public NodeRelationType GetOrCreateNodeRelationType(string alias, AbstractScopedCache repositoryScopedCache)
{
return(repositoryScopedCache.GetOrCreateTyped(
"NodeRelationType-" + alias,
() =>
{
var existing = NhSession.QueryOver <NodeRelationType>()
.Where(x => x.Alias == alias)
.Cacheable()
.Take(1)
.SingleOrDefault <NodeRelationType>();
return existing ?? new NodeRelationType()
{
Alias = alias, Id = alias.EncodeAsGuid()
};
}));
}
public void AddRelation(IReadonlyRelation <IRelatableEntity, IRelatableEntity> item, AbstractScopedCache repositoryScopedCache)
{
var sessionIdAsString = GetSessionId().ToString("n");
using (DisposableTimer.TraceDuration <NhSessionHelper>("In AddRelation for session " + sessionIdAsString, "End AddRelation for session " + sessionIdAsString))
{
// Get the source and destination items from the Nh session
var sourceNode = NhSession.Get <Node>((Guid)item.SourceId.Value);
var destNode = NhSession.Get <Node>((Guid)item.DestinationId.Value);
// Check the Nh session is already aware of the items
if (sourceNode == null || destNode == null)
{
string extraMessage = string.Empty;
if (sourceNode == null)
{
extraMessage = "Source {0} cannot be found.\n".InvariantFormat(item.SourceId.Value);
}
if (destNode == null)
{
extraMessage += "Destination {0} cannot be found.".InvariantFormat(item.DestinationId.Value);
}
throw new InvalidOperationException(
"Before adding a relation between source {0} and destination {1}, you must call AddOrUpdate with those items or they must already exist in the datastore.\n{2}"
.InvariantFormat(item.SourceId, item.DestinationId, extraMessage));
}
// Try to load an existing relation of the same type between the two
var relationType = GetOrCreateNodeRelationType(item.Type.RelationName, repositoryScopedCache);
// Grab the existing relation (if exists) using the compound key of start node / end node / relation type
var cacheKey = GenerateCacheKeyForRelation(item, relationType);
NodeRelation relationToReturn = repositoryScopedCache.GetOrCreateTyped(
cacheKey,
() =>
{
return(NhSession
.QueryOver <NodeRelation>()
.Where(x => x.StartNode == sourceNode && x.EndNode == destNode && x.NodeRelationType == relationType)
.Cacheable()
.SingleOrDefault());
});
// Avoid a duplicate by checking if one already exists
if (relationToReturn != null)
{
// Make sure existing relation has ordinal
relationToReturn.Ordinal = item.Ordinal;
}
else
{
// Create a new relation
relationToReturn = new NodeRelation {
StartNode = sourceNode, EndNode = destNode, NodeRelationType = relationType, Ordinal = item.Ordinal
};
relationToReturn = NhSession.Merge(relationToReturn) as NodeRelation;
}
// Ensure metadata correct on existing or new entity
CreateAndAddRelationTags(item, relationToReturn);
}
}
