/// <summary>
/// Gets the numeric value of the function in the given Evaluation Context for the given Binding ID
/// </summary>
/// <param name="context">Evaluation Context</param>
/// <param name="bindingID">Binding ID</param>
/// <returns></returns>
public override IValuedNode Evaluate(SparqlEvaluationContext context, int bindingID)
{
IValuedNode temp = _expr.Evaluate(context, bindingID);
if (temp != null)
{
return(ValueInternal(temp.AsDateTimeOffset()));
}
else
{
throw new RdfQueryException("Unable to evaluate an XPath Date Time function on a null argument");
}
}
/// <summary>
/// Calculates the value of the function in the given Evaluation Context for the given Binding ID.
/// </summary>
/// <param name="context">Evaluation Context.</param>
/// <param name="bindingID">Binding ID.</param>
/// <returns></returns>
public virtual IValuedNode Evaluate(SparqlEvaluationContext context, int bindingID)
{
IValuedNode temp = _expr.Evaluate(context, bindingID);
if (temp != null)
{
DateTimeOffset dt = temp.AsDateTimeOffset();
// Regex based check to see if the value has a Timezone component
// If not then the result is a null
if (!Regex.IsMatch(temp.AsString(), "(Z|[+-]\\d{2}:\\d{2})$"))
{
return(null);
}
// Now we have a DateTime we can try and return the Timezone
if (dt.Offset.Equals(TimeSpan.Zero))
{
// If Zero it was specified as Z (which means UTC so zero offset)
return(new StringNode(null, "PT0S", UriFactory.Create(XmlSpecsHelper.XmlSchemaDataTypeDayTimeDuration)));
}
else
{
// If the Offset is outside the range -14 to 14 this is considered invalid
if (dt.Offset.Hours < -14 || dt.Offset.Hours > 14)
{
return(null);
}
// Otherwise it has an offset which is a given number of hours and minutse
string offset = "PT" + Math.Abs(dt.Offset.Hours) + "H";
if (dt.Offset.Hours < 0)
{
offset = "-" + offset;
}
if (dt.Offset.Minutes != 0)
{
offset = offset + Math.Abs(dt.Offset.Minutes) + "M";
}
if (dt.Offset.Hours == 0 && dt.Offset.Minutes < 0)
{
offset = "-" + offset;
}
return(new StringNode(null, offset, UriFactory.Create(XmlSpecsHelper.XmlSchemaDataTypeDayTimeDuration)));
}
}
else
{
throw new RdfQueryException("Unable to evaluate an XPath Date Time function on a null argument");
}
}
/// <summary>
/// Gets the date based on the stored value using the default value if there was no stored value
/// </summary>
/// <param name="t">Triple whose object is the stored value</param>
/// <param name="defaultValue">Default value</param>
/// <returns>Date</returns>
private static DateTimeOffset?GetDate(Triple t, DateTimeOffset?defaultValue)
{
if (t == null)
{
return(defaultValue);
}
INode n = t.Object;
if (n.NodeType == NodeType.Literal)
{
IValuedNode value = n.AsValuedNode();
try
{
return(value.AsDateTimeOffset());
}
catch (RdfQueryException)
{
return(defaultValue);
}
}
return(defaultValue);
}
/// <summary>
/// Gets the Timezone of the Argument Expression as evaluated for the given Binding in the given Context
/// </summary>
/// <param name="context">Evaluation Context</param>
/// <param name="bindingID">Binding ID</param>
/// <returns></returns>
public override IValuedNode Evaluate(SparqlEvaluationContext context, int bindingID)
{
IValuedNode temp = _expr.Evaluate(context, bindingID);
if (temp != null)
{
DateTimeOffset dt = temp.AsDateTimeOffset();
// Regex based check to see if the value has a Timezone component
// If not then the result is a null
if (!Regex.IsMatch(temp.AsString(), "(Z|[+-]\\d{2}:\\d{2})$"))
{
return(new StringNode(null, string.Empty));
}
// Now we have a DateTime we can try and return the Timezone
if (dt.Offset.Equals(TimeSpan.Zero))
{
// If Zero it was specified as Z (which means UTC so zero offset)
return(new StringNode(null, "Z"));
}
else
{
// If the Offset is outside the range -14 to 14 this is considered invalid
if (dt.Offset.Hours < -14 || dt.Offset.Hours > 14)
{
return(null);
}
// Otherwise it has an offset which is a given number of hours (and minutes)
return(new StringNode(null, dt.Offset.Hours.ToString("00") + ":" + dt.Offset.Minutes.ToString("00")));
}
}
else
{
throw new RdfQueryException("Unable to evaluate a Date Time function on a null argument");
}
}