io.spine.client

EventSubscriptionRequest

client/io.spine.client/EventSubscriptionRequest

EventSubscriptionRequest

public final class EventSubscriptionRequest<E extends EventMessage> extends SubscribingRequest<M, C, W, B>

Allows to subscribe to events using filtering conditions.

Similarly to subscriptions to entity states, event subscriptions may use filtering by values of the proto types of subscribed messages:


clientRequest.subscribeToEvent(MyEventMessage.class)
             .where(eq(MyEventMessage.Field.myProtoField(), fieldValue))
             .observe((event, context) -> {...})
             .post();

In addition to regular filtering conditions, event subscription requests may also reference fields of spine.core.EventContext. For example, in order to filter events originate from commands of the given user, please use the following code:


clientRequest.subscribeToEvent(MyEventMessage.class)
             .where(eq(EventContext.Field.pastMessage().actorContext().actor(), userId))
             .observe((event, context) -> {...})
             .post();

Parameters

<E>

the type of the event messages

Functions

public EventSubscriptionRequest<E> observe(EventConsumer<E> consumer)

public EventSubscriptionRequest<E> where(Array<CompositeEventFilter> filter)

public EventSubscriptionRequest<E> where(Array<EventFilter> filter)

Configures the request to return results matching all the passed filters.

Inherited functions

public B byId(Array<Message> ids)

public B byId(Array<Integer> ids)

public B byId(Iterable<? extends Object> ids)

public B byId(Array<Long> ids)

public B byId(Array<String> ids)

Requests only passed IDs to be included into the result of the request.

protected Optional<StreamObserver<SubscriptionUpdate>> chain()

Returns an observer of raw SubscriptionUpdates, which will be called in addition to notifying the consumers.

protected final Client client()

Obtains the client instance that will perform the request.

public CommandRequest command(CommandMessage c)

Creates a builder for customizing command request.

public B observe(Consumer<M> consumer)

Subscribes the passed consumer to receive messages of the subscribed type.

onConsumingError

public B onConsumingError(ConsumerErrorHandler<M> handler)

Assigns a handler for an error that may occur in the code of one of the consumers.

public ClientRequest onServerError(ServerErrorHandler handler)

Assigns a handler for an error occurred on the server-side (such as validation error) in response to posting a request.

onStreamingError

public ClientRequest onStreamingError(ErrorHandler handler)

Assigns a handler for errors occurred when delivering messages from the server.

public B onStreamingError(ErrorHandler handler)

Assigns a handler for the error reported to onError of the StreamObserver responsible for delivering messages to the consumers.

public Subscription post()

Creates and posts the subscription request to the server.

public QueryRequest<S> select<S extends EntityState>(Class<S> type)

Creates a builder for constructing a query for messages of the specified type.

public SubscriptionRequest<S> subscribeTo<S extends EntityState>(Class<S> type)

Creates a builder for customizing subscription for the passed entity state type.

subscribeToEvent

public EventSubscriptionRequest<E> subscribeToEvent<E extends EventMessage>(Class<E> type)

Creates a builder for customizing subscription for the passed event type.

protected final UserId user()

Obtains the ID of the user of the request.

public B ~~where~~(Array<CompositeFilter> filter)

public B ~~where~~(Array<Filter> filter)

Configures the request to return results matching all the passed filters.

public B withMask(Iterable<String> fieldNames)

public B withMask(Array<String> fieldNames)

Instructs to populate only fields with the passed names in the results of the request.