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.component.event; 018 019import org.apache.camel.Exchange; 020import org.apache.camel.Processor; 021import org.apache.camel.Producer; 022import org.apache.camel.impl.DefaultEndpoint; 023import org.apache.camel.impl.DefaultProducer; 024import org.apache.camel.processor.loadbalancer.LoadBalancer; 025import org.apache.camel.processor.loadbalancer.TopicLoadBalancer; 026import org.apache.camel.spi.UriEndpoint; 027import org.apache.camel.spi.UriPath; 028import org.apache.camel.util.ObjectHelper; 029import org.springframework.beans.BeansException; 030import org.springframework.context.ApplicationContext; 031import org.springframework.context.ApplicationContextAware; 032import org.springframework.context.ApplicationEvent; 033 034import static org.apache.camel.util.ObjectHelper.wrapRuntimeCamelException; 035 036/** 037 * The spring-event component allows to listen for Spring Application Events. 038 */ 039@UriEndpoint(firstVersion = "1.4.0", scheme = "spring-event", title = "Spring Event", syntax = "spring-event:name", consumerClass = EventConsumer.class, label = "spring,eventbus") 040public class EventEndpoint extends DefaultEndpoint implements ApplicationContextAware { 041 private LoadBalancer loadBalancer; 042 private ApplicationContext applicationContext; 043 044 @UriPath(description = "Name of endpoint") 045 private String name; 046 047 public EventEndpoint(String endpointUri, EventComponent component, String name) { 048 super(endpointUri, component); 049 this.applicationContext = component.getApplicationContext(); 050 this.name = name; 051 } 052 053 /** 054 * <b>Note:</b> It is preferred to create endpoints using the associated 055 * component. 056 * @deprecated 057 */ 058 @Deprecated 059 public EventEndpoint(String endpointUri) { 060 super(endpointUri); 061 } 062 063 public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { 064 this.applicationContext = applicationContext; 065 } 066 067 public ApplicationContext getApplicationContext() { 068 return applicationContext; 069 } 070 071 public String getName() { 072 return name; 073 } 074 075 public void setName(String name) { 076 this.name = name; 077 } 078 079 public boolean isSingleton() { 080 return true; 081 } 082 083 public Producer createProducer() throws Exception { 084 ObjectHelper.notNull(applicationContext, "applicationContext"); 085 return new DefaultProducer(this) { 086 public void process(Exchange exchange) throws Exception { 087 ApplicationEvent event = toApplicationEvent(exchange); 088 applicationContext.publishEvent(event); 089 } 090 }; 091 } 092 093 public EventConsumer createConsumer(Processor processor) throws Exception { 094 ObjectHelper.notNull(applicationContext, "applicationContext"); 095 EventConsumer answer = new EventConsumer(this, processor); 096 configureConsumer(answer); 097 return answer; 098 } 099 100 public void onApplicationEvent(ApplicationEvent event) { 101 Exchange exchange = createExchange(); 102 exchange.getIn().setBody(event); 103 try { 104 getLoadBalancer().process(exchange); 105 } catch (Exception e) { 106 throw wrapRuntimeCamelException(e); 107 } 108 } 109 110 public LoadBalancer getLoadBalancer() { 111 if (loadBalancer == null) { 112 loadBalancer = createLoadBalancer(); 113 } 114 return loadBalancer; 115 } 116 117 public void setLoadBalancer(LoadBalancer loadBalancer) { 118 this.loadBalancer = loadBalancer; 119 } 120 121 @Override 122 public EventComponent getComponent() { 123 return (EventComponent) super.getComponent(); 124 } 125 126 // Implementation methods 127 // ------------------------------------------------------------------------- 128 public synchronized void consumerStarted(EventConsumer consumer) { 129 getComponent().consumerStarted(this); 130 getLoadBalancer().addProcessor(consumer.getProcessor()); 131 } 132 133 public synchronized void consumerStopped(EventConsumer consumer) { 134 getComponent().consumerStopped(this); 135 getLoadBalancer().removeProcessor(consumer.getProcessor()); 136 } 137 138 protected LoadBalancer createLoadBalancer() { 139 return new TopicLoadBalancer(); 140 } 141 142 protected ApplicationEvent toApplicationEvent(Exchange exchange) { 143 ApplicationEvent event = exchange.getIn().getBody(ApplicationEvent.class); 144 if (event != null) { 145 return event; 146 } 147 return new CamelEvent(this, exchange); 148 } 149}