Hi Lior,
I'm revisiting this thread and posting some of my ideas on the sorting issue.
Page-able data widgets like tables with paging buttons, should use server-side sorting:
clicking on table column header updates the search string ("sortby
<attribute>") which causes CommonModel.search() to be called and new data
presented in the given table.
Non-page-able data widgets like tables without paging buttons, i.e. tables bound to
SearchableListModel whose "Search{Next|Previous}PageCommand" isn't
available, can use client-side sorting. However, instead of manipulating UiCommon model
data (items) directly and possibly breaking some hidden expectations within UiCommon code
(as Tomas mentioned earlier), I'd rather do client-side sorting on model provider
level.
Model providers represent a layer between GUI and UiCommon: GUI <--> model provider
<--> UiCommon model
Model providers are adapters between GUI and UiCommon models, listening to important
events fired by models and updating GUI accordingly & providing API (facade) for GUI
to trigger operations on models. For client-side sorting, I think it's better to
implement this feature on model provider level, i.e. inside
DataBoundTabModelProvider.updateData() method:
List<T> items = (List<T>) getModel().getItems();
// possibly use comparator to sort items
As for GWT's native support for table sorting: this is already in GWT 2.3, see
AbstractCellTable.addColumnSortHandler() method. It's just a handler that keeps track
of current sort options, i.e. "column2 asc & column 1 desc & column 3
asc". In other words, GWT provides a mechanism to notify our code what are current
sort options, but it's up to us to re-render data based on these sort options, i.e.
using Comparator on UiCommon model items.
Vojtech
----- Original Message -----
From: "Tomas Jelinek" <tjelinek(a)redhat.com>
To: "Einav Cohen" <ecohen(a)redhat.com>
Cc: "Lior Vernia" <lvernia(a)redhat.com>, "Vojtech Szocs"
<vszocs(a)redhat.com>, "Eli Mesika" <emesika(a)redhat.com>,
engine-devel(a)ovirt.org, "Alexander Wels" <awels(a)redhat.com>, "Daniel
Erez" <derez(a)redhat.com>, "Gilad Chaplik"
<gchaplik(a)redhat.com>, "Alona Kaplan" <alkaplan(a)redhat.com>
Sent: Friday, June 28, 2013 9:00:47 AM
Subject: Re: [Engine-devel] Sorting in tabs
----- Original Message -----
> From: "Tomas Jelinek" <tjelinek(a)redhat.com>
> To: "Einav Cohen" <ecohen(a)redhat.com>
> Cc: "Lior Vernia" <lvernia(a)redhat.com>, "Vojtech Szocs"
> <vszocs(a)redhat.com>, "Eli Mesika" <emesika(a)redhat.com>,
> engine-devel(a)ovirt.org, "Alexander Wels" <awels(a)redhat.com>,
"Daniel Erez"
> <derez(a)redhat.com>, "Gilad Chaplik"
> <gchaplik(a)redhat.com>, "Alona Kaplan" <alkaplan(a)redhat.com>
> Sent: Friday, June 28, 2013 8:45:17 AM
> Subject: Re: [Engine-devel] Sorting in tabs
>
>
>
> ----- Original Message -----
> > From: "Einav Cohen" <ecohen(a)redhat.com>
> > To: "Lior Vernia" <lvernia(a)redhat.com>
> > Cc: "Vojtech Szocs" <vszocs(a)redhat.com>, "Eli
Mesika"
> > <emesika(a)redhat.com>,
> > engine-devel(a)ovirt.org, "Alexander Wels"
> > <awels(a)redhat.com>, "Daniel Erez" <derez(a)redhat.com>,
"Gilad Chaplik"
> > <gchaplik(a)redhat.com>, "Alona Kaplan"
> > <alkaplan(a)redhat.com>, "Tomas Jelinek"
<tjelinek(a)redhat.com>
> > Sent: Thursday, June 27, 2013 6:40:56 PM
> > Subject: Re: [Engine-devel] Sorting in tabs
> >
> > > ----- Original Message -----
> > > From: "Lior Vernia" <lvernia(a)redhat.com>
> > > Sent: Thursday, June 27, 2013 12:15:14 PM
> > >
> > >
> > >
> > > On 27/06/13 18:15, Einav Cohen wrote:
> > > >> ----- Original Message -----
> > > >> From: "Lior Vernia" <lvernia(a)redhat.com>
> > > >> Sent: Thursday, June 27, 2013 10:38:04 AM
> > > >>
> > > >>
> > > >>
> > > >> On 27/06/13 16:42, Einav Cohen wrote:
> > > >>>> ----- Original Message -----
> > > >>>> From: "Lior Vernia" <lvernia(a)redhat.com>
> > > >>>> Sent: Thursday, June 27, 2013 8:53:59 AM
> > > >>>>
> > > >>>>
> > > >>>>
> > > >>>> On 27/06/13 15:37, Einav Cohen wrote:
> > > >>>>>> ----- Original Message -----
> > > >>>>>> From: "Eli Mesika"
<emesika(a)redhat.com>
> > > >>>>>> Sent: Thursday, June 27, 2013 6:46:58 AM
> > > >>>>>>
> > > >>>>>>
> > > >>>>>> ----- Original Message -----
> > > >>>>>>> From: "Lior Vernia"
<lvernia(a)redhat.com>
> > > >>>>>>> To: engine-devel(a)ovirt.org
> > > >>>>>>> Sent: Thursday, June 27, 2013 10:12:33 AM
> > > >>>>>>> Subject: [Engine-devel] Sorting in tabs
> > > >>>>>>>
> > > >>>>>>> Hello everyone (UI peeps in particular),
> > > >>>>>>>
> > > >>>>>>> I've pushed (not yet merged) a patch that
would enable us to
> > > >>>>>>> keep
> > > >>>>>>> items
> > > >>>>>>> in tabs (main/sub) sorted at all times by
setting a comparator
> > > >>>>>>> in
> > > >>>>>>> SearchableListModel:
> > > >>>>>>
> > > >>>>>> But tabs includes only 100 records and supports
paging , how you
> > > >>>>>> deal
> > > >>>>>> with
> > > >>>>>> that ???
> > > >>>>>
> > > >>>>> if this is in the GUI level, then I assume that the
comparator is
> > > >>>>> simply
> > > >>>>> comparing the
> > > >>>>> items within the current page, and not
"globally".
> > > >>>>> so the sorting doesn't affect the set of items
that is displayed
> > > >>>>> in
> > > >>>>> the
> > > >>>>> page (it would
> > > >>>>> be the same as before the sorting) - just their
order.
> > > >>>>
> > > >>>> Yes, if I understand correctly how the paging works,
Einav is
> > > >>>> correct
> > > >>>> -
> > > >>>> only the items passed to the UI are sorted.
> > > >>>>
> > > >>>>> also: @Lior - what happens when the search query
contains a "sort
> > > >>>>> by"
> > > >>>>> part?
> > > >>>>> there is a chance that the behaivor would be
unexpected in this
> > > >>>>> case;
> > > >>>>
> > > >>>> Yes, I thought about this case, and it may result in a
confusing
> > > >>>> user
> > > >>>> experience if developers aren't careful. Together
with the issue
> > > >>>> of
> > > >>>> paging, this probably makes this sorting mechanism a
better
> > > >>>> candidate
> > > >>>> for use within subtabs rather than main tabs.
> > > >>>
> > > >>> note that at some point, I think that we would want to
introduce
> > > >>> paging
> > > >>> also to search-
> > > >>> based sub-tabs - it will be useful especially for sub-tabs
that
> > > >>> potentially
> > > >>> display a
> > > >>> large number of results (e.g. Disks sub-tab in Storage main
tab).
> > > >>> In addition, at some point, we would want to get rid of the
paging
> > > >>> UI
> > > >>> as
> > > >>> it
> > > >>> is now
> > > >>> (i.e. "next"/"prev" buttons at the top
panel) and move to paging
> > > >>> triggered
> > > >>> by scroll
> > > >>> (i.e. have a very long grid, dynamically loaded as you
continue to
> > > >>> scroll
> > > >>> -
> > > >>> similar
> > > >>> to the behavior of some e-mail web-clients, for example). In
this
> > > >>> case,
> > > >>> sorting on
> > > >>> the client side will make no sense at all (i.e. from the
user
> > > >>> perspective,
> > > >>> only a
> > > >>> portion of a very large grid will be sorted, the other
portions
> > > >>> won't
> > > >>> be).
> > > >>>
> > > >>> So for now - yes, I think it makes sense to introduce your
> > > >>> mechanism
> > > >>> to
> > > >>> all
> > > >>> sub-tabs,
> > > >>> however in the long-term - we would probably want the
search-based
> > > >>> sub-tabs
> > > >>> (which
> > > >>> will support paging) to move to search-based sorting, rather
than
> > > >>> GUI-based-sorting.
> > > >>
> > > >> Sounds good to me. Let me just re-iterate that it is not
mandatory
> > > >> to
> > > >> set a comparator, so in technical terms it's not even
necessary to
> > > >> introduce it at once to all sub-tabs, if they're already
sorting
> > > >> their
> > > >> items some other way. It could happen gradually, and only if
> > > >> developers
> > > >> find it more convenient. In either case, dropping the GUI
sorting
> > > >> once
> > > >> search-based sorting is implemented shouldn't be difficult.
> > > >>
> > > >>> BTW (maybe the other GUI maintainers can help me with that
one) -
> > > >>> what
> > > >>> about sub-tabs
> > > >>> that are not search-based (i.e. display results from a
"regular"
> > > >>> query
> > > >>> or
> > > >>> even from a
> > > >>> field within the selected item in the main grid, e.g.
Applications
> > > >>> in
> > > >>> VM)
> > > >>> -
> > > >>> are these
> > > >>> managed via SearchableListModel as well? since the
comparator
> > > >>> mechanism
> > > >>> *is* relevant
> > > >>> for them.
> > > >>
> > > >> As far as I've seen, some are managed via SearchableListModel
and
> > > >> some
> > > >> aren't. Those that aren't are those that display
non-trivial
> > > >> behaviour
> > > >> upon receipt of the items to display (setItems() method) - often
> > > >> this
> > > >> non-trivial behaviour is exactly sorting :) And if it's doing
its
> > > >> job,
> > > >> then there's no necessity to change it either. But anyway, I
don't
> > > >> know
> > > >> all of them, so I'd also love to hear GUI maintainers.
> > > >>
> > > >>> Also: Worth mentioning "Bug 893999 - webadmin: please
allow column
> > > >>> sorting", which
> > > >>> requests to enable sorting when clicking on a grid-column
header;
> > > >>> when
> > > >>> implementing
> > > >>> column-sorting, probably worth attaching your mechanism to
it
> > > >>> somehow
> > > >>> (i.e.
> > > >>> clicking on
> > > >>> a column header should set the relevant comparator in the
relevant
> > > >>> SearchableListModel).
> > > >>
> > > >> I didn't want to say it, because if we upgrade to a newer
version of
> > > >> GWT
> > > >> then we could probably use their table column sorting. But this
> > > >> mechanism could allow us to achieve this without upgrading, and
it
> > > >> was
> > > >> definitely sitting in the back of my head when I implemented it.
All
> > > >> that's needed is, as you said, to listen to table header
clicks in
> > > >> the
> > > >> view, and then appropriately set the comparator in the model.
> > > >>
> > > >
> > > > [Vojtech/GUI-maintainers - your input would be appreciated here]
> > > >
> > > > we are actually planning on upgrading the GWT version *really* soon
> > > > (to
> > > > GWT
> > > > 2.5),
> > > > so my question is: should we wait until the new GWT is introduced,
> > > > and
> > > > implement
> > > > client-sorting based on the GWT-grid-widget built-in mechanism
> > > > (assuming
> > > > there is
> > > > one)?
> > > > also, not sure if it is better to utilize the widget
default-built-in
> > > > sorting mechanism
> > > > (which doesn't manipulate the uicommon model data at all), or if
it
> > > > is
> > > > better to utilize
> > > > your comparator mechanism, which manipulates the uicommon model
data,
> > > > and
> > > > the GUI-widget
> > > > just reflects this data at any given time.
> > > > thoughts?
> > >
> > > I'll just give my two cents concerning this and then let others have
> > > the
> > > stage: I don't think it really matters.
> > >
> > > Manipulating the models directly is supposedly more portable in case we
> > > ever move away from GWT, but we'd still have the pain of adding new
> > > listeners to the new framework's table headers which could be just as
> > > bad as using its sorting mechanism.
> > >
> > > Graphically, the UI might look tighter if we use GWT's mechanism.
> > > However, we could probably mimic everything using GWT's graphics
(once
> > > we upgrade) even if we perform the actual sorting using the tab model
> > > and not their mechanism.
> > >
> > > My gut feeling actually says to use GWT's built-in mechanism, mainly
> > > because it will force us to put all sorting logic in the same place and
> > > to always use the same sorting mechanism (whereas currently the sorting
> > > logic is scattered and works differently in different places, even if
> > > we
> > > use this tab mechanism other widgets will differ). But it shouldn't
> > > stop
> > > us from setting a comparator for a tab where convenient.
> >
> > [again, GUI maintainers - your input would be appreciated]
> >
> > Thanks, Lior. Need to keep in mind several things:
> >
> > - we are now talking only about client-sorting, which generally we would
> > like
> > to apply only to grids that display none-"pagable"-results; for
grids
> > that
> > would
> > display pagable-results, we would want to use search-based (i.e. server)
> > sorting.
> > [so the sorting logic across the application would be somewhat-scattered
> > anyway].
> >
> > - I think that if we are choosing to utilize GWT's built-in mechanism,
> > then
> > using
> > a comparator would makes sense in case you want your results to be
> > initially
> > displayed
> > in a specific order that would not be obtainable using the column-header
> > sorting.
> >
> > e.g. (dumb example, for demonstration only) if you would want your VMs to
> > be
> > displayed
> > by default sorted alphabetically according to the VM's description (and
> > keep
> > in mind
> > that description is NOT one of the columns in the VMs grid), then you
> > would
> > probably
> > want to do that via the comparator.
> >
> > Or (perhaps a better example), if you would want your Templates to be
> > ordered
> > by default
> > in a way that "Blank" would appear first, and the rest would appear
> > sorted
> > alphabetically
> > by name, utilizing the comparator can be a good idea.
> > [After the initial load of the grid, if the user chooses to sort by name,
> > he
> > can click on
> > the "Name" column header, which will sort the Templates
alphabetically
> > "regularly" (i.e.
> > not taking "Blank" into special consideration)]
> >
> > But - if, by default, we would want, for example, to sort VMs
> > alphabetically
> > by name,
> > I think that we should imitate a mouse-click on the "Name"
column-header,
> > rather than
> > utilize a comparator for that (the exact same result shouldn't be
> > achieved
> > by
> > two different
> > implementations).
>
> Hi Lior,
>
> fist of all, I would be really careful about introducing something to
> UiCommon which could
> potentially cause class cast exceptions - not that your approach would be
> incorrect but the
> UiCommon has lot's of hidden expectations and it is hard to keep tract who
> expects the
> ListModel.getItems will be a list. I would be double careful about this
> kind
> of change right
> before the freeze. Maybe create a SortedSearchableListModel as a child of
> SearchableListModel
> would be a much more safe approach.
>
> About the GWT built-in vs Comparator -
> I would also go with the GWT's built in approach.
> If we are using a framework we should make use of it and not
> try to decouple too much to make it simpler to migrate to a different one.
>
> So I agree with Lior that we should go with GWT's built in approach.
> AFAIK Vojtech is already working on the GWT2.5 integration...
>
> Also I would say that we should have the same user experience regardless
> the
> table is paged or not
> e.g. the user needs to have the same button to click on and the result must
> make sense after he clicked
> it everywhere. So I would say we will have to integrate this GUI sorting
> with
> server side sorting for paged tables.
>
> But maybe this integration (however a ideal target) is a bit out of the
> scope
> of your initial intention ;)
>
> If you have a good reason to have something always sorted and it is not a
> paged table, I'm not against.
> Just please be a bit more careful in changing return types in a non-generic
> code like UiCommon.
Ooops, now I have looked into your code and realized that you return a
different type only if the comparator is set
which makes your patch much less risky - but at the same time much less
predictable.
But this kind of implementation details should be discussed on gerrit, so if
it will be
decided that the patch should go in in some form we can continue the
discussion on gerrit.
>
> >
> > >
> > > >>>>
> > > >>>>>
> > > >>>>> I believe that the correct thing to do is to
"attach" the GUI
> > > >>>>> sorting
> > > >>>>> mechanism
> > > >>>>> to the one in the search mechanism.
> > > >>>>>
> > > >>>>> thoughts?
> > > >>>>
> > > >>>> This can be done, however I'm not sure there's
much utility in it.
> > > >>>> Main
> > > >>>> tabs are always sorted according to some default ordering
even if
> > > >>>> one
> > > >>>> was not entered in the search panel, and this sorting is
also
> > > >>>> performed
> > > >>>> consistently with respect to paging. So maybe the right
thing to
> > > >>>> do
> > > >>>> would be to just "block" the GUI sorting
mechanism for main tabs
> > > >>>> (i.e.
> > > >>>> override the setter method and make it no-op)?
> > > >>>
> > > >>> yes, and related to what I mentioned above - at some point in
the
> > > >>> future,
> > > >>> we'd might want
> > > >>> to block it for search-based sub-tabs as well.
> > > >>>
> > > >>>>
> > > >>>>>>
> > > >>>>>>
> > > >>>>>>>
> > > >>>>>>>
http://gerrit.ovirt.org/#/c/15846/
> > > >>>>>>>
> > > >>>>>>> If a comparator isn't set, then
everything should behave as
> > > >>>>>>> before.
> > > >>>>>>> If
> > > >>>>>>> a
> > > >>>>>>> comparator is set, then from that moment on
the tab items will
> > > >>>>>>> be
> > > >>>>>>> kept
> > > >>>>>>> in a SortedSet, so that even if an item is
added in a way that
> > > >>>>>>> doesn't
> > > >>>>>>> trigger an event (e.g. getItems().add()) the
items will be kept
> > > >>>>>>> sorted
> > > >>>>>>> according to the given comparator. If the
comparator is set to
> > > >>>>>>> null,
> > > >>>>>>> from that moment on the tab should revert to
its old behaviour.
> > > >>>>>>>
> > > >>>>>>> You're most welcome to have a look and
let me know if this
> > > >>>>>>> might
> > > >>>>>>> break
> > > >>>>>>> something (remember though that it's not
obligatory to set a
> > > >>>>>>> comparator,
> > > >>>>>>> so only possible breakage should be in
generic flows).
> > > >>>>>>>
> > > >>>>>>> Feel free to use it once it's merged;
along with
> > > >>>>>>> SortedListModel,
> > > >>>>>>> this
> > > >>>>>>> should make sorting less painful. Just keep
in mind that once
> > > >>>>>>> you
> > > >>>>>>> set
> > > >>>>>>> a
> > > >>>>>>> comparator, you can't cast getItems() to
a List. This shouldn't
> > > >>>>>>> be
> > > >>>>>>> a
> > > >>>>>>> problem in general, as mostly it's as
useful (and probably more
> > > >>>>>>> correct)
> > > >>>>>>> to cast to a Collection.
> > > >>>>>>>
> > > >>>>>>> Lior.
> > > >>>>>>>
_______________________________________________
> > > >>>>>>> Engine-devel mailing list
> > > >>>>>>> Engine-devel(a)ovirt.org
> > > >>>>>>>
http://lists.ovirt.org/mailman/listinfo/engine-devel
> > > >>>>>>>
> > > >>>>>> _______________________________________________
> > > >>>>>> Engine-devel mailing list
> > > >>>>>> Engine-devel(a)ovirt.org
> > > >>>>>>
http://lists.ovirt.org/mailman/listinfo/engine-devel
> > > >>>>>>
> > > >>>>
> > > >>
> > >
> >