Generator Trait
The GeneratorTrait provides an implementation of the GeneratorInterface to accumulate events and release them at a later time.
There are two methods provided by this trait:
- public function releaseGeneratedEvents
- protected function addEvent
The addEvent method’s visibility is protected to ensure events are only added from within,
preventing outside interference and to ensure the implementor has full control over which
events are emitted.
Implementation Example
use League\Event\GeneratorTrait;
use League\Event\GeneratorInterface;
class User implements GeneratorInterface
{
use GeneratorTrait;
public function updateAddress(Address $address)
{
$this->address = $address;
$this->addEvent(new UserAddressWasChanged($this, $address));
}
}
$user = new User;
$user->updateAddress(new Address(...));
Emitting and Releasing Generated Events
Once events are generated, you’ll want to release them so they can be emitted. The
GeneratorInterface specifies a releaseGeneratedEvents which returns an array
of events to be emitted.
$events = $user->releaseGeneratedEvents();
$emitter->emitBatch($events);
// Or the shorter version
$emitter->emitGeneratedEvents($user);
When you prefer a more expressive syntax you can alter the addEvent method name like so:
class User
{
use GeneratorTrait {
addEvent as recordThat;
}
public function updateAddress(Address $address)
{
$this->address = $address;
$this->recordThat(new UserAddressWasChanged($this, $address));
}
}