Package org.axonframework.commandhandling

Class AsynchronousCommandBus

java.lang.Object

org.axonframework.commandhandling.SimpleCommandBus

org.axonframework.commandhandling.AsynchronousCommandBus

All Implemented Interfaces:

CommandBus, MessageDispatchInterceptorSupport<CommandMessage<?>>, MessageHandlerInterceptorSupport<CommandMessage<?>>

public class AsynchronousCommandBus
extends SimpleCommandBus

Specialization of the SimpleCommandBus that processed Commands asynchronously from the calling thread. By default, the AsynchronousCommandBus uses a Cached Thread Pool (see Executors.newCachedThreadPool()). It will reuse threads while possible, and shut them down after 60 seconds of inactivity.

Each Command is dispatched in a separate task, which is processed by the Executor.

Note that you should call shutdown() to stop any threads waiting for new tasks. Failure to do so may cause the JVM to hang for up to 60 seconds on JVM shutdown.

Since:

1.3.4

Author:

Allard Buijze

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	AsynchronousCommandBus.Builder	Builder class to instantiate a AsynchronousCommandBus.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AsynchronousCommandBus(AsynchronousCommandBus.Builder builder)	Instantiate a AsynchronousCommandBus based on the fields contained in the AsynchronousCommandBus.Builder.

Method Summary

Modifier and Type	Method	Description
static AsynchronousCommandBus.Builder	builder()	Instantiate a Builder to be able to create a AsynchronousCommandBus.
protected <C, R> void	handle(CommandMessage<C> command, MessageHandler<? super CommandMessage<?>> handler, CommandCallback<? super C,? super R> callback)	Performs the actual handling logic.
void	shutdown()	Shuts down the Executor used to asynchronously dispatch incoming commands.

Methods inherited from class org.axonframework.commandhandling.SimpleCommandBus

dispatch, dispatch, doDispatch, intercept, registerDispatchInterceptor, registerHandlerInterceptor, setRollbackConfiguration, subscribe

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

AsynchronousCommandBus

protected AsynchronousCommandBus(AsynchronousCommandBus.Builder builder)

Instantiate a AsynchronousCommandBus based on the fields contained in the AsynchronousCommandBus.Builder.

Will assert that the TransactionManager, MessageMonitor, RollbackConfiguration and Executor are not null, and will throw an AxonConfigurationException if any of them is null.

Parameters:

builder - the AsynchronousCommandBus.Builder used to instantiate a AsynchronousCommandBus instance

Method Details

builder

public static AsynchronousCommandBus.Builder builder()

Instantiate a Builder to be able to create a AsynchronousCommandBus.

The TransactionManager is defaulted to a NoTransactionManager, the MessageMonitor is defaulted to a NoOpMessageMonitor, RollbackConfiguration defaults to a RollbackConfigurationType.UNCHECKED_EXCEPTIONS, the DuplicateCommandHandlerResolver defaults to DuplicateCommandHandlerResolution.logAndOverride(), the Executor defaults to a Executors.newCachedThreadPool() and the CommandBusSpanFactory defaults to a DefaultCommandBusSpanFactory backed by a NoOpSpanFactory. The defaultexecutor uses an AxonThreadFactory to create threads with a sensible naming scheme. The TransactionManager, MessageMonitor, RollbackConfiguration and Executor are hard requirements. Thus setting them to null will result in an AxonConfigurationException.

Returns:

a Builder to be able to create a AsynchronousCommandBus

handle

protected <C,
R> void handle(CommandMessage<C> command,
 MessageHandler<? super CommandMessage<?>> handler,
 CommandCallback<? super C,? super R> callback)

Description copied from class: SimpleCommandBus

Performs the actual handling logic.

Overrides:

handle in class SimpleCommandBus

Type Parameters:

C - The type of payload of the command

R - The type of result expected from the command handler

Parameters:

command - The actual command to handle

handler - The handler that must be invoked for this command

callback - The callback to notify of the result

shutdown

public void shutdown()

Shuts down the Executor used to asynchronously dispatch incoming commands. If the Executor provided in the constructor does not implement ExecutorService, this method does nothing.