Hi,
<side note>
In the following mails, and all the mails related to the schema, I will
use those acronyms :
AT : AttributeType
C : Comparator (LdapCOnparator in this case)
DCR : DitContentRule
DSR : DitStructureRule
MR : MatchingRule
MRU : MatchingRuleUse
N : Normalizer
NF : NameForm
OC : ObjectClass
S : Syntax (or LdapSyntax)
SC : SyntaxChecker
SO : SchemaObject (one of the 11 previous elements)
today, while fixing some code, and testing all the atomic operation (Add
is ok, I started to look at Del), I faced an issue : if we try to remove
an AT, we may let the Registries in an inconsistent state, as many OC
may have referenced this AT.
We started to discuss about this problem, and it appeared that many
different kind of relations exist between each SO. For instance :
AT:
o has a S (can be inherited)
o may have some superior AT
o have some MR (can be inherited)
o may be referenced by OCs in theirs MAY or MUST fields
o may be referenced by DCRs in theirs MAY, MUST or NOT fields,
o may be referenced in the MRU's APPLIES field
o may be referenced by NFs in theirs MAY or MUST fields,
If we simply delete this AT without any check, then we may have some
descendant AT pointing to an AT which is not any more part of the
schema, or any of the OCs, DCRs, MRUs or NFs referencing this AT.
We have to be able to check that quickly (ie, without visiting all those
SO looking for this AT), that mean either adding some added fields in
all those SO (something like the list of OCs using this AT, added as a
set in the AT instance), or having a Map associating an SO with all the
SO's referencing it.
I think that the second solution is way better, as it does not add many
fields and setters/getters in a bunch of classes, and also is easy to
attach to the Registries. We just have to define a hashCode() for each
SO which is built using their OID (or ruleId) combined with their
ObjectType (to avoid collision, as some SO may have the same OID : MRUs
have the MR's ODI they are associated with).
At this point, the only risk I forsee is that this Map is not accessible
if the Registries is not accessible when we want to update it. Will see...
Thoughts ?
--
--
cordialement, regards,
Emmanuel Lécharny
www.iktek.com
directory.apache.org
