/// <summary>
/// Extracts the corresponding value from the SemWeb results for a member access projection.
/// </summary>
/// <param name="vb">The SemWeb results.</param>
/// <returns>the value that was extracted (and converted) from the results.</returns>
private object ExtractMemberAccess(SparqlResult vb)
{
// work out if the SelectExpression really is a member access
var ue = (SelectExpression).Arguments[1] as UnaryExpression;
if (ue == null)
{
throw new ArgumentException("incompatible expression type");
}
var le = ue.Operand as LambdaExpression;
if (le == null)
{
throw new LinqToRdfException("Incompatible expression type found when building ontology projection");
}
if (le.Body is MemberExpression)
{
// work out which member is being queried on
var memberExpression = (MemberExpression)le.Body;
MemberInfo memberInfo = memberExpression.Member;
// get its name and use that as a key into the results
//string vVal = vb[memberInfo.Name].ToString();
// convert the result from XSDT format to .NET types
if (!vb.HasValue(memberInfo.Name))
{
return(null);
}
var tc = new XsdtTypeConverter();
return(tc.Parse(vb[memberInfo.Name]));
//return tc.Parse(vVal);
}
return(null);
}
/// <summary>
/// stores the result from a SemWeb result into a <see cref="PropertyInfo"/> doing whatever conversions are required.
/// </summary>
/// <param name="semwebBindings">The incoming result from semweb.</param>
/// <param name="obj">The object instance on wqhich the property is to be set</param>
/// <param name="propertyInfo">The <see cref="PropertyInfo"/> identifying the property to be populated with the value stored in <see cref="semwebBindings"/>.</param>
public static void PopulateProperty(SparqlResult semwebBindings, object obj, PropertyInfo propertyInfo)
{
if (semwebBindings.HasValue(propertyInfo.Name))
{
if (semwebBindings[propertyInfo.Name] == null)
{
return;
}
var tc = new XsdtTypeConverter();
object x = tc.Parse(semwebBindings[propertyInfo.Name]);
if (x is IConvertible)
{
propertyInfo.SetValue(obj, Convert.ChangeType(x, propertyInfo.PropertyType), null);
}
else
// if it's not convertible, it could be because the type is an MS XSDT type rather than a .NET primitive
if (x.GetType().Namespace == "System.Runtime.Remoting.Metadata.W3cXsd2001")
{
switch (x.GetType().Name)
{
case "SoapDate":
var d = (SoapDate)x;
propertyInfo.SetValue(obj, Convert.ChangeType(d.Value, propertyInfo.PropertyType), null);
break;
default:
break;
}
}
else if (propertyInfo.PropertyType == typeof(string))
{
propertyInfo.SetValue(obj, x.ToString(), null);
}
}
}
/// <summary>
/// Initializes a new instance of the <see cref="QueryFactory{T}"/> class.
/// </summary>
/// <param name="queryType">the <see cref="LinqToRdf.QueryType"/> of the query.</param>
/// <param name="context">The <see cref="IRdfContext"/> data context that will track results, connections and instances.</param>
public QueryFactory(LinqQueryMethod queryType, IRdfContext context)
{
QueryType = queryType;
DataContext = context;
TypeTranslator = new XsdtTypeConverter();
}
