Subj : How to use Rhino scopes in a multithreaded environment
To   : netscape.public.mozilla.jseng
From : torntrousers
Date : Sun Mar 06 2005 02:37 am

I'm embedding Rhino in a multithreaded environment and I'm trying to
understand how scopes work based on the info at
http://www.mozilla.org/rhino/scopes.html

I'd like to use a scope shared across threads which contains compiled
function definitions, and for each thread to have its own scope for
running calls to those functions. I'd also like to be able to add some
custom objects to the thread specific scope for use by the function
calls.

The problem is the functions don't seem to find the objects I add to
the thread specific scope. The following code demonstrates the
problem:

public class Test {

  public static void main(String[] args) {
    Context cx = Context.enter();
    try {

      Scriptable sharedScope = cx.initStandardObjects(null, true);

      String script = "function foo() {out.println(\"in foo\");}";
      Script compiledScript = cx.compileString(script,"bla",1,null);
      compiledScript.exec(cx, sharedScope);
      Function foo = (Function) sharedScope.get("foo", sharedScope);

      Scriptable scope = cx.newObject(sharedScope);
      scope.setPrototype(sharedScope);
      scope.setParentScope(null);

      Object wrappedOut = Context.javaToJS(System.out, scope);
      ScriptableObject.putProperty(scope, "out", wrappedOut);

      foo.call(cx, scope, scope, new Object[] {});

    } finally {
      Context.exit();
    }
  }
}

Running this fails with: Exception in thread "main"
org.mozilla.javascript.EcmaError: ReferenceError: "out" is not
defined. (bla#1)

What am I doing wrong?

I guess a supplementary question is is this a sensible approach to
calling functions in a multithreaded environment in the most
performant way?

Thanks for any help.

       ...ant

.