[rules-users] Comparing Strings (sort order)

[Charles Binford]

I'm trying to figure out how to compare strings in drools.  I'd prefer 
to just be able to say something like:
when
  obj(member > "string")
....

This doesn't work because the > or < operations are not allowed (though 
I saw in a May 6th post Edson gave a pointer to how to add it.)  Next I 
tried using eval().  Based on everything I've read this should work.  My 
problem is getting the syntax correct.  My object "ActionArchive" has a 
member called "mediaPool".  I'd like to choose the one with the lowest 
(alphabetically) mediaPool string.

Try one.....
rule "testme"
    when
        $ar : ActionArchive($mp : mediaPool)
        not (eval (ActionArchive(getMediaPool().CompareTo($mp)) < 0))
    then
        System.out.println("low mp= " + $ar.getMediaPool());
end
-----------
Rule Compilation error : [Rule name=junk, agendaGroup=MAIN, salience=0, 
no-loop=false]
    rules/Rule_testme_0.java (8:997) : The method getMediaPool() is 
undefined for the type Rule_junk_0


Try two......
rule "testme"
    when
        $ar : ActionArchive($mp : mediaPool)
        not (eval (ActionArchive(mediaPool.CompareTo($mp)) < 0))
    then
        System.out.println("low mp= " + $ar.getMediaPool());
end
-----------
Rule Compilation error : [Rule name=testme, agendaGroup=MAIN, 
salience=0, no-loop=false]
    rules/Rule_testme_0.java (8:999) : mediaPool cannot be resolved

Thanks for any pointers.
Charles
p.s. consider this a vote for adding > < support for Strings....