Add Store Update

[berezovskyi]

This patch is moved from Gerrit Change 95016.

FIxes #3

---

• Fix https://github.com/eclipse/lyo.store/pull/14/checks?check_run_id=1375606757#step:4:1640
• Fix PR self-review comments
• Add to the 4.0 roadmap

[jadelkhoury]

Code looks good to me.
The readme.md file is the same as the Store-core?
It would have been nice otherwise with some explanations of the main classes (oslcMessage, Handler, ChangeProvider). Alternatively, a very simple documentation of how it all fits together could be nice.

[jadelkhoury]

+1 for review

[berezovskyi]

@jamsden did you have time to look at this?

This patch adds all the remaing "boxes" from the architecture depicted here: https://github.com/eclipse/lyo-store/blob/cb11ca9fd9c01c817b3554e7f197d84f788e8b64/src/store-update/doc/architecture.png: change provider, update manager, and handlers.

[berezovskyi]

I think we should replace my handmade pub-sub mechanism with http://www.baeldung.com/guava-eventbus if it is able to fulfill all our needs.

[jamsden]

I haven't had any time to do anything with this yet.

[berezovskyi]

@jadelkhoury @jamsden shall we add it to the 4.0 release?

[berezovskyi]

@jadelkhoury @jamsden I hit a snag with the earlier breaking API change where we split TRS log interaction interface in two: PagedTrs and TrsEventHandler. The latter now requires a Resource to be supplied when it is added/modified/deleted. TRS Sync Handler only has metadata. For now, I have extracted TRS handlers from store-sync into store-sync-trs and disabled the module from the build/deploy.

[jadelkhoury]

This PR from 2017. I no longer have any ideas what it is about. What's TRS stuff doing under Store?

[berezovskyi]

This PR from 2017. I no longer have any ideas what it is about.

Yes, my memory has faded a bit too. But I think it's about having Store being a cache in front of a non-OSLC app, synchronising the data without making N requests to the API for N requests to the OSLC endpoint. But it was too long ago.

What's TRS stuff doing under Store?

That's one of the few things I can explain clearly: when a resource is added/modified/deleted through Lyo Store, we add it automatically to the TRS log without having you manually edit it (the log).