small changes to factory and implemented rmi awareness with a simple register/deregister program

rmi_Awareness/HelloImplemented.java

@@ -0,0 +1,44 @@
+package rmi_Awareness;
+
+import java.rmi.RemoteException;
+import java.rmi.server.UnicastRemoteObject;
+import java.util.Iterator;
+import java.util.Vector;
+
+/**
+ * Created by Giovanni on 01/12/2014.
+ */
+public class HelloImplemented extends UnicastRemoteObject implements HelloInterface, register_to_server {
+
+    public HelloImplemented () throws RemoteException{
+        v = new Vector<call_me_back>();
+    }
+
+    @Override
+    public String sayhello() throws RemoteException {
+        return "HI!";
+    }
+
+    @Override
+    public void register(call_me_back obj) throws RemoteException {
+        v.add(obj);
+        Iterator<call_me_back> it = v.iterator();
+        for (;it.hasNext();){
+            it.next().notify("Un nuovo utente si e' registrato");
+        }
+
+    }
+
+    @Override
+    public void deregister(call_me_back obj) throws RemoteException {
+        v.remove(obj);
+        Iterator<call_me_back> it = v.iterator();
+        for (;it.hasNext();){
+            it.next().notify("Un  utente si e' cancellato ");
+        }
+
+    }
+
+    private Vector<call_me_back> v;
+
+}