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.concurrent.CopyOnWriteArrayList;
020
021 import org.apache.camel.Consumer;
022 import org.apache.camel.Exchange;
023 import org.apache.camel.Processor;
024 import org.apache.camel.Producer;
025 import org.apache.camel.impl.DefaultConsumer;
026 import org.apache.camel.impl.DefaultEndpoint;
027 import org.apache.camel.impl.DefaultExchange;
028 import org.apache.camel.impl.DefaultProducer;
029 import org.apache.commons.logging.Log;
030 import org.apache.commons.logging.LogFactory;
031
032 /**
033 * Represents a direct endpoint that synchronously invokes the consumers of the
034 * endpoint when a producer sends a message to it.
035 *
036 * @org.apache.xbean.XBean
037 * @version $Revision: 519973 $
038 */
039 public class DirectEndpoint<E extends Exchange> extends DefaultEndpoint<E> {
040 private static final Log LOG = LogFactory.getLog(DirectEndpoint.class);
041
042 boolean allowMultipleConsumers = true;
043 private final CopyOnWriteArrayList<DefaultConsumer<E>> consumers = new CopyOnWriteArrayList<DefaultConsumer<E>>();
044
045 public DirectEndpoint(String uri, DirectComponent<E> component) {
046 super(uri, component);
047 }
048
049 public Producer createProducer() throws Exception {
050 return new DefaultProducer(this) {
051 public void process(Exchange exchange) throws Exception {
052 DirectEndpoint.this.process(exchange);
053 }
054 };
055 }
056
057 protected void process(Exchange exchange) throws Exception {
058 if (consumers.isEmpty()) {
059 LOG.warn("No consumers available on " + this + " for " + exchange);
060 } else {
061 for (DefaultConsumer<E> consumer : consumers) {
062 consumer.getProcessor().process(exchange);
063 }
064 }
065 }
066
067 public Consumer<E> createConsumer(Processor processor) throws Exception {
068 return new DefaultConsumer<E>(this, processor) {
069 @Override
070 public void start() throws Exception {
071 if (!allowMultipleConsumers && !consumers.isEmpty()) {
072 throw new IllegalStateException("Endpoint " + getEndpointUri() + " only allows 1 active consumer but you attempted to start a 2nd consumer.");
073 }
074
075 consumers.add(this);
076 super.start();
077 }
078
079 @Override
080 public void stop() throws Exception {
081 super.stop();
082 consumers.remove(this);
083 }
084 };
085 }
086
087 public E createExchange() {
088 // How can we create a specific Exchange if we are generic??
089 // perhaps it would be better if we did not implement this.
090 return (E)new DefaultExchange(getContext());
091 }
092
093 public boolean isAllowMultipleConsumers() {
094 return allowMultipleConsumers;
095 }
096
097 public void setAllowMultipleConsumers(boolean allowMutlipleConsumers) {
098 this.allowMultipleConsumers = allowMutlipleConsumers;
099 }
100
101 public boolean isSingleton() {
102 return true;
103 }
104
105 }