/// <summary>
/// Retrieve the collection that is being loaded as part of processing this result set.
/// </summary>
/// <param name="persister">The persister for the collection being requested. </param>
/// <param name="key">The key of the collection being requested. </param>
/// <returns> The loading collection (see discussion above). </returns>
/// <remarks>
/// Basically, there are two valid return values from this method:<ul>
/// <li>an instance of {@link PersistentCollection} which indicates to
/// continue loading the result set row data into that returned collection
/// instance; this may be either an instance already associated and in the
/// midst of being loaded, or a newly instantiated instance as a matching
/// associated collection was not found.</li>
/// <li><i>null</i> indicates to ignore the corresponding result set row
/// data relating to the requested collection; this indicates that either
/// the collection was found to already be associated with the persistence
/// context in a fully loaded state, or it was found in a loading state
/// associated with another result set processing context.</li>
/// </ul>
/// </remarks>
public IPersistentCollection GetLoadingCollection(ICollectionPersister persister, object key)
{
CollectionKey collectionKey = new CollectionKey(persister, key);
if (log.IsDebugEnabled())
{
log.Debug("starting attempt to find loading collection [{0}]", MessageHelper.InfoString(persister.Role, key));
}
LoadingCollectionEntry loadingCollectionEntry = loadContexts.LocateLoadingCollectionEntry(collectionKey);
if (loadingCollectionEntry == null)
{
// look for existing collection as part of the persistence context
IPersistentCollection collection = loadContexts.PersistenceContext.GetCollection(collectionKey);
if (collection != null)
{
if (collection.WasInitialized)
{
log.Debug("collection already initialized; ignoring");
return(null); // ignore this row of results! Note the early exit
}
else
{
// initialize this collection
log.Debug("collection not yet initialized; initializing");
}
}
else
{
object owner = loadContexts.PersistenceContext.GetCollectionOwner(key, persister);
bool newlySavedEntity = owner != null && loadContexts.PersistenceContext.GetEntry(owner).Status != Status.Loading;
if (newlySavedEntity)
{
// important, to account for newly saved entities in query
// todo : some kind of check for new status...
log.Debug("owning entity already loaded; ignoring");
return(null);
}
else
{
// create one
if (log.IsDebugEnabled())
{
// Do not log the resultSet as-is, it is an IEnumerable which may get enumerated by loggers.
// (Serilog does that.) See #1667.
log.Debug("instantiating new collection [key={0}, rs={1}]", key, resultSet.GetType());
}
collection = persister.CollectionType.Instantiate(loadContexts.PersistenceContext.Session, persister, key);
}
}
collection.BeforeInitialize(persister, -1);
collection.BeginRead();
localLoadingCollectionKeys.Add(collectionKey);
loadContexts.RegisterLoadingCollectionXRef(collectionKey, new LoadingCollectionEntry(resultSet, persister, key, collection));
return(collection);
}
else
{
if (loadingCollectionEntry.ResultSet == resultSet)
{
log.Debug("found loading collection bound to current result set processing; reading row");
return(loadingCollectionEntry.Collection);
}
else
{
// ignore this row, the collection is in process of
// being loaded somewhere further "up" the stack
log.Debug("collection is already being initialized; ignoring row");
return(null);
}
}
}