* * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ declare(strict_types=1); namespace OCC\Basics\Traits; use LogicException; /** * Allows just a single instance of the class using this trait. * * @author Sebastian Meyer * @package Basics\Traits */ trait Singleton { /** * Holds the singleton instance. * * @var array * * @internal */ private static array $singleton = []; /** * Get a singleton instance of this class. * * @param mixed ...$args Constructor parameters * * @return static The singleton instance * * @api */ final public static function getInstance(mixed ...$args): static { if (!isset(static::$singleton[static::class])) { static::$singleton[static::class] = new static(...$args); } return static::$singleton[static::class]; } /** * This is a singleton class, thus the constructor is private. * * Usage: Get an instance of this class by calling static::getInstance() * * @return void */ abstract private function __construct(); /** * This is a singleton class, thus cloning is prohibited. * * @return void * * @throws LogicException * * @internal */ final public function __clone(): void { throw new LogicException('Cloning a singleton is prohibited.'); } }