On Mon, 29 Sep 2008, Michael Sparer wrote:
> possible yes, recommended, no i'd say :-)
>
> if you need specific values from MyPanel then pass it via constructor, if
> you need values/attributes on component (e.g. isVisible) level use
> getParent()
I think that getParent() is generally a bad idea, because it
adds too much coupling and makes testing difficult.
Whenever you can simply pass dependencies in a constructor,
or set them from the parent after construction, that's
probably the best way. You can even make the object
references updateable by passing and storing a model
wrapping the object instead of the object itself.
The visitor-based event mechanisms discussed in WICKET-1312
could be used to some extent, or you can use the visitors
for pull-style stuff as well as my colleague did recently
public interface SelectedUserSource {
IModel<User> selectedUser();
}
public class UserProfile extends Panel implements SelectedUserSource {...
and in calling component
private IModel<User> findSelectedUser() {
return (IModel<User>) getPage().visitChildren(SelectedUserSource.class,
new IVisitor() {
public Object component(Component component) {
return ((SelectedUserSource) component).selectedUser();
}
}):
}
Having the dependent class as an inner class of the dependee
makes sense in trivial cases but is often just a more explicit
way of doing getParent(). I think that we desperately need to
find ways to make our UI (Wicket) code good object-oriented
code. I for one find myself often putting way too much stuff
and coupling in a component class.
Best wishes,
Timo
--
Timo Rantalaiho
Reaktor Innovations Oy <URL: http://www.ri.fi/ >
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
