/// <summary>
/// Specifies a data retrieval strategy if the desired value does not exist in the cache or is invalid
/// </summary>
/// <param name="retrieve">A delegate that specifies how the value is to be retrieved</param>
/// <returns>An updated cache strategy that includes the retrieval strategy</returns>
public CacheStrategy <T> RetrieveUsing <T>(Func <P1, T> retrieve)
{
CacheStrategy <T> strategy = base.Complete <T>();
var p1 = strategy.GetParameter <P1>(0);
strategy.RetrieveCallback = () => retrieve(p1);
return(strategy);
}
