Bulat, can you direct me to any documentation anywhere which explains
the use of the <?> and <I> constructs?
Thanks,
J
On Sep 21, 4:03 am, Bulat Sirazetdinov <bula...@gmail.com> wrote:
> You should do it this way:
> At first you'll need to create a class that implements
> HasValueChangeHandlers interface. It is because of the fact that
> ValueChangeEvent.fire() method requires a class that implements
> HasValueChangeHandlers interface passed in a first parameter.
> So let name that class MyHandlers (see below).
>
> Then you should get an instance of MyHandlers class:
> -----------------------
> MyHandlers<String> exampleHandlers = new Handlers<String>();
> -----------------------
>
> and register ValueChangeHandler objects in that instance:
> -----------------------
> exampleHandlers.addValueChangeHandler(someHandler1);
> exampleHandlers.addValueChangeHandler(someHandler2);
> exampleHandlers.addValueChangeHandler(someHandler3);
> -----------------------
>
> Now you can fire ValueChangeEvent to all handlers that you've
> registered in exampleHandlers object:
> -----------------------
> ValueChangeEvent.fire(exampleHandlers, "text");
> -----------------------
>
> MyHandlers class declaration:
> -------------------------------------
> public class MyHandlers<I> implements HasValueChangeHandlers<I> {
>
> private final List<ValueChangeHandler<I>> list = new
> ArrayList<ValueChangeHandler<I>>();
>
> public void fireEvent(GwtEvent<?> event) {
> if (event instanceof ValueChangeEvent) {
> for (ValueChangeHandler<I> handler : list) {
> handler.onValueChange((ValueChangeEvent<I>) event);
> }
> }
> }
>
> public HandlerRegistration addValueChangeHandler(final
> ValueChangeHandler<I> handler) {
> list.add(handler);
> return new HandlerRegistration() {
>
> public void removeHandler() {
> list.remove(handler);
> }
> };
> }}
>
> -------------------------------------
>
> Hope that helps.
> Best wishes!
>
> On Aug 20, 4:33 am, jscheller <jschel...@csoftware.com> wrote:
>
> > Hello -
>
> > So, I've got a composite that has something like this inside it...
>
> > private HandlerManager changeHandlers = new HandlerManager( null );
>
> > public HandlerRegistration addValueChangeHandler(ValueChangeHandler
> > handler)
> > { return changeHandlers.addHandler(ValueChangeEvent.getType(),
> > handler); }
>
> > ...and somewhere down the pipeline, I want to actually fire off an
> > event to anyone who registered a handler when the composite decides
> > it's represented value has changed and wants the rest of the world to
> > know. However, the syntax for actually constructing and firing the
> > event off has got me pulling my hair out.
>
> > I've tried variants of sending the event through the change
> > handlers...
>
> > changeHandlers.fireEvent( new ValueChangeEvent("foo") );
> > changeHandlers.fireEvent( new ValueChangeEvent<String>("foo") );
>
> > ...and using the static fire() method in the event class itself...
>
> > ValueChangeEvent<String>.fire( changeHandlers, "foo");
>
> > ...and Eclipse complains loudly about all of these constructions. I
> > mean, I know this can't be that hard, but I can't find any good
> > examples of things like this using the new (GWT 1.6 or later) event
> > handlers, and reading the code sends me down a DOM event/Java generics
> > rabbit hole that I'm frankly not experienced enough to deal with
> > yet...
>
> > Any help appreciated!
>
> > Jim
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