autodispose-lifecycle

public interface LifecycleScopeProvider<E> extends ScopeProvider {
Observable<E> lifecycle();

Function<E, E> correspondingEvents();

E peekLifecycle();

// Inherited from ScopeProvider
CompletableSource requestScope();
}

A common use case for this is objects that have implicit lifecycles, such as Android's Activity, Fragment, and View classes. Internally at subscription-time, AutoDispose will resolve a CompletableSource representation of the target end event in the lifecycle, and exposes an API to dictate what corresponding events are for the current lifecycle state (e.g. ATTACH ->DETACH). This also allows you to enforce lifecycle boundary requirements, and by default will error if the lifecycle has either not started yet or has already ended.

LifecycleScopeProvider is a special case targeted at binding to things with lifecycles. Its API is as follows:

• lifecycle() - returns an Observable of lifecycle events. This should be backed by a BehaviorSubject or something similar (BehaviorRelay, etc).

• correspondingEvents() - a mapping of events to corresponding ones, i.e. Attach -> Detach.

• peekLifecycle() - returns the current lifecycle state of the object.

In requestScope(), the implementation expects to these pieces to construct a CompletableSource representation of the proper end scope, while also doing precondition checks for lifecycle boundaries. If a lifecycle has not started, it will send you to onError with a LifecycleNotStartedException. If the lifecycle as ended, it is recommended to throw a LifecycleEndedException in your correspondingEvents() mapping, but it is up to the user.

To simplify implementations, there's an included LifecycleScopes utility class with factories for generating CompletableSource representations from LifecycleScopeProvider instances.