Mailing-List: contact user-help@cayenne.apache.org; run by ezmlm
Precedence: bulk
Reply-To: user@cayenne.apache.org
Received-SPF: pass (athena.apache.org: domain of ari@ish.com.au designates
 59.167.240.32 as permitted sender)
Message-Id: <51C00326-03EC-456D-9CA5-2AB49A9B27D4@ish.com.au>
From: Aristedes Maniatis <ari@ish.com.au>
To: user@cayenne.apache.org
In-Reply-To: <e20494c40902122030k16dc34fdv4b3298e05a19e41e@mail.gmail.com>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
Content-Transfer-Encoding: 7bit
Mime-Version: 1.0 (Apple Message framework v930.3)
Subject: Re: Commits not visible across contexts in ROP
Date: Fri, 13 Feb 2009 16:28:11 +1100
References: <e20494c40902122030k16dc34fdv4b3298e05a19e41e@mail.gmail.com>


On 13/02/2009, at 3:30 PM, Tarik Cherkovi wrote:

> Hi,I just had a strange behavior from ROP and maybe missing  
> something basic.
> I have multiple clients connecting to the same server, and when one  
> of them
> performs a commit, the changes are not visible to the other  
> client(s).  Is
> there a way to make all remote contexts?

You'll need to implement that behaviour yourself. Obviously the  
simplistic approach is to refresh all caches and queries on the remote  
client before you use data where freshness is important.

The problem isn't a trivial one. If you have a bunch of clients on  
different subnets, they can't necessarily pass events directly to each  
other using JMS or something similar. So the server needs to be  
responsible for holding a list of update events which are then passed  
out to clients upon request. You could implement something with  
SnapshotEvents [1] which are passed either directly between clients  
(if they have direct access to each other) or via the server as an  
intermediary. Personally I didn't get much further than identifying a  
couple of libraries such as Apache Mina and Apache ActiveMQ which  
might be useful in such an implementation.

But I am keen on implementing something for our own applications, if  
only we had more time....

Ari


[1] http://cayenne.apache.org/doc/object-caching.html


-------------------------->
ish
http://www.ish.com.au
Level 1, 30 Wilson Street Newtown 2042 Australia
phone +61 2 9550 5001   fax +61 2 9550 4001
GPG fingerprint CBFB 84B4 738D 4E87 5E5C  5EFA EF6A 7D2E 3E49 102A