K - the type of the key in the incoming MessageEnvelope.
            Windows that are not keyed have a Void key type.public class WindowKey<K>
extends java.lang.Object
WindowPane emitted from a Window.| Constructor and Description | 
|---|
| WindowKey(K key,
         java.lang.String windowId) | 
| Modifier and Type | Method and Description | 
|---|---|
| K | getKey() | 
| java.lang.String | getWindowId() |