JSNI: JsArray<JsArrayNumber> type signature

问题

My JavaScript code gives me an array of arrays of float values:

var serverData = new Array();
var fArray = new Array();
// .. calc mx and my here
fArray.push(mx);
fArray.push(my);
this.serverData.push(fArray);

var out = window.letServerWork(this.serverData);

which I want to work with on the server. this.serverData will look something like this:

{ 

0:  0: 1.123
    1: 1.459

1:  0: 0.543
    1: 1.679

2:  0: 1.157
    1: 0.987
}

Therefore I need to know the right signature for this call. This here:

  public static native void exportDoLinearRegression() /*-{ 
        $wnd.letServerWork = $entry(@ew.server.algorithm.LinearRegression::doLinearRegression(Lcom/google/gwt/core/client/JsArray<Lcom/google/gwt/core/client/JsArrayNumber;>;));
  }-*/;

is wrong, but it should look something like this. Does anybody know how the signature has to look like so that this works?

Thank you!

回答1:

It turned out, that it's not necessary to tell about the generic type. The GWT compiler is happy if it knows that there will be a JsArray. The Java function then defines the generic type. This is how it worked for me:

  public static String doLinearRegression(JsArray<JsArrayNumber> points) {

    for(int i = 0; i < points.length(); i++) {
      System.out.println(points.get(i).get(0) + " " +  points.get(i).get(1));
      // do stuff
    }
    return result;
  }

  public static native void exportDoLinearRegression() /*-{ 
        $wnd.letServerWork = $entry(@ew.server.algorithm.LinearRegression::doLinearRegression(Lcom/google/gwt/core/client/JsArray;));
  }-*/;

来源：https://stackoverflow.com/questions/16701465/jsni-jsarrayjsarraynumber-type-signature