Re: [dspace-tech] Collection getParentCommunityList()

Fri, 20 May 2016 10:25:35 -0700 

After some more thought on this, I agree with Monika.
Since we have no known use cases for having a Collection appear in multiple Communities, let's leave the REST API as-is in 6.0. It doesn't need to surface this "feature" of the underlying Java API, until we actually have a reason to do so.
I also agree that eventually we might want to just simplify these REST API params to "parent" and "parentList". But, that can be a future task (not for 6.0).
So, Terry, that should answer your #2. Don't bother updating the REST API for this. As for #1, I think we just need to make "parentCommunityList" act similar to 5.x in the 6.x codebase, which should solve https://jira.duraspace.org/browse/DS-2766 

- Tim

On 5/18/2016 5:11 PM, Monika Mevenkamp wrote:

Well I guess _ i rephrase - I’d vote for hiding  :-)

On another note - would it make sense to get away from names like
parentCommunity
parentCollection

in favor of parent  / parentList
again looking ahead to the bright future where collections and communities become the same 

Monika

—
Monika Mevenkamp
Digital Repository Infrastructure Developer
Princeton University
Phone: 609-258-4161
Skype: mo-meven
On May 18, 2016, at 5:58 PM, Tim Donohue <[email protected] <mailto:[email protected]>> wrote: 

Hi Monika,
Those are good questions. To clarify, I'm not recommending we add a new "map collections" feature. I was just pointing out to Terry, that *at the Java API level*, DSpace has supported the idea of a Collection having multiple parents for some time. That is not a change, it's just how the Java API has worked. However, at the UI level, this feature has never been implemented because we never had a clear use case for it (and I'm not exactly sure myself why the API was built this way to begin with).
When it comes to the REST API, we'd then have a decision. Do we let it act more like the Java API or do we just "hide" this feature of the Java API and make the REST API look more like the current UIs. I think this is the basics of what Terry is asking in his #2. I'm not sold on the fact that we need to let the REST API even support this feature (it's definitely not a high priority).
I think the real issue here is just finding a solution to https://jira.duraspace.org/browse/DS-2766, which is more about just figuring out what "parentCommunityList" was meant to do. 

- Tim


On 5/18/2016 3:08 PM, Monika Mevenkamp wrote:
Right now DSpace has a conceptually clean structure, an almost perfect hierarchy, except where items are mapped to multiple collections. So for example: it is clear what it means to show a collection in the UI. For a mapped item that is not necessarily true. Image styling different collections in different ways in a future flexible UI - what style should be picked for a mapped item ? In other words - mapping things - means moving away from a hierarchy - means life will be more complicated.
My question here: Mapping Collection to multiple communities — Is it worth it ? 

What is the use case for mapping collections to multiple communities   ?
Can the same be achieved with solr and ‘virtual’ collections which could be defined as whatever matches some kind of query ?
What is the implication in terms of getting rid of the distinction between communities and collections ? That is a feature I am looking forward to: we have several communities with a single collection with few items.
Where does that position the DSPACE model in relation to the Portland Data Model ?
My gut tells me to not to map collections. I don’t have a good overview of the wider DSPace world though. 
But it would be  worthwhile discussing before hacking …


Monika
—
Monika Mevenkamp
Digital Repository Infrastructure Developer
Princeton University
Phone: 609-258-4161
Skype: mo-meven
On May 18, 2016, at 12:33 PM, Terry Brady <[email protected]> wrote: 

Tim,

Thanks for the explanation.
To implement #1, I recommend that we add the necessary hibernate configuration logic to recursively traverse community2community. Who could advise on that change?
To implement #2, we would probably want to change the method return type to return a list of lists: one list for each immediate community parent. 

Terry
On Wed, May 18, 2016 at 7:39 AM, Tim Donohue <[email protected]> wrote: 

    Hi Terry,

    Some quick answers...

    I'm not sure of the correct answer to #1 myself (Peter Dietz,
    did you create this behavior?). Since it's called a "List"
    though, it sounds to me like the behavior in DSpace 5.x is more
    correct (that the intension may be to locate the full location
    of the collection, similar to breadcrumbs).

    As for #2, the API / database has always supported the "idea"
    of a Collection existing in multiple locations (i.e. a "linked"
    Collection). However, we've never found a reason to fully build
    this out with unit tests, etc. So, it's a partially created
    concept, and it's never really been proven to "work". In
    addition, the UIs have never supported this idea...at the UI
    level, a Collection only ever belongs to a single Community.

    So, essentially, #2 would/should be treated as a new feature.
    The groundwork is there in the API / database layer. But, it
    has never been fully built out. It'd need a volunteer to dig in
    and implement this concept so that it's actually usable in the
    UIs.  It also may require some refactoring at the REST API
    layer, as you've noted.

    - Tim

    On 5/17/2016 1:03 PM, Terry Brady wrote:

    I am investigating the following ticket:
    https://jira.duraspace.org/browse/DS-2766

    Here are my questions.
    1. In the collections endpoint, of the REST api, what is the
    intended behavior of expand=parentCommunityList?
    2. In DSpace, can a collection exist in multiple communities?

    Question 1. expand=parentCommunityList

    In DSpace5x, the expand=parentCommunityList option returns the
    full hierarchy of owing communities for a collection (all the
    way to the top level community).

    In DSpace 6x, this option returns the subcommunity that is an
    immediate parent of the collection.

    Assuming that this behavior is incorrect in DSpace 6, the
    following configuration will need to be updated to follow the
    community2community hierarchy:
    
https://github.com/DSpace/DSpace/blob/master/dspace-api/src/main/java/org/dspace/content/Collection.java#L81-L86

    Question 2: Can a collection exist in multiple communities?

    The following method in DSpace 5x could imply that a
    collection can exist in multiple communities:
    
https://github.com/DSpace/DSpace/blob/dspace-5_x/dspace-api/src/main/java/org/dspace/content/Collection.java#L1402

    But, the REST API implies that there is a single
    "parentCommunity".
    
https://github.com/DSpace/DSpace/blob/dspace-5_x/dspace-rest/src/main/java/org/dspace/rest/common/Collection.java#L136

    and a separate parentCommunityList
    
https://github.com/DSpace/DSpace/blob/dspace-5_x/dspace-rest/src/main/java/org/dspace/rest/common/Collection.java#L156

    What is the intended set of relationships to be supported?

    If a collection can exist in multiple communities, how should
    the REST api respond to "expand=parentCommunityList" option?

    If a collection can exist in multiple communities, how can
    this relationship be created in our UIs?

    Terry
-- Terry Brady 
    Applications Programmer Analyst
    Georgetown University Library Information Technology
    https://www.library.georgetown.edu/lit/code
    425-298-5498 <tel:425-298-5498> (Seattle, WA)
-- You received this message because you are subscribed to the 
    Google Groups "DSpace Technical Support" group.
    To unsubscribe from this group and stop receiving emails from
    it, send an email to [email protected].
    To post to this group, send email to [email protected].
    Visit this group at https://groups.google.com/group/dspace-tech.
    For more options, visit https://groups.google.com/d/optout.
-- Tim Donohue 
    Technical Lead for DSpace & DSpaceDirect
    DuraSpace.org <http://duraspace.org/>  |DSpace.org <http://dspace.org/>  
|DSpaceDirect.org <http://dspacedirect.org/>
-- You received this message because you are subscribed to the 
    Google Groups "DSpace Technical Support" group.
    To unsubscribe from this group and stop receiving emails from
    it, send an email to [email protected].
    To post to this group, send email to [email protected].
    Visit this group at https://groups.google.com/group/dspace-tech.
    For more options, visit https://groups.google.com/d/optout.




--
Terry Brady
Applications Programmer Analyst
Georgetown University Library Information Technology
https://www.library.georgetown.edu/lit/code
425-298-5498 (Seattle, WA)

--
You received this message because you are subscribed to the Google Groups "DSpace Technical Support" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected] <mailto:[email protected]>. 
To post to this group, send email to [email protected].
Visit this group at https://groups.google.com/group/dspace-tech.
For more options, visit https://groups.google.com/d/optout.




--
Tim Donohue
Technical Lead for DSpace & DSpaceDirect
DuraSpace.org <http://DuraSpace.org>  |DSpace.org <http://DSpace.org>  
|DSpaceDirect.org <http://DSpaceDirect.org>




--
Tim Donohue
Technical Lead for DSpace & DSpaceDirect
DuraSpace.org | DSpace.org | DSpaceDirect.org

--
You received this message because you are subscribed to the Google Groups "DSpace 
Technical Support" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To post to this group, send email to [email protected].
Visit this group at https://groups.google.com/group/dspace-tech.
For more options, visit https://groups.google.com/d/optout.

Reply via email to