<?php
namespace PSC\Library\Calc;

class Cache {
    private static $instance = null;
    private $cache = [];

    private function __construct() {}

    public static function getInstance() {
        if (self::$instance === null) {
            self::$instance = new Cache();
        }
        return self::$instance;
    }

    public function set($key, $value) {
        $this->cache[$key] = $value;
    }

    public function get($key) {
        return $this->cache[$key] ?? null;
    }
}