* // register a callback for the "start" event
* Efs_Event::listen('start', function () {return 'Started!';});
*
* // register an object instance callback for the given event
* Efs_Event::listen('event', array($object, 'method'));
*
*
* Fire an event and return the first response.
*
*
* // fire the "start" event
* $response = Efs_Event::first('start');
*
* // fire the "start" event passing an array of parameters
* $response = Efs_Event::first('start', array('Pimf', 'Framework'));
*
*
* Fire an event so that all listeners are called.
*
*
* // fire the "start" event
* $responses = Efs_Event::fire('start');
*
* // fire the "start" event passing an array of parameters
* $responses = Efs_Event::fire('start', array('Pimf', 'Framework'));
*
* // fire multiple events with the same parameters
* $responses = Efs_Event::fire(array('start', 'loading'), $parameters);
*
*
* @package Pimf
* @author Gjero Krsteski
*/
class Event
{
/**
* All registered events.
*
* @var array
*/
protected static $events = array();
/**
* Determine if an event has any registered listeners.
*
* @param string $event
*
* @return bool
*/
public static function listeners($event)
{
return isset(static::$events[$event]);
}
/**
* Register a callback for a given event.
*
* @param string $event
* @param mixed $callback
*
* @return void
*/
public static function listen($event, $callback)
{
static::$events[$event][] = $callback;
}
/**
* Override all callbacks for a given event with a new callback.
*
* @param string $event
* @param mixed $callback
*
* @return void
*/
public static function override($event, $callback)
{
static::clear($event);
static::listen($event, $callback);
}
/**
* Clear all event listeners for a given event.
*
* @param string $event
*
* @return void
*/
public static function clear($event)
{
unset(static::$events[$event]);
}
/**
* Fire an event and return the first response.
*
* @param string $event
* @param \Exception[] $parameters
*
* @return mixed
*/
public static function first($event, $parameters = array())
{
$responses = static::fire($event, $parameters);
return reset($responses);
}
/**
* Fire an event and return the first response.
* Execution will be halted after the first valid response is found.
*
* @param string $event
* @param array $parameters
*
* @return mixed
*/
public static function until($event, $parameters = array())
{
return static::fire($event, $parameters, true);
}
/**
* Fire an event so that all listeners are called.
*
* @param string $events
* @param array $parameters
* @param bool $halt
*
* @return array|null
*/
public static function fire($events, $parameters = array(), $halt = false)
{
$responses = array();
$parameters = (array)$parameters;
// If the event has listeners, iterate through them and call each listener,
// passing in the parameters.
foreach ((array)$events as $event) {
if (static::listeners($event)) {
foreach (static::$events[$event] as $callback) {
$response = call_user_func_array($callback, $parameters);
// If the event is set to halt,
// return the first response that is not null.
if ($halt and !is_null($response)) {
return $response;
}
$responses[] = $response;
}
}
}
return $halt ? null : $responses;
}
}