org.axonframework.commandhandling.gateway

Interface CommandGateway

All Superinterfaces:

MessageDispatchInterceptorSupport<CommandMessage<?>>

All Known Implementing Classes:

DefaultCommandGateway

public interface CommandGateway
extends MessageDispatchInterceptorSupport<CommandMessage<?>>

Interface towards the Command Handling components of an application. This interface provides a friendlier API toward the CommandBus. The CommandGateway allows for components dispatching commands to wait for the result.

Since:

2.0

Author:

Allard Buijze

See Also:

DefaultCommandGateway

Method Summary

Modifier and Type	Method and Description
<C,R> void	send(C command, CommandCallback<? super C,? super R> callback) Sends the given command, and have the result of the command's execution reported to the given callback.
<R> CompletableFuture<R>	send(Object command) Sends the given command and returns a CompletableFuture immediately, without waiting for the command to execute.
<R> R	sendAndWait(Object command) Sends the given command and wait for it to execute.
<R> R	sendAndWait(Object command, long timeout, TimeUnit unit) Sends the given command and wait for it to execute.

Methods inherited from interface org.axonframework.messaging.MessageDispatchInterceptorSupport

registerDispatchInterceptor

Method Detail

send

<C,R> void send(C command,
                CommandCallback<? super C,? super R> callback)

Sends the given command, and have the result of the command's execution reported to the given callback.

The given command is wrapped as the payload of the CommandMessage that is eventually posted on the CommandBus, unless the command already implements Message. In that case, a CommandMessage is constructed from that message's payload and MetaData.

Type Parameters:

R - the type of result expected from command execution

Parameters:

command - the command to dispatch

callback - the callback to notify when the command has been processed

sendAndWait

<R> R sendAndWait(Object command)

Sends the given command and wait for it to execute. The result of the execution is returned when available. This method will block indefinitely, until a result is available, or until the Thread is interrupted. When the thread is interrupted, this method returns null. If command execution resulted in an exception, it is wrapped in a CommandExecutionException. If command dispatching failed, CommandDispatchException is thrown instead.

The given command is wrapped as the payload of the CommandMessage that is eventually posted on the CommandBus, unless the command already implements Message. In that case, a CommandMessage is constructed from that message's payload and MetaData.

Note that the interrupted flag is set back on the thread if it has been interrupted while waiting.

Type Parameters:

R - the type of result expected from command execution

Parameters:

command - the command to dispatch

Returns:

the result of command execution, or null if the thread was interrupted while waiting for the command to execute

Throws:

CommandExecutionException - when an exception occurred while processing the command

CommandDispatchException - when an exception occurred while dispatching the command

sendAndWait

<R> R sendAndWait(Object command,
                  long timeout,
                  TimeUnit unit)

Sends the given command and wait for it to execute. The result of the execution is returned when available. This method will block until a result is available, or the given timeout was reached, or until the Thread is interrupted. When the timeout is reached or the thread is interrupted, this method returns null. If command execution resulted in an exception, it is wrapped in a CommandExecutionException. If command dispatching failed, CommandDispatchException is thrown instead.

The given command is wrapped as the payload of the CommandMessage that is eventually posted on the CommandBus, unless the command already implements Message. In that case, a CommandMessage is constructed from that message's payload and MetaData.

Note that the interrupted flag is set back on the thread if it has been interrupted while waiting.

Type Parameters:

R - the type of result expected from command execution

Parameters:

command - the command to dispatch

timeout - the amount of time in the given unit the thread is allowed to wait for the result

unit - the unit in which timeout is expressed

Returns:

the result of command execution, or null if the thread was interrupted while waiting for the command to execute

Throws:

CommandExecutionException - when an exception occurred while processing the command

CommandDispatchException - when an exception occurred while dispatching the command

send

<R> CompletableFuture<R> send(Object command)

Sends the given command and returns a CompletableFuture immediately, without waiting for the command to execute. The caller will therefore not receive any immediate feedback on the command's execution. Instead hooks can be added to the returned CompletableFuture to react on success or failure of command execution.

The given command is wrapped as the payload of the CommandMessage that is eventually posted on the CommandBus, unless the command already implements Message. In that case, a CommandMessage is constructed from that message's payload and MetaData.

Parameters:

command - the command to dispatch

Returns:

a CompletableFuture which will be resolved successfully or exceptionally based on the eventual command execution result