/// <summary>
/// Creates a chain of time zone retrieving.
/// </summary>
/// <returns>Chain.</returns>
protected virtual ChainOfCircumstances <TimeZoneInfo> CreateChain()
{
var chain = new ChainOfCircumstances <TimeZoneInfo>();
chain.AddLast(GetFromServiceCalendar, chain.NotDefault());
chain.AddLast(GetFromSysSetting);
return(chain);
}
/// <summary>
/// Creates a chain of time zone retrieving.
/// </summary>
/// <returns>Chain.</returns>
protected override ChainOfCircumstances <TimeZoneInfo> CreateChain()
{
var chain = new ChainOfCircumstances <TimeZoneInfo>();
chain.AddLast(GetFromServiceInServicePact, chain.NotDefault());
chain.AddLast(GetFromServicePact, chain.NotDefault());
return(chain + base.CreateChain());
}
/// <summary>
/// Concatenates two chains into a new one.
/// </summary>
/// <param name="first">First chain.</param>
/// <param name="second">Second chain.</param>
/// <returns>Concatenated.</returns>
public static ChainOfCircumstances <TResult> operator +(
ChainOfCircumstances <TResult> first,
ChainOfCircumstances <TResult> second)
{
var result = new ChainOfCircumstances <TResult>();
foreach (var circumstance in first._circumstances)
{
result.AddLast(circumstance);
}
foreach (var circumstance in second._circumstances)
{
result.AddLast(circumstance);
}
return(result);
}
/// <summary>
/// A common postcondition pointing that the result mustn't be
/// a default value of <paramref name="TResult"/>.
/// </summary>
/// <typeparam name="TResult">Type of result.</typeparam>
/// <param name="chain">The chain.</param>
/// <returns>Postcondition.</returns>
public static Predicate <TResult> NotDefault <TResult>(this ChainOfCircumstances <TResult> chain)
{
return(result => !Equals(result, default(TResult)));
}