private function _setWayValue($way, TableInterface $table, array $optionalTables = array())
	{
		$this->joinArray['way']    = $way;
		$this->joinArray['tables'] = array($table);
		foreach($optionalTables as $arg)
		{
			if(!$arg instanceof TableInterface)
			{
				throw new \InvalidArgumentException('arguments has to be of type table interface');
			}
			$this->joinArray['tables'][] = $arg;
		}

		return $this;
	}