Accessing java Maps & Lists as JavaScript Objects in Rhino

Question

Is there a way to access Java Maps and Lists as JavaScript Objects in Rhino?

I have a Map which contains only other maps and lists of primitives and Strings, I'd like to pass this to a Rhino script and do stuff to it, and return the modified object back out to Java - but since they are java.util.Map and java.util.List Objects, I can't use standard JavaScript associative array syntax. ie: fooMap.get("keyName") will work, but fooMap.keyName and fooMap["keyName"] will not.

I don't know if there is a Rhino-specific way to do this, or if there is some conversion/cast utility that will help. Commons BeanUtils is not sufficient, because to convert a Map to a bean (which can be accessed via associative array syntax), you must first create a class which has all of the named mutators/accessors. I won't know the structure of the object at runtime.

Answer 1

Take a look at RingoJS. It has convenient wrappers for list and map for Rhino such as this one

Answer 2

iterators seem to be the key!

if you want to iterate over all entries of a map, you could do the following

JAVA

//pass  the map and map.keySet().iterator() to the javascript
Object wrappedParameterMap = Context.javaToJS(parameterMap, scope);
ScriptableObject.putProperty(scope, "parameterMap", wrappedParameterMap);
Object wrappedParameterNames = Context.javaToJS(parameterMap.keySet().iterator(), scope);
ScriptableObject.putProperty(scope, "parameterNames", wrappedParameterNames);

JAVASCRIPT

while(parameterNames.hasNext()) {
  key = parameterNames.next();
  value = parameterMap.get(key);
}