'Check connection status to the server currently  selected by user and
show a status box indicating current operation.
:param url: The link of the server chose by user.This string could be
a domain name or the IP address of a server.
.. seealso:: :attr:`link` in
:meth:`~util.common.CommonUtil.check_connection`.
:type url: str
:return: A flag indicating connection status is good or not.
.. seealso:: :meth:`~util.common.CommonUtil.check_connection`. in
:class:`~util.common.CommonUtil` class.
:rtype: int'

def check_connection(self, url):

    self.messagebox('Checking    Server    Status...')
    conn = CommonUtil.check_connection(url)
    if conn:
        self.statusinfo[0][1] = 'OK'
        self.statusinfo[0][2] = 'GREEN'
    else:
        self.statusinfo[0][1] = 'Error'
        self.statusinfo[0][2] = 'RED'
    self.status()
    return conn
