When Wifi disconnect, how does Socket on Android server side know that? -

i developed android app, works in wifi ap mode socket server. clients setup wifi connection , socket connection app. when socket connected, disconnect wifi connection client, there no exception nor read method of socket return -1 in server app. questions are:

1. how detect broken wifi connection
2. how detect client's wifi connection broken

thanks.

use in thread

public static boolean checknetworkconnection(context context)    {        final connectivitymanager connmgr = (connectivitymanager)context.getsystemservice(context.connectivity_service);        final android.net.networkinfo wifi =connmgr.getnetworkinfo(connectivitymanager.type_wifi);       final android.net.networkinfo mobile =connmgr.getnetworkinfo(connectivitymanager.type_mobile);        if(wifi.isavailable()||mobile.isavailable())           return true;       else          return false;    }