RE: How to implement getIdentities(int start, int limit) more effectively

[Xu, Yaning]

Hi Kiran,


1.       The administrator may need to list all principal names, and then use 
the principal name he is interested in to get the Identity;

2.      There may be too many principals to scan at once, so the system may 
need to get only a part of them at once, as Stefan pointed out;

3.       We need to make Kerby compatible to Krb5, and it has implemented this 
interface as list_principals 
http://web.mit.edu/KERBEROS/krb5-1.12/doc/admin/admin_commands/kadmin_local.html
 ;

Regards,

Yaning


From: Kiran Ayyagari [mailto:kayyag...@apache.org]
Sent: Thursday, July 02, 2015 3:59 PM
To: Apache Directory Developers List
Subject: Re: How to implement getIdentities(int start, int limit) more 
effectively

Hi Yaning,
  where in the server or client are we going to need this interface, iow, can 
you describe the usecase
  that requires this getIdentities(s,l) method.
  (I just want to understand the need for this method before we dive into 
implementing it)

On Thu, Jul 2, 2015 at 3:39 PM, Xu, Yaning 
<yaning...@intel.com<mailto:yaning...@intel.com>> wrote:
Hi all,


        As we have discussed https://issues.apache.org/jira/browse/DIRKRB-295 , 
IdentityService.getIdentities() should be removed. However, to implement 
getIdentities(int start, int limit), which returns a sorted result, I have to 
get all identities from the ldap server and then sort them. Is it possible for 
the Ldap server to return a sorted result for the client connection?



In [1], I see a test about Page Search on client side 
testPagedSearchWrongCookie(), and it uses pagedSearchControl.setSize(3) to set 
the page size, the problem are:



        *how can I get a search result based on the start index and pageSize, 
like I may use getIdentities(int start, int limit) to return a result;

        *how can I get a sorted result from the server, so that I don’t have to 
get all the entries and then sort them to get the result;



[1] 
https://svn.apache.org/repos/asf/directory/apacheds/trunk/server-integ/src/test/java/org/apache/directory/server/operations/search/PagedSearchIT.java





public List<String> getIdentities(int start, int limit) {
    List<String> identities = getIdentities();

    if (limit == -1) {
        return identities;
    }

    return getIdentities().subList(start, start + limit);
}


private List<String> getIdentities() {
    List<String> identityNames = new ArrayList<>();
    EntryCursor cursor;
    Entry entry;
    try {
        cursor = connection.search( getConfig().getString("base_dn"),
                "(objectclass=*)", SearchScope.ONELEVEL, 
KerberosAttribute.KRB5_PRINCIPAL_NAME_AT);
        if (cursor == null) {
            return null;
        }
        while (cursor.next()) {
            entry = cursor.get();
            
identityNames.add(entry.get(KerberosAttribute.KRB5_PRINCIPAL_NAME_AT).getString());
        }
        cursor.close();
        Collections.sort(identityNames);
    } catch (LdapException e) {
        e.printStackTrace();
    } catch (CursorException e) {
        e.printStackTrace();
    }
    return identityNames;
}


Regards,

Yaning




--
Kiran Ayyagari
http://keydap.com