org.axonframework.queryhandling

Class DefaultQueryGateway

java.lang.Object

org.axonframework.queryhandling.DefaultQueryGateway

All Implemented Interfaces:

MessageDispatchInterceptorSupport<QueryMessage<?,?>>, QueryGateway

public class DefaultQueryGateway
extends Object
implements QueryGateway

Implementation of the QueryGateway interface that allows the registration of dispatchInterceptors.

Since:

3.1

Author:

Marc Gathier, Allard Buijze, Steven van Beelen

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	DefaultQueryGateway.Builder Builder class to instantiate a DefaultQueryGateway.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	DefaultQueryGateway(DefaultQueryGateway.Builder builder) Instantiate a DefaultQueryGateway based on the fields contained in the DefaultQueryGateway.Builder.

Method Summary

Modifier and Type	Method and Description
static DefaultQueryGateway.Builder	builder() Instantiate a Builder to be able to create a DefaultQueryGateway.
<R,Q> CompletableFuture<R>	query(String queryName, Q query, ResponseType<R> responseType) Sends given query over the QueryBus, expecting a response in the form of responseType from a single source.
Registration	registerDispatchInterceptor(MessageDispatchInterceptor<? super QueryMessage<?,?>> interceptor) Register the given DispatchInterceptor.
<R,Q> Stream<R>	scatterGather(String queryName, Q query, ResponseType<R> responseType, long timeout, TimeUnit timeUnit) Sends given query over the QueryBus, expecting a response in the form of responseType from several sources.
<Q,I,U> SubscriptionQueryResult<I,U>	subscriptionQuery(String queryName, Q query, ResponseType<I> initialResponseType, ResponseType<U> updateResponseType, SubscriptionQueryBackpressure backpressure, int updateBufferSize) Sends given query over the QueryBus and returns result containing initial response and incremental updates (received at the moment the query is sent, until it is cancelled by the caller or closed by the emitting side).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.axonframework.queryhandling.QueryGateway

query, query, query, scatterGather, subscriptionQuery, subscriptionQuery, subscriptionQuery, subscriptionQuery

Constructor Detail

DefaultQueryGateway

protected DefaultQueryGateway(DefaultQueryGateway.Builder builder)

Instantiate a DefaultQueryGateway based on the fields contained in the DefaultQueryGateway.Builder.

Will assert that the QueryBus is not null, and will throw an AxonConfigurationException if it is null.

Parameters:

builder - the DefaultQueryGateway.Builder used to instantiate a DefaultQueryGateway instance

Method Detail

builder

public static DefaultQueryGateway.Builder builder()

Instantiate a Builder to be able to create a DefaultQueryGateway.

The dispatchInterceptors is defaulted to an empty list. The QueryBus is a hard requirement and as such should be provided.

Returns:

a Builder to be able to create a DefaultQueryGateway

query

public <R,Q> CompletableFuture<R> query(String queryName,
                                        Q query,
                                        ResponseType<R> responseType)

Description copied from interface: QueryGateway

Sends given query over the QueryBus, expecting a response in the form of responseType from a single source. Execution may be asynchronous, depending on the QueryBus implementation.

Specified by:

query in interface QueryGateway

Type Parameters:

R - The response class contained in the given responseType

Q - The query class

Parameters:

queryName - A String describing the query to be executed

query - The query to be sent

responseType - The ResponseType used for this query

Returns:

A CompletableFuture containing the query result as dictated by the given responseType

scatterGather

public <R,Q> Stream<R> scatterGather(String queryName,
                                     Q query,
                                     ResponseType<R> responseType,
                                     long timeout,
                                     TimeUnit timeUnit)

Description copied from interface: QueryGateway

Sends given query over the QueryBus, expecting a response in the form of responseType from several sources. The stream is completed when a timeout occurs or when all results are received. Execution may be asynchronous, depending on the QueryBus implementation.

Specified by:

scatterGather in interface QueryGateway

Type Parameters:

R - The response class contained in the given responseType

Q - The query class

Parameters:

queryName - A String describing the query to be executed

query - The query to be sent

responseType - The ResponseType used for this query

timeout - A timeout of long for the query

timeUnit - The selected TimeUnit for the given timeout

Returns:

A stream of results.

subscriptionQuery

public <Q,I,U> SubscriptionQueryResult<I,U> subscriptionQuery(String queryName,
                                                              Q query,
                                                              ResponseType<I> initialResponseType,
                                                              ResponseType<U> updateResponseType,
                                                              SubscriptionQueryBackpressure backpressure,
                                                              int updateBufferSize)

Description copied from interface: QueryGateway

Sends given query over the QueryBus and returns result containing initial response and incremental updates (received at the moment the query is sent, until it is cancelled by the caller or closed by the emitting side).

Note: Any null results, on the initial result or the updates, wil lbe filtered out by the QueryGateway. If you require the null to be returned for the initial and update results, we suggest using the QueryBus instead.

Specified by:

subscriptionQuery in interface QueryGateway

Type Parameters:

Q - The type of the query

I - The type of the initial response

U - The type of the incremental update

Parameters:

queryName - A String describing query to be executed

query - The query to be sent

initialResponseType - The initial response type used for this query

updateResponseType - The update response type used for this query

backpressure - The backpressure mechanism to deal with producing of incremental updates

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

Returns:

registration which can be used to cancel receiving updates

See Also:

QueryBus.subscriptionQuery(SubscriptionQueryMessage), QueryBus.subscriptionQuery(SubscriptionQueryMessage, SubscriptionQueryBackpressure, int)

registerDispatchInterceptor

public Registration registerDispatchInterceptor(MessageDispatchInterceptor<? super QueryMessage<?,?>> interceptor)

Description copied from interface: MessageDispatchInterceptorSupport

Register the given DispatchInterceptor. After registration, the interceptor will be invoked for each Message dispatched on the messaging component that it was registered to.

Specified by:

registerDispatchInterceptor in interface MessageDispatchInterceptorSupport<QueryMessage<?,?>>

Parameters:

interceptor - The interceptor to register

Returns:

a Registration, which may be used to remove the unregister the interceptor