<?php

namespace Box\Spout\Common;

/**
 * Class Singleton
 * Defines a class as a singleton.
 *
 * @package Box\Spout\Common
 */
trait Singleton {

	protected static $instance;

	/**
	 * @return static
	 */
	final public static function getInstance() {
		return isset( static::$instance )
			? static::$instance
			: static::$instance = new static();
	}

	/**
	 * Singleton constructor.
	 */
	final private function __construct() {
		$this->init();
	}

	/**
	 * Initializes the singleton
	 * @return void
	 */
	protected function init() {}

	final private function __wakeup() {}
	final private function __clone() {}
}