Rhino Javascript: How to convert Object to a Javascript primitive?

Question

I am utilizing the javax.scripting with Rhino in this project.

I have a Java method that returns a Java Object (Double, Long, Integer, etc). I want to call that method from javascript and reference the result as a Javascript primitive type. However, javacript recognizes the return type as an Object.

How do I force it to convert to a javascript primitive?

This question is very similar to http://groups.google.com/group/mozilla.dev.tech.js-engine.rhino/browse_thread/thread/2f3d43bb49d5288a/dde79e1aa72e1301

The problem with that is how do I get a reference to the context and the WrapFactory?

Sample Code:

public class data 
{ 
   Double value = 1.0d; 
   public Number get()  {  return value; } 
} 


  public static void main(String[] args) 
    { 
            ScriptEngine engine = new ScriptEngineManager().getEngineByName ("rhino"); 
            data data = new data(); 
            try 
            { 
                    engine.eval("function test(data) { return data.getD('value1') + 5;};"); 
                    System.out.println("Result:" + ((Invocable)engine).invokeFunction("test", data)); 
            } 
            catch (Exception e) 
            { 
                    e.printStackTrace(); 
            } 
    } 

Output: Result: 15

Answer 1

Try the following

 public static void main(String [] args) throws Exception {
        ScriptEngine engine = new ScriptEngineManager().getEngineByName ("rhino"); 
        data data = new data();
        Context.enter().getWrapFactory().setJavaPrimitiveWrap(false);

        try 
        { 
                engine.eval("function test(data) { return data.get('value1') + 5;};"); 
                System.out.println("Result:" + ((Invocable)engine).invokeFunction("test", data)); 
        } 
        catch (Exception e) 
        { 
                e.printStackTrace(); 
        } 
    }

    public static class data 
    { 
       Double value = 1.0d; 
       public Number get(String arg)  {  return value; } 
    } 

---

Alternatively, you could modify the javascript function to explicitly cast the value to a number:

function test(data) { return parseInt(data.get('value1'), 10) + 5;}