Re: [ldap-sdk-discuss] LDAP SDK Java question

[Neil A. W. <nei...@un...>]

On 09/19/2016 12:21 PM, Kasim Doctor wrote:
> Hi there,
> 
> I am playing around with the LDAP Java SDK API to get a list of OUs from a
> source directory.
> 
> I searched everywhere but can't seem to find the answer to the following
> question:
> 
> When I get the list of OUs, what guarantee is there that the parent OUs are
> returned before the child OUs are returned ?
> 
> Please let me know if there is a spec somewhere for this
> 
> Thanks,
> Kasim


There is no specification that requires a superior entry to be returned
in search results before its subordinates.  In fact, RFC 4511 section
4.5.2 states "The SearchResultEntry and SearchResultReference messages
may come in any order.", so it would be legal for subordinate entries to
be returned before their superiors.

However, I expect that most LDAP servers do try to return superior
entries before subordinates.  I know that with the UnboundID Directory
Server, we do guarantee that superior entries will be returned before
any of their subordinates, with only a couple of exceptions (for
example, searches including the server-side sort or persistent search
request control). I can't speak definitively for other directory
servers, but I expect that most servers do try to maintain this ordering
under normal circumstances.

If you're really paranoid about this, and if you expect that your search
won't return a large number of entries, you can have the LDAP SDK sort
the results for you, and you can specify that the sorting should order
each entry first based on its position in the hierarchy and then based
on its content.  See the EntrySorter
(https://docs.ldap.com/ldap-sdk/docs/javadoc/index.html?com/unboundid/ldap/sdk/EntrySorter.html)
class for more information.  However, client-side sorting can only be
done if you can hold all of the entries in memory, so you shouldn't do
this if you think there might be a large number of matching entries.


Neil