On Feb 4, 5:54 pm, Ryan Heaton <[email protected]> wrote:
> Hi.
>
> Here's my problem. I've got a GWT client-side service method that
> makes a remote call to a server. Since the result of the remote call
> is returned asynchronously, the service method takes a "callback" as a
> parameter. It's basically just an interface with two methods
> "onSuccess" and "onFailure".
>
> So everything works great when invoking the service from GWT code, but
> the problem is exposing this service method to be invokable by a
> separate javascript library. Exposing the service method is possible
> with tools akin to GWT exporter, but the problem is with the callback.
> The "onSuccess" and "onFailure" methods are obfuscated by the compiler
> so I have no reliable way to create a callback object from handwritten
> javascript that will work when that method is invoked.
>
> Here's an example for the sake of clarity. Let's say I've got a
> service interface defined like this:
>
> public interface MyService {
> void getStuff(new MyCallback());
>
> }
>
> And the "MyCallback" interface is defined like this:
>
> public interface MyCallback {
> void onSuccess(Stuff stuff);
>
> }
>
> Let's say I bind the "getStuff" method to a javascript method of the
> same name. I can then invoke the method from javascript, but I have no
> way of reliably constructing an instance of "MyCallback" from
> javascript because I don't know what the "onSuccess" method will be
> named in javascript after is passes through the GWT compiler.
>
> What I'd really like is to be able to define my callback like this:
>
> public interface MyCallback {
> @PreserveMethodName //or some annotation like that.
> void onSuccess(Stuff stuff);
>
> }
>
> And then my javascript would look something like:
>
> var callback = {};
> callback.onSuccess = function(stuff) {...}
> getStuff(callback);
>
> Thoughts? Any suggestions for me?
Something like this maybe (not tested, just an idea):
private static void publishGetStuff(MyService service) /*-{
$wnd.getStuff = $entry(@my.package.Foo::staticGetStuff(Lcom/google/
gwt/core/client/JavaScriptObject;));
}-*/;
private static void staticGetStuff(final JavaScriptObject onSuccessFn)
{
service.getStuff(new MyCallBack() {
public void onSuccess(Stuff stuff) {
nativeOnSuccess(onSuccessFn, stuff);
}
private void native nativeOnSuccess(JavaScriptObject onSuccessFn,
Stuff stuff) /*-{
onSuccessFn(stuff);
}-*/;
}
}
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