        public BrowseEndpoint() {
046        }
047    
048        public BrowseEndpoint(String uri, Component component) {
049            super(uri, component);
050        }
051    
052        public boolean isSingleton() {
053            return true;
054        }
055    
056        public List<Exchange> getExchanges() {
057            if (exchanges == null) {
058                exchanges = createExchangeList();
059            }
060            return exchanges;
061        }
062    
063        public Producer createProducer() throws Exception {
064            return new DefaultProducer(this) {
065                public void process(Exchange exchange) throws Exception {
066                    onExchange(exchange);
067                }
068            };
069        }
070    
071        public Consumer createConsumer(Processor processor) throws Exception {
072            return new LoadBalancerConsumer(this, processor, loadBalancer);
073        }
074    
075        protected List<Exchange> createExchangeList() {
076            return new CopyOnWriteArrayList<Exchange>();
077        }
078    
079        /**
080         * Invoked on a message exchange being sent by a producer
081         *
082         * @param exchange the exchange
083         * @throws Exception is thrown if failed to process the exchange
084         */
085        protected void onExchange(Exchange exchange) throws Exception {
086            getExchanges().add(exchange);
087    
088            // now fire any consumers
089            loadBalancer.process(exchange);
090        }
091    
092        @Override
093        protected void doStart() throws Exception {
094            exchanges = createExchangeList();
095            super.doStart();
096        }
097    
098        @Override
099        protected void doStop() throws Exception {
100            if (exchanges != null) {
101                exchanges.clear();
102                exchanges = null;
103            }
104            super.doStop();
105        }
106    }