/// <summary>
/// Creates a new instance of <see cref="BclDateTimeZone" /> from the <see cref="TimeZoneInfo"/> with the given
/// ID. The ID must be a known system time zone ID.
/// </summary>
/// <param name="id">The ID of the system time zone to convert</param>
/// <exception cref="ArgumentException">The given zone doesn't exist.</exception>
/// <returns>The Noda Time representation of the given BCL time zone</returns>
public BclDateTimeZone ForId(string id)
{
try
{
TimeZoneInfo zone = TimeZoneInfoInterceptor.FindSystemTimeZoneById(id);
return(BclDateTimeZone.FromTimeZoneInfo(zone));
}
catch (TimeZoneNotFoundException)
{
throw new ArgumentException(id + " is not a system time zone ID", nameof(id));
}
}
/// <summary>
/// Returns a time zone converted from the BCL representation of the system local time zone.
/// </summary>
/// <remarks>
/// <para>
/// This method is approximately equivalent to calling <see cref="IDateTimeZoneProvider.GetSystemDefault"/> with
/// an implementation that wraps <see cref="BclDateTimeZoneSource"/> (e.g.
/// <see cref="DateTimeZoneProviders.Bcl"/>), with the exception that it will succeed even if the current local
/// time zone was not one of the set of system time zones captured when the source was created (which, while
/// highly unlikely, might occur either because the local time zone is not a system time zone, or because the
/// system time zones have themselves changed).
/// </para>
/// <para>
/// This method will retain a reference to the returned <c>BclDateTimeZone</c>, and will attempt to return it if
/// called repeatedly (assuming that the local time zone has not changed) rather than creating a new instance,
/// though this behaviour is not guaranteed.
/// </para>
/// </remarks>
/// <returns>A <see cref="BclDateTimeZone"/> wrapping the "local" (system) time zone as returned by
/// <see cref="TimeZoneInfo.Local"/>.</returns>
public static BclDateTimeZone ForSystemDefault()
{
TimeZoneInfo local = TimeZoneInfo.Local;
BclDateTimeZone currentSystemDefault = systemDefault;
// Cached copy is out of date - wrap a new one
if (currentSystemDefault?.OriginalZone != local)
{
currentSystemDefault = FromTimeZoneInfo(local);
systemDefault = currentSystemDefault;
}
// Always return our local variable; the variable may have changed again.
return(currentSystemDefault);
}
/// <summary>
/// Returns a time zone converted from the BCL representation of the system local time zone.
/// </summary>
/// <remarks>
/// <para>
/// This method is approximately equivalent to calling <see cref="IDateTimeZoneProvider.GetSystemDefault"/> with
/// an implementation that wraps <see cref="BclDateTimeZoneSource"/> (e.g.
/// <see cref="DateTimeZoneProviders.Bcl"/>), with the exception that it will succeed even if the current local
/// time zone was not one of the set of system time zones captured when the source was created (which, while
/// highly unlikely, might occur either because the local time zone is not a system time zone, or because the
/// system time zones have themselves changed).
/// </para>
/// <para>
/// This method will retain a reference to the returned <c>BclDateTimeZone</c>, and will attempt to return it if
/// called repeatedly (assuming that the local time zone has not changed) rather than creating a new instance,
/// though this behaviour is not guaranteed.
/// </para>
/// </remarks>
/// <exception cref="InvalidOperationException">The system does not provide a time zone.</exception>
/// <returns>A <see cref="BclDateTimeZone"/> wrapping the "local" (system) time zone as returned by
/// <see cref="TimeZoneInfo.Local"/>.</returns>
[NotNull] public static BclDateTimeZone ForSystemDefault()
{
TimeZoneInfo?local = TimeZoneInfoInterceptor.Local;
if (local is null)
{
throw new InvalidOperationException("No system default time zone is available");
}
BclDateTimeZone currentSystemDefault = systemDefault;
// Cached copy is out of date - wrap a new one
if (currentSystemDefault?.OriginalZone != local)
{
currentSystemDefault = FromTimeZoneInfo(local);
systemDefault = currentSystemDefault;
}
// Always return our local variable; the variable may have changed again.
return(currentSystemDefault);
}
/// <summary>
/// Returns a time zone converted from the BCL representation of the system local time zone.
/// </summary>
/// <remarks>
/// <para>
/// This method is approximately equivalent to calling <see cref="IDateTimeZoneProvider.GetSystemDefault"/> with
/// an implementation that wraps <see cref="BclDateTimeZoneSource"/> (e.g.
/// <see cref="DateTimeZoneProviders.Bcl"/>), with the exception that it will succeed even if the current local
/// time zone was not one of the set of system time zones captured when the source was created (which, while
/// highly unlikely, might occur either because the local time zone is not a system time zone, or because the
/// system time zones have themselves changed).
/// </para>
/// <para>
/// This method will retain a reference to the returned <c>BclDateTimeZone</c>, and will attempt to return it if
/// called repeatedly (assuming that the local time zone has not changed) rather than creating a new instance,
/// though this behaviour is not guaranteed.
/// </para>
/// </remarks>
/// <exception cref="InvalidOperationException">The system does not provide a time zone.</exception>
/// <returns>A <see cref="BclDateTimeZone"/> wrapping the "local" (system) time zone as returned by
/// <see cref="TimeZoneInfo.Local"/>.</returns>
public static BclDateTimeZone ForSystemDefault()
{
TimeZoneInfo?local = TimeZoneInfoInterceptor.Local;
if (local is null)
{
throw new InvalidOperationException("No system default time zone is available");
}
BclDateTimeZone currentSystemDefault = systemDefault;
// Cached copy is out of date - wrap a new one.
// If currentSystemDefault is null, we always enter this block (as local isn't null).
if (currentSystemDefault?.OriginalZone != local)
{
currentSystemDefault = FromTimeZoneInfo(local);
systemDefault = currentSystemDefault;
}
// Always return our local variable; the field may have changed again.
// The ! is because the compiler doesn't recognize the logic around
// "always fetch if we currentSystemDefault is null".
return(currentSystemDefault !);
}
/// <summary>
/// Returns a time zone converted from the BCL representation of the system local time zone.
/// </summary>
/// <remarks>
/// <para>
/// This method is approximately equivalent to calling <see cref="IDateTimeZoneProvider.GetSystemDefault"/> with
/// an implementation that wraps <see cref="BclDateTimeZoneSource"/> (e.g.
/// <see cref="DateTimeZoneProviders.Bcl"/>), with the exception that it will succeed even if the current local
/// time zone was not one of the set of system time zones captured when the source was created (which, while
/// highly unlikely, might occur either because the local time zone is not a system time zone, or because the
/// system time zones have themselves changed).
/// </para>
/// <para>
/// This method will retain a reference to the returned <c>BclDateTimeZone</c>, and will attempt to return it if
/// called repeatedly (assuming that the local time zone has not changed) rather than creating a new instance,
/// though this behaviour is not guaranteed.
/// </para>
/// </remarks>
/// <returns>A <see cref="BclDateTimeZone"/> wrapping the "local" (system) time zone as returned by
/// <see cref="TimeZoneInfo.Local"/>.</returns>
public static BclDateTimeZone ForSystemDefault()
{
TimeZoneInfo local = TimeZoneInfo.Local;
BclDateTimeZone currentSystemDefault = systemDefault;
// Cached copy is out of date - wrap a new one
if (currentSystemDefault?.OriginalZone != local)
{
currentSystemDefault = FromTimeZoneInfo(local);
systemDefault = currentSystemDefault;
}
// Always return our local variable; the variable may have changed again.
return currentSystemDefault;
}
