client/io.spine.client

Package-level declarations

This package provides classes and interfaces for performing client requests like posting commands, running queries, or creating subscriptions.

The term actor used in this API means the user on behalf of whom requests are created and executed. The package provides two levels of API.

High-level io.spine.client.Client API: is meant for client-side Java applications that would communicate with backend services via a gRPC connection. An instance of the io.spine.client.Client class establishes this connection and serves as a fluent API gateway for composing and posting requests.
Low-level io.spine.client.ActorRequestFactory API: is meant for server-side code which needs to speak to backend services without involving gRPC. This API is also by the High-level API implementation.

The io.spine.client.Filters utility class provides methods for composing filtering conditions for both levels of the API.

When subscribing the Client API accepts an implementation of a functional interface (see io.spine.client.StateConsumer and io.spine.client.EventConsumer). Errors occurred when streaming or consuming messages are handled via io.spine.client.ErrorHandler and io.spine.client.ConsumerErrorHandler correspondingly.

Types

ActorRequestFactory

public class ActorRequestFactory

A factory for various requests fired from the client-side by an actor.

Client

public class Client implements AutoCloseable

The gRPC-based gateway for backend services such as CommandService, QueryService, or SubscriptionService.

ClientRequest

public class ClientRequest

Entry point for creating client requests.

CommandFactory

public final class CommandFactory

A factory of Command instances.

CommandRequest

public final class CommandRequest extends ClientRequest

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

CompositeEntityStateFilter

public final class CompositeEntityStateFilter extends TypedCompositeFilter<M>

A subscription filter which aggregates one or more EntityState filters.

CompositeEventFilter

public final class CompositeEventFilter extends TypedCompositeFilter<M>

A composite subscription filter which can aggregate both event message and event context filters.

CompositeQueryFilter

public final class CompositeQueryFilter extends TypedCompositeFilter<M>

A composite query filter which targets one or more entity columns.

ConnectionConstants

public final class ConnectionConstants

Constant values shared between the client and the server code.

ConsumerErrorHandler

@FunctionalInterface()

public interface ConsumerErrorHandler<M extends Message> implements BiConsumer<T, U>

Functional interface for handlers of errors caused by consumers of messages.

EntityStateFilter

public final class EntityStateFilter extends TypedFilter<M>

A subscription filter which targets an EntityState.

ErrorHandler

@FunctionalInterface()

public interface ErrorHandler implements Consumer<T>

Functional interface for error handlers.

EventConsumer

@FunctionalInterface()

public interface EventConsumer<E extends EventMessage> implements MessageConsumer<M, C>

Represents an operation which accepts an event message and its context.

EventFilter

public final class EventFilter extends TypedFilter<M>

A subscription filter which targets an Event.

EventObserver

public interface EventObserver<E extends EventMessage> implements EventConsumer<E>

Adapts gRPC streaming API to EventConsumer by passing the received Event to the accept method.

EventSubscriptionRequest

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

Allows to subscribe to events using filtering conditions.

FilteringRequest

public abstract class FilteringRequest<M extends Message, R extends Message, A extends TargetBuilder<R, A>, B extends FilteringRequest<M, R, A, B>> extends ClientRequest

Abstract base for client requests that may filter messages by certain criteria.

Filters

public final class Filters

A factory of Filter instances.

OperatorEvaluator

public enum OperatorEvaluator

A boolean non-typed comparison operation on two given instances.

QueryBuilder

public final class QueryBuilder extends TargetBuilder<T, B>

A builder for the Query instances.

QueryFactory

public final class QueryFactory

A factory of Query instances.

QueryFilter

public final class QueryFilter extends TypedFilter<M>

A query filter which targets a column of an entity.

QueryMixin

public interface QueryMixin

Useful methods for Query.

QueryRequest

public final class QueryRequest<S extends EntityState> extends FilteringRequest<M, R, A, B>

Allows to create a post a query for messages of the given type.

ServerErrorHandler

public interface ServerErrorHandler implements BiConsumer<T, U>

A handler for an error occurred when posting a message for asynchronous processing at the server side.

StateConsumer

@FunctionalInterface()

public interface StateConsumer<S extends EntityState> implements Consumer<T>, MessageConsumer<M, C>

Represents an operation that accepts a state of an entity.

SubscribingRequest

public abstract class SubscribingRequest<M extends Message, C extends MessageContext, W extends Message, B extends SubscribingRequest<M, C, W, B>> extends FilteringRequest<M, R, A, B>

Abstract base for client requests that subscribe to messages.

SubscriptionMixin

public interface SubscriptionMixin

Useful methods for Subscription.

SubscriptionRequest