/*
* Copyright 2010 The Fornax Project Team, including the original
* author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.sculptor.framework.event;
import java.util.HashMap;
import java.util.Map;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.integration.MessageRejectedException;
import org.springframework.integration.channel.PublishSubscribeChannel;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageDeliveryException;
import org.springframework.messaging.MessageHandler;
import org.springframework.messaging.MessageHandlingException;
import org.springframework.messaging.support.GenericMessage;
import org.springframework.stereotype.Component;
@Component
public class SpringIntegrationEventBusImpl implements EventBus, ApplicationContextAware {
private ApplicationContext ctx;
private final Map<EventListener, MessageHandler> listeners = new HashMap<EventListener, MessageHandler>();
@Override
public boolean publish(String topic, Event event) {
PublishSubscribeChannel intChannel = getChannel(topic);
GenericMessage<Object> intMessage = new GenericMessage<Object>(event);
intChannel.send(intMessage);
return true;
}
@Override
public boolean subscribe(String topic, final EventSubscriber subscriber) {
PublishSubscribeChannel intChannel = getChannel(topic);
MessageHandler messageHandler = new MessageHandler() {
@Override
public void handleMessage(Message<?> message) throws MessageRejectedException, MessageHandlingException,
MessageDeliveryException {
subscriber.receive((Event) message.getPayload());
}
};
EventListener eventListener = new EventListener(topic, subscriber);
boolean success = intChannel.subscribe(messageHandler);
if (success) {
synchronized (listeners) {
listeners.put(eventListener, messageHandler);
}
}
return success;
}
@Override
public boolean unsubscribe(String topic, EventSubscriber subscriber) {
PublishSubscribeChannel intChannel = getChannel(topic);
EventListener eventListener = new EventListener(topic, subscriber);
MessageHandler messageHandler = null;
boolean success = true;
synchronized (listeners) {
messageHandler = listeners.get(eventListener);
listeners.remove(eventListener);
}
if (messageHandler != null) {
success = intChannel.unsubscribe(messageHandler);
}
return success;
}
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
ctx = applicationContext;
}
private PublishSubscribeChannel getChannel(String topic) {
return (PublishSubscribeChannel) ctx.getBean(topic);
}
}