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.spring;
018
019 import org.apache.camel.Endpoint;
020 import org.apache.camel.component.bean.BeanProcessor;
021 import org.apache.camel.component.event.EventComponent;
022 import org.apache.camel.component.event.EventEndpoint;
023 import org.apache.camel.impl.DefaultCamelContext;
024 import org.apache.camel.impl.ProcessorEndpoint;
025 import org.apache.camel.spi.Injector;
026 import org.apache.camel.spi.Registry;
027 import org.apache.camel.spring.spi.ApplicationContextRegistry;
028 import org.apache.camel.spring.spi.SpringInjector;
029 import org.slf4j.Logger;
030 import org.slf4j.LoggerFactory;
031 import org.springframework.beans.BeansException;
032 import org.springframework.beans.factory.DisposableBean;
033 import org.springframework.beans.factory.InitializingBean;
034 import org.springframework.context.ApplicationContext;
035 import org.springframework.context.ApplicationContextAware;
036 import org.springframework.context.ApplicationEvent;
037 import org.springframework.context.ConfigurableApplicationContext;
038 import org.springframework.context.event.ContextRefreshedEvent;
039 import org.springframework.context.event.ContextStoppedEvent;
040 import org.springframework.context.support.ClassPathXmlApplicationContext;
041
042 import static org.apache.camel.util.ObjectHelper.wrapRuntimeCamelException;
043
044 /**
045 * A Spring aware implementation of {@link org.apache.camel.CamelContext} which
046 * will automatically register itself with Springs lifecycle methods plus allows
047 * spring to be used to customize a any <a
048 * href="http://camel.apache.org/type-converter.html">Type Converters</a>
049 * as well as supporting accessing components and beans via the Spring
050 * {@link ApplicationContext}
051 *
052 * @version
053 */
054 public class SpringCamelContext extends DefaultCamelContext implements InitializingBean, DisposableBean,
055 ApplicationContextAware {
056
057 private static final transient Logger LOG = LoggerFactory.getLogger(SpringCamelContext.class);
058 private ApplicationContext applicationContext;
059 private EventEndpoint eventEndpoint;
060
061 public SpringCamelContext() {
062 }
063
064 public SpringCamelContext(ApplicationContext applicationContext) {
065 setApplicationContext(applicationContext);
066 }
067
068 public static SpringCamelContext springCamelContext(ApplicationContext applicationContext) throws Exception {
069 // lets try and look up a configured camel context in the context
070 String[] names = applicationContext.getBeanNamesForType(SpringCamelContext.class);
071 if (names.length == 1) {
072 return (SpringCamelContext)applicationContext.getBean(names[0], SpringCamelContext.class);
073 }
074 SpringCamelContext answer = new SpringCamelContext();
075 answer.setApplicationContext(applicationContext);
076 answer.afterPropertiesSet();
077 return answer;
078 }
079
080 public static SpringCamelContext springCamelContext(String configLocations) throws Exception {
081 return springCamelContext(new ClassPathXmlApplicationContext(configLocations));
082 }
083
084 public void afterPropertiesSet() throws Exception {
085 maybeStart();
086 }
087
088 public void destroy() throws Exception {
089 stop();
090 }
091
092 public void onApplicationEvent(ApplicationEvent event) {
093 if (LOG.isDebugEnabled()) {
094 LOG.debug("onApplicationEvent: " + event);
095 }
096
097 if (event instanceof ContextRefreshedEvent) {
098 // now lets start the CamelContext so that all its possible
099 // dependencies are initialized
100 try {
101 maybeStart();
102 } catch (Exception e) {
103 throw wrapRuntimeCamelException(e);
104 }
105 } else if (event instanceof ContextStoppedEvent) {
106 try {
107 maybeStop();
108 } catch (Exception e) {
109 throw wrapRuntimeCamelException(e);
110 }
111 }
112
113 if (eventEndpoint != null) {
114 eventEndpoint.onApplicationEvent(event);
115 } else {
116 LOG.info("No spring-event endpoint enabled to handle event: " + event);
117 }
118 }
119
120 // Properties
121 // -----------------------------------------------------------------------
122
123 public ApplicationContext getApplicationContext() {
124 return applicationContext;
125 }
126
127 public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
128 this.applicationContext = applicationContext;
129 ClassLoader cl;
130
131 // set the application context classloader
132 if (applicationContext != null && applicationContext.getClassLoader() != null) {
133 cl = applicationContext.getClassLoader();
134 } else {
135 LOG.warn("Cannot find the class loader from application context, using the thread context class loader instead");
136 cl = Thread.currentThread().getContextClassLoader();
137 }
138 if (LOG.isDebugEnabled()) {
139 LOG.debug("Set the application context classloader to: " + cl);
140 }
141 this.setApplicationContextClassLoader(cl);
142
143 if (applicationContext instanceof ConfigurableApplicationContext) {
144 // only add if not already added
145 if (hasComponent("spring-event") == null) {
146 addComponent("spring-event", new EventComponent(applicationContext));
147 }
148 }
149 }
150
151 public EventEndpoint getEventEndpoint() {
152 return eventEndpoint;
153 }
154
155 public void setEventEndpoint(EventEndpoint eventEndpoint) {
156 this.eventEndpoint = eventEndpoint;
157 }
158
159 // Implementation methods
160 // -----------------------------------------------------------------------
161
162 @Override
163 protected void doStart() throws Exception {
164 super.doStart();
165 if (eventEndpoint == null) {
166 eventEndpoint = createEventEndpoint();
167 }
168 }
169
170 @Override
171 protected Injector createInjector() {
172 if (applicationContext instanceof ConfigurableApplicationContext) {
173 return new SpringInjector((ConfigurableApplicationContext)applicationContext);
174 } else {
175 LOG.warn("Cannot use SpringInjector as applicationContext is not a ConfigurableApplicationContext as its: "
176 + applicationContext);
177 return super.createInjector();
178 }
179 }
180
181 protected EventEndpoint createEventEndpoint() {
182 return getEndpoint("spring-event:default", EventEndpoint.class);
183 }
184
185 protected Endpoint convertBeanToEndpoint(String uri, Object bean) {
186 // We will use the type convert to build the endpoint first
187 Endpoint endpoint = getTypeConverter().convertTo(Endpoint.class, bean);
188 if (endpoint != null) {
189 endpoint.setCamelContext(this);
190 return endpoint;
191 }
192
193 return new ProcessorEndpoint(uri, this, new BeanProcessor(bean, this));
194 }
195
196 @Override
197 protected Registry createRegistry() {
198 return new ApplicationContextRegistry(getApplicationContext());
199 }
200
201 private void maybeStart() throws Exception {
202 if (!isStarted() && !isStarting()) {
203 start();
204 } else {
205 // ignore as Camel is already started
206 LOG.trace("Ignoring maybeStart() as Apache Camel is already started");
207 }
208 }
209
210 private void maybeStop() throws Exception {
211 if (!isStopping() && !isStopped()) {
212 stop();
213 } else {
214 // ignore as Camel is already stopped
215 LOG.trace("Ignoring maybeStop() as Apache Camel is already stopped");
216 }
217 }
218
219 @Override
220 public String toString() {
221 StringBuilder sb = new StringBuilder();
222 sb.append("SpringCamelContext(").append(getName()).append(")");
223 if (applicationContext != null) {
224 sb.append(" with spring id ").append(applicationContext.getId());
225 }
226 return sb.toString();
227 }
228
229 }