openjpa-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Frederic_Bell...@capgroup.com
Subject Re: difference between datacache and systemDataCache?
Date Thu, 03 Apr 2008 22:31:16 GMT
Patrick - thanks a lot for the answer - it helps a great deal understand
the design of openjpa.

But - please - could clarify one part:

You said - "OpenJPA has a single DataCache" - this is correct in how the
data cache is coded currently. But reading the source code of the
StoreManager - I can see that OpenJPA understand the concept of multiple
named cache very well. In fact I love the fact that the StoreManager
aggregate all changes at the cache level (based on name) before propagating
them to the datacache manager (it calls getCache(name)). This is fantastic
for me becuase since I am doing a new cache plug in for open jpa I can take
the call by the CacheStore and send one call to the cache and do the work
for the entire collection for a particular cache - This is a far more
efficient approach.

So just to be sure -
Is OpenJPA going to keep the concept of multiple named cache in place at
the StoreManager level at least?
Is what you meant only from the perspective of the datacache layer itslef?
(I Hope it is ;) ).
Why does OpenJPA do not have multiple named cache capability in its
datacache layer?

F



                                                                           
             "Patrick Linskey"                                             
             <plinskey@gmail.c                                             
             om>                                                        To 
                                       dev@openjpa.apache.org              
                                                                        cc 
             04/03/2008 11:42                                              
             AM                                                    Subject 
                                       Re: difference between datacache    
                                       and systemDataCache?                
             Please respond to                                             
             dev@openjpa.apach                                             
                   e.org                                                   
                                                                           
                                                                           
                                                                           




>  What is the exact concept behind the system wide datacache?
>  Is it just a simplified way to get a proxy to all the caches in case
>  someone needs it and does not know which cache exactly they should get?
It
>  seems to just be fullfiling this role.

Yep, that's its job. Since OpenJPA has just a single data cache (vs.
Kodo's multiple named caches), in OpenJPA this is not a proxy.

>  Why does the broker gets a reference to the systemDataCache when it is
>  created?

What code in particular are you asking about?

-Patrick

On Thu, Apr 3, 2008 at 10:29 AM,  <Frederic_Bellier@capgroup.com> wrote:
>
>  What is the exact concept behind the system wide datacache?
>  Is it just a simplified way to get a proxy to all the caches in case
>  someone needs it and does not know which cache exactly they should get?
It
>  seems to just be fullfiling this role.
>
>  Why does the broker gets a reference to the systemDataCache when it is
>  created?
>
>  F
>
>



--
Patrick Linskey
202 669 5907



Mime
View raw message