Throw unsupportedoperationexception if username specified is null.

git-svn-id: http://svn.igniterealtime.org/svn/repos/openfire/branches/openfire_3_5_0@9975 b35dd754-fafc-0310-a699-88a17e54d16e

src/java/org/jivesoftware/openfire/lockout/LockOutManager.java

@@ -126,6 +126,9 @@ public class LockOutManager {
      * @throws NotLockedOutException if user account specified is not currently locked out (disabled).
      */
     public LockOutFlag getDisabledStatus(String username) throws NotLockedOutException {
+        if (username == null) {
+            throw new UnsupportedOperationException("Null username not allowed!");
+        }
         LockOutFlag flag = lockOutCache.get(username);
         // If ID wan't found in cache, load it up and put it there.
         if (flag == null) {