Rhino: How to call JS function from Java

Question

I'm using Mozilla Rhino 1.7r2 (not the JDK version), and I want to call a JS function from Java.

My JS function is like this:

function abc(x,y)
{
  return x+y
}

How do I do this?

Edit: (The JS function is in a separate file)

Gerard

mozilla.org/rhino/tutorial.html#callingJSfuns – Helsinki

@org That example is not very clear to me. Where do I specify the path of the JS file? I guess it assumes that I'd just type the entire JS code in cmdline and pass it as an arg to my java app! ^^" – Gerard

Answer 1

String script = "function abc(x,y) {return x+y;}";
Context context = Context.enter();
try {
    ScriptableObject scope = context.initStandardObjects();
    Scriptable that = context.newObject(scope);
    Function fct = context.compileFunction(scope, script, "script", 1, null);
    Object result = fct.call(
            context, scope, that, new Object[] {2, 3});
    System.out.println(Context.jsToJava(result, int.class));
} finally {
    Context.exit();
}

UPDATE: when the function is loaded in the scope, along with other functions and variables

String script = "function abc(x,y) {return x+y;}"
        + "function def(u,v) {return u-v;}";
Context context = Context.enter();
try {
    ScriptableObject scope = context.initStandardObjects();
    context.evaluateString(scope, script, "script", 1, null);
    Function fct = (Function)scope.get("abc", scope);
    Object result = fct.call(
            context, scope, scope, new Object[] {2, 3});
    System.out.println(Context.jsToJava(result, int.class));
} finally {
    Context.exit();
}

Lorica

Don't forget to add this before try block context.setOptimizationLevel(-1); – Barbicel

@Maurice Perry if i want to call function using multidimensional integer array like [[1,3],[4,5],[6,9]] then how can i pass Object[] ? – Cincinnatus

@SamirMangroliya I guess you would need to call Context.newArray for each inner array, and then one more time for the outer array. – Lorica