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From Andrus Adamchik <and...@objectstyle.org>
Subject Re: A way to refreshObject()
Date Wed, 22 Feb 2017 06:37:45 GMT
Since we mostly focused on policy- and event-based *query* caches, the API for managing caching
of individual objects is not as streamlined, but here it is FWIW:

T myObject = ..;
ObjectContext context = myObject.getObjectContext();
ObjectId id = myObject.getObjectId();

// kick it out, unset ObjectContext (side effect - sets ObjectId to null)
context.getGraphManager().unregisterNode(id);

// restore ObjectId.. it was set to null in the call above (which we probably should change)
myObject.setObjectId(id);

// get a fresh fault
myObject = context.localObject(myObject);

Andrus


> On Feb 21, 2017, at 11:54 PM, Musall, Maik <maik@selbstdenker.ag> wrote:
> 
> Hi all,
> 
> I have an application using a big shared snapshot cache. Objects freshly instantiated
in an ObjectContext get their attributes populated based on the snapshot cache at the time,
and keep them during the context's lifetime, which is also what I want. (Last week I found
a page on cayenne.apache.org <http://cayenne.apache.org/> explaining this behaviour,
but I can't find it again. Seems not to live within the linked Guide hierarchy.)
> 
> In some cases though, I have object instances in ObjectContext 1 which I know are getting
modified in ObjectContext 2, and I want them to be updated after commit in context 1. In EOF,
I could call oc1.refreshObject(obj), or even oc1.refreshAllObjects(), which will merge the
new values in from the snapshot cache. Is there any way to do this in Cayenne, short of refetching
which would cost a roundtrip to the database even though I know I already have the current
values in the snapshot cache?
> 
> (I had a question posted recently about "creating a fault for an ObjectId", but this
is different because I need the commit in context 2 to go through to the database.)
> 
> Maik
> 


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