public IAsyncResult BeginExecOnNearServer <S, R>(IAPMServices <S, R> s, Uri[] servers, S service,
AsyncCallback ac, object state)
{
GenericAsyncResult <R> gar = new GenericAsyncResult <R>(ac, state, false);
int got = 0, failures = 0;
for (int i = 0; i < servers.Length; i++)
{
s.BeginPingServer(servers[i], onPingServer, null);
}
void onPingServer(IAsyncResult ar)
{
try
{
Uri uri = s.EndPingServer(ar);
if (Interlocked.Exchange(ref got, 1) == 0)
{
s.BeginExecService(uri, service, onExecService, null);
}
}
catch (Exception ex)
{
if (Interlocked.Increment(ref failures) == servers.Length)
{
gar.SetException(ex);
}
}
}
void onExecService(IAsyncResult ar)
{
try
{
gar.SetResult(s.EndExecService(ar));
}
catch (Exception ex)
{
gar.SetException(ex);
}
}
return(gar);
}
