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<?php
declare(strict_types = 1);
namespace DASPRiD\Enum;
use DASPRiD\Enum\Exception\CloneNotSupportedException;
use DASPRiD\Enum\Exception\SerializeNotSupportedException;
use DASPRiD\Enum\Exception\UnserializeNotSupportedException;
final class NullValue
{
/**
* @var self
*/
private static $instance;
private function __construct()
{
}
public static function instance() : self
{
return self::$instance ?: self::$instance = new self();
}
/**
* Forbid cloning enums.
*
* @throws CloneNotSupportedException
*/
final public function __clone()
{
throw new CloneNotSupportedException();
}
/**
* Forbid serializing enums.
*
* @throws SerializeNotSupportedException
*/
final public function __sleep() : void
{
throw new SerializeNotSupportedException();
}
/**
* Forbid unserializing enums.
*
* @throws UnserializeNotSupportedException
*/
final public function __wakeup() : void
{
throw new UnserializeNotSupportedException();
}
}
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