[jsr-314-open-mirror] [jsr-314-open] composite components: targets attribute revisited

[Leonardo Uribe]

Hi

To be more explicit, this is the example that should fail:

<ez:loginPanel id="loginPanel" model="#{bean}">
       <f:actionListener for="loginEvent"
                         binding="#{bean.loginEventListener}" />
       <f:actionListener for="loginEvent"
                         binding="#{bean.loginEventListener2}" />
       <f:actionListener for="cancelEvent"
                         binding="#{bean.cancelEventListener}" />
     </ez:loginPanel>

     <composite:interface name="loginPanel">
       <composite:actionSource name="loginEvent" />
       <composite:actionSource name="cancelEvent" />
     </composite:interface>
     <composite:implementation>
                 <h:commandButton name="button1">
                        <f:actionListener
binding="#{cc.actionSource.loginEvent}"/>
                 </h:commandButton>
                 <x:mycompositecomponent name="button2">
                        <f:actionListener
binding="#{cc.actionSource.cancelEvent}" for="someOtherEvent"/>
                 </x:mycompositecomponent>
     </composite:implementation>

In this case, the binding #{cc.actionSource.loginEvent} does not point to
just
one actionListener.

regards,

Leonardo


2010/10/28 Jakob Korherr <jakob.korherr at gmail.com>

> Hi,
>
> In option 2 the f:actionListener is just used as a reference to the
> cc:actionSource (just as in option 1 but without introducing a new
> composite-tag).
>
> Thus it would actually be possible to have multiple ones!
>
> Regards,
> Jakob
>
> 2010/10/28 Leonardo Uribe <lu4242 at gmail.com>:
> > Hi
> >
> > 2010/10/28 Jakob Korherr <jakob.korherr at gmail.com>
> >>
> >> Hi,
> >>
> >> Currently there are a lot of discussions (on spec-issues, on this list
> >> and also internally) about the problems with the targets attribute in
> >> the composite component interface and I'd like to wrap these up here.
> >>
> >> IMHO the targets attribute is something we should get rid of, because
> >> it directly points to the implementation section and frankly somehow
> >> feels like the following piece of code:
> >>
> >> if (this instanceof Foo)
> >> {
> >>    // do something
> >> }
> >>
> >> The interface section should just specify the interface for the
> >> composite component and should not include any information about the
> >> implementation section. However, the implementation section should of
> >> course refer to the interface section. Unfortunately the targets
> >> attribute works against this. And furthermore the targets attribute
> >> also confuses users, because the don't really know which clientid to
> >> use (especially with nested components in the implementation section).
> >>
> >> The first step needed here is to put all attributes (also the
> >> "well-known" ones like action, actionListener, valueChangeListener) on
> >> the composite component attribute map in order to access them via
> >> #{cc.attrs.attributeName}. In this way the user can refer from the
> >> implementation section to the related attribute in the interface
> >> section, regardless of what it does. This was already discussed and is
> >> also already accepted, I guess.
> >>
> >> The next step is to remove the targets attribute from cc:actionSource,
> >> cc:editableValueHolder and cc:valueHolder. Here we have two options:
> >>
> >> 1) add new composite tags that insert the related listeners in the
> >> implementation section (proposed by Leonardo):
> >>
> >>     <ez:loginPanel id="loginPanel" model="#{bean}">
> >>        <f:actionListener for="loginEvent"
> >>                          binding="#{bean.loginEventListener}" />
> >>        <f:actionListener for="cancelEvent"
> >>                          binding="#{bean.cancelEventListener}" />
> >>      </ez:loginPanel>
> >>
> >>      <composite:interface name="loginPanel">
> >>        <composite:actionSource name="loginEvent" />
> >>        <composite:actionSource name="cancelEvent" />
> >>      </composite:interface>
> >>      <composite:implementation>
> >>                  <h:commandButton name="button1">
> >>                         <composite:insertActionSource
> name="loginEvent"/>
> >>                  </h:commandButton>
> >>                  <x:mycompositecomponent name="button2">
> >>                         <composite:insertActionSource
> >> name="cancelEvent" for="someOtherEvent"/>
> >>                  </x:mycompositecomponent>
> >>      </composite:implementation>
> >>
> >>
> >> 2) use the existing tags like f:actionListener and
> >> f:valueChangeListener and provide the actionSource,.. via
> >> ValueExpression:
> >>
> >> <ez:loginPanel id="loginPanel" model="#{bean}">
> >>        <f:actionListener for="loginEvent"
> >>                          binding="#{bean.loginEventListener}" />
> >>        <f:actionListener for="cancelEvent"
> >>                          binding="#{bean.cancelEventListener}" />
> >>      </ez:loginPanel>
> >>
> >>      <composite:interface name="loginPanel">
> >>        <composite:actionSource name="loginEvent" />
> >>        <composite:actionSource name="cancelEvent" />
> >>      </composite:interface>
> >>      <composite:implementation>
> >>                  <h:commandButton name="button1">
> >>                         <f:actionListener
> >> binding="#{cc.actionSource.loginEvent}"/>
> >>                  </h:commandButton>
> >>                  <x:mycompositecomponent name="button2">
> >>                         <f:actionListener
> >> binding="#{cc.actionSource.cancelEvent}" for="someOtherEvent"/>
> >>                  </x:mycompositecomponent>
> >>      </composite:implementation>
> >>
> >>
> >> Frankly I'd prefer option 2, because it is very similar to how we
> >> handle cc:attribute --> #{cc.attrs.xxx}.
> >>
> >>
> >> One remaining problem here, however, is how to handle non-required
> >> method-attributes (there's a thread about this on the
> >> myfaces-user-list). IMO the default attribute of cc:attribute should
> >> be able to resolve to a MethodExpression and not only to a String (I
> >> think this is already a spec-issue), but it should also work without
> >> providing a default value. In that case #{cc.attrs.thatAttribute}
> >> should internally return an empty action/listener/... so that there
> >> are no problems with the related implementation-components which refer
> >> to this attribute.
> >>
> >> What do you think?
> >>
> >
> > Well, unfortunately use option 2 forces to use just one f:actionListener
> per
> > actionSource, and in theory, it should be possible to have multiple ones.
> >
> > best regards,
> >
> > Leonardo Uribe
> >
> >>
> >> Regards,
> >> Jakob
> >>
> >> --
> >> Jakob Korherr
> >>
> >> blog: http://www.jakobk.com
> >> twitter: http://twitter.com/jakobkorherr
> >> work: http://www.irian.at
> >
> >
>
>
>
> --
> Jakob Korherr
>
> blog: http://www.jakobk.com
> twitter: http://twitter.com/jakobkorherr
> work: http://www.irian.at
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.jboss.org/pipermail/jsr-314-open-mirror/attachments/20101028/63477a50/attachment.html