Mapping collection

[KevinVdV]

This PR includes alterations to the items.md contract to add for mapping of items to collections.

JIRA: https://jira.duraspace.org/browse/DS-4097

[abollini]

This should be managed using the spring data rest approach for association endpoint
https://docs.spring.io/spring-data/rest/docs/current/reference/html/#repository-resources.association-

it will be useful to state something about the "inverse endpoint". Which is our plan? do we want to implement the item mapper functionality also on the collection side (i.e. /api/core/collections/:uuid/items)?

[abollini]

It is an association. This should be included in the list of links returned by the single item endpoint.
It is important to clarify if the returned list include or not the owningCollection. I have no strong preference about it: probably excluding the owningCollection from the returned list could simplify some use cases on the client side but I guess it will add extra effort on the rest implementation or at least some "hack" on the code.

[tdonohue]

I agree with @abollini.

Also, I wonder if this should simply be called collections in the links on an Item...especially if we have it also include the owningCollection. I don't see a reason to actually use the term "mapping" or "mapped" in the REST API unless we really need to distinguish it from owningCollection.

[benbosman]

For the "included in the list of links returned by the single item endpoint", are you implying the HAL link to mappingCollections as displayed in
https://dspace7-internal.atmire.com/rest/#/rest/api/core/items/a649a58a-6b5a-4c15-9151-093cd6841491
Would you just want us to also update the item Rest Contract to contain this HAL links in the sample JSON?

The mapping collections don't include the owning collection, we will mention that explicitly in the Rest Contract

The reason to be explicit about this being mapping collections is to also easily allow a UI to add/remove mapping collections for an item. The difference with the owning collection is important here

[abollini]

ok

[tdonohue]

👍 Overall, this looks good now. I will however admit that I don't really like the term mappingCollections as "mapping" sounds like an action, not an object/resource. I'd prefer this endpoint be renamed to mappedCollections. But, if others are OK with this terminology, I'll let it go (I don't feel that strongly here).

[abollini]

I have created an alternative PR #44 based on the Spring Data Rest practice and the naming suggestion (mappedCollection) from @tdonohue

[abollini]

ok

[benbosman]

Thanks @abollini for the feedback.
I've updated the contract apart from the change which is also discussed in
#34 (comment) (for the consistency reasons detailed there)
I would recommend to keep that discussion limited to PR34

[abollini]

conflict on #44 has been solved. I suggest to merge it as by my understanding it reflects what we agree and don't require further work in fixing links

[tdonohue]

Merging, as this has been updated as requested and has approval from myself & @abollini .

[tdonohue]

I've reverted the merger of this PR (see #51). My apologies, I merged the wrong PR. Will merge #44 instead.

[tdonohue]

Disregard my previous comment. This (and #44) were replaced by #52. Please refer to #52 now.