How to access objects/arrays defined in JavaScript from Java applets.

Question

Using LiveConnect getMember(String) method of a window JSObject, a Java object of type "Object" is returned but I don't find the expected members defined on it. Neither can I cast it to a JSObject to continue using the getMember().

Accessing DOM nodes and elements (DOM Objects) works as expected.

Answer 1

@Michael Borgwardt

This is what I'm trying to do.

Global JavaScript Object.

foo = {"one":1, "two":2};

Processing code.

import netscape.javascript.*;
JSObject win;
JSObject got1;
Object   got2;

void setup(){
  size(400,200,P2D);
  background(255);
  win  = JSObject.getWindow(this); //gets the root JSObject
  //got1 = win.getMember("obj"); //fails to cast from Object to JSObject
  got2 = win.getMember("obj"); //works in the sense that I get an Object.
}

void draw(){
  if (mousePressed == true){
    println(got2.getMember("one")); //fails, there is no getMember() method.
  }
}

This is perhaps not Processing specific. That's why I didn't originally post the code.

Answer 2

I'm confused by the line got2 = win.getMember("obj");. It seems like you're expecting that line to get the foo object. As I understand it, win.getMember("obj") will get you the obj property on the DOM window node, which doesn't exist. For example, from this page:

JSObject win = JSObject.getWindow(this);
JSObject doc = (JSObject) win.getMember("document");
JSObject loc = (JSObject) doc.getMember("location");

If you want to get the foo object, the best way I'm aware of is to make a JavaScript method you can call from the Java applet.

JavaScript:

<script type="text/javascript">
var foo = {"one":1, "two":2};

function getFoo() { return foo; }
</script>

Applet:

import netscape.javascript.*;
JSObject win;
JSObject foo;

void setup(){
  size(400,200,P2D);
  background(255);
  win  = JSObject.getWindow(this); //gets the root JSObject
  foo = (JSObject)win.call("getFoo", null);
}

void draw(){
  if (mousePressed == true){
    println(foo.getMember("one"));
  }
}