io.smallrye.mutiny.subscription

Interface UniSubscriber<T>

Type Parameters:

T - the expected type of item

All Known Implementing Classes:

UniCache, UniCallbackSubscriber, UniDelegatingSubscriber, UniSerializedSubscriber

public interface UniSubscriber<T>

Will receive call to onSubscribe(UniSubscription) once after passing an instance of this UniSubscriber to UniSubscribe.withSubscriber(UniSubscriber) retrieved from Uni.subscribe(). Unlike Reactive Streams Subscriber, UniSubscriber does not request items.

After subscription, it can receive:

• a item event triggering onItem(Object). The item can be null.
• a failure event triggering onFailure(Throwable) which signals an error state.

Once this subscriber receives an item or failure event, no more events will be received.

Note that unlike in Reactive Streams, the value received in onItem(Object) can be null.

Method Summary

Modifier and Type	Method and Description
void	onFailure(Throwable failure) Called if the computation of the item by the subscriber Uni failed.
void	onItem(T item) Event handler called once the item has been computed by the subscribed Uni.
void	onSubscribe(UniSubscription subscription) Event handler called once the subscribed Uni has taken into account the subscription.

Method Detail

onSubscribe

void onSubscribe(UniSubscription subscription)

Event handler called once the subscribed Uni has taken into account the subscription. The Uni have triggered the computation of the item. IMPORTANT: onItem(Object) and onFailure(Throwable) would not be called before the invocation of this method.

• Executor: Operate on no particular executor, except if Uni.runSubscriptionOn(Executor) has been called
• Exception: Throwing an exception cancels the subscription, onItem(Object) and onFailure(Throwable) won't be called

Parameters:

subscription - the subscription allowing to cancel the computation.

onItem

void onItem(T item)

Event handler called once the item has been computed by the subscribed Uni. IMPORTANT: this method will be only called once per subscription. If onFailure(Throwable) is called, this method won't be called.

• Executor: Operate on no particular executor, except if Uni.emitOn(java.util.concurrent.Executor) has been called
• Exception: Throwing an exception cancels the subscription.

Parameters:

item - the item, may be null.

onFailure

void onFailure(Throwable failure)

Called if the computation of the item by the subscriber Uni failed. IMPORTANT: this method will be only called once per subscription. If onItem(Object) is called, this method won't be called.

• Executor: Operate on no particular executor, except if Uni.emitOn(java.util.concurrent.Executor) has been called
• Exception: Throwing an exception cancels the subscription.

Parameters:

failure - the failure, cannot be null.