Are there any patterns described how to use PageReference efficiently?
Žilvinas Vilutis Mobile: (+370) 652 38353 E-mail: cika...@gmail.com On Mon, May 17, 2010 at 9:55 AM, Jeremy Thomerson <jer...@wickettraining.com > wrote: > You should use PageReference (Page#getPageReference()). > > -- > Jeremy Thomerson > http://www.wickettraining.com > > > > On Sun, May 16, 2010 at 11:52 PM, Rik van der Kleij <rikvdkl...@gmail.com > >wrote: > > > Hi Jeremy, > > > > So an instance field inside a page that points to another page is also > > something you should avoid? In our application we using this pattern a > lot > > (for going back to previous page) but it never seems to be any problem. > So > > probably because our pages don't consume a lot of memory. > > > > Regards, > > Rik > > > > On 17 mei 2010, at 06:13, Jeremy Thomerson wrote: > > > > > In general, you should not pass references to components to other > pages. > > > That section on anonymous inner classes is telling you that when you > > create > > > an anonymous inner class and pass it to another page, you > > > will inadvertently be passing a reference to the outer class, which is > > > typically a page. This builds up memory and you will get a OOM. > Passing > > > models between pages is absolutely fine - as long as you're not > > accidentally > > > passing a bunch of other stuff with it (including large domain objects > - > > > which should be detached by using a detachable model). The page linked > > to > > > even says that you will often pass models between pages. > > > > > > -- > > > Jeremy Thomerson > > > http://www.wickettraining.com > > > > > > > > > > > > On Sun, May 16, 2010 at 11:05 PM, Rik van der Kleij < > > rikvdkl...@gmail.com>wrote: > > > > > >> Hi Bernard and Mike, > > >> > > >> According to > > >> > > > https://cwiki.apache.org/WICKET/best-practices-and-gotchas.html#BestPracticesandGotchas-AnonymousInnerclassessharingmodelscould > eventually lead to Out of memory error. > > >> > > >> Holding a page reference in an instance field that points to another > > page > > >> looks the same but it is doesn't seems to be a problem. What's the > > >> difference? > > >> > > >> Regards, > > >> Rik > > >> > > >> > > >> On 16 mei 2010, at 04:39, Michael O'Cleirigh wrote: > > >> > > >>> Hello, > > >>> > > >>> I'm not sure on the answer to your question about the anonymous inner > > >> class but in general sharing models between pages can be a bad idea. > > >>> > > >>> The memory issues comes into play if the IModel is like Model and the > > >> contained object is not transient (it is serialized as part of the > > page). > > >>> > > >>> While Pages are serialized each page is serialized independently so > on > > >> page reload the IModel from the first page is no longer the same > object > > >> instance as the IModel from the second page. At deserialization time > > the > > >> page1.model.getObject().equals page2.model.getObject() but > > >> page1.model.getObject() != page2.model.getObject(); so any changes to > > either > > >> model are not shared between then. > > >>> > > >>> This is not a problem if the model is loadable since the memory of > the > > >> page it is contained in doesn't matter as the value is loaded from the > > >> backend db or some other independent data source like the httpsession, > > or > > >> with wicketApplication. > > >>> > > >>> You can see the same effect if you try and share a model between a > > panel > > >> and a ModelWindow that uses a PageCreator > > >>> > > >>> Hope this helps, > > >>> > > >>> Mike > > >>>> Hi, > > >>>> > > >>>> Can someone explain me why it is a memory issue when an instance of > an > > >> anonymous IModel class is passed to another page to be shared, but it > > seems > > >> to be no problem when a page reference is passed to another page and > is > > put > > >> in an instance field (for example to be used in a button to navigate > > back to > > >> previous page)? > > >>>> > > >>>> Many thanks. > > >>>> > > >>>> Regards, > > >>>> Rik > > >>>> > > >>>> > > >>>> > > >>>> > --------------------------------------------------------------------- > > >>>> To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org > > >>>> For additional commands, e-mail: users-h...@wicket.apache.org > > >>>> > > >>>> > > >>> > > >>> > > >>> --------------------------------------------------------------------- > > >>> To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org > > >>> For additional commands, e-mail: users-h...@wicket.apache.org > > >>> > > >> > > >> > > >> --------------------------------------------------------------------- > > >> To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org > > >> For additional commands, e-mail: users-h...@wicket.apache.org > > >> > > >> > > > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org > > For additional commands, e-mail: users-h...@wicket.apache.org > > > > >
