ApacheDS Specific Schema Descriptions

ApacheDS includes 3 new schema descriptions as held within schemaSubentries.
These new descriptions govern how syntax checking is performed and how
searches are conducted by defining the atomic elements composing matchingRules.

Comparator Description Syntax

Comparators determine ordering and hence govern matchingRules used for ordering
with greater than or equal to and less than or equal to filter assertions. The
description for these entities either reference an existing comparator or contain
bytecode for loading and creating a new comparator for use with matchingRules.

Comparators do not have an OID specific to them. Instead they reference the OID
(numeric identifier) of the matchingRule they will be used in conjunction with. So
before a novel matchingRule can be added to the system, a comparator and a normalizer
for that comparator must be added with it's OID.

Here's the description syntax of a comparator according to the ABNF:

    ComparatorDescription = LPAREN WSP
          numericId                           ; object identifier
          [ SP "DESC" SP qdstring ] ; description
          SP "FQCN" SP qdstring     ; fully qualified class name
          [ SP "BYTECODE" SP qdstring ] ; optional base64 encoded bytecode
          extensions WSP RPAREN               ; extensions
    where:
        [numericoid] is object identifier assigned to the matchingRule 
            associated with this comparator;
        DESC [qdstring] is a short descriptive string;
        FQCN [qdstring] is the fully qualified class name of the comparator's class;
        BYTECODE [base64] is the base64 encoded byte code for the comparator's class;
        [extensions] describe extensions.