/// <summary>
/// Compares two Nodes
/// </summary>
/// <param name="x">Node</param>
/// <param name="y">Node</param>
/// <returns></returns>
public override int Compare(IValuedNode x, IValuedNode y)
{
// Nulls are less than everything
if (x == null && y == null)
{
return(0);
}
if (x == null)
{
return(-1);
}
if (y == null)
{
return(1);
}
// If the Node Types are different use Node ordering
if (x.NodeType != y.NodeType)
{
return(x.CompareTo(y));
}
if (x.NodeType == NodeType.Literal)
{
try
{
// Do they have supported Data Types?
String xtype, ytype;
try
{
xtype = XmlSpecsHelper.GetSupportedDataType(x);
ytype = XmlSpecsHelper.GetSupportedDataType(y);
}
catch (RdfException)
{
// Can't determine a Data Type for one/both of the Nodes so use Node ordering
return(x.CompareTo(y));
}
if (xtype.Equals(String.Empty) || ytype.Equals(String.Empty))
{
// One/both has an unknown type
if (x.Equals(y))
{
// If RDF Term equality returns true then we return that they are equal
return(0);
}
else
{
// If RDF Term equality returns false then we fall back to Node Ordering
return(x.CompareTo(y));
}
}
else
{
// Both have known types
SparqlNumericType xnumtype = x.NumericType;
SparqlNumericType ynumtype = y.NumericType;
SparqlNumericType numtype = (SparqlNumericType)Math.Max((int)xnumtype, (int)ynumtype);
if (numtype != SparqlNumericType.NaN)
{
if (xnumtype == SparqlNumericType.NaN)
{
return(1);
}
else if (ynumtype == SparqlNumericType.NaN)
{
return(-1);
}
// Both are Numeric so use Numeric ordering
try
{
return(this.NumericCompare(x, y, numtype));
}
catch (FormatException)
{
if (x.Equals(y))
{
return(0);
}
// Otherwise fall back to Node Ordering
return(x.CompareTo(y));
}
catch (RdfQueryException)
{
// If this errors try RDF Term equality since that might still give equality
if (x.Equals(y))
{
return(0);
}
// Otherwise fall back to Node Ordering
return(x.CompareTo(y));
}
}
else if (xtype.Equals(ytype))
{
switch (xtype)
{
case XmlSpecsHelper.XmlSchemaDataTypeDate:
return(DateCompare(x, y));
case XmlSpecsHelper.XmlSchemaDataTypeDateTime:
return(DateTimeCompare(x, y));
case XmlSpecsHelper.XmlSchemaDataTypeString:
// Both Strings so use Lexical string ordering
return(((ILiteralNode)x).Value.CompareTo(((ILiteralNode)y).Value));
default:
// Use node ordering
return(x.CompareTo(y));
}
}
else
{
String commontype = XmlSpecsHelper.GetCompatibleSupportedDataType(xtype, ytype, true);
if (commontype.Equals(String.Empty))
{
// Use Node ordering
return(x.CompareTo(y));
}
else
{
switch (commontype)
{
case XmlSpecsHelper.XmlSchemaDataTypeDate:
return(DateCompare(x, y));
case XmlSpecsHelper.XmlSchemaDataTypeDateTime:
return(DateTimeCompare(x, y));
default:
// Use Node ordering
return(x.CompareTo(y));
}
}
}
}
}
catch
{
// If error then can't determine ordering so fall back to node ordering
return(x.CompareTo(y));
}
}
else
{
// If not Literals use Node ordering
return(x.CompareTo(y));
}
}
/// <summary>
/// Compares two valued Nodes
/// </summary>
/// <param name="x">Node</param>
/// <param name="y">Node</param>
/// <returns></returns>
public virtual int Compare(IValuedNode x, IValuedNode y)
{
if (x == null && y == null)
{
return(0);
}
if (x == null)
{
return(-1);
}
if (y == null)
{
return(1);
}
// If the Node Types are different use Node ordering
if (x.NodeType != y.NodeType)
{
return(x.CompareTo(y));
}
if (x.NodeType == NodeType.Literal)
{
// Do they have supported Data Types?
String xtype, ytype;
try
{
xtype = XmlSpecsHelper.GetSupportedDataType(x);
ytype = XmlSpecsHelper.GetSupportedDataType(y);
}
catch (RdfException)
{
// Can't determine a Data Type for one/both of the Nodes so use Node ordering
return(x.CompareTo(y));
}
if (xtype.Equals(String.Empty) || ytype.Equals(String.Empty))
{
// One/both has an unknown type
if (x.Equals(y))
{
// If RDF Term equality returns true then we return that they are equal
return(0);
}
else
{
// If RDF Term equality returns false then we error
// UNLESS they have the same Datatype
throw new RdfQueryException("Unable to determine ordering since one/both arguments has an Unknown Type");
}
}
else
{
// Both have known types
SparqlNumericType xnumtype = x.NumericType;
SparqlNumericType ynumtype = y.NumericType;
SparqlNumericType numtype = (SparqlNumericType)Math.Max((int)xnumtype, (int)ynumtype);
if (numtype != SparqlNumericType.NaN)
{
if (xnumtype == SparqlNumericType.NaN || ynumtype == SparqlNumericType.NaN)
{
// If one is non-numeric then we can't assume non-equality
throw new RdfQueryException("Unable to determine ordering since one/both arguments does not return a Number");
}
// Both are Numeric so use Numeric ordering
try
{
return(this.NumericCompare(x, y, numtype));
}
catch (FormatException)
{
if (x.Equals(y))
{
return(0);
}
throw new RdfQueryException("Unable to determine ordering since one/both arguments does not contain a valid value for it's type");
}
catch (RdfQueryException)
{
// If this errors try RDF Term equality since
if (x.Equals(y))
{
return(0);
}
throw new RdfQueryException("Unable to determine ordering since one/both arguments was not a valid numeric");
}
}
else if (xtype.Equals(ytype))
{
switch (xtype)
{
case XmlSpecsHelper.XmlSchemaDataTypeDate:
return(DateCompare(x, y));
case XmlSpecsHelper.XmlSchemaDataTypeDateTime:
return(DateTimeCompare(x, y));
case XmlSpecsHelper.XmlSchemaDataTypeString:
// Both Strings so use Lexical string ordering
#if NETCORE
return(Options.DefaultCulture.CompareInfo.Compare(((ILiteralNode)x).Value, ((ILiteralNode)y).Value, Options.DefaultComparisonOptions));
#else
return(String.Compare(((ILiteralNode)x).Value, ((ILiteralNode)y).Value, Options.DefaultCulture, Options.DefaultComparisonOptions));
#endif
default:
// Use node ordering
return(x.CompareTo(y));
}
}
else
{
String commontype = XmlSpecsHelper.GetCompatibleSupportedDataType(xtype, ytype, true);
if (commontype.Equals(String.Empty))
{
// Use Node ordering
return(x.CompareTo(y));
}
else
{
switch (commontype)
{
case XmlSpecsHelper.XmlSchemaDataTypeDate:
return(DateCompare(x, y));
case XmlSpecsHelper.XmlSchemaDataTypeDateTime:
return(DateTimeCompare(x, y));
default:
// Use Node ordering
return(x.CompareTo(y));
}
}
}
}
}
else
{
// If not Literals use standard Node ordering
return(x.CompareTo(y));
}
}