如何存储多个事件类型的侦听器

Question

I'm trying to implement Observer/Listener pattern with multiple listeners and multiple event types in Java. Each event listener can be interested in one or more event types.

What is the most efficient way to store listeners for each particular event type and iterate over them (List of Lists, maybe)?

Of course, thread-safe solution is strongly preferred.

Answer 1

You can use java.util.concurrent.ConcurrentHashMap for Thread safe hash map.

The structure you need is:

ConcurrentHashMap<EventType,List<Listener>> map;

That way, each listener is registered to several event types.

Answer 2

Perhaps you're looking for the EventListenerList class? But I may have misunderstood you.

Answer 3

Take a look at EventListenerList . It holds a list of anything implementing EventListener . Then you can call getListeners(class) to get the listeners of type class .