/// <summary>
/// Compares two Dates for Date ordering
/// </summary>
/// <param name="x">Node</param>
/// <param name="y">Node</param>
/// <returns></returns>
protected int DateCompare(INode x, INode y)
{
if (x == null || y == null)
{
throw new RdfQueryException("Cannot evaluate date equality when one or both arguments are Null");
}
try
{
ILiteralNode a = (ILiteralNode)x;
ILiteralNode b = (ILiteralNode)y;
DateTimeOffset c = SparqlSpecsHelper.ToDateTimeOffset(a);
DateTimeOffset d = SparqlSpecsHelper.ToDateTimeOffset(b);
if (!c.Offset.Equals(d.Offset))
{
throw new RdfQueryException("Cannot order Dates which are from different time zones");
}
int res = c.Year.CompareTo(d.Year);
if (res == 0)
{
res = c.Month.CompareTo(d.Month);
if (res == 0)
{
res = c.Day.CompareTo(d.Day);
}
}
return(res);
}
catch (FormatException)
{
throw new RdfQueryException("Cannot evaluate date equality since one of the arguments does not have a valid lexical value for a Date");
}
}
