org.axonframework.queryhandling

Interface QueryUpdateEmitter

All Superinterfaces:

MessageDispatchInterceptorSupport<SubscriptionQueryUpdateMessage<?>>

All Known Implementing Classes:

SimpleQueryUpdateEmitter

public interface QueryUpdateEmitter
extends MessageDispatchInterceptorSupport<SubscriptionQueryUpdateMessage<?>>

Component which informs subscription queries about updates, errors and when there are no more updates.

If any of the emitter functions in this interface are called from a message handling function (e.g. an EventHandler annotated function), then that call will automatically be tied into the lifecycle of the current UnitOfWork to ensure correct order of execution.

Added, implementations of this class should thus respect any current UnitOfWork in the UnitOfWork.Phase.STARTED phase for any of the emitting functions. If this is the case then the emitter call action should be performed during the UnitOfWork.Phase.AFTER_COMMIT. Otherwise the operation can be executed immediately.

Since:

3.3

Author:

Milan Savic

Method Summary

Modifier and Type	Method and Description
default Set<SubscriptionQueryMessage<?,?,?>>	activeSubscriptions() Provides the set of running subscription queries.
default <Q> void	complete(Class<Q> queryType, Predicate<? super Q> filter) Completes subscription queries matching given query type and filter.
void	complete(Predicate<SubscriptionQueryMessage<?,?,?>> filter) Completes subscription queries matching given filter.
default <Q> void	completeExceptionally(Class<Q> queryType, Predicate<? super Q> filter, Throwable cause) Completes with an error subscription queries matching given query type and filter
void	completeExceptionally(Predicate<SubscriptionQueryMessage<?,?,?>> filter, Throwable cause) Completes with an error subscription queries matching given filter.
default <Q,U> void	emit(Class<Q> queryType, Predicate<? super Q> filter, SubscriptionQueryUpdateMessage<U> update) Emits given incremental update to subscription queries matching given query type and filter.
default <Q,U> void	emit(Class<Q> queryType, Predicate<? super Q> filter, U update) Emits given incremental update to subscription queries matching given query type and filter.
<U> void	emit(Predicate<SubscriptionQueryMessage<?,?,U>> filter, SubscriptionQueryUpdateMessage<U> update) Emits incremental update (as return value of provided update function) to subscription queries matching given filter.
default <U> void	emit(Predicate<SubscriptionQueryMessage<?,?,U>> filter, U update) Emits given incremental update to subscription queries matching given filter.
boolean	queryUpdateHandlerRegistered(SubscriptionQueryMessage<?,?,?> query) Checks whether there is a query update handler for a given query.
<U> UpdateHandlerRegistration<U>	registerUpdateHandler(SubscriptionQueryMessage<?,?,?> query, int updateBufferSize) Registers an Update Handler for given query with given updateBufferSize.
<U> UpdateHandlerRegistration<U>	registerUpdateHandler(SubscriptionQueryMessage<?,?,?> query, SubscriptionQueryBackpressure backpressure, int updateBufferSize) Deprecated. in favour of using {registerUpdateHandler(SubscriptionQueryMessage, int)}

Methods inherited from interface org.axonframework.messaging.MessageDispatchInterceptorSupport

registerDispatchInterceptor

Method Detail

emit

<U> void emit(Predicate<SubscriptionQueryMessage<?,?,U>> filter,
              SubscriptionQueryUpdateMessage<U> update)

Emits incremental update (as return value of provided update function) to subscription queries matching given filter.

Type Parameters:

U - the type of the update

Parameters:

filter - predicate on subscription query message used to filter subscription queries

update - incremental update message

emit

default <U> void emit(Predicate<SubscriptionQueryMessage<?,?,U>> filter,
                      U update)

Emits given incremental update to subscription queries matching given filter. If an update is null, emit will be skipped. In order to send nullable updates, use emit(Class, Predicate, SubscriptionQueryUpdateMessage) or emit(Predicate, SubscriptionQueryUpdateMessage) methods.

Type Parameters:

U - the type of the update

Parameters:

filter - predicate on subscription query message used to filter subscription queries

update - incremental update

emit

default <Q,U> void emit(Class<Q> queryType,
                        Predicate<? super Q> filter,
                        SubscriptionQueryUpdateMessage<U> update)

Emits given incremental update to subscription queries matching given query type and filter.

Type Parameters:

Q - the type of the query

U - the type of the update

Parameters:

queryType - the type of the query

filter - predicate on query payload used to filter subscription queries

update - incremental update message

emit

default <Q,U> void emit(Class<Q> queryType,
                        Predicate<? super Q> filter,
                        U update)

Emits given incremental update to subscription queries matching given query type and filter. If an update is null, emit will be skipped. In order to send nullable updates, use emit(Class, Predicate, SubscriptionQueryUpdateMessage) or emit(Predicate, SubscriptionQueryUpdateMessage) methods.

Type Parameters:

Q - the type of the query

U - the type of the update

Parameters:

queryType - the type of the query

filter - predicate on query payload used to filter subscription queries

update - incremental update

complete

void complete(Predicate<SubscriptionQueryMessage<?,?,?>> filter)

Completes subscription queries matching given filter.

Parameters:

filter - predicate on subscription query message used to filter subscription queries

complete

default <Q> void complete(Class<Q> queryType,
                          Predicate<? super Q> filter)

Completes subscription queries matching given query type and filter.

Type Parameters:

Q - the type of the query

Parameters:

queryType - the type of the query

filter - predicate on query payload used to filter subscription queries

completeExceptionally

void completeExceptionally(Predicate<SubscriptionQueryMessage<?,?,?>> filter,
                           Throwable cause)

Completes with an error subscription queries matching given filter.

Parameters:

filter - predicate on subscription query message used to filter subscription queries

cause - the cause of an error

completeExceptionally

default <Q> void completeExceptionally(Class<Q> queryType,
                                       Predicate<? super Q> filter,
                                       Throwable cause)

Completes with an error subscription queries matching given query type and filter

Type Parameters:

Q - the type of the query

Parameters:

queryType - the type of the query

filter - predicate on query payload used to filter subscription queries

cause - the cause of an error

queryUpdateHandlerRegistered

boolean queryUpdateHandlerRegistered(SubscriptionQueryMessage<?,?,?> query)

Checks whether there is a query update handler for a given query.

Parameters:

query - the subscription query for which we have registered the update handler

Returns:

true if there is an update handler registered for given query, false otherwise

registerUpdateHandler

@Deprecated
<U> UpdateHandlerRegistration<U> registerUpdateHandler(SubscriptionQueryMessage<?,?,?> query,
                                                                   SubscriptionQueryBackpressure backpressure,
                                                                   int updateBufferSize)

Deprecated. in favour of using {registerUpdateHandler(SubscriptionQueryMessage, int)}

Registers an Update Handler for given query with given backpressure and updateBufferSize.

Type Parameters:

U - the incremental response types of the query

Parameters:

query - the subscription query for which we register an Update Handler

backpressure - the backpressure mechanism to be used for emitting updates

updateBufferSize - the size of buffer which accumulates updates before subscription to the flux is made

Returns:

the object which contains updates and a registration which can be used to cancel them

registerUpdateHandler

<U> UpdateHandlerRegistration<U> registerUpdateHandler(SubscriptionQueryMessage<?,?,?> query,
                                                       int updateBufferSize)

Registers an Update Handler for given query with given updateBufferSize.

Type Parameters:

U - the incremental response types of the query

Parameters:

query - the subscription query for which we register an Update Handler

updateBufferSize - the size of buffer which accumulates updates before subscription to the flux is made

Returns:

the object which contains updates and a registration which can be used to cancel them

activeSubscriptions

default Set<SubscriptionQueryMessage<?,?,?>> activeSubscriptions()

Provides the set of running subscription queries. If there are changes to subscriptions they will be reflected in the returned set of this method. Implementations should provide an unmodifiable set of the active subscriptions.

Returns:

the set of running subscription queries