I've added an example with
https://github.com/apache/wicket/commit/2417322673238d57a794c237e84dd5dacf890804

I think we should explain that those are just convenience. It is better to
use the "old way" one cares about memory usage. I'll add it soon.

Martin Grigorov
Wicket Training and Consulting
https://twitter.com/mtgrigorov

On Fri, Apr 1, 2016 at 2:48 PM, Tobias Soloschenko <
tobiassolosche...@googlemail.com> wrote:

> Hi,
>
> would be great to see some information how to use lambda models in the
> user guide.
>
> kind regards
>
> Tobias
>
> > Am 01.04.2016 um 13:57 schrieb Martin Grigorov <mgrigo...@apache.org>:
> >
> >> On Fri, Apr 1, 2016 at 12:45 AM, Sven Meier <s...@meiers.net> wrote:
> >>
> >> Hi,
> >>
> >> yeah, of course this is right:
> >>
> >>    protected void onComponentTag(final ComponentTag tag) {
> >>
> >>        if (getModelObject().doubleValue() < 0.0) {
> >>            tag.put("class", " negative");
> >>        }
> >>    }
> >>
> >> Otherwise you'll end up with one additional behavior for each render -
> >> stupid copy-paste error :/.
> >>
> >> BTW this might be an additional candidate for the new Wicket 8 lambdas:
> >>
> >>    label.add(onTag(tag -> if (getModelObject().doubleValue() < 0.0)
> >> tag.put("class", "negative") ));
> >
> > +1
> >
>
> +1
>
> >
> >>
> >> Sven
> >>
> >>
> >>
> >>> On 31.03.2016 21:16, Martin Grigorov wrote:
> >>>
> >>> Hi,
> >>>
> >>> On Thu, Mar 31, 2016 at 4:29 PM, Sven Meier <s...@meiers.net> wrote:
> >>>
> >>> Hi,
> >>>>
> >>>> you can access a component's model with #getDefaultModel() or - if it
> is
> >>>> a
> >>>> generic component - with #getModel().
> >>>>
> >>>> To properly 'bind' to a model you should delay invocation of
> #getObject()
> >>>> as late as possible, so better overwrite #onComponentTag():
> >>>>
> >>>>     protected void onComponentTag(final ComponentTag tag) {
> >>>>
> >>>>         if (getModelObject().doubleValue() < 0.0) {
> >>>>             add(new AttributeAppender("class", " negative"));
> >>>>
> >>>> Since you are in #onComponentTag() there is no reason to add a
> Behavior.
> >>> Just use the tag: tag.append("class", "negative", " ");
> >>>
> >>>
> >>>         }
> >>>>     }
> >>>>
> >>>>
> >>>> Have fun
> >>>> Sven
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> On 31.03.2016 16:06, Ron Smits wrote:
> >>>>
> >>>> I have searched but I dont find a clear way of getting the model when
> one
> >>>>> is creating a custom component:
> >>>>>
> >>>>>
> >>>>> public MoneyLabel(String id) {
> >>>>>      super(id);
> >>>>>      add(new AttributeAppender("class", " number"));
> >>>>> }
> >>>>>
> >>>>> It sounds like you always need the model.
> >>> If there is a CompoundPropertyModel in the parents' hierarchy then move
> >>> your logic to #onComponentTag(), as per Sven's suggestion.
> >>> If there is no CPM in the parents then just remove this constructor.
> >>>
> >>>
> >>> public MoneyLabel(String id, Model<? extends BigDecimal>
> bigDecimalModel)
> >>>>> {
> >>>>>      super(id, bigDecimalModel);
> >>>>>      add(new AttributeAppender("class", " number"));
> >>>>>      if (bigDecimalModel.getObject().doubleValue() < 0.0) {
> >>>>>          add(new AttributeAppender("class", " negative"));
> >>>>>      }
> >>>>> }
> >>>>>
> >>>>> In the second constructor I can use the supplied model to determine
> to
> >>>>> add
> >>>>> the negative class. However in the first constructor I cannot find a
> way
> >>>>> to
> >>>>> access the model.
> >>>>>
> >>>>> What am I missing?
> >>>>>
> >>>>> Ron
> >>>>> ‚Äč
> >>>>>
> >>>>>
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> >>
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