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));
}
