Class PagedResultsControl

Requests that the results of a search operation be returned by the LDAP server in batches of a specified size. The requestor controls the rate at which batches are returned by the rate at which it invokes search operations.

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

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

     // Activate paged results
     int pageSize = 20; // 20 entries per page
     byte[] cookie = null;
     int total;
     ctx.setRequestControls(new Control[]{
         new PagedResultsControl(pageSize, Control.CRITICAL) });

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

         // Iterate over a batch of 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 paged results control response
         Control[] controls = ctx.getResponseControls();
         if (controls != null) {
             for (int i = 0; i < controls.length; i++) {
                 if (controls[i] instanceof PagedResultsResponseControl) {
                     PagedResultsResponseControl prrc =
                         (PagedResultsResponseControl)controls[i];
                     total = prrc.getResultSize();
                     cookie = prrc.getCookie();
                 } else {
                     // Handle other response controls (if any)
                 }
             }
         }

         // Re-activate paged results
         ctx.setRequestControls(new Control[]{
             new PagedResultsControl(pageSize, cookie, Control.CRITICAL) });
     } while (cookie != null);

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

This class implements the LDAPv3 Control for paged-results as defined in RFC 2696. The control's value has the following ASN.1 definition:

realSearchControlValue ::= SEQUENCE {
         size      INTEGER (0..maxInt),
                           -- requested page size from client
                           -- result set size estimate from server
         cookie    OCTET STRING
     }

Fields

OID

public static final String OID

The paged-results control's assigned object identifier is 1.2.840.113556.1.4.319.

See Also:

Constant Field Values

Constructors

PagedResultsControl

public PagedResultsControl(int pageSize,
                           boolean criticality)
                    throws IOException

Constructs a control to set the number of entries to be returned per page of results.

Parameters:

pageSize - The number of entries to return in a page.

criticality - If true then the server must honor the control and return search results as indicated by pageSize or refuse to perform the search. If false, then the server need not honor the control.

Throws:

IOException - If an error was encountered while encoding the supplied arguments into a control.

PagedResultsControl

public PagedResultsControl(int pageSize,
                           byte[] cookie,
                           boolean criticality)
                    throws IOException

Parameters:

pageSize - The number of entries to return in a page.

cookie - A possibly null server-generated cookie.

criticality - If true then the server must honor the control and return search results as indicated by pageSize or refuse to perform the search. If false, then the server need not honor the control.

Throws:

IOException - If an error was encountered while encoding the supplied arguments into a control.