Flow2Lab/EventSourcing

<?php
namespace Flow2Lab\EventSourcing\Command\Bus;

use Flow2Lab\EventSourcing\Command\Command;
use Flow2Lab\EventSourcing\Command\Bus\Exception\UnableToHandleCommandException;
use Flow2Lab\EventSourcing\Command\Handler\CommandHandlerInterface;
use TYPO3\Flow\Object\ObjectManagerInterface;
use TYPO3\Flow\Annotations as Flow;
use TYPO3\Flow\Reflection\ReflectionService;

/**
 * @Flow\Scope("singleton")
 */
class InternalCommandBus
{

    /**
     * @var ObjectManagerInterface
     * @Flow\Inject
     */
    protected $objectManager;

    /**
     * @var CommandHandlerInterface[]
     */
    protected $commandHandlers = [];

    public function initializeObject()
    {
        $eventHandlerClassNames = self::getCommandHandlerImplementationClassNames($this->objectManager);

        foreach ($eventHandlerClassNames as $eventHandlerClassName) {
            $this->commandHandlers[$eventHandlerClassName] = $this->objectManager->get($eventHandlerClassName);
        }
    }

    /**
     * @todo Use CommandInterface
     * @param Command $command
     * @throws UnableToHandleCommandException
     */
    public function handle(Command $command)
    {
        $commandHandled = FALSE;

        foreach ($this->commandHandlers as $commandHandler) {
            if ($commandHandler->canHandleCommand($command)) {
                try {
                    $commandHandler->handle($command);
                    $commandHandled = TRUE;
                    $this->emitCommandHandlingSuccess($command, $commandHandler);
                    break;
                } catch (\Exception $exception) {
                    $this->emitCommandHandlingFailure($command, $commandHandler, $exception);
                    throw $exception;
                }
            }
        }

        if ($commandHandled === FALSE) {
            throw new UnableToHandleCommandException('The command "' . get_class($command) . '" could not be handled by the command bus.', 1428327683);
        }
    }

    /**
     * @param Command $command
     * @param CommandHandlerInterface $commandHandler
     * @return void
     * @Flow\Signal
     */
    protected function emitCommandHandlingSuccess(Command $command, CommandHandlerInterface $commandHandler)
    {
    }

    /**
     * @param Command $command
     * @param CommandHandlerInterface $commandHandler
     * @param \Exception $exception
     * @return void
     * @Flow\Signal
     */
    protected function emitCommandHandlingFailure(Command $command, CommandHandlerInterface $commandHandler, \Exception $exception)
    {
    }

    /**
     * @param ObjectManagerInterface $objectManager
     * @return array Class names of all command handler class names
     * @Flow\CompileStatic
     */
    static public function getCommandHandlerImplementationClassNames(ObjectManagerInterface $objectManager)
    {
        $reflectionService = $objectManager->get(ReflectionService::class);
        return $reflectionService->getAllImplementationClassNamesForInterface(CommandHandlerInterface::class);
    }

}