Subj : Re: Rhino - general method in JS
To   : Yossi B <yossib@mercury.co.il>
From : Igor Bukanov <igor@fastmail.fm>
Date : Tue Sep 16 2003 06:12 pm

Yossi B wrote:
> I'm looking for a way to call a method from within the JS BUT this
> method must not be in the JS itself.
> 
> the JS:
> .....
> root = Packages.com.mercury.topaz.fm.execution.DataCollectorsAPI;
> SS = root.getSiteScopeInstance();
> host = GetMapParam("Host");
> ......
> 
> where the GetMapParam() is not in the JS.
> 
> is there a way to announce the method before evaluate the JS using the
> Context or the Scriptable(scope) ?

See API docs for the constructor of 
org.mozilla.javascript.FunctionObject or for the method 
defineFunctionProperties of ScriptableObject where the later is a 
convinience method to call the former when you need to define multiple 
functions.

A possible usage would be to call the methods after you called 
Context.initStandardObjects:

ScriptableObject scope = Context.initStandardObjects(null, false);

// Export the following function to JS
String[] names = { "print", "anotherFunction", "GetMapParam" };
try {
   scope.defineFunctionProperties(names, ClassThatDefinesFunctions.class,
                                  ScriptableObject.DONTENUM);
} catch (PropertyException e) {
   throw RuntimeException("Unexpected");
}

where the code supposes that there is ClassThatDefinesFunctions class 
that defines the functions:

class ClassThatDefinesFunctions
{
   public static int print(String arg)
   {
     // Rhino converts JS types into Java types automatically
     System.out.print(arg);
     return arg.length();
   }

   public static Object anotherFunction(Context cx, Scriptable thisObj,
                                        Object[] args, Function funObj)
   {
     // Working with raw JS objects
     System.out.println("Number of suplied arguments: "+args.length);
     return thisObj;
   }

   public static String GetMapParam(String paramName)
   {
     ...
   }
}

See FunctionObject for details on method signatures.

Regards, Igor

.