Ohh my god yes!!!!

I ran into all these problems in JDOMax, and they are
all solved in Shades.

I won't drop the name, but some very influential
person on EJB and JDO specs now believe that exposing
object identity in the form of API's was a mistake.

I agree -- you will notice shades has no methods to
retrieve an object by identity. Shades only has
queries.

-geoff



--- Igor Vaynberg <[EMAIL PROTECTED]> wrote:

> another interesting problem i find with identity in
> full blown orms is that
> it can cause a nasty cascade of loading object graph
> when using "business"
> identity instead of db identity.
> 
> if you have school->semester->class relationships
> and you do not want to
> depend on db identity which is the "recommended" way
> most likely you will
> have
> 
> class.equals(class other) {
> this.name.equals(other.name
> )&&this.semester.equals(other.semster); }
> semester.equals(semester other) {
> this.code.equals(other.code
> )&&this.school.equals(other.school); }
> 
> so now every time you equals/hashcode a class you
> load the semester and the
> school. given they they are loaded-by-id and might
> be in 2nd level
> cache....but still. this is the kind of troubles you
> always have when
> working on such a highly abstracted level that
> doesnt always map properly to
> the bare metal.
> 
> -Igor
> 
> 
> On 8/26/06, Geoff hendrey <[EMAIL PROTECTED]>
> wrote:
> >
> > Sure - but honestly I don't want to convince
> anyone
> > they need Shades.
> >
> > One problem I found with JDO was that the
> > PersistenceManager was not serializable. Another
> is
> > that detachment had to be handled explicitely.
> >
> > In Shades all pojo's are inherently detached.
> Change
> > tracking is automagic. The DatabaseSession is
> > ultra-leightweight and totally appropriate for
> keeping
> > in a Session.
> >
> > A big innovation in Shades is how identity is
> handled
> > - that really solved a lot of problems for me
> related
> > to change of identity within transactions.
> Identity is
> > a much more fluid concept in Shades, due to the
> > dynamic ORMapping interface, which you can even
> > implement on the fly as an anonynmous inner class.
> >
> > To be clear, I found ways to make JDO work just
> fine
> > with Wicket. Certainly JDO was a huge step forward
> in
> > making it easier to use Pojo-based frameworks like
> > Wicket.
> >
> > I blogged a bit on my motivation for Shades:
> > http://notskateboarding.blogspot.com/
> >
> > -geoff
> >
> >
> >
> > --- Igor Vaynberg <[EMAIL PROTECTED]> wrote:
> >
> > > i glanced over the code - but i dont get it
> after
> > > the first glance. perhaps
> > > you can explain what difficulties you hit when
> using
> > > wicket and an orm to
> > > help us better understand.
> > >
> > > seems to me like you are trying to work with a
> ui
> > > connected to a persistence
> > > layer - without a service layer in between. have
> you
> > > seen databinder which
> > > glues wicket and hibernate together?
> > >
> > > also your point about wicket and tapestry -
> wicket
> > > is much more flexible
> > > because it has IModel which gives you an extra
> layer
> > > of indirection that can
> > > hide a lot of orm logic and make the code
> > > cleaner/easier.
> > >
> > > -Igor
> > >
> > >
> > > On 8/26/06, Geoff hendrey
> <[EMAIL PROTECTED]>
> > > wrote:
> > > >
> > > > Hi All,
> > > >
> > > > I was one of the early users of Wicket before
> 1.0.
> > > I
> > > > did a lot of work to use Wicket with my JDO
> > > > implementation JDOMax (no longer supported).
> In
> > > the
> > > > process I learned a lot about why it is harder
> > > than it
> > > > has to be to use many ORM frameworks with
> Wicket
> > > and
> > > > Tapestry.
> > > >
> > > > I'm a member of JSR 243 Java Data Objects
> Experts
> > > > Group, and I advocated hard within that spec
> for
> > > the
> > > > "fixing" of the JDO spec with regard to
> > > > non-transaction-write behavior, along with
> Eric
> > > Samson
> > > > and others. The JDO group  was receptive,
> having
> > > > gotten similar feedback from Howard Lewis Ship
> of
> > > > Tapestry. I believe this change will benefit
> > > Wicket
> > > > users, and make it much easier to use JDO 2.0
> than
> > > JDO
> > > > 1.1, from Wicket.
> > > >
> > > > However, I still wasn't satisfied that it was
> > > "easy"
> > > > to do ORM from Wicket or Tapestry. So I
> started a
> > > new
> > > > project, based on what I learned -- it's a
> better
> > > way
> > > > to do ORM -- I call it Shades. Following the
> > > wicket
> > > > style,Shades works without any XML
> configuration.
> > > >
> > > > Rather than make this any longer-winded, I
> thought
> > > I
> > > > would just begin passing back some code,
> showing
> > > the
> > > > Library sample application using Shades. The
> > > attached
> > > > zipfile is just the "library" folder from the
> > > wicket
> > > > sample applications. EditBook.java and
> > > > LibrarySession.java have been altered to use
> > > Shades
> > > > for database access. LibraryORMDictionary.java
> is
> > > the
> > > > only new file required.
> > > >
> > > > Please let me know what you think. Also, I do
> not
> > > have
> > > > a website for Shades yet but I hope to find
> the
> > > right
> > > > venue for open sourcing the code soon. (see
> > > attached
> > > > zip file 'library.zippo' with library-example
> > > directory)
> > > >
> > > >
> > >
> >
>
-------------------------------------------------------------------------
> > > > Using Tomcat but need to do more? Need to
> support
> > > web services, security?
> > > > Get stuff done quickly with pre-integrated
> > > technology to make your job
> > > > easier
> > > > Download IBM WebSphere Application Server
> v.1.0.1
> > > based on Apache Geronimo
> > > >
> 
=== message truncated ===>
-------------------------------------------------------------------------
> Using Tomcat but need to do more? Need to support
> web services, security?
> Get stuff done quickly with pre-integrated
> technology to make your job easier
> Download IBM WebSphere Application Server v.1.0.1
> based on Apache Geronimo
>
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642>
_______________________________________________
> Wicket-user mailing list
> Wicket-user@lists.sourceforge.net
>
https://lists.sourceforge.net/lists/listinfo/wicket-user
> 


-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
_______________________________________________
Wicket-user mailing list
Wicket-user@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/wicket-user

Reply via email to