Reactive Pattern

Some interfaces to understand -

Interfaces
Watcher
     - onNext
     - onCompleted
     - onError
Watchable
    - Merge
    - Subscribe etc.
WatchableSubscription
    - Unsubscribe
WatchableNotifcation
   - A object representing a notification sent to a watchable
   - this object could represent a onNext, onError, onResume objects

Implementations
AbstractWatchable implements Watchable
    -
Watcher
        An object that listens for push based notifications.