<?php
class Repository
{
	const FILE_NAME="./repository.ser";

	private $map;
	private $updated;

	public static function getInstance()
	{
		if(file_exists(self::FILE_NAME))
			$repository=unserialize(file_get_contents(self::FILE_NAME));
		else
			$repository=new Repository();

		return $repository;
	}

	private function __construct()
	{
		$this->map=array();
		$this->updated=false;
	}

	public function set($key,$val)
	{
		$this->map[$key]=$val;
		$this->updated=true;
	}

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

	public function __destruct()
	{
		if($this->updated)
		{
			$this->updated=false;
			file_put_contents(self::FILE_NAME,serialize($this));
		}
	}
}
?>