Esper terminating partitioned context

I have a steam of ThingEvent.

create schema ThingEvent {
  thingID int,
  isLast  boolean
}

I want to process things with the same thingIDs together so I created a context.

create context ThingContext
  partition by thingID from ThingEvent

However, when I get a thing with isLast set to true, that means we're never going to see a ThingEvent with the same thingID again. But the context will hang around forever causing a resource leak.

I found that an overlapping context can be terminated.

create context ThingContext
  initiated by distinct(thingID) ThingEvent(isLast <> true) as startEvent
  terminated by ThingEvent(thingID = startEvent.thingID, isLast = true);

But when I use it, I have to manually filter the events.

context ThingContext
  select *
  from ThingEvent(thingID=context.startEvent.thingID)
  output when terminated;

When I start using patterns, this becomes way too verbose. Is there a way to get the best of both worlds?

Solution

I don't think there is a termination clause for keyed contexts.

There is a programmatic way of termination any context partition, link to documentation.

Instead of repeating expressions there is a predefined expression alias "expression alias {}".

Edit:

This functionality was added in the 7.0.0 release http://www.espertech.com/esper/esper-changehistory/