Javadoc
filtercomp = and / or / not / item
and = '&' filterlist
or = '|' filterlist
not = '!' filter
item = simple / present / substring / extensible
simple = attr filtertype assertionvalue
present = attr EQUALS ASTERISK
substring = attr EQUALS [initial] any [final]
extensible = ( attr [dnattrs]
[matchingrule] COLON EQUALS assertionvalue )
/ ( [dnattrs]
matchingrule COLON EQUALS assertionvalue )