[ovirt-devel] Sortable Ui Columns

[Alexander Wels]

On Monday, June 02, 2014 11:27:26 AM Lior Vernia wrote:
> After discussing this with Alex on another thread, I just pushed this:
> http://gerrit.ovirt.org/#/c/28268/
> 
> If it's approved, then it'll take care of the secondary criterion for
> you, so you only need to pass the criterion that actually interests you.
> Should simplify our work in the next couple of weeks.
> 

Okay, I think we need to get everyone on the same page with this, right now we 
have several solutions to the problem, and I think we should pick one and go 
with that. Right now we have the following solutions available:

1. Attempt to keep the current order in case of 'duplication' in the 
comparator. So the fallback is to keep the current order. This is implemented 
in Liors patch [1].
2. Use the hash code as a fallback in case of 'duplication' in the comparator. 
Due to hashcode rules this should result in the 'natural' order in case of 
duplicates. This is implemented in my patch [2].
3. Do ad-hoc fallback mechanism which can specialize to do the proper thing 
based on domain knowledge. It looks like this is what Anmol is doing in his 
gluster sorting patch [3]
4. Replace the SortedSet with a List but lose the ability to automatically 
sort when calling getItems().add(X).

To me it seems that 3 and 4 are off the table as we want to keep the ability to 
automatically sort. And doing ad hoc solutions for every single sorting column 
is going to take a lot of time and is going to lead to maintainability issues 
down the road. That leaves 1 and 2 on which I would like to have a discussion, 
so we can pick the appropriate method and go forward with that.


[1] http://gerrit.ovirt.org/#/c/28268/

[2] http://gerrit.ovirt.org/#/c/28225/

[3] http://gerrit.ovirt.org/#/c/28233/

> On 31/05/14 15:35, Anmol Babu wrote:
> > Thanks a lot Alexander.Your idea of having a second criteria based sorting
> > just in case of comparing same values(compare returning 0) looks good to
> > me and now, I have also done the same in my patch set
> > http://gerrit.ovirt.org/#/c/28233/.I have added you as a reviewer as
> > well. Thanks,
> > Anmol
> > 
> > ----- Original Message -----
> > From: "Alexander Wels" <awels at redhat.com>
> > To: devel at ovirt.org
> > Cc: "Anmol Babu" <anbabu at redhat.com>
> > Sent: Friday, May 30, 2014 5:55:20 PM
> > Subject: Re: [ovirt-devel] Sortable Ui Columns
> > 
> > Anmol,
> > 
> > This is due to the fact that the sorting is done by a SortedSet instead of
> > a list in the SortedListModel. To fix this we have to do one of two
> > things:
> > 
> > 1. Change the sorting to use a list of some sort, but apparently that is
> > not much of an option as people want automatic sorting when they add new
> > items to the collection.
> > 2. Make sure that the comparator never returns 0 for two entities that are
> > really not the same. The reason you are seeing the issue is because you
> > are
> > using a different comparator that does return 0 on whatever field you are
> > comparing against. I had the exact same issue and I solved it by using a
> > compound comparator. Basically what I did was create a comparator that
> > contains the field I am trying to compare on and if that returns 0 then I
> > use a different comparator that is guaranteed to not return 0 for the
> > entity.
> > 
> > I have a patch that implements sorting for all the data center main tab
> > and
> > sub tabs here [1] that demonstrates how I solved the issue. This patch
> > hasn't been reviewed yet, and my solution might get rejected, but it does
> > work and doesn't make your entries disappear when you sort.
> > 
> > 
> > [1] http://gerrit.ovirt.org/#/c/28225/
> > 
> > On Friday, May 30, 2014 02:32:17 AM Anmol Babu wrote:
> >> Hi,
> >> 
> >>    While applying client-side sort using the sorting infra, to the
> >>    "Server"
> >> 
> >> column of the "Volumes" sub tab "Bricks", I had 2 Bricks with same server
> >> name.So,when I sorted it, it removed one of the bricks that had the same
> >> server name. I found that this issue occurs when the sort values compared
> >> are same(i.e, comparator's compare returns 0). Regards,
> >> Anmol.B
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> > 
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