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Re: users, please give us your opinion: what is your take on generics with Wicket
by Martin Funk-3
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Hi Sebastiann,
just for clarifying my understanding of the vocabulary:
A_HomePage extends WebPage
and
B_HomePage extends WebPage<Void>
are both non-generified java classes.
It is just that
A_HomePage extends the raw type of the generic type WebPage<T>
whereas
B_HomePage extends the parameterized type, with type parameter 'Void' of the
generic type WebPage<T>
So if I get it right it is not the generification of the HomePage, that
makes the difference but its weather it is derived of a parameterized type.
Esp. if the signature of 'public abstract Class<? extends Page<?>>
getHomePage();' stays that way the HomePage can't be generified.
Can someone pleas elaborate on this?
mf
2008/6/2 Sebastiaan van Erk <sebster@...>:
> A raw type is a parameterized type in which the type parameters are not
> filled in, i.e., new HashMap() (instead of new HashMap<String, Integer>()).
>
> Just try to return one of your old (non-generified) HomePage.class classes
> (i.e., HomePage extends WebPage instead of HomePage extends WebPage<Void>)
> in your WebApplication's getHomePage() method, and you will see that it does
> not compile.
>
> Regards,
> Sebastiaan
>
>
> Brill Pappin wrote:
>
>> I'm likely missing something here, but why would you want to return
>> something other than a *Page object? Wouldn't that cause some issues with
>> the application?
>>
>> Maybe I don't understand what you mean by "raw type".
>>
>> - Brill Pappin
>>
>> -----Original Message-----
>> From: Sebastiaan van Erk [mailto:sebster@...] Sent: Monday, June
>> 02, 2008 11:53 AM
>> To: users@...
>> Subject: Re: users, please give us your opinion: what is your take on
>> generics with Wicket
>>
>> James Carman wrote:
>>
>>> I'm adding a "Gotchas" section now.
>>>
>>
>> Your pallete gotcha seems more like a JIRA to me. :-) It's not really
>> about
>> generics in general, but about a specific choice in 1 component (which
>> really seems incorrect to me, i.e., PECS).
>>
>> One of the gotcha's I think is the getHomePage() signature...
>>
>> public abstract Class<? extends Page<?>> getHomePage();
>>
>> This breaks raw types (you can't return raw home page).
>>
>> I don't see any way out of this one without making the getHomePage()
>> signature incorrect (i.e., you can't make it a generic method, which was
>> used to solve the problem where a method argument had the type Class<?
>> extends Page<?>>).
>>
>> Regards,
>> Sebastiaan
>>
>>
>>
>>
>> On Mon, Jun 2, 2008 at 11:13 AM, Hoover, William <whoover@...>
>>>
>> wrote:
>>
>>> Sounds like a good idea... Are you going to create it?
>>>>
>>>> -----Original Message-----
>>>> From: jcarman@... [mailto:jcarman@...
>>>> ]
>>>> On Behalf Of James Carman
>>>> Sent: Monday, June 02, 2008 11:06 AM
>>>> To: users@...
>>>> Subject: Re: users, please give us your opinion: what is your take on
>>>> generics with Wicket
>>>>
>>>> Why don't we use the Wiki page to list our *specific* "gotchas" we
>>>> encounter and try to come up with a solution for them. My guess is that we
>>>> can do so.
>>>>
>>>> On Mon, Jun 2, 2008 at 11:03 AM, Hoover, William <whoover@...>
>>>> wrote:
>>>>
>>>>> +1
>>>>> I would like to see what the major issues are as to why people are
>>>>> rejecting model/component generics. None that I have seen so far are that
>>>>> convincing- especially the complaints of verbosity.
>>>>>
>>>>> -----Original Message-----
>>>>> From: jcarman@...
>>>>> [mailto:jcarman@...]
>>>>> On Behalf Of James Carman
>>>>> Sent: Monday, June 02, 2008 10:56 AM
>>>>> To: users@...
>>>>> Subject: Re: users, please give us your opinion: what is your take on
>>>>> generics with Wicket
>>>>>
>>>>> On Mon, Jun 2, 2008 at 10:45 AM, Matej Knopp <matej.knopp@...>
>>>>> wrote:
>>>>>
>>>>>> I'm not sure I like where this discussion is going. I don't see anyone
>>>>>> having any particular objections against current state. I think before we
>>>>>> even think of (partially) reverting generics we have to discuss what's wrong
>>>>>> (except the verbosity of course, but that's not something we can really do
>>>>>> about) with current state. I use wicket with generics daily and I don't see
>>>>>> any particular show stopper so far.
>>>>>>
>>>>>> +1, I agree. I think this discussion might be counter-productive if
>>>>> folks who aren't using the generified versions are voting.
>>>>>
>>>>> --------------------------------------------------------------------
>>>>> - To unsubscribe, e-mail: users-unsubscribe@...
>>>>> For additional commands, e-mail: users-help@...
>>>>>
>>>>>
>>>>>
>>>>> --------------------------------------------------------------------
>>>>> - To unsubscribe, e-mail: users-unsubscribe@...
>>>>> For additional commands, e-mail: users-help@...
>>>>>
>>>>>
>>>>> ---------------------------------------------------------------------
>>>> To unsubscribe, e-mail: users-unsubscribe@...
>>>> For additional commands, e-mail: users-help@...
>>>>
>>>>
>>>>
>>>> ---------------------------------------------------------------------
>>>> To unsubscribe, e-mail: users-unsubscribe@...
>>>> For additional commands, e-mail: users-help@...
>>>>
>>>>
>>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: users-unsubscribe@...
>>> For additional commands, e-mail: users-help@...
>>>
>>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: users-unsubscribe@...
>> For additional commands, e-mail: users-help@...
>>
>>
just for clarifying my understanding of the vocabulary:
A_HomePage extends WebPage
and
B_HomePage extends WebPage<Void>
are both non-generified java classes.
It is just that
A_HomePage extends the raw type of the generic type WebPage<T>
whereas
B_HomePage extends the parameterized type, with type parameter 'Void' of the
generic type WebPage<T>
So if I get it right it is not the generification of the HomePage, that
makes the difference but its weather it is derived of a parameterized type.
Esp. if the signature of 'public abstract Class<? extends Page<?>>
getHomePage();' stays that way the HomePage can't be generified.
Can someone pleas elaborate on this?
mf
2008/6/2 Sebastiaan van Erk <sebster@...>:
> A raw type is a parameterized type in which the type parameters are not
> filled in, i.e., new HashMap() (instead of new HashMap<String, Integer>()).
>
> Just try to return one of your old (non-generified) HomePage.class classes
> (i.e., HomePage extends WebPage instead of HomePage extends WebPage<Void>)
> in your WebApplication's getHomePage() method, and you will see that it does
> not compile.
>
> Regards,
> Sebastiaan
>
>
> Brill Pappin wrote:
>
>> I'm likely missing something here, but why would you want to return
>> something other than a *Page object? Wouldn't that cause some issues with
>> the application?
>>
>> Maybe I don't understand what you mean by "raw type".
>>
>> - Brill Pappin
>>
>> -----Original Message-----
>> From: Sebastiaan van Erk [mailto:sebster@...] Sent: Monday, June
>> 02, 2008 11:53 AM
>> To: users@...
>> Subject: Re: users, please give us your opinion: what is your take on
>> generics with Wicket
>>
>> James Carman wrote:
>>
>>> I'm adding a "Gotchas" section now.
>>>
>>
>> Your pallete gotcha seems more like a JIRA to me. :-) It's not really
>> about
>> generics in general, but about a specific choice in 1 component (which
>> really seems incorrect to me, i.e., PECS).
>>
>> One of the gotcha's I think is the getHomePage() signature...
>>
>> public abstract Class<? extends Page<?>> getHomePage();
>>
>> This breaks raw types (you can't return raw home page).
>>
>> I don't see any way out of this one without making the getHomePage()
>> signature incorrect (i.e., you can't make it a generic method, which was
>> used to solve the problem where a method argument had the type Class<?
>> extends Page<?>>).
>>
>> Regards,
>> Sebastiaan
>>
>>
>>
>>
>> On Mon, Jun 2, 2008 at 11:13 AM, Hoover, William <whoover@...>
>>>
>> wrote:
>>
>>> Sounds like a good idea... Are you going to create it?
>>>>
>>>> -----Original Message-----
>>>> From: jcarman@... [mailto:jcarman@...
>>>> ]
>>>> On Behalf Of James Carman
>>>> Sent: Monday, June 02, 2008 11:06 AM
>>>> To: users@...
>>>> Subject: Re: users, please give us your opinion: what is your take on
>>>> generics with Wicket
>>>>
>>>> Why don't we use the Wiki page to list our *specific* "gotchas" we
>>>> encounter and try to come up with a solution for them. My guess is that we
>>>> can do so.
>>>>
>>>> On Mon, Jun 2, 2008 at 11:03 AM, Hoover, William <whoover@...>
>>>> wrote:
>>>>
>>>>> +1
>>>>> I would like to see what the major issues are as to why people are
>>>>> rejecting model/component generics. None that I have seen so far are that
>>>>> convincing- especially the complaints of verbosity.
>>>>>
>>>>> -----Original Message-----
>>>>> From: jcarman@...
>>>>> [mailto:jcarman@...]
>>>>> On Behalf Of James Carman
>>>>> Sent: Monday, June 02, 2008 10:56 AM
>>>>> To: users@...
>>>>> Subject: Re: users, please give us your opinion: what is your take on
>>>>> generics with Wicket
>>>>>
>>>>> On Mon, Jun 2, 2008 at 10:45 AM, Matej Knopp <matej.knopp@...>
>>>>> wrote:
>>>>>
>>>>>> I'm not sure I like where this discussion is going. I don't see anyone
>>>>>> having any particular objections against current state. I think before we
>>>>>> even think of (partially) reverting generics we have to discuss what's wrong
>>>>>> (except the verbosity of course, but that's not something we can really do
>>>>>> about) with current state. I use wicket with generics daily and I don't see
>>>>>> any particular show stopper so far.
>>>>>>
>>>>>> +1, I agree. I think this discussion might be counter-productive if
>>>>> folks who aren't using the generified versions are voting.
>>>>>
>>>>> --------------------------------------------------------------------
>>>>> - To unsubscribe, e-mail: users-unsubscribe@...
>>>>> For additional commands, e-mail: users-help@...
>>>>>
>>>>>
>>>>>
>>>>> --------------------------------------------------------------------
>>>>> - To unsubscribe, e-mail: users-unsubscribe@...
>>>>> For additional commands, e-mail: users-help@...
>>>>>
>>>>>
>>>>> ---------------------------------------------------------------------
>>>> To unsubscribe, e-mail: users-unsubscribe@...
>>>> For additional commands, e-mail: users-help@...
>>>>
>>>>
>>>>
>>>> ---------------------------------------------------------------------
>>>> To unsubscribe, e-mail: users-unsubscribe@...
>>>> For additional commands, e-mail: users-help@...
>>>>
>>>>
>>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: users-unsubscribe@...
>>> For additional commands, e-mail: users-help@...
>>>
>>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: users-unsubscribe@...
>> For additional commands, e-mail: users-help@...
>>
>>
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