Well, I think that's quite obvious when you consider that each page is the "root" of a "tree" (not directed, acyclic graph) of components. Each component can have at most one parent.
On Tue, May 18, 2010 at 6:54 AM, Rik van der Kleij <rikvdkl...@gmail.com> wrote: > No, that is not what I mention. The point is that the Best practise has to > be: Do not share Wicket components between pages. > > Regards, > Rik > > > On 18 mei 2010, at 12:37, James Carman wrote: > >> It's just a matter of understanding how anonymous inner classes (or >> named inner classes) work. It's not a Wicket thing. It's a Java >> thing. So, if it's confusing, take it up with Oracle. >> >> On Tue, May 18, 2010 at 3:05 AM, Rik van der Kleij <rikvdkl...@gmail.com> >> wrote: >>> To mine opinion this Best practise is confusing. It is just a matter of do >>> not share Wicket components between pages because Wicket will not detect >>> while serializing pages that components are already serialized. >>> >>> The case of sharing anonymous IModel implementations is a special case >>> because implicitly a Wicket component is shared. So you have to be careful >>> with sharing models. >>> >>> Regards, >>> Rik >>> >>> >>> >>> On 17 mei 2010, at 18:55, Jeremy Thomerson 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-AnonymousInnerclassessharingmodels >>>>> could 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 >>>>> >>>>> >>> >>> >>> --------------------------------------------------------------------- >>> 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
