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From Andrus Adamchik <and...@objectstyle.org>
Subject Re: Cayenne shared cache invalidation
Date Wed, 22 Aug 2012 13:20:12 GMT
> Is this acceptable (at least .. waiting for our update to cayenne) ?

Yep. See my other message. We both guessed the cause of the issue simultaneously :)

Andrus



On Aug 22, 2012, at 4:12 PM, Francesco Romano wrote:

> On Aug 22, 2012, at 3:04 PM, Andrus Adamchik wrote:
> 
>>> Local cache is local to a data context (right?). But currently the application
creates a new datacontext for every "transaction", so if I understood correctly the local
cache is useless and I should use the shared cache.
>> 
>> Correct.
>> 
>>> I also tried to add a listener (on postPersist, postUpdate and postRemove) to
clear the cache for that particular group, but it does not work:
>>> 
>>> private void clearCache(Object entity) {
>>> 	Persistent object = (Persistent)entity;
>>> 	QueryCache cache = ((BaseContext)object.getObjectContext()).getQueryCache();
>>> 	cache.removeGroup(object.getClass().getName());
>>> }
>> 
>> This is going in the right direction. So is listener method invoked, but the cache
is not cleared, or the listener method is never invoked. 
>> 
>> BTW Cayenne 3.1 has a nice set of extensions called cayenne-lifecycle. The docs are
still sparse (we are working on those), but there is a @CacheGroups annotation placed on persistent
classes that tells Cayenne that any changes to a given type of objects should generate a cache
invalidation event. E.g.:
>> 
>> @CacheGroups("news")
>> public class News extends com.foo.auto._News { }
>> 
>> processing of this annotation is enabled by installing org.apache.cayenne.lifecycle.cache.CacheInvalidationFilter
(also part of cayenne-lifecycle):
>> 
>> DataChannelFilter filter = new CacheInvalidationFilter();
>> 
>> CayenneRuntime runtime = ...
>> 
>> // a bit clunky.. may merge the following 2 lines in one in the future releases:
>> runtime.getDataDomain().addFilter(filter);
>> runtime.getDataDomain().getEntityResolver().getCallbackRegistry().addListener(filter);
>> 
>> Cheers,
>> Andrus
>> 
> 
> Thank you for your answer.
> I don't think we can update our cayenne right now, but we will take a look at the annotations
asap (it means: when we can spend some time to update cayenne).
> 
> This morning I think I found a solution which seems to work:
> 
> private void clearCache(Object entity) {
> 		Persistent object = (Persistent)entity;
> 		ObjectContext context = object.getObjectContext();
> 		if (context instanceof DataContext) {
> 			DataContext dataContext = (DataContext)context;
> 			QueryCache cache = dataContext.getParentDataDomain().getQueryCache();
> 			cache.removeGroup(object.getClass().getName());
> 		}
> 	}
> 
> Is this acceptable (at least .. waiting for our update to cayenne) ?
> 
> Regards
> Francesco Romano
> 
>> 
>> On Aug 21, 2012, at 6:36 PM, Francesco Romano wrote:
>>> Hi everybody.
>>> 
>>> I'm trying to add caching support (query cache) to a project which uses cayenne.
>>> For what I understood in the online documentation there are two types of caches:
local and shared.
>>> Local cache is local to a data context (right?). But currently the application
creates a new datacontext for every "transaction", so if I understood correctly the local
cache is useless and I should use the shared cache.
>>> 
>>> Now... the problem.. I have a query cached (a sort of select * from table) and
a new row is added in the table. I would like that the next time the same query is called
also the new row is fetched.
>>> 
>>> This is the query cache
>>> 
>>> SelectQuery select = new SelectQuery(t);
>>> Class t; //this is the class of the persistent object to be fetched		
>>> select.setCacheStrategy(QueryCacheStrategy.SHARED_CACHE);
>>> 		
>>> select.setCacheGroups(t.getName());
>>> 
>>> This is my "sample" test code (Network is a Cayenne Object class) (GetAllNetwork
is a selectquery with the above caching. AddNetwork adds a new object and commit it. A new
DataContext is used every time)
>>> 
>>> List<Network> networks = dbHandle.GetAllNetwork();
>>> Network net = dbHandle.AddNetwork();
>>> List<Network> newNetworks = dbHandle.GetAllNetwork();
>>> 
>>> assertEquals(networks.size() + 1, newNetworks.size());
>>> 
>>> 
>>> Now... my assert is not true, because the query is cached.
>>> I also tried to add a listener (on postPersist, postUpdate and postRemove) to
clear the cache for that particular group, but it does not work:
>>> 
>>> private void clearCache(Object entity) {
>>> 	Persistent object = (Persistent)entity;
>>> 	QueryCache cache = ((BaseContext)object.getObjectContext()).getQueryCache();
>>> 	cache.removeGroup(object.getClass().getName());
>>> }
>>> 
>>> Any help?
>>> 
>>> Thanks
>>> Regards
>>> 
>>> Francesco Romano
>>> 
>> 
>> 
> 


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