public static Dns GetInstance <T>(string resolver) where T : Dns
{
Dns instance;
try
{
instance = DoGetInstance(typeof(T), resolver);
}
catch (Exception e)
{
Logger.GetInstance(typeof(Dns)).Fatal("Instance initialization error " + e);
Logger.GetInstance(typeof(Dns)).Info("Initializing " + typeof(DefaultDns).FullName + "...");
instance = new DefaultDns(resolver);
}
return(instance);
}
private static Dns DoGetInstance(Type type, string resolver)
{
if (type == null || resolver == null)
{
throw new ArgumentException("Invalid arguments to get " + typeof(Dns).Name + " instance");
}
var key = type.FullName + "_" + resolver;
Dns instance = null;
if (Instances.ContainsKey(key))
{
instance = Instances[key];
}
if (instance == null)
{
Logger.GetInstance(typeof(Dns)).Info("Initializing " + key + "...");
var constructor = type.GetConstructor(new[] { typeof(string) });
if (constructor != null)
{
instance = (Dns)constructor.Invoke(new object[] { resolver });
}
}
if (instance == null)
{
Logger.GetInstance(typeof(Dns)).Info("Initializing " + typeof(DefaultDns).FullName + "[" + resolver + "]...");
instance = new DefaultDns(resolver);
}
lock (InstancesLock)
{
if (!Instances.ContainsKey(key))
{
Instances.Add(key, instance);
}
}
return(instance);
}
