API java : PagedResultsControl

javax.naming.ldap
Class PagedResultsControl

java.lang.Object
  javax.naming.ldap.BasicControl
      javax.naming.ldap.PagedResultsControl

All Implemented Interfaces:

Serializable, Control

public final class PagedResultsControl
extends BasicControl

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
}

Since:

1.5

See Also:

PagedResultsResponseControl, Serialized Form

Field Summary
static String	OID           The paged-results control's assigned object identifier is 1.2.840.113556.1.4.319.

 

Fields inherited from class javax.naming.ldap.BasicControl
criticality, id, value

 

Fields inherited from interface javax.naming.ldap.Control
CRITICAL, NONCRITICAL

 

Constructor Summary
PagedResultsControl(int pageSize, boolean criticality)           Constructs a control to set the number of entries to be returned per page of results.
PagedResultsControl(int pageSize, byte[] cookie, boolean criticality)           Constructs a control to set the number of entries to be returned per page of results.

 

Method Summary

 

Methods inherited from class javax.naming.ldap.BasicControl
getEncodedValue, getID, isCritical

 

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

 

Field Detail

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

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

Constructs a control to set the number of entries to be returned per page of results. The cookie is provided by the server and may be obtained from the paged-results response control.

A sequence of paged-results can be abandoned by setting the pageSize to zero and setting the cookie to the last cookie received from the server.

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.