client/io.spine.client/CommandRequest

CommandRequest

public final class CommandRequest extends ClientRequest

Allows to post a command optionally subscribing to events that are immediate results of handling this command.

Usage example:


Subscription loginSubscription =
    client.asGuest()
          .command(logInUser)
          .observe(UserLoggedIn.class, (event, context) -> { ... })
          .observe(UserAlreadyLoggedIn.class, (rejection, context) -> { ... })
          .onStreamingError((throwable) -> { ... })
          .post();

The subscription obtained from the post should be cancelled to preserve both client-side and server-side resources. The moment of cancelling the subscriptions depends on the nature of the posted command and the outcome expected by the client application.

Functions

observe

public CommandRequest observe<E extends EventMessage>(Class<E> type, EventConsumer<E> consumer)

Adds the passed event consumer to the subscribers of the event of the passed type.

public CommandRequest observe<E extends EventMessage>(Class<E> type, Consumer<E> consumer)

Adds the passed consumer to the subscribers of the event of the passed type.

onConsumingError

public CommandRequest onConsumingError(ConsumerErrorHandler<EventMessage> handler)

Assigns a handler for errors occurred in consumers of events.

onServerError

public CommandRequest onServerError(ServerErrorHandler handler)

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

onStreamingError

public CommandRequest onStreamingError(ErrorHandler handler)

Assigns a handler for errors occurred when delivering events.

post

public ImmutableSet<Subscription> post()

Subscribes the consumers to events to receive events resulting from the command as they happen, then sends the command to the server.

postAndForget

public void postAndForget()

Posts the command without subscribing to events that may be generated during the command handling.

Inherited functions

client

protected final Client client()

Obtains the client instance that will perform the request.

command

public CommandRequest command(CommandMessage c)

Creates a builder for customizing command request.

select

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

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

subscribeTo

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.

user

protected final UserId user()

Obtains the ID of the user of the request.