Package io.axoniq.framework.axonserver.connector.query

Class AbstractQueryResponseMessageStream<T>

java.lang.Object
org.axonframework.messaging.core.AbstractMessageStream<QueryResponseMessage>
io.axoniq.framework.axonserver.connector.query.AbstractQueryResponseMessageStream<T>
Type Parameters:
T - The type of the objects in the underlying ResultStream to be transformed into QueryResponseMessages.
All Implemented Interfaces:
MessageStream<QueryResponseMessage>
Direct Known Subclasses:
QueryResponseMessageStream, QueryUpdateMessageStream
@Internal public abstract class AbstractQueryResponseMessageStream<T> extends AbstractMessageStream<QueryResponseMessage>
An abstract implementation of the MessageStream interface that wraps a ResultStream. This class provides functionality for transforming the data in the ResultStream into QueryResponseMessages, handling any encountered errors, and managing stream lifecycle events.
Since:
5.0.0
Author:
Allard Buijze, Jan Gallinkski, John Hendrikx

  • Constructor Details

    • AbstractQueryResponseMessageStream

      protected AbstractQueryResponseMessageStream(io.axoniq.axonserver.connector.ResultStream<T> stream)
      Constructs an instance of the AbstractQueryResponseMessageStream class with the provided result stream.
      Parameters:
      stream - The ResultStream instance from which query response data will be fetched. Must not be null.

  • Method Details

    • fetchNext

      protected AbstractMessageStream.FetchResult<MessageStream.Entry<QueryResponseMessage>> fetchNext()
      Description copied from class: AbstractMessageStream
      Attempts to fetch the next available MessageStream.Entry from the underlying source.

      This method is invoked exclusively by the enclosing AbstractMessageStream implementation. Calls are serialized under a single internal lock; the method is never executed concurrently with itself or other lifecycle methods of this instance. Implementations may assume single-threaded access and do not need to provide their own synchronization for correctness of this method.

      This method is invoked by AbstractMessageStream.next() when no previously peeked entry is available. Implementations must return a AbstractMessageStream.FetchResult describing the current state of the stream:

      Returning AbstractMessageStream.FetchResult.NotReady will transition the stream into an awaiting data state. Implementations must subsequently invoke AbstractMessageStream.signalProgress() when progress may be possible again (e.g., when new data arrives or the stream completes).

      Implementations must ensure that any state changes observable via this method are fully applied before invoking AbstractMessageStream.signalProgress(). A signal that arrives before the consumer has entered the awaiting state is not replayed; correctness relies on this method returning the updated state when the consumer calls it next. See AbstractMessageStream.signalProgress() for the full ordering contract.

      This method must be non-blocking. It should return immediately with the best available information about the stream's current state.

      Implementations must not attempt to complete or close the stream directly. Instead, they must return AbstractMessageStream.FetchResult.Completed or AbstractMessageStream.FetchResult.Error to signal termination.

      If an implementation throws an exception, the stream completes exceptionally with that exception.

      Specified by:
      fetchNext in class AbstractMessageStream<QueryResponseMessage>
      Returns:
      a AbstractMessageStream.FetchResult representing the outcome of the fetch attempt

    • onCompleted

      protected void onCompleted()
      Description copied from class: AbstractMessageStream
      Callback invoked when the stream is about to transition to a completed state, either successfully or exceptionally. Subclasses may override this method to perform custom actions on completion.

      This method is invoked exclusively by the enclosing AbstractMessageStream implementation. Calls are serialized under a single internal lock; the method is never executed concurrently with itself or other lifecycle methods of this instance. Implementations may assume single-threaded access and do not need to provide their own synchronization for correctness of this method.

      If the implementation throws an exception, the stream still completes, but it will complete with the thrown exception. If the stream was about to complete with an error, and the callback fails as well, the exception is added as a suppressed exception.

      Overrides:
      onCompleted in class AbstractMessageStream<QueryResponseMessage>

    • isError

      protected abstract boolean isError(T t)

    • isEmptyResult

      @Deprecated(forRemoval=true, since="5.2.1") protected boolean isEmptyResult(T t)
      Deprecated, for removal: This API element is subject to removal in a future version.
      as this method purely exists for interoperability between Axon Framework 4 and Axon Framework 5
      Whether the given t represents an entry that carries no payload and should be skipped rather than surfaced as a MessageStream entry.
      Parameters:
      t - the entry to check
      Returns:
      true if t carries no payload, false otherwise