The following code sample shows how the class may be used:

     // Open an LDAP association
     LdapContext ctx = new InitialLdapContext();

     // Activate sorting
     String sortKey = "cn";
     ctx.setRequestControls(new Control[]{ 
         new SortControl(sortKey, Control.CRITICAL) });

     // Perform a search
     NamingEnumeration results =
         ctx.search("", "(objectclass=*)", new SearchControls());

     // Iterate over search results
     while (results != null && results.hasMore()) {
         // Display an entry
         SearchResult entry = (SearchResult)results.next();
         System.out.println(entry.getName());
         System.out.println(entry.getAttributes());

         // Handle the entry's response controls (if any)
         if (entry instanceof HasControls) {
             // ((HasControls)entry).getControls();
         }
     }
     // Examine the sort control response 
     Control[] controls = ctx.getResponseControls();
     if (controls != null) {
         for (int i = 0; i < controls.length; i++) {
             if (controls[i] instanceof SortResponseControl) {
                 SortResponseControl src = (SortResponseControl)controls[i];
                 if (! src.isSorted()) {
                     throw src.getException();
                 }
             } else {
                 // Handle other response controls (if any)
             }
         }
     }

     // Close the LDAP association
     ctx.close();
     ...

 

This class implements the LDAPv3 Request Control for server-side sorting as defined in RFC 2891. The control's value has the following ASN.1 definition:

     SortKeyList ::= SEQUENCE OF SEQUENCE {
         attributeType     AttributeDescription,
         orderingRule  [0] MatchingRuleId OPTIONAL,
         reverseOrder  [1] BOOLEAN DEFAULT FALSE }