/// <summary>
/// 是否超過暫存時間
/// 當主要時間 > 關聯時間 即為超過，反之則無
/// </summary>
/// <param name="source">主要暫存物件</param>
/// <param name="target">關聯暫存物件</param>
/// <typeparam name="T">主要暫存泛型</typeparam>
/// <typeparam name="U">關聯暫存泛型</typeparam>
/// <returns></returns>
public static bool OverDependencyTime <T, U>(this CacheFactory <T> source, CacheFactory <U> target)
{
var targetTime = target.GetCacheTime();
var sourceTime = source.GetCacheTime();
return(targetTime.HasValue && sourceTime.HasValue && targetTime > sourceTime);
}