org.directwebremoting.Hub Maven / Gradle / Ivy
package org.directwebremoting;
import org.directwebremoting.event.MessageListener;
/**
* A server-side hub that can publish data across reverse ajax and sync with
* a number of other hubs, including: JMS, the OpenAjax Alliance hub, and
* potentially others.
* @author Joe Walker [joe at getahead dot ltd dot uk]
*/
public interface Hub
{
/**
* Called to create a subscription so that future publishes to a similarly
* named topic alert the MessageListener that a publish has happened.
* Warning
* Currently the topic is a simple string pattern match. This more closely
* resembles JMS rather than the OpenAjax hub because we're taking the
* simplistic approach for now. I'm sure there will be some nasty problems
* that fall out of this.
*
The OpenAjax hub allows subscriber data that is passed back to the
* subscriber when the event happens. Since listeners are an ideal place for
* this data it isn't supported here. The OAA hub also allows for filters,
* but I'm thinking that this can be easily supported by the listener. What
* am I missing?
* @param topicName The topic to subscribe to.
* @param listener The object to notify of matching calls to publish()
*/
void subscribe(String topicName, MessageListener listener);
/**
* Reverse the action of {@link #subscribe(String, MessageListener)}
* @param topicName The topic to subscribe to.
* @param listener The object to notify of matching calls to publish()
* @return ...
*/
boolean unsubscribe(String topicName, MessageListener listener);
/**
* Publish some data to a certain topic.
* @param topicName The topic to subscribe to.
* @param message The data to publish
*/
void publish(String topicName, Object message);
}