+----------------+
     |                <----+
     |   Controller   |    |
     +-------+--------+    |
             |             |
             |             |
         ECA |             | ECA
       Model |             | Notification
             |             |
             |             |
+------------V-------------+-----+
|Device                    |     |
| +-------+ +---------+ +--+---+ |
| | Event +-> Event   +->Event | |
| | Source| |Condition| |Action| |
| +-------+ +---------+ +------+ |
+--------------------------------+