private ISparqlExpression BuildSparqlFilter(SingleValueNode filterNode, string suffix = "")
{
NodeFactory nodeFactory = new NodeFactory();
if (filterNode.GetType() == typeof(SingleValueFunctionCallNode))
{
return(BuildFunctionExpression(filterNode as SingleValueFunctionCallNode));
}
else if (filterNode.GetType() == typeof(SingleValuePropertyAccessNode))
{
return(new VariableTerm($"?{(filterNode as SingleValuePropertyAccessNode).Property.Name}{suffix}"));
}
else if (filterNode.GetType() == typeof(ConstantNode))
{
return(new ConstantTerm(CreateLiteralNode(filterNode as ConstantNode)));
}
else if (filterNode.GetType() == typeof(ConvertNode))
{
var convert = filterNode as ConvertNode;
if (convert.Source is SingleValueFunctionCallNode)
{
return(BuildSparqlFilter(convert.Source as SingleValueFunctionCallNode, suffix));
}
else if (convert.Source is ConstantNode)
{
return(new ConstantTerm(CreateLiteralNode(convert.Source as ConstantNode)));
}
else if (convert.Source is SingleValuePropertyAccessNode)
{
var varName = (convert.Source as SingleValuePropertyAccessNode).Property.Name;
if (varName.ToLower() == "localid")
{
var node = LiteralExtensions.ToLiteral(NamespaceUri.ToString().Length + 1, nodeFactory);
varName = EdmNodeList[EdmNodeList.Count - 1].Name;
return((new UnaryExpressionFilter(
new SubStrFunction(new StrFunction(new VariableTerm($"?{varName}{suffix}")),
(new ConstantTerm(node))))).Expression);
}
else
{
return(new VariableTerm($"?{varName}{suffix}"));
}
}
}
else if (filterNode.GetType() == typeof(BinaryOperatorNode))
{
var binaryOperator = filterNode as BinaryOperatorNode;
var left = BuildSparqlFilter(binaryOperator.Left, suffix);
var right = BuildSparqlFilter(binaryOperator.Right, suffix);
if (binaryOperator.OperatorKind == BinaryOperatorKind.And)
{
return(new AndExpression(left, right));
}
else if (binaryOperator.OperatorKind == BinaryOperatorKind.Or)
{
return(new OrExpression(left, right));
}
else if (binaryOperator.OperatorKind == BinaryOperatorKind.Equal)
{
return(new EqualsExpression(left, right));
}
else if (binaryOperator.OperatorKind == BinaryOperatorKind.NotEqual)
{
return(new NotEqualsExpression(left, right));
}
else if (binaryOperator.OperatorKind == BinaryOperatorKind.GreaterThan)
{
return(new GreaterThanExpression(left, right));
}
else if (binaryOperator.OperatorKind == BinaryOperatorKind.GreaterThanOrEqual)
{
return(new GreaterThanOrEqualToExpression(left, right));
}
else if (binaryOperator.OperatorKind == BinaryOperatorKind.LessThan)
{
return(new LessThanExpression(left, right));
}
else if (binaryOperator.OperatorKind == BinaryOperatorKind.LessThanOrEqual)
{
return(new LessThanOrEqualToExpression(left, right));
}
else if (binaryOperator.OperatorKind == BinaryOperatorKind.Add)
{
return(new AdditionExpression(left, right));
}
else if (binaryOperator.OperatorKind == BinaryOperatorKind.Subtract)
{
return(new SubtractionExpression(left, right));
}
else if (binaryOperator.OperatorKind == BinaryOperatorKind.Divide)
{
return(new DivisionExpression(left, right));
}
else if (binaryOperator.OperatorKind == BinaryOperatorKind.Multiply)
{
return(new MultiplicationExpression(left, right));
}
}
else if (filterNode.GetType() == typeof(UnaryOperatorNode))
{
var unaryOperator = filterNode as UnaryOperatorNode;
if (unaryOperator.OperatorKind == UnaryOperatorKind.Not)
{
return(new NotEqualsExpression(BuildSparqlFilter(unaryOperator.Operand, suffix),
new ConstantTerm(LiteralExtensions.ToLiteral(true, nodeFactory))));
}
}
return(null);
}
