php-ddd/command

The command part of the Command Query Responsibility Segregation

Command

This library provides some useful tools in order to create a simple command system., _(*1)

How it works

// configuration
$handler = new AddItemToChartCommandHandler();
$locator = new CommandHandlerLocator();
$locator->register('AddItemToChartCommand', $handler);

$bus = new SequentialCommandBus($locator);

// usage
$command = new AddItemToChartCommand($item, $chart);
$bus->dispatch($command); // internally, the bus will call the corresponding handler.

Conventions

We want to follow the Single Responsibility principle. Hence: * A CommandHandler can only handle one CommandInterface * A CommandBus will only dispatch some CommandInterface (and nothing more) * A CommandHandlerLocator is responsible of registering associations between Command and CommandHandler, _(*2)

It allows us to force some other conventions like the name of the CommandHandler class that needs to match the name of the Command it handle. E.g: AddItemToChartCommand will be handled by a AddItemToChartCommandHandler object., _(*3)