On Wed, 2009-03-04 at 10:04 -0500, Brill Pappin wrote: > I actually wasn't saying they were the same. > What I said (meant) was that: > > a) don't lock down
Locking down means *removing* the wildcard. Adding the wildcard *widens* the collection. To be clear: Wildcard --> it fits for everybody No wildcard --> it fits only for some special cases (maybe yours) > b) I prefer the explicit form rather than the "Any of type" form. i.e. > <List<T>> rather than <List<? extends T>>. They mean something completely different. I understand that you prefer the shorter version. Many do. But it stays wrong... If the constructor accepts "List<Number>", everybody *has* to give you exactly a List<Number>. List<Number> n = new List<Number>; If the constructor accepts the widened type, you can add all those lists... List<? extends Number> n = new List<Number>; List<? extends Number> n = new List<Integer>; List<? extends Number> n = new List<Double>; If you don't believe me, take a look at GlazedLists. Compare version 1.7 and version 1.8. They changed exactly that thing (a non backward compatible change!). They made exactly the same fault... Regards, Johannes > > - Brill > > On 4-Mar-09, at 6:26 AM, Johannes Schneider wrote: > > > On Tue, 2009-03-03 at 16:02 -0500, Brill Pappin wrote: > >> I'd hate to be > >> prevented from doing so simply because someone wanted to lock down an > >> API that didn't really need locking down. > > > > You are wrong. *Widening* a collection is the exact opposite of > > "locking > > down". > > If you want to have some fancy (read "hacky") write access to the > > model > > you are free to simply cast... > > That is the right choice here. You know that you have a special > > model in > > there, so cast it. > > > > But the "common" case is, that you don't know for sure whether the > > model > > supports adding of choices or not. > > > > > > If you don't believe me, take a look at JComboBox. > > javax.swing.JComboBox#getModel returns a *read only* view of the > > model. > > > > > > > > Regards, > > > > Johannes > > > > > >> I think the syntax doesn't really mean read only, and if the wicket > >> developers really want it to be read only, wrapping the list would be > >> the way to go. > >> > >> I'm for the plain old <List<T>> because its simple and explicit... > >> <List<? extends T>> would be my next choice because it widens the > >> scope. > >> > >> - Brill > >> > >> On 2-Mar-09, at 3:44 PM, James Carman wrote: > >> > >>> Aren't both the "choices" model in DDC and the actual model of > >>> ListView supposed to be considered read-only (as far as the > >>> component > >>> is concerned)? The DDC and ListView don't need to be able to alter > >>> those models anyway, right? Perhaps my experience is just too > >>> limited, but I don't think I've ever tried to do either one of your > >>> usecases (I always consider them read-only). > >>> > >>> > >>> On Mon, Mar 2, 2009 at 3:24 PM, Igor Vaynberg > >>> <igor.vaynb...@gmail.com> wrote: > >>>> see WICKET-2126 > >>>> > >>>> -igor > >>>> > >>>> On Mon, Mar 2, 2009 at 12:19 PM, James Carman > >>>> <jcar...@carmanconsulting.com> wrote: > >>>>> I vote -0.99 on this (non-binding of course). I'd vote +1 to > >>>>> making > >>>>> ListView accept List<? extends T> rather than making DDC less > >>>>> flexible. > >>>>> > >>>>> On Mon, Mar 2, 2009 at 3:11 PM, Brill Pappin <br...@pappin.ca> > >>>>> wrote: > >>>>>> Ok, as suggested, here is the thread, and the first vote. > >>>>>> > >>>>>> +1 > >>>>>> for making the generic definition the same for all list type > >>>>>> components. > >>>>>> > >>>>>> FYI - you can also "vote" in the issue I just created at (which > >>>>>> might > >>>>>> actually be a better place to vote): > >>>>>> https://issues.apache.org/jira/browse/WICKET-2137 > >>>>>> > >>>>>> - Brill > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>>>> On 28-Feb-09, at 5:18 PM, Jeremy Thomerson wrote: > >>>>>> > >>>>>>> Perhaps start a vote thread, with the subject something like: > >>>>>>> "VOTE: > >>>>>>> Remove > >>>>>>> ? extends from constructor of DropDownChoice". > >>>>>>> > >>>>>>> I'd be +1 non-binding > >>>>>>> > >>>>>>> > >>>>>>> -- > >>>>>>> Jeremy Thomerson > >>>>>>> http://www.wickettraining.com > >>>>>>> > >>>>>>> > >>>>>>> On Sat, Feb 28, 2009 at 3:33 PM, Brill Pappin <br...@pappin.ca> > >>>>>>> wrote: > >>>>>>> > >>>>>>>> I'm of the don't widen it camp anyway :) > >>>>>>>> > >>>>>>>> So how do I go about gathering support for having the > >>>>>>>> DropDownChoice work > >>>>>>>> with the models the way everything else does? > >>>>>>>> > >>>>>>>> - Brill > >>>>>>>> > >>>>>>>> > >>>>>>>> On 28-Feb-09, at 1:42 AM, Igor Vaynberg wrote: > >>>>>>>> > >>>>>>>> yes, the choice was intentional. personally i do not care if it > >>>>>>>> is <T> > >>>>>>>>> > >>>>>>>>> all the way, some users complained so we widened it on the > >>>>>>>>> choices > >>>>>>>>> model, we cannot widen it on the main model. > >>>>>>>>> > >>>>>>>>> -igor > >>>>>>>>> > >>>>>>>>> On Fri, Feb 27, 2009 at 8:51 PM, Brill Pappin > >>>>>>>>> <br...@pappin.ca> wrote: > >>>>>>>>> > >>>>>>>>>> I see... but this would i think because Bar "is a" Foo: > >>>>>>>>>> > >>>>>>>>>> class Bar exends Foo {} > >>>>>>>>>> List<? extends Foo> list = ... > >>>>>>>>>> list.add(new Bar()); > >>>>>>>>>> > >>>>>>>>>> Anyway, what your saying is that the generics choice was > >>>>>>>>>> intentional? > >>>>>>>>>> > >>>>>>>>>> - Brill > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> On 27-Feb-09, at 3:19 PM, Igor Vaynberg wrote: > >>>>>>>>>> > >>>>>>>>>> list<? extends string> stings=... > >>>>>>>>>>> > >>>>>>>>>>> strings.add("asd"); <== wont compile > >>>>>>>>>>> > >>>>>>>>>>> -igor > >>>>>>>>>>> > >>>>>>>>>>> On Fri, Feb 27, 2009 at 11:13 AM, Adriano dos Santos > >>>>>>>>>>> Fernandes > >>>>>>>>>>> <adrian...@gmail.com> wrote: > >>>>>>>>>>> > >>>>>>>>>>>> > >>>>>>>>>>>> What do you mean with "read only" here? > >>>>>>>>>>>> > >>>>>>>>>>>> > >>>>>>>>>>>> Adriano > >>>>>>>>>>>> > >>>>>>>>>>>> > >>>>>>>>>>>> Igor Vaynberg escreveu: > >>>>>>>>>>>> > >>>>>>>>>>>>> > >>>>>>>>>>>>> <? extends Foo> collections are read only, it would be too > >>>>>>>>>>>>> inconvenient to make the model collection read only :) > >>>>>>>>>>>>> > >>>>>>>>>>>>> -igor > >>>>>>>>>>>>> > >>>>>>>>>>>>> On Thu, Feb 26, 2009 at 8:34 PM, Jeremy Thomerson > >>>>>>>>>>>>> <jer...@wickettraining.com> wrote: > >>>>>>>>>>>>> > >>>>>>>>>>>>> > >>>>>>>>>>>>>> This is what I was commenting on last week on the list > >>>>>>>>>>>>>> (or earlier > >>>>>>>>>>>>>> this > >>>>>>>>>>>>>> week). One expects List<? extends Foo> while the other > >>>>>>>>>>>>>> expects > >>>>>>>>>>>>>> List<Foo>. > >>>>>>>>>>>>>> I'm not fully convinced yet that the "? extends" is the > >>>>>>>>>>>>>> better > >>>>>>>>>>>>>> option. > >>>>>>>>>>>>>> Either way, I think they should be the same. > >>>>>>>>>>>>>> > >>>>>>>>>>>>>> -- > >>>>>>>>>>>>>> Jeremy Thomerson > >>>>>>>>>>>>>> http://www.wickettraining.com > >>>>>>>>>>>>>> > >>>>>>>>>>>>>> On Thu, Feb 26, 2009 at 8:27 PM, Brill Pappin <br...@pappin.ca > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>> wrote: > >>>>>>>>>>>>>> > >>>>>>>>>>>>>> > >>>>>>>>>>>>>> > >>>>>>>>>>>>>>> Roughly what I'm doing is: > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> class TypeA{} > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> class TypeAModel extends LoadableDetachableModel< > >>>>>>>>>>>>>>> List<TypeA>> { > >>>>>>>>>>>>>>> public List<TypeA> load(){ > >>>>>>>>>>>>>>> ... do the load ... > >>>>>>>>>>>>>>> return ... > >>>>>>>>>>>>>>> } > >>>>>>>>>>>>>>> } > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> TypeAModel model = new TypeAModel(); > >>>>>>>>>>>>>>> DropDownChoice< TypeA> ddc = new > >>>>>>>>>>>>>>> DropDownChoice<TypeA>("id", model > >>>>>>>>>>>>>>> ); > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> which gets complained about... in this case the generic > >>>>>>>>>>>>>>> def is > >>>>>>>>>>>>>>> DropDownChoice<List<? extends T>> > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> I think the problem is that the generic def of the class > >>>>>>>>>>>>>>> should > >>>>>>>>>>>>>>> actually > >>>>>>>>>>>>>>> be > >>>>>>>>>>>>>>> DropDownChoice<List<T>> because you are already > >>>>>>>>>>>>>>> identifying the > >>>>>>>>>>>>>>> type > >>>>>>>>>>>>>>> when > >>>>>>>>>>>>>>> you create a new instance. > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> Now... my generics are a bit hazy at this level, because > >>>>>>>>>>>>>>> I can > >>>>>>>>>>>>>>> understand > >>>>>>>>>>>>>>> why it was done that way... does anyone with more > >>>>>>>>>>>>>>> generics > >>>>>>>>>>>>>>> experience > >>>>>>>>>>>>>>> know > >>>>>>>>>>>>>>> what it should be? Is this a bug that needs filing? > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> - Brill > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> On 26-Feb-09, at 6:03 PM, Kaspar Fischer wrote: > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> On 26.02.2009, at 22:52, Brill Pappin wrote: > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> For some reason the DropDownChoice component doesn't > >>>>>>>>>>>>>>>> have the > >>>>>>>>>>>>>>>> same > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>>> generics as ListView and it will not accept a model > >>>>>>>>>>>>>>>>> that > >>>>>>>>>>>>>>>>> listview > >>>>>>>>>>>>>>>>> will, > >>>>>>>>>>>>>>>>> despite its saying that it will accept an IModel. > >>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>>> Is anyone else having that sort of trouble with > >>>>>>>>>>>>>>>>> DropDownChoice? > >>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>>> - Brill > >>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> Can you give us more information on what exactly is not > >>>>>>>>>>>>>>>> working > >>>>>>>>>>>>>>>> for > >>>>>>>>>>>>>>>> you? > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> DropDownChoice indeed does accept a model, see for > >>>>>>>>>>>>>>>> instance the > >>>>>>>>>>>>>>>> example > >>>>>>>>>>>>>>>> in > >>>>>>>>>>>>>>>> the class description at > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> http://wicket.apache.org/docs/1.4/org/apache/wicket/markup/html/form/DropDownChoice.html > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> This works for me. > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> Kaspar > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> -- > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> <!-- HTML: --> > >>>>>>>>>>>>>>>> <select wicket:id="site"> > >>>>>>>>>>>>>>>> <option>site 1</option> > >>>>>>>>>>>>>>>> <option>site 2</option> > >>>>>>>>>>>>>>>> </select> > >>>>>>>>>>>>>>>> <ul> > >>>>>>>>>>>>>>>> <li wicket:id="site2"><wicket:container > >>>>>>>>>>>>>>>> wicket:id="sitename"/></li> > >>>>>>>>>>>>>>>> </ul> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> // Code > >>>>>>>>>>>>>>>> List SITES = Arrays.asList(new String[] { > >>>>>>>>>>>>>>>> "The Server Side", "Java Lobby", "Java.Net" > >>>>>>>>>>>>>>>> }); > >>>>>>>>>>>>>>>> form.add(new DropDownChoice("site", SITES)); > >>>>>>>>>>>>>>>> form.add(new ListView("site2", SITES) > >>>>>>>>>>>>>>>> { > >>>>>>>>>>>>>>>> @Override > >>>>>>>>>>>>>>>> protected void populateItem(ListItem item) > >>>>>>>>>>>>>>>> { > >>>>>>>>>>>>>>>> item.add(new Label("sitename", item.getModel())); > >>>>>>>>>>>>>>>> } > >>>>>>>>>>>>>>>> }); > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> --------------------------------------------------------------------- > >>>>>>>>>>>>>>>> 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 > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> > >>>>>>>>>>>>>>> > >>>>>>>>>>>>> ? extends > >>>>>>>>>>>>> > >>>>>>>>>>>>> > >>>>>>>>>>>>> --------------------------------------------------------------------- > >>>>>>>>>>>>> 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 > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>> es, the choice > >>>>>>>>> > >>>>>>>>> --------------------------------------------------------------------- > >>>>>>>>> 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 > > > > > --------------------------------------------------------------------- > 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
