Is it possible to produce an ordered batch of events with an attribute stating the event (ordered) position?

Question

Using Esper engine to write continuous queries, is it possible to produce an ordered batch of events with an (extra) "column"/attribute witch states the event ordered position?

Imagine the following Esper's query:

SELECT  id, val                                                                         
FROM Datastream.win:length(10)
OUTPUT SNAPSHOT EVERY 1 EVENTS                                                          
ORDER BY val DESC

For instance, such query would produce the following type of output:

id | val  
 D | 17  
 B | 12  
 C | 11  
 A | 8    

I'm asking if there is any esper's operator capable to produce the extra "column" rank for the previous batch of (new) events:

id | val | rank 
 D | 17  | 1
 B | 12  | 2
 C | 11  | 3
 A | 8   | 4

For those who are familiar with pgSQL window functions, I'm looking for the rank() equivalent operator for Esper.

Answer 1

I don't think that currently exists. Esper project's JIRA is at http://jira.codehaus.org/browse/ESPER and JIRA accounts can be created at http://xircles.codehaus.org/