private void ProcessSelectableConditionalConstrainSelector(ConditionalConstrainSelector expression, bool isSubQuery, Func <string, string> createVariableName, StrongEntityAccessor mainEntityAccessor)
{
if (!isSubQuery)
{
if (mainEntityAccessor != null)
{
_currentStrongEntityAccessorVisitDelegate = entityAccessor =>
{
if (_metaGraphVariableName == null)
{
_commandText.AppendFormat("?G{0}", entityAccessor.About.Name);
}
else
{
_commandText.Append("IF(ISBLANK(");
VisitComponent(entityAccessor.About);
_commandText.Append("),");
VisitComponent(mainEntityAccessor.About);
_commandText.Append(",");
VisitComponent(entityAccessor.About);
_commandText.AppendFormat(") AS ?{0} ?{1}", _ownerVariableName, _entityVariableName);
}
};
_ownerVariableName = "entity";
}
_commandText.Append("DISTINCT ");
int index = 0;
foreach (IExpression selectable in ((ISelectableQueryComponent)expression).Expressions)
{
switch (index)
{
case 0:
_subjectVariableName = (selectable is Alias ? ((Alias)selectable).Name.Name : (selectable is Identifier ? ((Identifier)selectable).Name : null));
break;
case 1:
_predicateVariableName = (selectable is Alias ? ((Alias)selectable).Name.Name : (selectable is Identifier ? ((Identifier)selectable).Name : null));
break;
case 2:
_objectVariableName = (selectable is Alias ? ((Alias)selectable).Name.Name : (selectable is Identifier ? ((Identifier)selectable).Name : null));
break;
}
index++;
}
}
}
private void OverrideEntitySelector(Identifier identifier)
{
StrongEntityAccessor entityAccessor = _query.FindAllComponents <StrongEntityAccessor>().Where(item => item.About == identifier).FirstOrDefault();
if (entityAccessor == null)
{
entityAccessor = new StrongEntityAccessor(identifier);
_query.Elements.Add(entityAccessor);
}
if ((entityAccessor.UnboundGraphName == null) || (entityAccessor.UnboundGraphName == entityAccessor.About))
{
entityAccessor.UnboundGraphName = (from accessor in _query.FindAllComponents <StrongEntityAccessor>()
from constrain in accessor.Elements.OfType <EntityConstrain>()
where (constrain.Value is Identifier) && ((Identifier)constrain.Value == identifier)
select accessor.About).FirstOrDefault() ?? identifier;
UnboundConstrain genericConstrain = new UnboundConstrain()
{
Subject = new Identifier(identifier.Name + "_s"), Predicate = new Identifier(identifier.Name + "_p"), Value = new Identifier(identifier.Name + "_o")
};
entityAccessor.Elements.Add(genericConstrain);
UnboundConstrain targetConstrain = new UnboundConstrain()
{
Subject = identifier, Predicate = new Identifier(identifier.Name + "p"), Value = new Identifier(identifier.Name + "o")
};
entityAccessor.Elements.Add(targetConstrain);
_query.Select.Clear();
if (_mainFromComponent.Elements[0] is UnboundConstrain)
{
ConditionalConstrainSelector selector = new ConditionalConstrainSelector(entityAccessor, genericConstrain, (UnboundConstrain)_mainFromComponent.Elements[0]);
_query.Select.Add(selector);
}
_query.Select.Add(entityAccessor);
}
}
