Rhino, adding code from multiple javascript files

Question

I am embedding some javascript in a Java application using Rhino. I am following the example on the Rhino website, executing a script by calling the Context's evaluateString method and passing the actual script in as a String.

I have a whole bunch of existing javascript code that I would like to make use of. I don't want to concatenate it all into an enormous String and pass it in to evaluateString. I would rather be able to load the code in so that I can call it from the code that I do pass into evaluateString (kind of like the AddCode method works in Microsoft's scripting control). I would like to add code like I can currently add variables by using the ScriptableObject.putProperty method.

Is there a way to do this? Can someone provide a code snippet or a link to the documentation. Thanks!

Put all your javascript code in one file. Read the file into a StringWriter and use its toString method. Now use evaluateString to parse the entire javascript code and return a Scriptable object. After that you may simply use the get(String namespace,Scriptable jsObject) method of Scriptables to access any object in scope. — FK82
– FK82, Commented Jun 24, 2010 at 21:26
Just a remark: if you want to enable a continuation-passing-pattern (like you stated) you will need to have all relevant functions within scope and declare that scope in Function.call(Scriptable context,Scriptable scope,Scriptable thisObject,Object[] args). Therefore, I don't really see the benefit of splitting your code into fragments. — FK82
– FK82, Commented Jun 26, 2010 at 7:55

McDowell · Accepted Answer · 2010-06-19 13:03:09Z

From the documentation and examples it looks like references to previously evaluated objects are controlled by scopes.

Context context = Context.enter();
try {
  ScriptableObject scope = context.initStandardObjects();
  Object out = Context.javaToJS(System.out, scope);
  ScriptableObject.putProperty(scope, "out", out);
  context.evaluateString(scope,
      "function foo() { out.println('Hello, World!'); }", "<1>", 1, null);
  context
      .evaluateString(scope, "function bar() { foo(); }", "<2>", 1, null);
  context.evaluateString(scope, "bar();", "<3>", 1, null);
} finally {
  Context.exit();
}

(Rhino 1.7 release 2)

I know some people use Rhino directly to get the latest version, but the Java 6 implementation can evaluate scripts like this:

ScriptEngine engine = new ScriptEngineManager().getEngineByExtension("js");
engine.eval("function foo() { println('Hello, World!'); }");
engine.eval("function bar() { foo(); }");
engine.eval("bar();");

TheLQ · Accepted Answer · 2010-07-29 09:10:46Z

0

In my code I had that need (utility scripts and such), and I just simply concatenated them together in a giant StringBuilder and evaled it (Java 6). Its the only way since javascript can't do (without Java wrapper objects) otherJSScript.someUsefulFunction().

answered Jul 29, 2010 at 9:10

TheLQ

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