Declaring a Remote Method with Interface Parameters

You can declare @RemoteAction methods with interface parameters and return types, instead of being restricted to concrete classes. This, for example, allows a package provider to package a remote method and associated interface, which subscriber organizations can call from Visualforce pages, passing in their own class that implements the packaged interface.

Here’s a brief example:

1public class RemoteController {
2    public interface MyInterface { String getMyString(); }
3    public class MyClass implements MyInterface { 
4        private String myString; 
5        public String getMyString() { return myString; }
6        public void setMyString(String s) { myString = s; }
7    }
8    
9    @RemoteAction
10    public static MyInterface setMessage(MyInterface i) {
11        MyClass myC = new MyClass();
12        myC.setMyString('MyClassified says "' + i.getMyString() + '".');
13        return myC;
14    }
15}

Objects sent from a JavaScript remoting call to a @RemoteAction that declares interface parameters must include an apexType value, which must be a fully-qualified path to the concrete class, that is, namespace[.BaseClass][.ContainingClass].ConcreteClass. For example, to make a JavaScript remoting call to the above controller:

1Visualforce.remoting.Manager.invokeAction(
2    '{!$RemoteAction.RemoteController.setMessage}',
3    {'apexType':'thenamespace.RemoteController.MyClass', 'myString':'Lumos!'}, 
4    handleResult
5);

If the class definition is within your organization, you can simplify the remoting call, and also use the default c namespace:

1RemoteController.setMessage(
2    {'apexType':'c.RemoteController.MyClass', 'myString':'Lumos!'}, 
3    handleResult
4);

Visualforce Developer’s Guide

Declaring a Remote Method with Interface Parameters