public interface QueryBus
QueryMessage.getQueryName() and
QueryMessage.getResponseType() on the query bus. There may be multiple handlers for each combination of
queryName/responseType.| Modifier and Type | Method and Description |
|---|---|
<Q,R> CompletableFuture<QueryResponseMessage<R>> |
query(QueryMessage<Q,R> query)
Dispatch the given
query to a single QueryHandler subscribed to the given query's queryName
and responseType. |
<Q,R> Stream<QueryResponseMessage<R>> |
scatterGather(QueryMessage<Q,R> query,
long timeout,
TimeUnit unit)
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. |
default <Q,I,U> SubscriptionQueryResult<QueryResponseMessage<I>,SubscriptionQueryUpdateMessage<U>> |
subscriptionQuery(SubscriptionQueryMessage<Q,I,U> query)
Dispatch the given
query to a single QueryHandler subscribed to the given query's
queryName/initialResponseType/updateResponseType. |
default <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. |
<R> Registration subscribe(String queryName, Type responseType, MessageHandler<? super QueryMessage<?,R>> handler)
handler to queries with the given queryName and responseType.
Multiple handlers may subscribe to the same combination of queryName/responseType.queryName - the name of the query request to subscriberesponseType - the type of response the subscribed component answers withhandler - a handler that implements the query<Q,R> CompletableFuture<QueryResponseMessage<R>> query(QueryMessage<Q,R> query)
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.
Q - the payload type of the queryR - the response type of the queryquery - the query<Q,R> Stream<QueryResponseMessage<R>> scatterGather(QueryMessage<Q,R> query, long timeout, TimeUnit unit)
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.
Q - the payload type of the queryR - the response type of the queryquery - the querytimeout - time to wait for resultsunit - unit for the timeoutdefault <Q,I,U> SubscriptionQueryResult<QueryResponseMessage<I>,SubscriptionQueryUpdateMessage<U>> subscriptionQuery(SubscriptionQueryMessage<Q,I,U> query)
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.
Backpressure mechanism to be used is SubscriptionQueryBackpressure.defaultBackpressure(). The size of
buffer which accumulates the updates (not to be missed) is Queues.SMALL_BUFFER_SIZE.
Q - the payload type of the queryI - the response type of the queryU - the incremental response types of the queryquery - the querydefault <Q,I,U> SubscriptionQueryResult<QueryResponseMessage<I>,SubscriptionQueryUpdateMessage<U>> subscriptionQuery(SubscriptionQueryMessage<Q,I,U> query, SubscriptionQueryBackpressure backpressure, int updateBufferSize)
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.
Q - the payload type of the queryI - the response type of the queryU - the incremental response types of the queryquery - the querybackpressure - the backpressure mechanism to be used for emitting updatesupdateBufferSize - the size of buffer which accumulates updates before subscription to the flux is
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