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.direct;
018    
019    import java.util.List;
020    import java.util.concurrent.CopyOnWriteArrayList;
021    
022    import org.apache.camel.Consumer;
023    import org.apache.camel.Exchange;
024    import org.apache.camel.Processor;
025    import org.apache.camel.Producer;
026    import org.apache.camel.impl.DefaultConsumer;
027    import org.apache.camel.impl.DefaultEndpoint;
028    import org.apache.commons.logging.Log;
029    import org.apache.commons.logging.LogFactory;
030    
031    /**
032     * Represents a direct endpoint that synchronously invokes the consumers of the
033     * endpoint when a producer sends a message to it.
034     *
035     * @version $Revision: 41910 $
036     */
037    public class DirectEndpoint<E extends Exchange> extends DefaultEndpoint<E> {
038        private static final transient Log LOG = LogFactory.getLog(DirectEndpoint.class);
039        private boolean allowMultipleConsumers = true;
040        private final CopyOnWriteArrayList<DefaultConsumer<E>> consumers = new CopyOnWriteArrayList<DefaultConsumer<E>>();
041    
042        public DirectEndpoint(String uri, DirectComponent<E> component) {
043            super(uri, component);
044        }
045    
046        public DirectEndpoint(String endpointUri) {
047            super(endpointUri);
048        }
049    
050        public Producer createProducer() throws Exception {
051            return new DirectProducer<E>(this);
052        }
053    
054        public Consumer<E> createConsumer(Processor processor) throws Exception {
055            return new DefaultConsumer<E>(this, processor) {
056                @Override
057                public void start() throws Exception {
058                    if (!allowMultipleConsumers && !consumers.isEmpty()) {
059                        throw new IllegalStateException("Endpoint " + getEndpointUri() + " only allows 1 active consumer but you attempted to start a 2nd consumer.");
060                    }
061    
062                    consumers.add(this);
063                    super.start();
064                }
065    
066                @Override
067                public void stop() throws Exception {
068                    super.stop();
069                    consumers.remove(this);
070                }
071            };
072        }
073    
074        public boolean isAllowMultipleConsumers() {
075            return allowMultipleConsumers;
076        }
077    
078        public void setAllowMultipleConsumers(boolean allowMutlipleConsumers) {
079            this.allowMultipleConsumers = allowMutlipleConsumers;
080        }
081    
082        public boolean isSingleton() {
083            return true;
084        }
085    
086        public List<DefaultConsumer<E>> getConsumers() {
087            return consumers;
088        }
089    }