Re: JsInterop: Casting native javascript objects in gwt

You may want to use GWT 2.8.0-SNAPSHOT and the new JsInterop annotations; as your usecase maybe is just not supported with the "old" annotations.

On Monday, October 26, 2015 at 11:10:28 AM UTC+1, Brian Pedersen wrote:

I have a dispatch method, exposed through JsInterop, which can take various kinds of payloads.

Once called from native javascript, I need to cast the payload, but this doesn't quite work as I would like it too.

Here is a simplified example.

GWT:

@JsExport

@JsType

@JsNamespace("foo")

public class Dispatcher {

public String dispatch(String action, Payload payload){

if("action1".equals(action))

return dispatchWithCast(payload);

return "Unknown action: " + action;

}

public String dispatchWithCast(Payload payload){

ConcretePayload w = (ConcretePayload) payload;

return w.foo;

}

}

@JsExport

@JsType

public class Payload {}

@JsExport

@JsType

public class ConcretePayload extends Payload {

public String foo;

public int bar;

}

Javascript:

var test = new foo.Dispatcher();

alert("Dispatch: " + test.dispatch("action1", {"foo": "a", "bar": 2})); // Uncaught java.lang.ClassCastException

Everything works just fine if I replace the Payload type in the Dispatcher class with ConcretePayload, and removes the cast.

I guess this this may be beyond the capabilities of the transpiler, I just need to figure out an alternative approach.

Any ideas?

(By the way, I am using the sso linker.)

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