流口水收集图案问题

Question

I have a rule LHS like that

when 
    $location : Location() 
    $cabinets : ArrayList() from collect ( Cabinet() from $location.elements() )
then

an when I print the content of @cabinets in RHS I see that it contains all elements (also those that are not of class Cabinet ).

I want to collect ontly cabinets from $location>elements().

What did I do wrong ?

Answer 1

I think you would say something along the lines of

Cabinet(class == Cabinet.class)

I dont think that Drools is doing an explicit type check on the Cabinet classes as you have them afaik.

Answer 2

Your question is about the 'from' pattern, not the 'collect' one.

Following rule should help to test:

when 
  $location : Location() 
  $cabinet : Cabinet() from $location.elements()
then

This rule should fire for each Cabinet in location.

You can try to post your question on the rule-users user list