subscribe 

Requests the event management system to get an event that satisfies the filter provided. The method will validate the call-back object for the call-back method name and parameter (see below for more information). This method enables the caller to register multiple times with different filtering, target, and call-back parameters. 

unsubscribe 

Requests the event management system to stop forwarding events to this client based on the subscription the caller made using the subscribe method. Once all the callers unsubscribe all the IDs, any events that are waiting to be delivered to this client are discarded. 

getSubscriptionInformation 

Utility method that returns the parameters the client used to subscribe for alerts for the given subscription ID.