[Engine-devel] Guid & NGuid

[Laszlo Hornyak]

----- Original Message -----
> From: "Michael Kublin" <mkublin at redhat.com>
> To: engine-devel at ovirt.org
> Sent: Monday, February 4, 2013 8:47:29 AM
> Subject: Re: [Engine-devel] Guid & NGuid
> 
> 
> 
> ----- Original Message -----
> > From: "Roy Golan" <rgolan at redhat.com>
> > To: engine-devel at ovirt.org
> > Sent: Monday, February 4, 2013 9:18:21 AM
> > Subject: Re: [Engine-devel] Guid & NGuid
> > 
> > On 02/03/2013 03:19 PM, Alon Bar-Lev wrote:
> > >
> > > ----- Original Message -----
> > >> From: "Omer Frenkel" <ofrenkel at redhat.com>
> > >> To: "Michael Kublin" <mkublin at redhat.com>
> > >> Cc: "engine-devel" <engine-devel at ovirt.org>
> > >> Sent: Sunday, February 3, 2013 3:12:19 PM
> > >> Subject: Re: [Engine-devel] Guid & NGuid
> > >>
> > >>
> > >>
> > >> ----- Original Message -----
> > >>> From: "Michael Kublin" <mkublin at redhat.com>
> > >>> To: "engine-devel" <engine-devel at ovirt.org>
> > >>> Sent: Sunday, February 3, 2013 3:10:14 PM
> > >>> Subject: [Engine-devel] Guid & NGuid
> > >>>
> > >>> Hi,
> > >>>
> > >>> In ovirt-engine code we have Guid and NGuid objects.
> > >>> Guid is extends NGuid and also NGuid class has method
> > >>> getValue()
> > >>> which should return Guid.
> > >>> As for me these two classes are look like the same and I don't
> > >>> see
> > >>> to
> > >>> much differences between them.
> > >>> My proposal is to remove NGuid and move it functionality to
> > >>> Guid
> > >>> (Because of Guid is much more common)
> > >>>
> > >> i agree, but we need to take another step forward and allow Guid
> > >> to
> > >> be null (as it should)
> > >> and not assume its EMPTY or have a value (i'm pretty sure we
> > >> have
> > >> this assumption in many places)
> > > Hi,
> > >
> > > And for the new people out here... why not kill both and use
> > > plain
> > > standard java UUID[1]?
> > +1 for using java.util.UUID
> > 
> > NGuid functionality that should be extracted during the refactor is
> > -
> > 1. refactor DB and Java so empty or null return values are null and
> > not
> > EMPTY_GUID
> > 2. the special constructor of NGuid for UUID return by Microsoft AD
> > should be extracted to a factory/utility
> > > I think we should kill compat, I don't see any value in fixing
> > > anything about it while leaving it intact.
> > >
> > > Regards,
> > > Alon Bar-Lev.
> > >
> > > [1] http://docs.oracle.com/javase/6/docs/api/java/util/UUID.html
> Actually there is exists one reason not to use directly UUID at
> server side.
> The main operations on Guid today it is to convert object to Guid or
> Guid to string.
> Guid it is immutable object, number of Guids is limited and almost
> never changed,
> These sound like classical case for object that can be cached.
> Benefit - reduced number of string manipulations, reduced number of
> created instances, less work
> for garbage collection

UUID has the same properties, it is immutable. So you could do the same with UUID, but I am not sure you could effectively cache these objects and prove that you are saving either CPU, heap, or GC time.

> 
> 
> 
> 
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