Hi Florent,
We don't want to remove the transient space entirely. The proposal is to
detach the transient from the non-transient part. We would have two
separate objects.
The non-transient object is always consistent, can be shared across
threads and is cached. Changes are directly written to the repository.
This object would have an updateProperties(Map) method that immediately
refreshes the object after the update.
The transient object is owned by one thread and not thread safe. That
should prevent inconsistent views on the object. This object would have
setProperty() and save() methods. Internally it would use the
non-transient object to access all unchanged data. It's a wrapper around
the non-transient object that holds the transient data.
So you still could use the pattern that you are using today. The only
difference would be that you have to create a transient wrapper object.
That could look like this:
Document doc = (Document) session.getObject(id);
TransientDocument transDoc = new TransientDocument(doc);
transDoc.setProperty("prop1", "value1");
transDoc.setProperty("prop2", "value2");
transDoc.save(); // that also refreshes the underlying non-transient object
Or maybe we do something like this:
Document doc = (Document) session.getObject(id);
TransientDocument transDoc = doc.createTransientDocument():
transDoc.setProperty("prop1", "value1");
transDoc.setProperty("prop2", "value2");
transDoc.save();
Florian
On 18/10/2010 16:07, Florent Guillaume wrote:
Hi,
In Nuxeo the OpenCMIS client API is made available locally as another
API to manipulate documents, in addition to the Nuxeo native APIs.
I have a problem with removing CmisObject.updateProperties() and the
mini transient space because for me it's quite useful. The Nuxeo
internal non-CMIS session has a notion of a property-only transient
space, so in Nuxeo you update several properties and do some kind of
object save() to flush them. Without a similar flushing concept on the
OpenCMIS client API, I'm obliged to make a flush on every property
write, which leads to severely degraded performance.
If all method calls on a CmisObject immediately write everything
through the network and potentially refetch a full object there will
be many people that aren't happy with CMIS performance once they get
to use OpenCMIS. The client API is supposed to provide some
convenience to the user, and having a mini transient space for
properties is IMHO the very first step of convenience. There may be
problems with the semantics of interactions between this transient
space and caching / refetches, but let's solve them rather than remove
them.
Dave wrote:
For example, with a transient space, what is the behaviour when setProperty has been
called and an "update" method is then called prior to updateProperties. Are the
transient changes discarded, flushed, or just left as is?
So if I understand correctly you're talking about the case:
1. doc.setPropertyValue("foo", ...);
2. doc.updateProperties(map);
3. doc.setPropertyValue("bar", ...);
4. doc.updateProperties();
And you're asking if the "foo" change is sent with 2. or with 4. or
discarded? I'd say let's keep this undefined, as I feel that it's a
use pattern that's not natural. If we really want to specify this then
I have no problem mandating that the "foo" change should be sent with
2. by saying that updateProperties(map) is the same as
setPropertyValue() on all the properties of the map then calling
updateProperties() with the transient map.
Florent
On Mon, Oct 18, 2010 at 4:05 PM, Klevenz, Stephan
<[email protected]> wrote:
Hi,
Coming back to the cache discussion. I would like to support this proposal by
Dave/Florian and think we can also delete Methods on Session class like
cancel() and save() which are currently not implemented.
+1 for this:
- All write operations provided by CmisObject should automatically do an object
refresh after the update. That guarantees that the object is always consistent.
The cost for this consistency is an additional call to the repository.
- Is some cases you don't need or want this addition cost. Lets say you just
want to update a bunch of objects but you don't work with them afterwards.
That's what the operations provided by Session are good for. They just do
that and nothing else.
About the transient support we can design this as an optional add on with
additional interfaces and additional implementations. With a clear separation
the API become easier to use.
Regards,
Stephan
