[rules-users] How to retract events that don't match any rules (without @expires())

[Davide Sottara]

If your rules are dynamic, would you still want to retract a fact not
matching any of your current rules,
knowing that a new rule might appear later, which would be activated by that
fact?

This said, the problem here is "garbage-collecting" facts which have been
insert, but are in a "zombie" 
status, since there is no pattern matching them - not even partially. This
could be a useful feature (Mario?),
you could open a feature request JIRA and let the developers discuss it.

For now I would suggest this: whenever you insert an object, you will get
back a FactHandle. 
Cast it to org.drools.common.InternalFactHandle and look at
getFirstLeftTuple() and getFirstRightTuple().
I haven't checked it completely, but I would say that if the fact does not
participate in any tuple, it 
might be worthy retracting.

Best
Davide

ps your case "second after first" is a well known problem... and not only
for drools! If your "first"
matches your conditions, it will have to stay there waiting for a
"second"... You'll have to 
"close the horizon" explicitly to remove those "firsts" which have been
there for "too long", whatever
that means for you :)

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