org.axonframework.commandhandling.distributed

Interface CommandBusConnector

All Superinterfaces:

MessageHandlerInterceptorSupport<CommandMessage<?>>

public interface CommandBusConnector
extends MessageHandlerInterceptorSupport<CommandMessage<?>>

Interface describing the component that remotely connects multiple CommandBus instances.

Since:

2.0

Author:

Allard Buijze

Method Summary

Modifier and Type	Method and Description
default CompletableFuture<Void>	initiateShutdown() Initiate the shutdown of a CommandBusConnector.
default Optional<CommandBus>	localSegment() Return an Optional containing the CommandBus which is used by this CommandBusConnector to dispatch local and incoming CommandMessages on.
<C> void	send(Member destination, CommandMessage<? extends C> command) Sends the given command to the node assigned to handle messages with the given routingKey.
<C,R> void	send(Member destination, CommandMessage<C> command, CommandCallback<? super C,R> callback) Sends the given command to the node assigned to handle messages with the given routingKey.
Registration	subscribe(String commandName, MessageHandler<? super CommandMessage<?>> handler) Subscribes a command message handler for commands with given commandName.

Methods inherited from interface org.axonframework.messaging.MessageHandlerInterceptorSupport

registerHandlerInterceptor

Method Detail

send

<C> void send(@Nonnull
              Member destination,
              @Nonnull
              CommandMessage<? extends C> command)
       throws Exception

Sends the given command to the node assigned to handle messages with the given routingKey. The sender does not expect a reply.

If this method throws an exception, the sender is guaranteed that the destination of the command did not receive it. If the method returns normally, the actual implementation of the connector defines the delivery guarantees.

Connectors route the commands based on the given routingKey. Using the same routingKey will result in the command being sent to the same member. Each message must be sent to exactly one member.

Parameters:

destination - The member of the network to send the message to

command - The command to send to the (remote) member

Throws:

Exception - when an error occurs before or during the sending of the message

send

<C,R> void send(@Nonnull
                Member destination,
                @Nonnull
                CommandMessage<C> command,
                @Nonnull
                CommandCallback<? super C,R> callback)
         throws Exception

Sends the given command to the node assigned to handle messages with the given routingKey. The sender expect a reply, and will be notified of the result in the given callback.

If this method throws an exception, the sender is guaranteed that the destination of the command did not receive it. If the method returns normally, the actual implementation of the connector defines the delivery guarantees. Implementations should always invoke the callback with an outcome.

If a member's connection was lost, and the result of the command is unclear, the CommandCallback.onResult(CommandMessage, CommandResultMessage)} method is invoked with a RemoteHandlingException describing the failed connection. A client may choose to resend a command.

Connectors route the commands based on the given routingKey. Using the same routingKey will result in the command being sent to the same member.

Type Parameters:

C - The type of object expected as command

R - The type of object expected as result of the command

Parameters:

destination - The member of the network to send the message to

command - The command to send to the (remote) member

callback - The callback

Throws:

Exception - when an error occurs before or during the sending of the message

subscribe

Registration subscribe(@Nonnull
                       String commandName,
                       @Nonnull
                       MessageHandler<? super CommandMessage<?>> handler)

Subscribes a command message handler for commands with given commandName.

Parameters:

commandName - the command name. Usually this equals the fully qualified class name of the command.

handler - the handler to subscribe

Returns:

a handle that can be used to end the subscription

localSegment

default Optional<CommandBus> localSegment()

Return an Optional containing the CommandBus which is used by this CommandBusConnector to dispatch local and incoming CommandMessages on. It is highly recommended to implement this method to ensure an actual CommandBus is provided instead of a default Optional.empty().

Returns:

an Optional containing the CommandBus which is used by this CommandBusConnector to dispatch local and incoming CommandMessages on

initiateShutdown

default CompletableFuture<Void> initiateShutdown()

Initiate the shutdown of a CommandBusConnector. CommandMessages should no longer be dispatched after this method has been invoked.

Returns:

a CompletableFuture indicating when all previously sent commands are completed