Learning RxJava

How Observables work

Before we do anything else, we need to study how an Observable sequentially passes items down a chain to an Observer. At the highest level, an Observable works by passing three types of events:

• onNext(): This passes each item one at a time from the source Observable all the way down to the Observer.
• onComplete(): This communicates a completion event all the way down to the Observer, indicating that no more onNext() calls will occur.
• onError(): This communicates an error up the chain to the Observer, where the Observer typically defines how to handle it. Unless a retry() operator is used to intercept the error, the Observable chain typically terminates, and no more emissions will occur.

These three events are abstract ...