public virtual void OnMerge(MergeEvent @event)
{
EventCache copyCache = new EventCache();
OnMerge(@event, copyCache);
// transientCopyCache may contain parent and child entities in random order.
// Child entities occurring ahead of their respective transient parents may fail
// to get merged in one iteration.
// Retries are necessary as more and more children may be able to merge on subsequent iterations.
// Iteratively get transient entities and retry merge until one of the following conditions is true:
// 1) transientCopyCache.size() == 0
// 2) transientCopyCache.size() is not decreasing
// TODO: find out if retrying can add entities to copyCache (don't think it can...)
// For now, just retry once; throw TransientObjectException if there are still any transient entities
IDictionary transientCopyCache = this.GetTransientCopyCache(@event, copyCache);
while (transientCopyCache.Count > 0)
{
var initialTransientCount = transientCopyCache.Count;
RetryMergeTransientEntities(@event, transientCopyCache, copyCache);
// find any entities that are still transient after retry
transientCopyCache = this.GetTransientCopyCache(@event, copyCache);
// if a retry did nothing, the remaining transient entities
// cannot be merged due to references to other transient entities
// that are not part of the merge
if (transientCopyCache.Count == initialTransientCount)
{
ISet<string> transientEntityNames = new HashSet<string>();
foreach (object transientEntity in transientCopyCache.Keys)
{
string transientEntityName = @event.Session.GuessEntityName(transientEntity);
transientEntityNames.Add(transientEntityName);
log.InfoFormat(
"transient instance could not be processed by merge: {0} [{1}]",
transientEntityName,
transientEntity.ToString());
}
throw new TransientObjectException("one or more objects is an unsaved transient instance - save transient instance(s) before merging: " + String.Join(",", transientEntityNames.ToArray()));
}
}
copyCache.Clear();
}
public virtual void OnMerge(MergeEvent @event)
{
EventCache copyCache = new EventCache();
OnMerge(@event, copyCache);
// TODO: iteratively get transient entities and retry merge until one of the following conditions:
// 1) transientCopyCache.size() == 0
// 2) transientCopyCache.size() is not decreasing and copyCache.size() is not increasing
// TODO: find out if retrying can add entities to copyCache (don't think it can...)
// For now, just retry once; throw TransientObjectException if there are still any transient entities
IDictionary transientCopyCache = this.GetTransientCopyCache(@event, copyCache);
if (transientCopyCache.Count > 0)
{
RetryMergeTransientEntities(@event, transientCopyCache, copyCache);
// find any entities that are still transient after retry
transientCopyCache = this.GetTransientCopyCache(@event, copyCache);
if (transientCopyCache.Count > 0)
{
ISet<string> transientEntityNames = new HashedSet<string>();
foreach (object transientEntity in transientCopyCache.Keys)
{
string transientEntityName = @event.Session.GuessEntityName(transientEntity);
transientEntityNames.Add(transientEntityName);
log.InfoFormat(
"transient instance could not be processed by merge: {0} [{1}]",
transientEntityName,
transientEntity.ToString());
}
throw new TransientObjectException("one or more objects is an unsaved transient instance - save transient instance(s) before merging: " + transientEntityNames);
}
}
copyCache.Clear();
copyCache = null;
}
/// <summary>
/// Retry merging transient entities
/// </summary>
/// <param name="event"></param>
/// <param name="transientCopyCache"></param>
/// <param name="copyCache"></param>
protected void RetryMergeTransientEntities(MergeEvent @event, IDictionary transientCopyCache, EventCache copyCache)
{
// TODO: The order in which entities are saved may matter (e.g., a particular
// transient entity may need to be saved before other transient entities can
// be saved).
// Keep retrying the batch of transient entities until either:
// 1) there are no transient entities left in transientCopyCache
// or 2) no transient entities were saved in the last batch.
// For now, just run through the transient entities and retry the merge
foreach(object entity in transientCopyCache.Keys)
{
object copy = transientCopyCache[entity];
EntityEntry copyEntry = @event.Session.PersistenceContext.GetEntry(copy);
if (entity == @event.Entity)
MergeTransientEntity(entity, copyEntry.EntityName, @event.RequestedId, @event.Session, copyCache);
else
MergeTransientEntity(entity, copyEntry.EntityName, copyEntry.Id, @event.Session, copyCache);
}
}
/// <summary>
/// Determine which merged entities in the copyCache are transient.
/// </summary>
/// <param name="event"></param>
/// <param name="copyCache"></param>
/// <returns></returns>
/// <remarks>Should this method be on the EventCache class?</remarks>
protected EventCache GetTransientCopyCache(MergeEvent @event, EventCache copyCache)
{
EventCache transientCopyCache = new EventCache();
foreach(object entity in copyCache.Keys)
{
object entityCopy = copyCache[entity];
if (entityCopy.IsProxy())
entityCopy = ((INHibernateProxy)entityCopy).HibernateLazyInitializer.GetImplementation();
// NH-specific: Disregard entities that implement ILifecycle and manage their own state - they
// don't have an EntityEntry, and we can't determine if they are transient or not
if (entityCopy is ILifecycle)
continue;
EntityEntry copyEntry = @event.Session.PersistenceContext.GetEntry(entityCopy);
if (copyEntry == null)
{
// entity name will not be available for non-POJO entities
// TODO: cache the entity name somewhere so that it is available to this exception
log.InfoFormat(
"transient instance could not be processed by merge: {0} [{1}]",
@event.Session.GuessEntityName(entityCopy),
entity);
// merge did not cascade to this entity; it's in copyCache because a
// different entity has a non-nullable reference to it;
// this entity should not be put in transientCopyCache, because it was
// not included in the merge;
throw new TransientObjectException(
"object is an unsaved transient instance - save the transient instance before merging: " + @event.Session.GuessEntityName(entityCopy));
}
else if (copyEntry.Status == Status.Saving)
{
transientCopyCache.Add(entity, entityCopy, copyCache.IsOperatedOn(entity));
}
else if (copyEntry.Status != Status.Loaded && copyEntry.Status != Status.ReadOnly)
{
throw new AssertionFailure(
String.Format(
"Merged entity does not have status set to MANAGED or READ_ONLY; {0} status = {1}",
entityCopy,
copyEntry.Status));
}
}
return transientCopyCache;
}
public virtual void OnMerge(MergeEvent @event, IDictionary copiedAlready)
{
EventCache copyCache = (EventCache)copiedAlready;
IEventSource source = @event.Session;
object original = @event.Original;
if (original != null)
{
object entity;
if (original.IsProxy())
{
ILazyInitializer li = ((INHibernateProxy)original).HibernateLazyInitializer;
if (li.IsUninitialized)
{
log.Debug("ignoring uninitialized proxy");
@event.Result = source.Load(li.EntityName, li.Identifier);
return; //EARLY EXIT!
}
else
{
entity = li.GetImplementation();
}
}
else
{
entity = original;
}
if (copyCache.Contains(entity) && copyCache.IsOperatedOn(entity))
{
log.Debug("already in merge process");
@event.Result = entity;
}
else
{
if (copyCache.Contains(entity))
{
log.Info("already in copyCache; setting in merge process");
copyCache.SetOperatedOn(entity, true);
}
@event.Entity = entity;
EntityState entityState = EntityState.Undefined;
if (ReferenceEquals(null, @event.EntityName))
{
@event.EntityName = source.BestGuessEntityName(entity);
}
// Check the persistence context for an entry relating to this
// entity to be merged...
EntityEntry entry = source.PersistenceContext.GetEntry(entity);
if (entry == null)
{
IEntityPersister persister = source.GetEntityPersister(@event.EntityName, entity);
object id = persister.GetIdentifier(entity);
if (id != null)
{
EntityKey key = source.GenerateEntityKey(id, persister);
object managedEntity = source.PersistenceContext.GetEntity(key);
entry = source.PersistenceContext.GetEntry(managedEntity);
if (entry != null)
{
// we have specialized case of a detached entity from the
// perspective of the merge operation. Specifically, we
// have an incoming entity instance which has a corresponding
// entry in the current persistence context, but registered
// under a different entity instance
entityState = EntityState.Detached;
}
}
}
if (entityState == EntityState.Undefined)
{
entityState = GetEntityState(entity, @event.EntityName, entry, source);
}
switch (entityState)
{
case EntityState.Persistent:
EntityIsPersistent(@event, copyCache);
break;
case EntityState.Transient:
EntityIsTransient(@event, copyCache);
break;
case EntityState.Detached:
EntityIsDetached(@event, copyCache);
break;
default:
throw new ObjectDeletedException("deleted instance passed to merge", null, GetLoggableName(@event.EntityName, entity));
}
}
}
}
/// <summary>
/// Retry merging transient entities
/// </summary>
/// <param name="event"></param>
/// <param name="transientCopyCache"></param>
/// <param name="copyCache"></param>
protected void RetryMergeTransientEntities(MergeEvent @event, IDictionary transientCopyCache, EventCache copyCache)
{
// TODO: The order in which entities are saved may matter (e.g., a particular
// transient entity may need to be saved before other transient entities can
// be saved).
// Keep retrying the batch of transient entities until either:
// 1) there are no transient entities left in transientCopyCache
// or 2) no transient entities were saved in the last batch.
// For now, just run through the transient entities and retry the merge
foreach (object entity in transientCopyCache.Keys)
{
object copy = transientCopyCache[entity];
EntityEntry copyEntry = @event.Session.PersistenceContext.GetEntry(copy);
if (entity == @event.Entity)
{
MergeTransientEntity(entity, copyEntry.EntityName, @event.RequestedId, @event.Session, copyCache);
}
else
{
MergeTransientEntity(entity, copyEntry.EntityName, copyEntry.Id, @event.Session, copyCache);
}
}
}