What about calling APanel.setDefaultModelObject(B.getObject()) instead
of APanel.setDefaultModel(B)?
On Thu, Sep 27, 2012 at 5:39 AM, Michael Mosmann <mich...@mosmann.de> wrote:
> Am 27.09.2012 09:51, schrieb Martin Grigorov:
>
> Hi,
>
> a dont care about the type issue here.. Maybe i can explain it again in an
> other way:
>
> APanel uses model instance A and the label uses a property model instance P
> which uses a reference to model instance A.
>
> After calling APanel.setDefaultModel(B) APanel uses model instance B,but
> label uses model instance P which uses model instance A as before. So the
> label does not see any changes, because no one tells the model instance P,
> that it should use B instead of A. I think, there are rare cases for such a
> usage.
>
> thanks
> Michael
>
>
>> Hi,
>>
>> In this particular code I think the "problem" is PropertyModel, since
>> it brings the type unsafety.
>>
>> Another solution is to make Component<T>, this way we can remove
>> #setDefaultModel() and have #setModel(IModel<T>) only and such
>> problems will go away.
>> But as discussed in early Wicket 1.4 days this will lead to more
>> typing. With Java 7 diamonds it is half the typing though.
>>
>> For now you can use GenericPanel, GenericPage and all FormComponent.
>>
>> On Thu, Sep 27, 2012 at 10:41 AM, Michael Mosmann <mich...@mosmann.de>
>> wrote:
>>>
>>> Am 27.09.2012 09:01, schrieb Martin Grigorov:
>>> Hi,
>>>
>>> I think, there is a little difference in using setDefaultModel and
>>> setDefaultModelObject .. the first one sets a new model instance, the
>>> second
>>> only change the value in the existing model. Some pseudo-code:
>>>
>>> class APanel extends Panel {
>>> APanel(String id,IModel<Some> model) {
>>> super(id,model);
>>>
>>> add(new Label("name",new
>>> PropertyModel(getDefaultModel(),"name"));
>>> }
>>> }
>>>
>>> If you replace the value in model, everything is fine and works as
>>> expected.
>>> If you call setDefaultModel you might think, that everything is fine, but
>>> its not. A child component does not use getParent().getDefaultModel() to
>>> get
>>> these changes. I saw a lot of code like this, which leads to trouble, if
>>> you
>>> change the model and not the value.
>>>
>>> If there is no benefit in using setDefaultModel over
>>> setDefaultModelObject i
>>> would like to remove this method. This could prevent many "you might not
>>> got
>>> the full picture how to use wicket the right way" errors.
>>>
>>> Michael
>>>
>>>
>>>> Hi,
>>>>
>>>> Most of the time it is recommended to use a dynamic model, so there is
>>>> no reason to replace the component's model.
>>>> Component#setDefaultModel() gives you semi-dynamic nature - you can
>>>> replace the model completely with a new one. Same with
>>>> #setDefaultModelObject().
>>>>
>>>> What is the problem you face with it ?
>>>>
>>>> On Thu, Sep 27, 2012 at 9:57 AM, Michael Mosmann <mich...@mosmann.de>
>>>> wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>> is there any usefull application of Component.setDefaultModel(...)?
>>>>> IMHO
>>>>> this Method is the cause for much trouble without any benefit. But
>>>>> maybe
>>>>> i
>>>>> did not understand when someone should replace a component model...
>>>>>
>>>>> thanks
>>>>> Michael
>>>>
>>>>
>>>>
>>
>>
>
