internal AggregateContainsRelationCollectionSpan(AggregateContainsRelationCollection parent, IRelation relation)
{
Requires.NotNull(parent, nameof(parent));
Requires.NotNull(relation, nameof(relation));
_parent = parent;
Relation = relation;
}
bool IRelatableItem.TryGetOrCreateContainsCollection(
IRelationProvider relationProvider,
[NotNullWhen(returnValue: true)] out AggregateContainsRelationCollection?relationCollection)
{
if (_containsCollection == null && AggregateContainsRelationCollection.TryCreate(this, relationProvider, out AggregateContainsRelationCollection? collection))
{
_containsCollection = collection;
}
relationCollection = _containsCollection;
return(relationCollection != null);
}
/// <summary>
/// Attempts to create a collection for the children of <paramref name="parentItem"/>.
/// Fails only when no relations exist to produce child items for the given item's type.
/// </summary>
public static bool TryCreate(IRelatableItem parentItem, IRelationProvider relationProvider, [NotNullWhen(returnValue: true)] out AggregateContainsRelationCollection?collection)
{
ImmutableArray <IRelation> containsRelations = relationProvider.GetContainsRelationsFor(parentItem.GetType());
if (containsRelations.IsEmpty)
{
collection = null;
return(false);
}
collection = new AggregateContainsRelationCollection(parentItem, containsRelations);
return(true);
}