private bool PrepareObjectToBeReplicated(object obj, object referencingObject, string
fieldName)
{
//TODO Optimization: keep track of the peer we are traversing to avoid having to look in both.
Logger4Support.LogIdentity(obj);
_obj = obj;
_referencingObject = referencingObject;
_fieldName = fieldName;
IReplicationReference refA = _providerA.ProduceReference(_obj, _referencingObject
, _fieldName);
IReplicationReference refB = _providerB.ProduceReference(_obj, _referencingObject
, _fieldName);
if (refA == null && refB == null)
{
throw new Exception(string.Empty + _obj.GetType() + " " + _obj + " must be stored in one of the databases being replicated."
);
}
//FIXME: Use db4o's standard for throwing exceptions.
if (refA != null && refB != null)
{
throw new Exception(string.Empty + _obj.GetType() + " " + _obj + " cannot be referenced by both databases being replicated."
);
}
//FIXME: Use db4o's standard for throwing exceptions.
IReplicationProviderInside owner = refA == null ? _providerB : _providerA;
IReplicationReference ownerRef = refA == null ? refB : refA;
IReplicationProviderInside other = Other(owner);
IDrsUUID uuid = ownerRef.Uuid();
IReplicationReference otherRef = other.ProduceReferenceByUUID(uuid, _obj.GetType(
));
if (refA == null)
{
refA = otherRef;
}
else
{
refB = otherRef;
}
//TODO for circular referenced object, otherRef should not be null in the subsequent pass.
//But db4o always return null. A bug. check!
if (otherRef == null)
{
//Object is only present in one ReplicationProvider. Missing in the other. Could have been deleted or never replicated.
if (WasProcessed(uuid))
{
IReplicationReference otherProcessedRef = other.ProduceReferenceByUUID(uuid, _obj
.GetType());
if (otherProcessedRef != null)
{
ownerRef.SetCounterpart(otherProcessedRef.Object());
}
return(false);
}
MarkAsProcessed(uuid);
long creationTime = ownerRef.Uuid().GetLongPart();
if (creationTime > owner.TimeStamps().From())
{
//if it was created after the last time two ReplicationProviders were replicated it has to be treated as new.
if (_isReplicatingOnlyDeletions)
{
return(false);
}
return(HandleNewObject(_obj, ownerRef, owner, other, _referencingObject, _fieldName
, true, false));
}
else
{
// If it was created before the last time two ReplicationProviders were replicated it has to be treated as deleted.
// No, not always, in a three-way replication setup it can also be new.
return(HandleMissingObjectInOther(_obj, ownerRef, owner, other, _referencingObject
, _fieldName));
}
}
if (_isReplicatingOnlyDeletions)
{
return(false);
}
ownerRef.SetCounterpart(otherRef.Object());
otherRef.SetCounterpart(ownerRef.Object());
if (WasProcessed(uuid))
{
return(false);
}
//Has to be done AFTER the counterpart is set because object yet to be replicated might reference the current one, replicated previously.
MarkAsProcessed(uuid);
object objectA = refA.Object();
object objectB = refB.Object();
bool changedInA = _providerA.WasModifiedSinceLastReplication(refA);
//System.out.println("changedInA = " + changedInA);
bool changedInB = _providerB.WasModifiedSinceLastReplication(refB);
//System.out.println("changedInB = " + changedInB);
if (!changedInA && !changedInB)
{
return(false);
}
bool conflict = false;
if (changedInA && changedInB)
{
conflict = true;
}
if (changedInA && _directionTo == _providerA)
{
conflict = true;
}
if (changedInB && _directionTo == _providerB)
{
conflict = true;
}
object prevailing = _obj;
_providerA.Activate(objectA);
_providerB.Activate(objectB);
_event.ResetAction();
_event.Conflict(conflict);
_event._creationDate = TimeStampIdGenerator.IdToMilliseconds(uuid.GetLongPart());
_stateInA.SetAll(objectA, false, changedInA, TimeStampIdGenerator.IdToMilliseconds
(ownerRef.Version()));
_stateInB.SetAll(objectB, false, changedInB, TimeStampIdGenerator.IdToMilliseconds
(otherRef.Version()));
_listener.OnReplicate(_event);
if (conflict)
{
if (!_event._actionWasChosen)
{
ThrowReplicationConflictException();
}
if (_event._actionChosenState == null)
{
return(false);
}
if (_event._actionChosenState == _stateInA)
{
prevailing = objectA;
}
if (_event._actionChosenState == _stateInB)
{
prevailing = objectB;
}
}
else
{
if (_event._actionWasChosen)
{
if (_event._actionChosenState == _stateInA)
{
prevailing = objectA;
}
if (_event._actionChosenState == _stateInB)
{
prevailing = objectB;
}
if (_event._actionChosenState == null)
{
return(false);
}
}
else
{
if (changedInA)
{
prevailing = objectA;
}
if (changedInB)
{
prevailing = objectB;
}
}
}
IReplicationProviderInside prevailingPeer = prevailing == objectA ? _providerA :
_providerB;
if (_directionTo == prevailingPeer)
{
return(false);
}
if (!conflict)
{
prevailingPeer.Activate(prevailing);
}
//Already activated if there was a conflict.
if (prevailing != _obj)
{
otherRef.SetCounterpart(_obj);
otherRef.MarkForReplicating(true);
MarkAsNotProcessed(uuid);
_traverser.ExtendTraversalTo(prevailing);
}
else
{
//Now we start traversing objects on the other peer! Is that cool or what? ;)
ownerRef.MarkForReplicating(true);
}
return(!_event._actionShouldStopTraversal);
}