[jboss-jira] [JBoss JIRA] Created: (JBRULES-546) Please implement "collect( ... ) from" functionality

[Dirk Bergstrom (JIRA)]

Please implement "collect( ... ) from" functionality
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                 Key: JBRULES-546
                 URL: http://jira.jboss.com/jira/browse/JBRULES-546
             Project: JBoss Rules
          Issue Type: Feature Request
      Security Level: Public (Everyone can see)
            Reporter: Dirk Bergstrom
         Assigned To: Mark Proctor


I need to count the number of sub-objects that meet various criteria.  As an example, suppose I have several hundred Town objects, each of which has a list of perhaps a few hundred Person objects.  I need to write rules like:

"Find all the towns that have more than three disabled people with incomes over $100K."
"For each town with more than 1000 residents that has more than 50 poor children under the age of 8, add a teacher for every 25 children."

I'm shaky on JBR syntax, but I think those would translate to something like:

rule "disabled"
  when
    ArrayList(size > 50) from collect( Person( disabled == "yes", income > 100000 ) from town.getPersons() )
  then
    //do stuff
end

rule "teachers"
  when
    town : Town( population > 1000 )
    count : Arraylist from collect( Person( disabled == "yes", income > 100000 ) from town.getPersons() )
    count( size > 50 )
  then
    town.addTeachers(count.size() / 25)
end

(I'm not really working with towns and people, but it makes for easily understood examples)

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