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<?php
/**
* Hoa
*
*
* @license
*
* New BSD License
*
* Copyright © 2007-2017, Hoa community. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the Hoa nor the names of its contributors may be
* used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS AND CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
namespace Psy\Readline\Hoa;
/**
* Events are asynchronous at registration, anonymous at use (until we
* receive a bucket) and useful to largely spread data through components
* without any known connection between them.
*/
class Event
{
/**
* Event ID key.
*/
const KEY_EVENT = 0;
/**
* Source object key.
*/
const KEY_SOURCE = 1;
/**
* Static register of all observable objects, i.e. `Hoa\Event\Source`
* object, i.e. object that can send event.
*/
private static $_register = [];
/**
* Collection of callables, i.e. observer objects.
*/
protected $_callable = [];
/**
* Privatize the constructor.
*/
private function __construct()
{
return;
}
/**
* Manage multiton of events, with the principle of asynchronous
* attachments.
*/
public static function getEvent(string $eventId): self
{
if (!isset(self::$_register[$eventId][self::KEY_EVENT])) {
self::$_register[$eventId] = [
self::KEY_EVENT => new self(),
self::KEY_SOURCE => null,
];
}
return self::$_register[$eventId][self::KEY_EVENT];
}
/**
* Declares a new object in the observable collection.
* Note: Hoa's libraries use `hoa://Event/anID` for their observable objects.
*/
public static function register(string $eventId, /* Source|string */ $source)
{
if (true === self::eventExists($eventId)) {
throw new EventException('Cannot redeclare an event with the same ID, i.e. the event '.'ID %s already exists.', 0, $eventId);
}
if (\is_object($source) && !($source instanceof EventSource)) {
throw new EventException('The source must implement \Hoa\Event\Source '.'interface; given %s.', 1, \get_class($source));
} else {
$reflection = new \ReflectionClass($source);
if (false === $reflection->implementsInterface('\Psy\Readline\Hoa\EventSource')) {
throw new EventException('The source must implement \Hoa\Event\Source '.'interface; given %s.', 2, $source);
}
}
if (!isset(self::$_register[$eventId][self::KEY_EVENT])) {
self::$_register[$eventId][self::KEY_EVENT] = new self();
}
self::$_register[$eventId][self::KEY_SOURCE] = $source;
}
/**
* Undeclares an object in the observable collection.
*
* If `$hard` is set to `true, then the source and its attached callables
* will be deleted.
*/
public static function unregister(string $eventId, bool $hard = false)
{
if (false !== $hard) {
unset(self::$_register[$eventId]);
} else {
self::$_register[$eventId][self::KEY_SOURCE] = null;
}
}
/**
* Attach an object to an event.
*
* It can be a callable or an accepted callable form (please, see the
* `Hoa\Consistency\Xcallable` class).
*/
public function attach($callable): self
{
$callable = Xcallable::from($callable);
$this->_callable[$callable->getHash()] = $callable;
return $this;
}
/**
* Detaches an object to an event.
*
* Please see `self::attach` method.
*/
public function detach($callable): self
{
unset($this->_callable[Xcallable::from($callable)->getHash()]);
return $this;
}
/**
* Checks if at least one callable is attached to an event.
*/
public function isListened(): bool
{
return !empty($this->_callable);
}
/**
* Notifies, i.e. send data to observers.
*/
public static function notify(string $eventId, EventSource $source, EventBucket $data)
{
if (false === self::eventExists($eventId)) {
throw new EventException('Event ID %s does not exist, cannot send notification.', 3, $eventId);
}
$data->setSource($source);
$event = self::getEvent($eventId);
foreach ($event->_callable as $callable) {
$callable($data);
}
}
/**
* Checks whether an event exists.
*/
public static function eventExists(string $eventId): bool
{
return
\array_key_exists($eventId, self::$_register) &&
self::$_register[$eventId][self::KEY_SOURCE] !== null;
}
}
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