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gwtweb-workergwt-jackson-apt

GWT-Jackson-APT fails on $wnd.window JSON web-worker code for encoding strings

Finally having gotten GWT-Jackson-APT processors working and properly generating code for my classes, the one remaining hiccup I have is that for some reason gwt-jackson-apt uses the window JSON stringify (& parse) function.

$wnd.window.JSON.stringify(STRING)

The problem is that due to this being on a web-worker, $wnd.window is not defined. Even though JSON.stringify() is available in web-worker, the result is that the code won't run correctly, even though if I modify it to be just JSON.stringify() before uploading it works pefectly.

Is there a clean way to redefine which of these functions gets used in this instance?

What is the best means of going about fixing this so that my web-worker code doesn't try to call the functions that are not available in their context.

Solution

  • The library right now uses the elemental2 version of JSON Global.JSON.stringify

    and if we look at the implementation of the JSON in the Global class we will find that it is assigned to the window instance here :

    @JsType(isNative = true, name = "window", namespace = JsPackage.GLOBAL)
public class Global {
  public static JSONType JSON;
}

    when this is used as Global.JSON.stringify(someJsonObject) from GWT java code when compile it will produce $wnd.window.JSON.stringify(someJsonObject) or something very similar.

    in order to fix this we need to access the native JSON in a different way that does not link it the current window instance.

    one solution to this is to use JsInterop to interface directly with the JSON, something like this 

    @JsType(isNative = true, namespace = JsPackage.GLOBAL)
public class JSON {
    public native static String stringify(Object jsonObj);
}

    with this implementation we can use the JSON without the window prefix and when we use it in java like this JSON.stringify(someJsonObject) and notice how we no longer use the one from Global we end up with a generated Js that looks like this $wnd.JSON.stringify(someJsonObject)

    i run a small test and implemented this JSON in the jackson-apt lib and switched to use the new implementation instead of using Global.JSON and all tests passed.

    to me this looks like a good issue to be reported on the project repository. and i will apply the fix ASAP.