anti-pattern?
why it makes testing much harder?
I use singleton for my own connection pooling and cache and cluster system.
All works very fine!
2009/10/13 Olle Hallin <olle.hal...@hit.se>
> Singletons is an anti-pattern that the Java community abandoned years ago!
> The main reason is that it makes testing much harder.
>
> Besides, your example is wrong. The constructor must be private, or else
> the
> singleton is broken.
>
> Olle Hallin
> Senior Java Developer and Architect
> olle.hal...@crisp.se
> www.crisp.se
>
>
>
>
> 2009/10/13 Argo Vilberg <wilps...@gmail.com>
>
> > very simple solution is creata Singleton java class.
> >
> >
> > public class MallBean{
> > public final static MallBean INSTANCE = new MallBean();
> >
> > public MallBean() {
> > }
> >
> > ....
> >
> > }
> >
> >
> > And access
> >
> > MallBean.INSTANCE.getSomething.
> >
> >
> > And if you first time calling this, class is created and only ONE this
> type
> > of class can be created.
> > And this class is accessible everyone.
> >
> >
> > Enjoy!
> >
> > Argo
> >
> >
> > 2009/10/13 TomMax <tryk...@poczta.onet.pl>
> >
> > >
> > > Hi all,
> > >
> > > I'm working in a developers team with Tapestry applications (version
> > 4.0.2)
> > > for more than 2 years. Our Tapestry applications works on various
> > > Application Servers (JBoss, SAP Netweaver), and usually we were able in
> > our
> > > team to resolve all problems, recently however, we spotted a problem
> with
> > > Application State Object, which is responsible for user session data
> and
> > we
> > > can't find the bug.
> > >
> > > The problem is that two users see sometimes the same data on a page. In
> > our
> > > scenario User1 and User2 have their own userSession objects (they are
> ASO
> > > object with session scope), these objects keep all their data, and
> these
> > > objects are injected to every page in .page file:
> > >
> > > <inject property="userSession" object="userSession" type="state" />
> > >
> > > Every user has own userSession object, so every user should see only
> his
> > > own
> > > data on a page, but sometimes (quite rarely), we got the situation,
> that
> > > User2 sees the data from User1 userSession object when he get the page,
> > > where User1 was earlier.
> > > So far I know, in case of ASO objects, the references in a page to
> these
> > > objects, should be set to null on pageDetach action. So each time when
> > the
> > > user is receiving the page from PagePool (or newly created page), he
> > should
> > > obtain also fresh ASO object from ApplicationStateManager.
> > > We have got currently this problem not so often (usually it is one or
> two
> > > times in a two week period, in case when the application is used by 3-4
> > > persons 8 hours per day), and when the problem happens, usually all
> > working
> > > users are receiving wrong data (they see the data from other users).
> > >
> > > I hope someone will be able to help me.
> > >
> > > Thanks
> > > Tomek
> > >
> > >
> > > --
> > > View this message in context:
> > >
> >
> http://www.nabble.com/-T4--Two-users-see-the-same-data---problem-with-ASO-objects-tp25872478p25872478.html
> > > Sent from the Tapestry - User mailing list archive at Nabble.com.
> > >
> > >
> > > ---------------------------------------------------------------------
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> > > For additional commands, e-mail: users-h...@tapestry.apache.org
> > >
> > >
> >
>
