Re: Call a service, but still with one DataContext

From: Kevin Menard (nirvdru..mail.com)
Date: Mon Aug 11 2008 - 20:40:37 EDT

  • Next message: Chris Murphy: "Re: Call a service, but still with one DataContext"

    Hi Chris,
    I'm not really sure I understand your question. I think you're slightly
    confused by our nomenclature. Cayenne server really is just a plain Java
    package. The server part comes from a three-tier role, where we have a
    separate client package. In this case, you'd run some sort of WS server to
    handle the client requests. Otherwise, you can use the "server" package in
    any app.

    Viewed that way, you're best bet is probably to use the servlet filter and
    bind your DataContext to the user session. This should ensure that you only
    have one DC per user. From there, you just need to apply basic principles
    for using a single DC. In particular, don't get messy with uncommitted
    state. 

    -- 
Kevin

    On Sun, Aug 10, 2008 at 9:24 PM, Chris Murphy <chri..trandz.org> wrote:

    > Hi Group,
>
> I am trying to get my head round how Cayenne would work with Spring
> services. The great advantage of Cayenne is that it is designed for exposing
> the domain model. But applications will still always have functions best
> performed as a service. Having two DataContexts leads to confusion. So is
> the solution is to have Tomcat embedded in Cayenne's server-side software?
> The requirement is to have no more than one DataContext per user on the
> server. (There will be a proxy-DataContext on each client to enable domain
> exposure). I'm trying to get my head around achieving "one DataContext".
>
> Would this embedded instance of Tomcat conflict with the server machine's
> already running Tomcat instance?
>
> I haven't yet looked at how Cayenne's server-side software is invoked. Can
> it only be sparked off as a servlet? Or can a program I write be sparked off
> say from the command line - in which case it could create a DataContext that
> is handed as a global to an embedded instance of Tomcat and thereby somehow
> made easily available to Spring services that the client apps will call back
> to?
>
> thanks - Chris
>
> --
> Seaweed Software Pty Ltd,
> http://www.strandz.org
>
>

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