/**
 *  A code example of Persistent Search Control JNDI Client for AD
 *  Note: This example has been tested to work with Active Directory 2003
 */
import javax.naming.*;
import javax.naming.directory.*;
import javax.naming.event.*;
import javax.naming.ldap.*;

import java.util.Hashtable;
import java.io.*;

public class PersistentSearchControlJndiClientAD 
{
     
  // no longer "2.16.840.1.113730.3.4.3"
  static final String PERSISTENT_SEARCH_OID = "1.2.840.113556.1.4.528";
  
  public static void main(String[] args)
  {
    LdapContext   rootContext;

    //create initial context
    Hashtable env = new Hashtable();
    env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
    env.put(Context.PROVIDER_URL, "ldap://myserevr.mycompany.com:389");
    env.put(Context.SECURITY_AUTHENTICATION, "simple");
    env.put(Context.SECURITY_PRINCIPAL, "mytest@mydomain.com");
    env.put(Context.SECURITY_CREDENTIALS, "mypassword");
    env.put(Context.BATCHSIZE, "1");  //return each change as it occurs
    env.put("java.naming.ldap.derefAliases", "never");
    
    try {
      // Create the initial directory context
      rootContext = new InitialLdapContext(env, null);
    
      // verify that persistent search is supported, exit if not supported
      if (!isPersistentSearchSupported(rootContext)){
        System.out.println(
            "The LDAP Server does not support persistent search");
        System.exit(1);
      }

      // Set up the search constraints
      SearchControls constraints = new SearchControls();
      constraints.setSearchScope(SearchControls.SUBTREE_SCOPE);
      constraints.setTimeLimit(0);
  
      //Request the LDAP Persistent Search control
      Control[] rqstCtls = new Control[]{new NotifyControl()};
      rootContext.setRequestControls(rqstCtls);

      //Specify the base for the search
      String searchBase = "dc=mydomain,dc=com";
      
      //For persistent search can only use objectClass=*
      String searchFilter = "(objectClass=*)";
 
      //Now perform the search
      NamingEnumeration answer = 
            rootContext.search(searchBase,searchFilter,constraints);
      SearchResult sr;
      Attributes attrs;
      
      //Continue waiting for changes....forever
      while(true) {
        System.out.println("Waiting for changes..., press Ctrl C to exit");
 
         sr = (SearchResult)answer.next();
            System.out.println(">>>" + sr.getName());
 
        //Print out the modified attributes
        //instanceType and objectGUID are always returned
        attrs = sr.getAttributes();
        if (attrs != null) {
          try {
            for (NamingEnumeration ae = attrs.getAll();ae.hasMore();) 
            {
              Attribute attr = (Attribute)ae.next();
              System.out.println("Attribute: " + attr.getID());
              for (NamingEnumeration e = attr.getAll();e.hasMore();
                System.out.println("   " + e.next().toString()));
            }
          } 
          catch (NullPointerException e)  {
            System.err.println("Problem listing attributes: " + e);
          }
        }
      }
    }
    catch (NamingException e) 
    {
      System.err.println("Problem searching directory: " + e);
    } 
    catch (Exception e) 
    {
      System.err.println("Problem searching directory: " + e);
    }
  }

  /**
   * isPersistentSearchSupported
   *
   * Query the rootDSE to find out if the persistent search control
   * is supported.
   */
  static boolean isPersistentSearchSupported(
    LdapContext   rootContext) throws NamingException
  {
    SearchResult     rootDSE;
    NamingEnumeration  searchResults;
    Attributes       attrs;
    NamingEnumeration  attrEnum;
    Attribute      attr;
    NamingEnumeration  values;
    String         value;
    String[]       attrNames = {"supportedControl"};
    SearchControls     searchControls = new SearchControls();

    searchControls.setCountLimit(0);  //0 means no limit
    searchControls.setReturningAttributes(attrNames);
    searchControls.setSearchScope(SearchControls.OBJECT_SCOPE);

    // search for the rootDSE object
    searchResults =
      rootContext.search("", "(objectClass=*)", searchControls);

    while (searchResults.hasMore())
    {
      rootDSE = (SearchResult)searchResults.next();

      attrs = rootDSE.getAttributes();
      attrEnum = attrs.getAll();
      while (attrEnum.hasMore())
      {
        attr = (Attribute)attrEnum.next();
        values = attr.getAll();
        while (values.hasMore())
        {
          value = (String) values.next();
          if (value.equals(PERSISTENT_SEARCH_OID))
            return true;
        }
      }
    }
    return false;
  }
} 

class DeletedControl implements Control {

  public byte[] getEncodedValue() {
    return new byte[] {};
  }

  public String getID() {
    return "1.2.840.113556.1.4.417";
  }

  public boolean isCritical() {
    return true;
  }

}

class NotifyControl implements Control {

  public byte[] getEncodedValue() {
          return new byte[] {};
  }

  public String getID() {
    return "1.2.840.113556.1.4.528";
  }

  public boolean isCritical() {
    return true;
  }
}