protected virtual ISelectionVisitorAction Visit(
ISelection selection,
TContext context)
{
var localContext = OnBeforeEnter(selection, context);
ISelectionVisitorAction result = Enter(selection, localContext);
localContext = OnAfterEnter(selection, localContext, result);
if (result.Kind == SelectionVisitorActionKind.Continue)
{
if (VisitChildren(selection, context).Kind == SelectionVisitorActionKind.Break)
{
return(Break);
}
}
if (result.Kind == SelectionVisitorActionKind.Continue ||
result.Kind == SelectionVisitorActionKind.SkipAndLeave)
{
localContext = OnBeforeLeave(selection, localContext);
result = Leave(selection, localContext);
OnAfterLeave(selection, localContext, result);
}
return(result);
}
protected override ISelectionVisitorAction VisitObjectType(
IOutputField field,
ObjectType objectType,
SelectionSetNode?selectionSet,
QueryableProjectionContext context)
{
var isAbstractType = field.Type.NamedType().IsAbstractType();
if (isAbstractType && context.TryGetQueryableScope(out QueryableProjectionScope? scope))
{
context.PushInstance(
Expression.Convert(context.GetInstance(), objectType.RuntimeType));
scope.Level.Push(new Queue <MemberAssignment>());
ISelectionVisitorAction res =
base.VisitObjectType(field, objectType, selectionSet, context);
context.PopInstance();
scope.AddAbstractType(objectType.RuntimeType, scope.Level.Pop());
return(res);
}
return(base.VisitObjectType(field, objectType, selectionSet, context));
}
protected virtual ISelectionVisitorAction VisitChildren(
IOutputField field,
TContext context)
{
IOutputType type = field.Type;
SelectionSetNode?selectionSet =
context.SelectionSetNodes.Peek();
INamedType namedType = type.NamedType();
if (namedType.IsAbstractType())
{
IReadOnlyList <ObjectType> possibleTypes =
context.Context.Schema.GetPossibleTypes(field.Type.NamedType());
foreach (var possibleType in possibleTypes)
{
ISelectionVisitorAction result =
VisitObjectType(field, possibleType, selectionSet, context);
if (result != Continue)
{
return(result);
}
}
}
else if (namedType is ObjectType a)
{
return(VisitObjectType(field, a, selectionSet, context));
}
return(DefaultAction);
}
protected override TContext OnAfterEnter(
ISelection selection,
TContext localContext,
ISelectionVisitorAction result)
{
if (selection is IProjectionSelection projectionSelection &&
projectionSelection.Handler is IProjectionFieldHandler <TContext> handler)
{
return(handler.OnAfterEnter(localContext, selection, result));
}
return(localContext);
}
/// <inheritdoc/>
public override bool TryHandleEnter(
Neo4JProjectionVisitorContext context,
ISelection selection,
out ISelectionVisitorAction action)
{
IObjectField field = selection.Field;
action = SelectionVisitor.SkipAndLeave;
if (!context.StartNodes.Any())
{
context.Projections.Add(field.GetName());
return(true);
}
if (context.StartNodes.Count != context.EndNodes.Count)
{
context.EndNodes.Push(Cypher.NamedNode(selection.DeclaringType.Name.Value));
}
if (context.StartNodes.Count != context.Relationships.Count)
{
Neo4JRelationshipAttribute rel = context.RelationshipTypes.Peek();
Node startNode = context.StartNodes.Peek();
Node endNode = context.EndNodes.Peek();
Relationship direction = rel.Direction switch
{
Incoming => startNode.RelationshipFrom(endNode, rel.Name),
Outgoing => startNode.RelationshipTo(endNode, rel.Name),
None => startNode.RelationshipBetween(endNode, rel.Name),
_ => throw new InvalidOperationException(
Neo4JResources.Projection_RelationshipDirectionNotSet)
};
context.Relationships.Push(direction);
}
context
.RelationshipProjections[context.CurrentLevel]
.Enqueue(selection.Field.GetName());
return(true);
}
}
public T OnAfterLeave(T context, ISelection selection, ISelectionVisitorAction result) => _handler.OnAfterLeave(context, selection, result);
public virtual T OnAfterLeave(
T context,
ISelection selection,
ISelectionVisitorAction action) => context;
protected virtual TContext OnAfterLeave(
ISelection selection,
TContext localContext,
ISelectionVisitorAction result) =>
localContext;
protected virtual TContext OnAfterEnter(
IOutputField field,
TContext localContext,
ISelectionVisitorAction result) =>
localContext;
