/**
* Adds the filter to the event dispatcher.
*
* @param string $when Either 'before' or 'after'
* @param string $action
* @param mixed $callback
*/
protected function addFilter($when, $action, $callback)
{
if (!is_callable($callback) && !is_array($callback)) {
$callback = [$this, $callback];
}
if (is_array($action)) {
foreach ($action as $method) {
$this->addFilter($when, $method, $callback);
}
} else {
EventDispatcher::addListener("{$when}." . get_called_class() . "::{$action}", $callback);
}
}
