org.axonframework.axonserver.connector.query

Class AxonServerQueryBus

java.lang.Object

org.axonframework.axonserver.connector.query.AxonServerQueryBus

All Implemented Interfaces:

MessageDispatchInterceptorSupport<QueryMessage<?,?>>, MessageHandlerInterceptorSupport<QueryMessage<?,?>>, QueryBus

public class AxonServerQueryBus
extends Object
implements QueryBus

AxonServer implementation for the QueryBus. Delegates incoming queries to the specified localSegment.

Since:

4.0

Author:

Marc Gathier

Constructor Summary

Constructors

Constructor and Description
AxonServerQueryBus(AxonServerConnectionManager axonServerConnectionManager, AxonServerConfiguration configuration, QueryUpdateEmitter updateEmitter, QueryBus localSegment, Serializer messageSerializer, Serializer genericSerializer, QueryPriorityCalculator priorityCalculator) Creates an instance of the AxonServerQueryBus

Method Summary

Modifier and Type	Method and Description
void	disconnect()
void	on(QueryProviderInbound.RequestCase requestCase, Consumer<QueryProviderInbound> consumer)
void	publish(QueryProviderOutbound providerOutbound)
<Q,R> CompletableFuture<QueryResponseMessage<R>>	query(QueryMessage<Q,R> queryMessage) Dispatch the given query to a single QueryHandler subscribed to the given query's queryName and responseType.
QueryServiceGrpc.QueryServiceStub	queryServiceStub()
QueryUpdateEmitter	queryUpdateEmitter() Gets the QueryUpdateEmitter associated with this QueryBus.
Registration	registerDispatchInterceptor(MessageDispatchInterceptor<? super QueryMessage<?,?>> dispatchInterceptor) Register the given DispatchInterceptor.
Registration	registerHandlerInterceptor(MessageHandlerInterceptor<? super QueryMessage<?,?>> interceptor) Register the given handlerInterceptor.
<Q,R> Stream<QueryResponseMessage<R>>	scatterGather(QueryMessage<Q,R> queryMessage, long timeout, TimeUnit timeUnit) Dispatch the given query to all QueryHandlers subscribed to the given query's queryName/responseType.
<R> Registration	subscribe(String queryName, Type responseType, MessageHandler<? super QueryMessage<?,R>> handler) Subscribe the given handler to queries with the given queryName and responseType.
<Q,I,U> SubscriptionQueryResult<QueryResponseMessage<I>,SubscriptionQueryUpdateMessage<U>>	subscriptionQuery(SubscriptionQueryMessage<Q,I,U> query, SubscriptionQueryBackpressure backPressure, int updateBufferSize) Dispatch the given query to a single QueryHandler subscribed to the given query's queryName/initialResponseType/updateResponseType.

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.QueryBus

subscriptionQuery

Constructor Detail

AxonServerQueryBus

public AxonServerQueryBus(AxonServerConnectionManager axonServerConnectionManager,
                          AxonServerConfiguration configuration,
                          QueryUpdateEmitter updateEmitter,
                          QueryBus localSegment,
                          Serializer messageSerializer,
                          Serializer genericSerializer,
                          QueryPriorityCalculator priorityCalculator)

Creates an instance of the AxonServerQueryBus

Parameters:

axonServerConnectionManager - creates connection to AxonServer platform

configuration - contains client and component names used to identify the application in AxonServer

updateEmitter - emits incremental updates to subscription queries

localSegment - handles incoming query requests

messageSerializer - serializer/deserializer for payload and metadata of query requests and responses

genericSerializer - serializer for communication of other objects than payload and metadata

priorityCalculator - calculates the request priority based on the content and adds it to the request

Method Detail

subscribe

public <R> Registration subscribe(String queryName,
                                  Type responseType,
                                  MessageHandler<? super QueryMessage<?,R>> handler)

Description copied from interface: QueryBus

Subscribe the given handler to queries with the given queryName and responseType. Multiple handlers may subscribe to the same combination of queryName/responseType.

Specified by:

subscribe in interface QueryBus

Parameters:

queryName - the name of the query request to subscribe

responseType - the type of response the subscribed component answers with

handler - a handler that implements the query

Returns:

a handle to un-subscribe the query handler

query

public <Q,R> CompletableFuture<QueryResponseMessage<R>> query(QueryMessage<Q,R> queryMessage)

Description copied from interface: QueryBus

Dispatch the given query to a single QueryHandler subscribed to the given query's queryName and responseType. This method returns all values returned by the Query Handler as a Collection. This may or may not be the exact collection as defined in the Query Handler.

If the Query Handler defines a single return object (i.e. not a collection or array), that object is returned as the sole entry in a singleton collection.

When no handlers are available that can answer the given query, the returned CompletableFuture will be completed with a NoHandlerForQueryException.

Specified by:

query in interface QueryBus

Type Parameters:

Q - the payload type of the query

R - the response type of the query

Parameters:

queryMessage - the query

Returns:

a CompletableFuture that resolves when the response is available

queryServiceStub

public QueryServiceGrpc.QueryServiceStub queryServiceStub()

scatterGather

public <Q,R> Stream<QueryResponseMessage<R>> scatterGather(QueryMessage<Q,R> queryMessage,
                                                           long timeout,
                                                           TimeUnit timeUnit)

Description copied from interface: QueryBus

Dispatch the given query to all QueryHandlers subscribed to the given query's queryName/responseType. Returns a stream of results which blocks until all handlers have processed the request or when the timeout occurs.

If no handlers are available to provide a result, or when all available handlers throw an exception while attempting to do so, the returned Stream is empty.

Note that any terminal operation (such as Stream.forEach(Consumer)) on the Stream may cause it to block until the timeout has expired, awaiting additional data to include in the stream.

Specified by:

scatterGather in interface QueryBus

Type Parameters:

Q - the payload type of the query

R - the response type of the query

Parameters:

queryMessage - the query

timeout - time to wait for results

timeUnit - unit for the timeout

Returns:

stream of query results

registerHandlerInterceptor

public Registration registerHandlerInterceptor(MessageHandlerInterceptor<? super QueryMessage<?,?>> interceptor)

Description copied from interface: MessageHandlerInterceptorSupport

Register the given handlerInterceptor. After registration, the interceptor will be invoked for each handled Message on the messaging component that it was registered to, prior to invoking the message's handler.

Specified by:

registerHandlerInterceptor in interface MessageHandlerInterceptorSupport<QueryMessage<?,?>>

Parameters:

interceptor - The interceptor to register

Returns:

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

registerDispatchInterceptor

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

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:

dispatchInterceptor - The interceptor to register

Returns:

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

disconnect

public void disconnect()

publish

public void publish(QueryProviderOutbound providerOutbound)

on

public void on(QueryProviderInbound.RequestCase requestCase,
               Consumer<QueryProviderInbound> consumer)

subscriptionQuery

public <Q,I,U> SubscriptionQueryResult<QueryResponseMessage<I>,SubscriptionQueryUpdateMessage<U>> subscriptionQuery(SubscriptionQueryMessage<Q,I,U> query,
                                                                                                                    SubscriptionQueryBackpressure backPressure,
                                                                                                                    int updateBufferSize)

Description copied from interface: QueryBus

Dispatch the given query to a single QueryHandler subscribed to the given query's queryName/initialResponseType/updateResponseType. The result is lazily created and there will be no execution of the query handler before there is a subscription to the initial result. In order not to miss updates, the query bus will queue all updates which happen after the subscription query is done and once the subscription to the flux is made, these updates will be emitted.

If there is an error during retrieving or consuming initial result, stream for incremental updates is NOT interrupted.

If there is an error during emitting an update, subscription is cancelled causing further emits not reaching the destination.

Provided backpressure mechanism will be used to deal with fast emitters.

Specified by:

subscriptionQuery in interface QueryBus

Type Parameters:

Q - the payload type of the query

I - the response type of the query

U - the incremental response types of the query

Parameters:

query - the query

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:

query result containing initial result and incremental updates

queryUpdateEmitter

public QueryUpdateEmitter queryUpdateEmitter()

Description copied from interface: QueryBus

Gets the QueryUpdateEmitter associated with this QueryBus.

Specified by:

queryUpdateEmitter in interface QueryBus

Returns:

the associated QueryUpdateEmitter