Complete example can be downloaded here.

First of all we create GraniteDS configuration file (services-config.xml)

    
        

            

          			clojureFactory
        		
      		
        
    

	
	   
	

	
        
            
        
    

This configuration contains destination (mydestination) that refers to service factory implemented in Java (org.aristov.blog.clojure.granite.ClojureServiceFactory). Service factory simple method that creates and caches of ClojureServiceInoker.

public ServiceInvoker getServiceInstance(RemotingMessage request)
			throws ServiceException
{
   if (invoker == null)
   {
       GraniteContext context = GraniteContext.getCurrentInstance();

       Destination destination = context.getServicesConfig()
		.findDestinationById(request.getClass().getName(),
					request.getDestination());

       invoker = new ClojureServiceInvoker(destination, this);
   }

   return invoker;
}

ClojureServiceInvoker dispatches every invocation to predefined clojure function (granite-dispatch) that is defined in the granite namespace. Invocation parameters, prefixed with concatenated endpoint and method names are passed to the dispatch function as is.

protected Object adjustInvokee(RemotingMessage request, String methodName,
			Object[] args) throws ServiceException
{
     return this;
}

protected Object[] beforeMethodSearch(Object invokee, String methodName,
			Object[] args)
{
     Object[] params = new Object[args.length + 1];
     System.arraycopy(args, 0, params, 1, args.length);
     params[0] = destination.getId() + "/" + methodName;

     return new Object[] { "invoke", new Object[] { params } };
}

public Object invoke(Object[] params) throws Exception
{
	return dispatch.applyTo(ArraySeq.create(params));
}

Clojure invocation handler – granite-dispatch uses convert-params function converts Map based arguments, that a created by GraniteDS from ActionScript objects.

(defn map-to-native [object]
	(into {}
		(map
			#(let [[k v] %]
				(cond
					(instance? java.util.Map v) (vector k (map-to-native v))
					:default %))
		 object)))

(defn convert-params [list]
	(map
		#(cond
			(instance? java.util.Map %) (map-to-native %)
			:default %)
	list))

(defn granite-dispatch [function & params]
	(apply (resolve (symbol function))(convert-params params)))

Finally invocation is redirected to a user defined function in a namespace that matches destination id.

(ns mydestination)

(defn doSomething [p1 p2 p3 p4 p5]
	(println p1 p2 p3 p4 p5))

On the Flex side it looks like this:

private var remoteObject: RemoteObject;

private function init() : void
{
  	remoteObject  = new RemoteObject();
	remoteObject.destination = "mydestination";

       	var cs:ChannelSet = new ChannelSet();
     	var c1:AMFChannel = new AMFChannel("channel", "http://localhost:9999/amf");
        cs.addChannel(c1);

        remoteObject.channelSet = cs;
}

private function doSomething()
{
       	remoteObject.doSomething(1, 2, 'Something',  new MyData(), 'More')
}