lubuntu.me/plugins/elementor/core/base/module.php

<?php
namespace Elementor\Core\Base;

if ( ! defined( 'ABSPATH' ) ) {
	exit; // Exit if accessed directly.
}

abstract class Module {

	/**
	 * @var \ReflectionClass
	 */
	private $reflection;

	private $components = [];

	/**
	 * @var Module
	 */
	protected static $_instances = [];

	/**
	 * Throw error on object clone
	 *
	 * The whole idea of the singleton design pattern is that there is a single
	 * object therefore, we don't want the object to be cloned.
	 *
	 * @since 1.7.0
	 * @access public
	 * @return void
	 */
	public function __clone() {
		// Cloning instances of the class is forbidden
		_doing_it_wrong( __FUNCTION__, esc_html__( 'Cheatin&#8217; huh?', 'elementor' ), '1.0.0' );
	}

	/**
	 * Disable unserializing of the class
	 *
	 * @since 1.7.0
	 * @access public
	 * @return void
	 */
	public function __wakeup() {
		// Unserializing instances of the class is forbidden
		_doing_it_wrong( __FUNCTION__, esc_html__( 'Cheatin&#8217; huh?', 'elementor' ), '1.0.0' );
	}

	/**
	 * @since 1.7.0
	 * @access public
	 * @static
	 */
	public static function class_name() {
		return get_called_class();
	}

	/**
	 * @since 1.7.0
	 * @access public
	 * @static
	 * @return static
	 */
	public static function instance() {
		if ( empty( static::$_instances[ static::class_name() ] ) ) {
			static::$_instances[ static::class_name() ] = new static();
		}

		return static::$_instances[ static::class_name() ];
	}

	/**
	 * @since 1.7.0
	 * @access public
	 * @abstract
	 */
	abstract public function get_name();

	/**
	 * @since 1.7.0
	 * @access public
	 */
	public function __construct() {
		$this->reflection = new \ReflectionClass( $this );
	}

	/**
	 * @since 1.7.0
	 * @access public
	 */
	public function add_component( $id, $instance ) {
		$this->components[ $id ] = $instance;
	}

	/**
	 * @since 1.7.0
	 * @access public
	 */
	public function get_component( $id ) {
		if ( isset( $this->components[ $id ] ) ) {
			return $this->components[ $id ];
		}

		return false;
	}
}