/**
 * 
 * PagedResultsControlJndiClient.java
 * Sample code to demostrate how Paged Results Control works.
 * 
 */
 
import javax.naming.*;
import javax.naming.directory.*;
import javax.naming.ldap.*;

import java.util.Hashtable;

public class PagedResultsControlJndiClient 
{
	
  static final String  PAGED_RESULT_CONTROL_OID = "1.2.840.113556.1.4.319";
    
  public static void main(String[] args)
  {
    Hashtable env = new Hashtable();
        
    env.put(Context.INITIAL_CONTEXT_FACTORY, 
                    "com.sun.jndi.ldap.LdapCtxFactory");
        
    // Note: Active Directory Server supports Paged Results Control 
    //       SunOne does not supports Paged Results Control but it supports 
    //       Virtual List View Control instead.
    env.put(Context.PROVIDER_URL, "ldap://myAD.mydomain.com:389");
    env.put(Context.SECURITY_AUTHENTICATION, "simple");
    env.put(Context.SECURITY_PRINCIPAL, "administrator@mydomain.com");
    env.put(Context.SECURITY_CREDENTIALS, "mypassword");
        
    try{
    	
      /* Open an LDAP connection for the provided principal and credentials */
      LdapContext ctx = new InitialLdapContext(env, null);
      System.out.println("Initial binding done!");
            
      /* Query the server to see if the paged result control is supported */ 
      if(!isPagedResultControlSupported(ctx)){
         System.out.println("The server does not support Paged Results Control.");
         System.exit(1);
      }

      /* Activate paged results */
      int pageSize = 5;
      byte[] cookie = null;
      int total;
	        
      ctx.setRequestControls(
              new Control[]{new PagedResultsControl(pageSize, Control.CRITICAL)});
      System.out.println("Paged control set!");

      int count = 0;
      while(true){
        count++;
        System.err.println("Search loop count = " + count);
                    
        SearchControls ctls = new SearchControls();
        ctls.setSearchScope(SearchControls.ONELEVEL_SCOPE);
        ctls.setCountLimit(0);
        // Perform the search
        NamingEnumeration results = ctx.search("dc=mydomain,dc=com", 
                                               "(objectclass=*)", ctls);
	            
        try{
          // Iterate over a batch of search results
          while (results != null && results.hasMore()) {
              // Display an entry
              SearchResult entry = (SearchResult)results.next();
              System.out.println("entryDN=" + entry.getName());
          }
        }catch(Exception pe){
          System.out.println(pe.toString());  // Patial Result Exception
        }
	            
        // Examine the paged results control response 
        Control[] controls = ctx.getResponseControls();
        if(controls!=null){
          for(int k = 0; k<controls.length; k++){
            if(controls[k] instanceof PagedResultsResponseControl){
              PagedResultsResponseControl prrc = 
                       (PagedResultsResponseControl)controls[k];
              total = prrc.getResultSize();
              cookie = prrc.getCookie();
            }else{
              // Handle other response controls (if any)
            }
          }
        }
	
        if(cookie==null)
          break;
	            
         // Re-activate paged results
         ctx.setRequestControls(new Control[]{
             new PagedResultsControl(pageSize, cookie, Control.CRITICAL)});
       }
	
       // Close the LDAP association
       ctx.close();
     }catch (Exception e){
       e.printStackTrace();
     }
  }

  /**
   * Is paged result control supported?
   *
   * Query the rootDSE object to find out if the paged result control
   * is supported.
   */
  static boolean isPagedResultControlSupported(LdapContext ctx) 
				throws NamingException
  {
    SearchControls ctl = new SearchControls();
    ctl.setReturningAttributes(new String[]{"supportedControl"});
    ctl.setSearchScope(SearchControls.OBJECT_SCOPE);

    /* search for the rootDSE object */
    NamingEnumeration results = ctx.search("", "(objectClass=*)", ctl);

    while(results.hasMore()){
      SearchResult entry = (SearchResult)results.next();
      NamingEnumeration attrs = entry.getAttributes().getAll();
      while (attrs.hasMore()){
      	Attribute attr = (Attribute)attrs.next();
       	NamingEnumeration vals = attr.getAll();
        while (vals.hasMore()){
        String value = (String) vals.next();
        if(value.equals(PAGED_RESULT_CONTROL_OID))
           return true;
        }
      }
    }
    return false;
  }

}