Re: Newby question about Cayenne, threads and EOF comparison

From: Eric Schneider (eri..entralparksoftware.com)
Date: Fri Apr 02 2004 - 11:31:30 EST

  • Next message: Mike Kienenberger: "Re: Newby question about Cayenne, threads and EOF comparison"

    Alexander,

    > > 2. Simply Tomcat + Tapestry + Cayenne? But then how about load
    > > balancing?

    Load balancing a something that is outside of the problem domain of Cayenne.
    Usually there are three approaches:

    1) Write stateless applications

    This is a bit brute force, but will keep you out of trouble. Based on query
    string parameters, cookies, etc. any application instance can handle any
    request. The major drawback is this takes away some of the thunder of
    Tapestry.

    2) Use a sticky web server configuration

    Once a new client makes a request to an application, the web server routes
    each additional request to the same application server instance. You'll
    need to refer to web server documentation on how to accomplish this.

    3) Override the engine implementations in Tapestry

    This is probably the most difficult, but a cute alternative. The base
    engine implementation in Tapestry serializes session information and holds
    it in memory. You can override this behavior and make your custom engine
    class commit serialized session data to the database. On additional
    requests, reinflated the session from the database. This approach allows
    any app server instance to handle any request. Keep in mind the database is
    only one alternative....you can store the session LDAP, file system, or
    whatever.

    Cheers,
    eric.

    ----- Original Message -----
    From: "Jim Menard" <jim..o.com>
    To: "Alexander Lamb" <Alexander.J.Lam..im.hcuge.ch>
    Cc: <cayenne-use..bjectstyle.org>
    Sent: Friday, April 02, 2004 11:12 AM
    Subject: Re: Newby question about Cayenne, threads and EOF comparison

    > Alexander,
    >
    > This is just one data point for you.
    >
    > On Apr 2, 2004, at 10:22 AM, Alexander Lamb wrote:
    >
    > > I am considering swiching to Cayenne for a small project after having
    > > several years of EOF (Objective-C + Java) and WebObjects experience.
    > [snip]
    >
    > > Now, for the view side, two questions:
    > >
    > > 1. Tapestry? or JSF (Java Server Faces)? in order to get back the
    > > component oriented design of WebObjects?
    >
    > Tapestry. I just finished a Tapestry/Cayenne project, and it was a
    > pleasure. I haven't used JSF.
    >
    > > Now for deployment, imagin I am comming from WebObjects, what would be
    > > the closest and most appropriate for a web app:
    > >
    > > 1. JBoss, as an EJB ? or without EJB?
    > > 2. Simply Tomcat + Tapestry + Cayenne? But then how about load
    > > balancing?
    >
    > I used Tomcat, but load balancing is not yet an issue for the app.
    >
    > Deployment was a breeze. One minor caveat: the Cayenne and Tapestry jar
    > files had to go in WEB-INF/lib instead of in $TOMCAT_HOME/shared/lib.
    > For some reason, somebody's class loader somewhere (Tomcat, Cayenne, or
    > Tapestry; I forgot which) couldn't handle the jar files being in the
    > shared library directory.
    >
    > Jim
    > --
    > Jim Menard, jim..o.com, http://www.io.com/~jimm/
    > "The world is divided into one group: those who start counting at 0,
    > and those who don't." -- Unknown



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