Package io.axoniq.framework.messaging.commandhandling.distributed

Class LocalShortcutCommandBusConnector

java.lang.Object
io.axoniq.framework.messaging.commandhandling.distributed.DelegatingCommandBusConnector
io.axoniq.framework.messaging.commandhandling.distributed.LocalShortcutCommandBusConnector
All Implemented Interfaces:
CommandBusConnector, DescribableComponent
public class LocalShortcutCommandBusConnector extends DelegatingCommandBusConnector
A CommandBusConnector that offers a "local shortcut".

This shortcut triggers for commands matching a LocalCommandDispatchPredicate, and for which the local segment subscribed a handler, the command is handed to the local segment directly instead of being dispatched through the wrapped connector. Furthermore, the shortcut only activates when the local segment can actually handle the command, tracked through the subscribe(QualifiedName, int)/unsubscribe(QualifiedName) calls this connector observes.

Short-cut commands are handled through the same CommandBusConnector.Handler as any other CommandBusConnector. As such, they are queued onto and executed by the same bounded, priority-ordered worker pool as commands arriving from remote segments. A burst of locally-preferred commands is therefore subject to the same back-pressure and cannot flood the local segment beyond what it would already accept from remote traffic.

Since:
5.4.0
Author:
Allard Buijze
See Also:

  • Constructor Details

    • LocalShortcutCommandBusConnector

      public LocalShortcutCommandBusConnector(CommandBusConnector delegate, LocalCommandDispatchPredicate shortcutPredicate)
      Initialize a connector with the given delegate, using the given shortcutPredicate to decide whether to shortcut a command yes or no.
      Parameters:
      delegate - the CommandBusConnector to delegate to when not dispatching locally
      shortcutPredicate - the predicate deciding whether a command should be dispatched to the local segment directly

  • Method Details

    • dispatch

      public CompletableFuture<CommandResultMessage> dispatch(CommandMessage command, @Nullable ProcessingContext processingContext)
      Description copied from interface: CommandBusConnector
      Dispatches the given command to the appropriate command bus, which may be local or remote.
      Specified by:
      dispatch in interface CommandBusConnector
      Overrides:
      dispatch in class DelegatingCommandBusConnector
      Parameters:
      command - the command message to dispatch
      processingContext - the processing context for the command
      Returns:
      a CompletableFuture that will complete with the result of the command handling

    • subscribe

      public CompletableFuture<Void> subscribe(QualifiedName commandName, int loadFactor)
      Description copied from interface: CommandBusConnector
      Subscribes to a command with the given commandName and a loadFactor.

      Subscribing a commandName this connector is already subscribed to replaces the earlier subscription, adopting the given loadFactor. A single unsubscribe of that commandName undoes any number of subscriptions to it.

      Specified by:
      subscribe in interface CommandBusConnector
      Overrides:
      subscribe in class DelegatingCommandBusConnector
      Parameters:
      commandName - The QualifiedName of the command to subscribe to.
      loadFactor - The load factor for the command, which can be used to control the distribution of command handling across multiple instances. The load factor should be a positive integer.
      Returns:
      A CompletableFuture that completes successfully when this connector subscribed to the given commandName with the given loadFactor.

    • unsubscribe

      public boolean unsubscribe(QualifiedName commandName)
      Description copied from interface: CommandBusConnector
      Unsubscribes from a command with the given commandName.

      Undoes any number of subscriptions to the given commandName, leaving no command of that name routed to this connector.

      Specified by:
      unsubscribe in interface CommandBusConnector
      Overrides:
      unsubscribe in class DelegatingCommandBusConnector
      Parameters:
      commandName - The QualifiedName of the command to unsubscribe from.
      Returns:
      true if the unsubscription was successful, false otherwise.

    • onIncomingCommand

      public void onIncomingCommand(CommandBusConnector.Handler handler)
      Description copied from interface: CommandBusConnector
      Registers a handler that will be called when an incoming command is received. The handler should process the command and call the provided ResultCallback to indicate success or failure.
      Specified by:
      onIncomingCommand in interface CommandBusConnector
      Overrides:
      onIncomingCommand in class DelegatingCommandBusConnector
      Parameters:
      handler - A BiConsumer that takes a CommandMessage and a CommandBusConnector.ResultCallback.

    • describeTo

      public void describeTo(ComponentDescriptor descriptor)
      Description copied from interface: DescribableComponent
      Describe the properties of this DescribableComponent with the given descriptor.

      Components should call the appropriate describeProperty methods on the descriptor to register their properties. The descriptor is responsible for determining how these properties are formatted and structured in the final output.

      Best Practices: As a general rule, all relevant fields of a DescribableComponent implementation should be described in this method. However, developers have discretion to include only the fields that make sense in the context. Not every field may be meaningful for description purposes, especially internal implementation details. Furthermore, components might want to expose different information based on their current state. The final decision on what properties to include lies with the person implementing the describeTo method, who should focus on providing information that is useful for understanding the component's configuration and state.

      Example implementation: 

       public void describeTo(ComponentDescriptor descriptor) {
     descriptor.describeProperty("name", this.name);
     descriptor.describeProperty("enabled", this.enabled);
     descriptor.describeProperty("configuration", this.configuration); // A nested component
     descriptor.describeProperty("handlers", this.eventHandlers);      // A collection
 }
      Specified by:
      describeTo in interface DescribableComponent
      Overrides:
      describeTo in class DelegatingCommandBusConnector
      Parameters:
      descriptor - The component descriptor to describe this DescribableComponentn its properties in.