I'm a WebObject/EOF guy too :-) the idea of use nested context is not bad, you can revert the object in the nested context one and it will get cached values from parent
Amedeo > On 15 Feb 2017, at 17:31, Michael Gentry <blackn...@gmail.com> wrote: > > Hi Maik, > > Would it be possible to use child DataContexts and then push the changes up > to the parent? > > > On Wed, Feb 15, 2017 at 11:17 AM, Musall, Maik <m...@selbstdenker.ag> wrote: > >> The use case is as follows. >> >> I have a large collection of objects which I want some function to be >> executed on. I want to use multiple threads to do this, so AFAIK I have to >> use separate ObjectContexts per thread like in EOF. So, I will then >> instantiate those objects in the per-thread contexts, do the processing, >> but then the wrapper function should return the entire collection of >> processed objects in the original context that they were in at the >> beginning. >> >> With EOF, I have a snapshot cache that will contain the changed >> attributes, but the EO instances in the original context have their >> original values. So, I will then call ec.faultForGlobalID() to have them >> refaulted from the snapshot cache, avoiding to refetch 100.000 objects from >> db. >> >> I suppose using a shared cache would make the problem obsolete, as those >> objects would receive changed attributes automatically, but I'm still on >> the fence whether or not to use a shared cache, because it's a major >> behavioural difference to EOF and I still have to think about that while >> migrating my project. >> >> Maik >> >> >>> Am 15.02.2017 um 15:49 schrieb Ken Anderson <ken.ander...@amphorainc.com >>> : >>> >>> Yes, use the objectID to pass around, but on the receiving end, you >> should turn it into a fault and release it into the wild. Then, if some >> code needs it, the fault fires, otherwise – no DB activity. >>> >>> Ken Anderson >>> CTO Amphora, Inc. >>> Mobile: +1 914 262 8540 >>> >>> >>> >>> www.amphorainc.com <http://www.amphorainc.com/> >>> >>> >>> >>> >>> On 2/15/17, 10:47 AM, "Amedeo Mantica" <amedeomant...@me.com> wrote: >>> >>> I would just use the ObjectId >>> >>>> On 15 Feb 2017, at 16:45, Hugi Thordarson <h...@karlmenn.is> wrote: >>>> >>>> It can be useful in some cases—one example is if you want to be able to >> pass objects around in an API without triggering a DB fetch unless they are >> actually used. >>>> >>>> Cheers, >>>> - hugi >>>> >>>> >>>>> On 15. feb. 2017, at 15:28, Amedeo Mantica <amedeomant...@me.com> >> wrote: >>>>> >>>>> no worries, but I cannot understand your goal, why do you want to get >> the fault ? >>>>> >>>>>> On 15 Feb 2017, at 16:25, Hugi Thordarson <h...@karlmenn.is> wrote: >>>>>> >>>>>> Thanks Ken, but the immediate fetch performed by Cayenne.objectForPk >> is precisely what I’d like to avoid. >>>>>> >>>>>> Cheers, >>>>>> - hugi >>>>>> >>>>>> S: Amedeo, sorry about calling you “Amadeo” in my last post. I have >> been properly lambasted. >>>>>> >>>>>> >>>>>>> On 15. feb. 2017, at 15:20, Ken Anderson < >> ken.ander...@amphorainc.com> wrote: >>>>>>> >>>>>>> I do this: >>>>>>> >>>>>>> dataObject = (DataObject) Cayenne.objectForPK(getObjectContext(), >> MyEntity.class, oid); >>>>>>> >>>>>>> But it will do the fetch if it’s not already in cache. >>>>>>> >>>>>>> Ken >>>>>>> >>>>>>> Ken Anderson >>>>>>> CTO Amphora, Inc. >>>>>>> Mobile: +1 914 262 8540 >>>>>>> >>>>>>> >>>>>>> >>>>>>> www.amphorainc.com <http://www.amphorainc.com/> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> On 2/15/17, 9:59 AM, "Hugi Thordarson" <h...@karlmenn.is> wrote: >>>>>>> >>>>>>> Thanks Amadeo, but I ended up creating a method that looks like >> this. It would be nice to get some feedback on it, if I’m violating any >> Cayenne Commandments. >>>>>>> >>>>>>> /** >>>>>>> * @return An existing object or fault if registered with the OC, >> otherwise creates a new hollow object based on the given ObjectId. >>>>>>> */ >>>>>>> public static Persistent faultForObjectId( ObjectContext oc, >> ObjectId objectId ) { >>>>>>> Persistent object = (Persistent) oc.getGraphManager().getNode( >> objectId ); >>>>>>> >>>>>>> if( object == null ) { >>>>>>> ClassDescriptor descriptor = oc.getEntityResolver(). >> getClassDescriptor(objectId.getEntityName()); >>>>>>> >>>>>>> object = (Persistent) descriptor.createObject(); >>>>>>> >>>>>>> object.setPersistenceState(PersistenceState.HOLLOW); >>>>>>> object.setObjectContext(oc); >>>>>>> object.setObjectId(objectId); >>>>>>> >>>>>>> oc.getGraphManager().registerNode(objectId, object); >>>>>>> } >>>>>>> >>>>>>> return object; >>>>>>> } >>>>>>> >>>>>>> Cheers, >>>>>>> - hugi >>>>>>> >>>>>>> >>>>>>>> On 15. feb. 2017, at 14:41, Amedeo Mantica <amedeomant...@me.com> >> wrote: >>>>>>>> >>>>>>>> may be you want invalidateObject ? >>>>>>>> >>>>>>>>> On 15 Feb 2017, at 14:15, Hugi Thordarson <h...@karlmenn.is> >> wrote: >>>>>>>>> >>>>>>>>> Hi all, >>>>>>>>> I need to get a fault for an ObjectId from an ObjectContext. How >> would I do this? >>>>>>>>> >>>>>>>>> I don’t see any public API for this—the implementation of >> createFault in CayenneContext seems to get me halfway there, but it will >> not return an existing fault, only create new ones. >>>>>>>>> >>>>>>>>> Cheers, >>>>>>>>> - hugi >>>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> Confidentiality Notice: This e-mail and accompanying documents >> contain confidential information intended for a specific individual and >> purpose. This e-mailed information is private and protected by law. If you >> are not the intended recipient, you are hereby notified that any >> disclosure, copying, or distribution, or the taking of any action based on >> the contents of this information, is strictly prohibited. >>>>>> >>>>> >>>> >>> >>> >>> >>> Confidentiality Notice: This e-mail and accompanying documents contain >> confidential information intended for a specific individual and purpose. >> This e-mailed information is private and protected by law. If you are not >> the intended recipient, you are hereby notified that any disclosure, >> copying, or distribution, or the taking of any action based on the contents >> of this information, is strictly prohibited. >> >>
