[Nepomuk] Re: Akonadi <-> Nepomuk interaction

Christian Mollekopf chrigi_1 at fastmail.fm
Tue Feb 22 16:04:38 CET 2011 

I agree that for a note I cannot give a real example since a note has only the 
text content as property.

I think the issue only exists for things like Todos or Events where we have 
additional properties which are not applicable to all Items.

I'm still not completely clear for myself if it makes sense to i.e. convert a 
note to a todo, since we could also add the note to the todo as property.
The problem is that this is not how todos/events work in akonadi, and also not 
how they are modeled in the ncal ontology.

So if we decide that it should be possible to convert i.e. a todo to an event, 
there are some annotations which apply to the content in general and some 
which apply only to the todo/event.

If i create a todo and collect files and websites to the topic of todo, but 
then decide that i need actually an event or a note with this information and 
not a todo, I will have to convert the item to a note or event. In this case I 
would of course want to keep all the files which I related to the todo, as they 
are basically part of the content. But I wouldn't want to keep a location 
which is associated to the todo if I convert it to a note.

Hope that makes it a bit clearer what I mean.

Cheers,

Chris

On Tuesday 22 February 2011 15:26:11 Sebastian Trüg wrote:
> I am confused - you want to annotate the text and not the note? But what
> is a note if not its text? I think I see the issue for something like an
> event though...
> Could you give a real example please.
> 
> Cheers,
> Sebastian
> 
> On 02/22/2011 02:53 PM, Christian Mollekopf wrote:
> > Just one thing which I forgot.
> > 
> > The point is that I need to annotate the content (text) of the Todo/Note
> > not the Todo/Note itself.
> > 
> > I annotate the content with pimo:Topics and random items like files,
> > other akonadi items, etc.
> > If I would simple set the Thing which I annotated with those items as the
> > Thing of the Todo/Note directly, another application could add annotation
> > to the Thing i.e. a location for a Todo.
> > Now that annotation is really only valid for the Todo not the content in
> > general. So if that item is converted to a Note, the location annotation
> > should not be kept, while all the associated files, etc and pimo:Topics
> > are still valid as they are actually annotations of the content (text).
> > 
> > That was also why I used the separate resource (for annotating the
> > content of the todo/note).
> > 
> > Cheers,
> > 
> > Chris
> > 
> > On Tuesday 22 February 2011 14:31:10 Sebastian Trüg wrote:
> >> Hi Chris,
> >> 
> >> On 02/22/2011 02:23 PM, Christian Mollekopf wrote:
> >>> On Tuesday 22 February 2011 11:41:27 Sebastian Trüg wrote:
> >>>> Hi Chris,
> >>>> 
> >>>> I always figured that there would be only two resources:
> >>>> 1. The main indexed resource created by the feeder
> >>>> 2. The pimo:Thing that contains all the annotations and relations.
> >>>> 
> >>>> IMHO there is no need for a third resource which is maintained by your
> >>>> app. The only problem I see here is the update by the feeder since
> >>>> that should maintain the relation to the pimo:Thing.
> >>>> But I think that could be handled by the feeder. It simply needs to
> >>>> handle updates differently than a simple delete+add. Instead it should
> >>>> make sure the resource URI is reused and the relation to the
> >>>> pimo:Thing is kept.
> >>> 
> >>> The problem with using the Resource created by the feeder is that it is
> >>> not clear if my app or the feeder is first to create it, so I would
> >>> have to make sure that also if I create the Resource first, the feeder
> >>> reuses it. But I guess that should be possible.
> >> 
> >> AFAIK Akonadi uses a dedicated property to identify their resources. You
> >> could reuse that.
> >> I suppose it would be best to put that into shared code somehow. That
> >> way it can be assured that the resources are reused.
> >> 
> >>> Further I also have to see when to delete the Thing, as sometimes I
> >>> wan't to reuse it (when converting the item).
> >>> 
> >>> What I don't really get: for one specific note there should only be one
> >>> Thing, right? So If I create the Thing and assign it to the Resource
> >>> created by the Feeder, will the feeeder delete the Thing, when he
> >>> deletes the Resource or will I have to do that?
> >>> 
> >>> The ownership of Resources/Things is not yet really clear to me....
> >> 
> >> The feeder does not delete the things. This is something that is not
> >> defined yet. It could of course be very easy to add thing deletion to
> >> the feeder.
> > 
> > In this case
> > 
> >> Cheers,
> >> Sebastian
> >> 
> >>>> Once that works you might only have to update the pimo:Thing type. I
> >>>> am not sure if this should also be done in the feeder or if your app
> >>>> should do that.
> >>>> 
> >>>> Cheers,
> >>>> Sebastian
> >>>> 
> >>>> On 02/19/2011 02:33 PM, Christian Mollekopf wrote:
> >>>>> Hi,
> >>>>> 
> >>>>> As I don't feel that there is a real solution how to handle notes and
> >>>>> kcal items in akonadi and nepomuk.  I'm going to explain here how I
> >>>>> plan to implement the interaction between aknoadi::items and
> >>>>> nepomuk::resources in my application.
> >>>>> 
> >>>>> I know there is some work going on in Baske/Semnotes/Kjots and the
> >>>>> issue has been discussed before focusing on notes. But as I couldn't
> >>>>> find a real conclusion on the ml, and since I have some more
> >>>>> requirements/usecases, I think it is time to continue this discussion
> >>>>> =)
> >>>>> 
> >>>>> Usecase:
> >>>>> My application manages Incidences (todos/events) and Notes using the
> >>>>> KCal and Akonotes resource in akonadi. (I do believe that storing
> >>>>> those in akonadi is the right way, and storing them in nepomuk is not
> >>>>> a valid option for various reasons).
> >>>>> 
> >>>>> I organize all items using PIMO::Topics (instead of collections
> >>>>> inside akonadi). Further I plan to add functionality to associate
> >>>>> random data (files, websites, mails, ...) with the topics and/or a
> >>>>> certain Akonadi::Item using Nepomuk.
> >>>>> 
> >>>>> One functionality which showed some further requirements, is
> >>>>> converting i.e. a note to an incidence. This made me realize that
> >>>>> I'm normally actually tagging the Content of the note/event/todo and
> >>>>> not i.e. todo itself.
> >>>>> 
> >>>>> 
> >>>>> All of this lead me to the following conclusion how to handle those
> >>>>> items in Nepomuk:
> >>>>> 
> >>>>> For each Akonadi::Item I create a Nepomuk::Resource (Content
> >>>>> Resource) of the type NFO:HtmlDocument (since it is only the
> >>>>> content, not the task itself) with an identifier consisting of an
> >>>>> application-specific prefix + akonadi::item url (to avoid conflicts
> >>>>> with the items generated in the nepomukfeeder agents). For all
> >>>>> annotations I use the pimoThing (Content Thing), on which I set the
> >>>>> type PIMO:Document. (See the attached diagram for reference)
> >>>>> 
> >>>>> So if I convert the item i.e. from note to todo, which means deleting
> >>>>> the old Akonadi::Item and creating a new one, I simply set the new
> >>>>> Nepomuk::Resource (created with the new akonadi::item url) as a
> >>>>> groundingOccurence of the existing Pimo:Document. This way all
> >>>>> annotations remain untouched.
> >>>>> 
> >>>>> The obvious downside of this is, that other applications do not
> >>>>> profit from annotations made in my application, and I am not yet
> >>>>> sure how to overcome this. Maybe I can annotate the
> >>>>> Nepomuk::Resource which has been created by the feederagent with the
> >>>>> Pimo:Document of the same item, and therefore implicitly share the
> >>>>> annotations?
> >>>>> 
> >>>>> Also I am not storing any real content in those Resources, I use the
> >>>>> Content Resource and the Content Thing only to annotate the content
> >>>>> of the item. For fulltext search or similar things I expect to use
> >>>>> the items created by the FeederAgent (meaning I will have to create
> >>>>> a feederagent for notes as well).
> >>>>> 
> >>>>> 
> >>>>> Anyhow, this solution doesn't seem ideal, so I'd be interested how
> >>>>> you guys intend to solve the issues. Especially what Resources you
> >>>>> create and how you tell them apart from the ones created by the
> >>>>> Feederagents.
> >>>>> 
> >>>>> Also are you using Nepomuk purely internal, or do you actually create
> >>>>> content which could be reused by other applications?
> >>>>> 
> >>>>> Cheers,
> >>>>> 
> >>>>> Chris
> >>>>> 
> >>>>> PS: Some background info on my app in case youre interested
> >>>>> http://gitorious.org/notetaker/pages/Home
> > 
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