Re: collections containing collections

My 2 cents:

On Jan 29, 2013, at 09:32, "Wilde, Erik" <Erik.Wilde@emc.com> wrote:

> hello ashok.
> 
> On 2013-01-29 2:21 , "Ashok Malhotra" <ashok.malhotra@oracle.com> wrote:
>> 3. Can collections contain collections?
>> There seems to be agreement that, yes, collections can contain
>> collections.
>> There also seems to be agreement that collections are LDPRs and should
>> be added to collections like any other LDPR.  I think this is settled
>> but, personally,
>> I would like to see a line in the spec saying collections can be added to
>> collections
>> just like any other LDPR rather than leaving this as an exercise for the
>> reader.
> 
> so if collections can contain collections, i can POST a collection
> representation to a collection. so far so good.

Yes

> if i GET all members of a
> collection that is nested, do i GET a mix of collections and members?

Yes, but just the collections and members that exist at that level.  That is, if a collection "foo" has a member "bar" and a sub collection "baz" then a GET would return those, but not baz's subcollections or members.

> the
> models of collections and members must have some difference (and hopefully
> do have quite a bit of overlap), because a collection has a list of
> members (and a member doesn't have that), and a member has (embedded or
> linked) content and a collection doesn't have that. if we make collections
> nestable, then implementations always must be aware that the set of
> resources returned is heterogeneous (members and/or collections).

Sure

> 
> if we take the delete model of "always deleting what's managed by the
> server", then deleting nested collections deletes everything directly or
> indirectly contained in that tree, i suppose.

Yes.

Regards,
Dave
--
http://about.me/david_wood


> 
> i am not saying that we shouldn't be doing it, but i just want to say that
> this has  number of non-trivial side-effects on the complexity of the
> model (i know because we're just going through the exact same exercise
> internally, where things are even worse because things can be moved and
> even linked into multiple collections). it certainly is doable, but rather
> than saying "why not do it?", i think we should only be doing it if we
> have people enthusiastically saying that this is critically necessary for
> LDP.
> 
> cheers,
> 
> dret.
> 
>