public override void VisitResultOperator(Remotion.Linq.Clauses.ResultOperatorBase resultOperator, QueryModel queryModel, int index)
{
if (index > 0)
{
_isInstanceQuery = false;
}
if (resultOperator is TakeResultOperator)
{
var take = resultOperator as TakeResultOperator;
_queryBuilder.Limit = take.GetConstantCount();
if (_queryBuilder.Limit != 1)
{
_isInstanceQuery = false;
}
return;
}
if (resultOperator is SkipResultOperator)
{
var skip = resultOperator as SkipResultOperator;
_queryBuilder.Offset = skip.GetConstantCount();
return;
}
if (resultOperator is AverageResultOperator && index == 0)
{
var varName = GetExpressionVariable(queryModel.SelectClause.Selector);
if (varName != null)
{
_queryBuilder.ApplyAggregate("AVG", varName);
return;
}
}
if (resultOperator is SumResultOperator && index == 0)
{
var varName = GetExpressionVariable(queryModel.SelectClause.Selector);
if (varName != null)
{
_queryBuilder.ApplyAggregate("SUM", varName);
return;
}
}
if (resultOperator is CountResultOperator && index == 0)
{
var varName = GetExpressionVariable(queryModel.SelectClause.Selector);
if (varName != null)
{
_queryBuilder.ApplyAggregate("COUNT", varName);
return;
}
}
if (resultOperator is LongCountResultOperator && index == 0)
{
var varName = GetExpressionVariable(queryModel.SelectClause.Selector);
if (varName != null)
{
_queryBuilder.ApplyAggregate("COUNT", varName);
return;
}
}
if (resultOperator is MinResultOperator && index == 0)
{
var varName = GetExpressionVariable(queryModel.SelectClause.Selector);
if (varName != null)
{
_queryBuilder.ApplyAggregate("MIN", varName);
return;
}
}
if (resultOperator is MaxResultOperator && index == 0)
{
var varName = GetExpressionVariable(queryModel.SelectClause.Selector);
if (varName != null)
{
_queryBuilder.ApplyAggregate("MAX", varName);
return;
}
}
if (resultOperator is SingleResultOperator && index == 0)
{
// Grab first 2 rows. If there are two then the outer wrapper will fail.
_queryBuilder.Limit = 2;
return;
}
if (resultOperator is FirstResultOperator)
{
_queryBuilder.Limit = 1;
return;
}
if (resultOperator is OfTypeResultOperator)
{
var ofType = resultOperator as OfTypeResultOperator;
var varName = GetExpressionVariable(queryModel.SelectClause.Selector);
if (varName != null)
{
var typeUri = _queryBuilder.Context.MapTypeToUri(ofType.SearchedItemType);
if (typeUri != null)
{
_queryBuilder.AddTripleConstraint(
GraphNode.Variable, varName,
GraphNode.Raw, "a",
GraphNode.Iri, typeUri);
return;
}
throw new EntityFrameworkException("No URI mapping found for type '{0}'",
ofType.SearchedItemType);
}
}
if (resultOperator is DistinctResultOperator)
{
_queryBuilder.IsDistinct = true;
return;
}
if (resultOperator is GroupResultOperator)
{
var groupOperator = resultOperator as GroupResultOperator;
var keyExpr = groupOperator.KeySelector;
var exprVar = GetExpressionVariable(keyExpr);
if (exprVar == null)
{
throw new EntityFrameworkException("Unable to convert GroupBy '{0}' operator to SPARQL.",
groupOperator);
}
_queryBuilder.AddGroupByExpression("?" + exprVar);
return;
}
if (resultOperator is CastResultOperator)
{
var castOperator = resultOperator as CastResultOperator;
var mappedUri = _queryBuilder.Context.MapTypeToUri(castOperator.CastItemType);
if (mappedUri == null)
{
throw new EntityFrameworkException("Unable to cast to type '{0}' as it is not a valid entity type.", castOperator.CastItemType);
}
return;
}
if (index > 0)
{
throw new NotSupportedException(
String.Format(
"LINQ-to-SPARQL does not currently support the result operator '{0}' as a second or subsequent result operator.",
resultOperator));
}
throw new NotSupportedException(
String.Format("LINQ-to-SPARQL does not currently support the result operator '{0}'", resultOperator));
}
protected override Expression VisitMemberExpression(MemberExpression expression)
{
string sourceVarName = null;
if (expression.Expression is QuerySourceReferenceExpression)
{
var source = expression.Expression as QuerySourceReferenceExpression;
Expression mappedSourceExpression;
sourceVarName = source.ReferencedQuerySource.ItemName;
if (_queryBuilder.TryGetQuerySourceMapping(source.ReferencedQuerySource, out mappedSourceExpression) && mappedSourceExpression is SelectVariableNameExpression)
{
sourceVarName = (mappedSourceExpression as SelectVariableNameExpression).Name;
}
}
else if (expression.Expression is MemberExpression)
{
var memberExpression = VisitExpression(expression.Expression);
if (memberExpression is SelectVariableNameExpression)
{
sourceVarName = (memberExpression as SelectVariableNameExpression).Name;
}
}
else if (expression.Expression is UnaryExpression)
{
var unary = expression.Expression as UnaryExpression;
if (unary.NodeType == ExpressionType.TypeAs &&
unary.Operand is QuerySourceReferenceExpression)
{
var targetType = unary.Type;
var source = unary.Operand as QuerySourceReferenceExpression;
if (source != null)
{
var itemType = source.ReferencedQuerySource.ItemType;
if (targetType.IsAssignableFrom(itemType))
{
expression = Expression.MakeMemberAccess(unary.Operand, expression.Member);
return(VisitExpression(expression));
}
}
}
var updatedExpression = VisitExpression(expression.Expression) as UnaryExpression;
if (updatedExpression != null && updatedExpression.Operand is SelectVariableNameExpression)
{
#if WINDOWS_PHONE || PORTABLE
return(Expression.MakeMemberAccess(updatedExpression, expression.Member));
#else
return(expression.Update(updatedExpression));
#endif
}
}
if (!String.IsNullOrEmpty(sourceVarName))
{
#if PORTABLE
if (expression.Member is PropertyInfo)
#else
if (expression.Member.MemberType == MemberTypes.Property)
#endif
{
var propertyInfo = expression.Member as PropertyInfo;
var propertyHint = _queryBuilder.Context.GetPropertyHint(propertyInfo);
if (propertyHint != null)
{
switch (propertyHint.MappingType)
{
case PropertyMappingType.Arc:
{
var memberVarName = _queryBuilder.GetVariableForObject(
GraphNode.Variable, sourceVarName,
GraphNode.Iri, propertyHint.SchemaTypeUri);
if (memberVarName == null)
{
memberVarName = _queryBuilder.NextVariable();
_queryBuilder.AddTripleConstraint(
GraphNode.Variable, sourceVarName,
GraphNode.Iri, propertyHint.SchemaTypeUri,
GraphNode.Variable, memberVarName);
}
return(new SelectVariableNameExpression(memberVarName, VariableBindingType.Resource, propertyInfo.PropertyType));
}
case PropertyMappingType.InverseArc:
{
var memberVarName = _queryBuilder.GetVariableForSubject(
GraphNode.Iri, propertyHint.SchemaTypeUri,
GraphNode.Variable, sourceVarName);
if (memberVarName == null)
{
memberVarName = _queryBuilder.NextVariable();
_queryBuilder.AddTripleConstraint(
GraphNode.Variable, memberVarName,
GraphNode.Iri, propertyHint.SchemaTypeUri,
GraphNode.Variable, sourceVarName);
}
return(new SelectVariableNameExpression(memberVarName, VariableBindingType.Resource, propertyInfo.PropertyType));
}
case PropertyMappingType.Property:
{
var propertyValueVarName = _queryBuilder.GetVariableForObject(GraphNode.Variable,
sourceVarName,
GraphNode.Iri,
propertyHint.
SchemaTypeUri);
if (propertyValueVarName == null)
{
propertyValueVarName = _queryBuilder.NextVariable();
_queryBuilder.AddTripleConstraint(
GraphNode.Variable, sourceVarName,
GraphNode.Iri, propertyHint.SchemaTypeUri,
GraphNode.Variable, propertyValueVarName);
}
return(new SelectVariableNameExpression(propertyValueVarName,
VariableBindingType.Literal, propertyInfo.PropertyType));
}
case PropertyMappingType.Address:
{
return(new SelectVariableNameExpression(sourceVarName, VariableBindingType.Resource, propertyInfo.PropertyType));
}
case PropertyMappingType.Id:
{
var prefix = EntityMappingStore.GetIdentifierPrefix(propertyInfo.DeclaringType);
return(new SelectIdentifierVariableNameExpression(sourceVarName, prefix));
//return new SelectVariableNameExpression(sourceVarName, VariableBindingType.Resource, propertyInfo.PropertyType);
}
}
}
}
}
return(base.VisitMemberExpression(expression));
}
