/**
* Adds a local object as a listener of messages.
*
* <p>The user (i.e., RemoteObject) of this class calls this method to register the RemoteObject
* as "local RemoteObject" with this class.
*
* <pre>
* [RemoteObject] [RemoteObject] [RemoteObject]
* dispatchEvent() dispatchRequest() dispatchRequest()
* ^ ^ ^
* | | |
* +---------------+ + +---------------+
* | | |
* [MessageDispatcher]<>-----[SubscribersMap]
* |
* message
* |
* [pubsub server]
* </pre>
*
* <p>This method also sends "SUBSCRIBE own-object-ID-as-channel" to pubsub server to receive
* PUBLISH destined to the remote object, since requestSync() method sends PUBLISH as "request" to
* the remote object.
*
* @param localObject a remote object
* @see org.o3project.odenos.remoteobject.RemoteObject#dispatchEvent
* @see org.o3project.odenos.remoteobject.RemoteObject#dispatchRequest
*/
public void addLocalObject(RemoteObject localObject) {
String objectId = localObject.getObjectId();
if (localObjectsMap.putIfAbsent(objectId, localObject) == null) {
driverImpl.subscribeChannel(objectId);
}
if (objectId.equals(systemManagerId)) {
driverImpl.systemManagerAttached();
}
}
/**
* Starts the services.
*
* <p>This method must be called after instantiating this class to start a {@link IPubSubDriver}
* implementation class.
*/
public void start() {
// This method blocks until the connectivity with pubsub server
// has become ready.
driverImpl.start();
// To receive Request from "remote" RemoteObject,
// MessageDispatcher needs to register itself w/ pubsub server.
driverImpl.subscribeChannel(sourceDispatcherId);
// This thread feeds subscription info to EventManager
// in an eventually-consistent manner.
subscriptionFeeder =
new Thread(
new Runnable() {
@Override
public void run() {
do {
Request request = null;
try {
request = eventManagerQueue.take();
Response response = requestSync(request);
if (response == null || !response.statusCode.equals(Response.OK)) {
log.warn("Unsuccessful transaction to EventManager: " + response.statusCode);
}
} catch (InterruptedException e) {
log.warn("Unsuccessful transaction to EventManager due to some internal error");
} catch (Exception e) {
log.warn("EventManager may be inactive");
}
} while (true); // TODO: graceful thread termination
}
});
subscriptionFeeder.start();
log.info("started");
}
