Improvements on EventListener Event ...

src/opensesim/world/TradingAPI.java

@@ -26,13 +26,16 @@
 package opensesim.world;
 
 import java.util.Set;
+import opensesim.world.scheduler.EventListener;
 
 /**
  *
  * @author tube
  */
 public interface TradingAPI {
-
+    
+    public void addOrderBookListener(EventListener listener);
+    
     public Order createOrder(Account account, Order.Type type, double volume, double limit);
 
     public Set getOrderBook(Order.Type type);