171215(금) - RxJava2 (empty/never/error)

RxJava2 

empty/never/error

empty

@CheckReturnValue
 @BackpressureSupport(value=PASS_THROUGH)
 @SchedulerSupport(value="none")
public static <T> Flowable<T> empty()

Returns a Flowable that emits no items to the Subscriber and immediately invokes its onComplete method.

Backpressure:

This source doesn't produce any elements and effectively ignores downstream backpressure.

Scheduler:

empty does not operate by default on a particular Scheduler.

Type Parameters:

T - the type of the items (ostensibly) emitted by the Publisher

Returns:

a Flowable that emits no items to the Subscriber but immediately invokes the Subscriber's onComplete method

See Also:

ReactiveX operators documentation: Empty

never

@CheckReturnValue
 @BackpressureSupport(value=PASS_THROUGH)
 @SchedulerSupport(value="none")
public static <T> Flowable<T> never()

Returns a Flowable that never sends any items or notifications to a Subscriber.

This Publisher is useful primarily for testing purposes.

Backpressure:

This source doesn't produce any elements and effectively ignores downstream backpressure.

Scheduler:

never does not operate by default on a particular Scheduler.

Type Parameters:

T - the type of items (not) emitted by the Publisher

Returns:

a Flowable that never emits any items or sends any notifications to a Subscriber

See Also:

ReactiveX operators documentation: Never

error

@CheckReturnValue
 @BackpressureSupport(value=PASS_THROUGH)
 @SchedulerSupport(value="none")
public static <T> Flowable<T> error(java.util.concurrent.Callable<? extends java.lang.Throwable> supplier)

Returns a Flowable that invokes a Subscriber's onError method when the Subscriber subscribes to it.

Backpressure:

This source doesn't produce any elements and effectively ignores downstream backpressure.

Scheduler:

error does not operate by default on a particular Scheduler.

Type Parameters:

T - the type of the items (ostensibly) emitted by the Publisher

Parameters:

supplier - a Callable factory to return a Throwable for each individual Subscriber

Returns:

a Flowable that invokes the Subscriber's onError method when the Subscriber subscribes to it

See Also:

ReactiveX operators documentation: Throw

@CheckReturnValue
 @BackpressureSupport(value=PASS_THROUGH)
 @SchedulerSupport(value="none")
public static <T> Flowable<T> error(java.lang.Throwable throwable)

Returns a Flowable that invokes a Subscriber's onError method when the Subscriber subscribes to it.

Backpressure:

This source doesn't produce any elements and effectively ignores downstream backpressure.

Scheduler:

error does not operate by default on a particular Scheduler.

Type Parameters:

T - the type of the items (ostensibly) emitted by the Publisher

Parameters:

throwable - the particular Throwable to pass to onError

Returns:

a Flowable that invokes the Subscriber's onError method when the Subscriber subscribes to it

See Also:

ReactiveX operators documentation: Throw