Re: [eclipselink-users] How to clear Cache

[Gordon Yorke <gordon.yorke@xxxxxxxxxx>]

InvalidateAll does not actually remove the instances from the cache like initializeAllIdentityMaps does.  Invalidation marks the cached objects as being invalid and they will be refreshed when queried for.  They are the same instances but will have different state.  It is important that the same instances are used to ensure referential integrity (the ability to navigate through java references from multiple nodes in your Entity tree and still be able to gain access to the same instance)

--Gordon
Joe Mc. wrote:

Hi Gordon,

yes right #invalidateAll() is the right Method; however, the call of this
method has no effect
I print always the maps out
(aSession.getIdentityMapAccessor().printIdentityMaps())

I have a search site, where it's possible to find some objects. 
If I use 
aSession.getIdentityMapAccessor().invalidateAll();
the maps seem to be empty, however if I return to the search page and fire a
selection. I see the same outputs with the same objects (hashcodes)
Does invalidateAll() flushs the cache immediately? 

I have the same effect with the other invalidate*-Methods (invalidateClass
etc.)

That's the reason, why I use 
aSession.getIdentityMapAccessor().initializeAllIdentityMaps();

To Cache-Coordination:
Yes, that will be the better solution. But I have at the moment not the time
in the projects to switch to this feature.


Thanks
Joe





Gordon Yorke-2 wrote:
  

Initializing the identity maps in a running system can lead to hard to 
diagnose errors.  IdentityMapAccessor.invalidateAll()  and the other 
invalidation APIs are the recommended approach.  Have you looked at 
Cache Coordination ( 
http://wiki.eclipse.org/Introduction_to_Cache_(ELUG)#Cache_Coordination_2 
) to automatically handle the notification for you.
--Gordon

Joe Mc. wrote:
    

Alright, my solution is:

- I am using a SessionCustomizer 
- adding a SessionEventAdapter
- override preExecuteQuery
- call Session.getIdentityMapAccessor().initializeAllIdentityMaps()

Codesnippet:

public void customize(Session session) throws Exception {
  
   SessionEventAdapter evtListener = new SessionEventAdapter() {
      
      @Override
      public void preExecuteQuery(SessionEvent event) {
          Session aSession = event.getSession();
          
          // check if cache invalidation is necessary....
          // if yes:
          aSession.getIdentityMapAccessor().initializeAllIdentityMaps();
      }
   }
}



Open Questions:
- is preExecuteQuery the right place?
- Does any better solution exist?


Thanks

Mc.Joe






Joe Mc. wrote:
  
      

Hi everybody,

I trying to provide a functionality to delete the whole cache, to
support
the possibility to refresh the objects in the cache.
How is the best practice to flush the whole cache?

I have the following use case:
- 2 separate Applications on different servers
- Both use JPA Eclipselink
- Application A reads the objects, I am using SoftWeak
- Application B modifies sometimes the data

desired is, that Application B gives Application A a signal (details are
here irrelevant), if he modified the data
Application A will flush his cache, if he gets this event.

Now the question is: Does any API exists to flush the (whole) cache?

Thanks in advance

Mc.Joe

    
        

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