On Sun, 8 May 2011, Justin Edelson wrote:
On Sun, May 8, 2011 at 12:32 PM, Tom Anderson <[email protected]> wrote:
Marcel Reutegger wrote:
you can look at workspaces as local checkouts of a revision control
system.
That's a really useful metaphor, because i understand revision control
systems. However, i don't understand how the parts map on to JCR. The
workspace corresponds to a local working copy, right? So what's the
equivalent of the central repository? What are the equivalents of
updating and committing? How about branching and merging?
I think you're taking the metaphor a bit too literally.
One of the dangers of metaphors!
It might be easier to think of workspaces as branches. You'd designate a
single workspace (probably "default") as the "trunk" workspace. In this
context, Node.update() could handle both "commit" and "update"
operations; Workspace.createWorkspace(name, srcWorkspace) is the
"branch" operation and VersionManager.merge() is the "merge" operation.
To be picky, i think that's still a badly-fitting metaphor, because update
moves changes from one workspace to another, which here would mean moving
across branches, whereas commit/update in CVS and friends affect a single
branch. The thing is that in this metaphor, there is no working copy.
Unless the changes in memory are the working copy, and
Session.save()/Session.refresh(true) are commit and update?
Maybe i should give up on the metaphors.
About update() - it works if the node whose content i want to propagate
from one workspace to another already exists in the destination. What do i
do if it doesn't? Workspace.clone()?
If i have a node which exists in two workspaces, but where both have some
content i want to keep (different child nodes, for instance), is there any
way i can use update (and/or clone) to do that? Or is this where i need to
use VersionManager.merge? Do i need to be using versioning for that?
I see from the javadoc that there are methods checkin, checkout, and
merge - but that these are (as of JCR 2.0) on the VersionManager. That
suggests to me that if i'm going to use them, i'm also going to be
getting involved with versions. Is that the case? Are workspaces and
versioning inextricably linked? Can i use workspaces without
versioning? Can i use versioning without workspaces?
checkin/checkout have nothing to do with workspaces.
Great.
If you're going to be using workspaces as branches, then yes, you'll
need to use versioning at some level (especially for merge operations).
Okay. This sounds like something i need to understand; is there something
i can read which walks through the process of using workspaces this way,
or in some related way from which i can build? Or is there any software
whose source code i can read to learn more about this?
You can use workspaces without versioning. You can use versioning
without workspaces.
Okay, thanks. I wonder if it might be simplest for me to use a single
workspace with multiple versions, actually. Would it be plausible to have
a style where each client did something like:
1. Get a session
2. Get the root node
3. Check it out (so creating a new version?)
4. Do all sorts of work, but always relative to the root node
5. Check the root node in
6. Do merging as necessary to restore a single head
? Or is that completely misunderstanding how versioning works?
tom
--
Initial thoughts - who cares? Subsequent thoughts - omg!!! (Female, 14,
Scotland) -- 4.5 million young Brits' futures could be compromised by
their electronic footprint, Information Commissioner's Office
