public override T PutIfAbsent(T entity, string key, object value)
{
KernelTransaction ktx = TxBridge.get();
try
{
using (Statement ignore = ktx.AcquireStatement())
{
// Does it already exist?
T existing = Iterators.single(InternalGet(key, value, ktx), null);
if (existing != null)
{
return(existing);
}
// No, OK so Grab lock
ktx.Locks().acquireExclusiveExplicitIndexLock(explicitIndexResourceId(NameConflict, key));
// and check again -- now holding an exclusive lock
existing = Iterators.single(InternalGet(key, value, ktx), null);
if (existing != null)
{
// Someone else created this entry before us just before we got the lock,
// release the lock as we won't be needing it
ktx.Locks().releaseExclusiveExplicitIndexLock(explicitIndexResourceId(NameConflict, key));
return(existing);
}
InternalAdd(entity, key, value, ktx);
return(default(T));
}
}
catch (EntityNotFoundException e)
{
throw new NotFoundException(format("%s %d not found", Type, Type.id(entity)), e);
}
catch (InvalidTransactionTypeKernelException e)
{
throw new ConstraintViolationException(e.Message, e);
}
catch (ExplicitIndexNotFoundKernelException e)
{
throw new Exception(e);
}
}
public virtual Lock SharedLock(KernelTransaction ktx, PropertyContainer container)
{
using (Statement ignore = ktx.AcquireStatement())
{
if (container is Node)
{
long id = (( Node )container).Id;
ktx.Locks().acquireSharedNodeLock(id);
return(new CoreAPILock(() => ktx.Locks().releaseSharedNodeLock(id)));
}
else if (container is Relationship)
{
long id = (( Relationship )container).Id;
ktx.Locks().acquireSharedRelationshipLock(id);
return(new CoreAPILock(() => ktx.Locks().releaseSharedRelationshipLock(id)));
}
else
{
throw new System.NotSupportedException("Only relationships and nodes can be locked.");
}
}
}
