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package org.ietf.ldap.controls;

import java.io.*;
import org.ietf.ldap.ber.stream.*;
import org.ietf.ldap.client.JDAPBERTagDecoder;
import org.ietf.ldap.*;

/**
 * Represents an LDAP v3 server control that specifies information
 * about a change to an entry in the directory.  (The OID for this
 * control is 2.16.840.1.113730.3.4.7.)  You need to use this control in
 * conjunction with a "persistent search" control (represented
 * by <CODE>LDAPPersistentSearchControl</CODE> object.
 * <P>
 *
 * To use persistent searching for change notification, you create a
 * "persistent search" control that specifies the types of changes that
 * you want to track.  When an entry is changed, the server sends that
 * entry back to your client and may include an "entry change notification"
 * control that specifies additional information about the change.
 * <P>
 *
 * Typically, you use the <CODE>getResponseControls</CODE> method of
 * the <CODE>LDAPConnection</CODE> object to get any 
 * <CODE>LDAPEntryChangeControl</CODE> objects returned by the server.
 * <P>
 *
 * Once you retrieve an <CODE>LDAPEntryChangeControl</CODE> object from
 * the server, you can get the following additional information about
 * the change made to the entry:
 * <P>
 *
 * <UL>
 * <LI>The type of change made (add, modify, delete, or modify DN)
 * <LI>The change number identifying the record of the change in the
 * change log (if the server supports change logs)
 * <LI>If the entry was renamed, the old DN of the entry
 * </UL>
 * <P>
 *
 * @see org.ietf.ldap.controls.LDAPPersistSearchControl
 * @see org.ietf.ldap.LDAPConnection#getResponseControls
 */

public class LDAPEntryChangeControl extends LDAPControl {

    /**
     * Constructs a new <CODE>LDAPEntryChangeControl</CODE> object.
     * @see org.ietf.ldap.LDAPControl
     * @see org.ietf.ldap.controls.LDAPPersistSearchControl
     */
    public LDAPEntryChangeControl() {
        super(ENTRYCHANGED, false, null);
    }

    /**
     * Contructs an <CODE>LDAPEntryChangedControl</CODE> object. 
     * This constructor is used by <CODE>LDAPControl.register</CODE> to 
     * instantiate entry change controls.
     * @param oid this parameter must be 
     * <CODE>LDAPEntryChangeControl.ENTRYCHANGED</CODE>
     * or an <CODE>LDAPException</CODE> is thrown
     * @param critical <code>true</code> if this control is critical
     * @param value the value associated with this control
     * @exception org.ietf.ldap.LDAPException If oid is not 
     * <CODE>LDAPEntryChangeControl.ENTRYCHANGED</CODE>.
     * @exception java.io.IOException If value is not a valid BER sequence.
     * @see org.ietf.ldap.LDAPControl#register
     */
    public LDAPEntryChangeControl(String oid, boolean critical, byte[] value) 
        throws LDAPException, IOException {
	super(ENTRYCHANGED, false, value);
	
	if (!oid.equals( ENTRYCHANGED )) {
	    throw new LDAPException("oid must be LDAPEntryChangeControl." +
				    "ENTRYCHANGED", LDAPException.PARAM_ERROR);
	}

        
        ByteArrayInputStream inStream = new ByteArrayInputStream(_value);
        BERSequence seq = new BERSequence();
        JDAPBERTagDecoder decoder = new JDAPBERTagDecoder();
        int[] numRead = new int[1];
        numRead[0] = 0;

	BERSequence s = (BERSequence)BERElement.getElement(decoder, inStream,
							   numRead);
	
	BEREnumerated itr = (BEREnumerated)s.elementAt(0);
	    
	_changeTypes = itr.getValue();

	if (s.size() > 1) {
	    if (s.elementAt(1) instanceof BEROctetString) {
	        BEROctetString str = (BEROctetString)s.elementAt(1);
		try {
		    _previousDN = new String(str.getValue(), "UTF8");
		} catch (UnsupportedEncodingException e) {
		}
	    } else if (s.elementAt(1) instanceof BERInteger) {
	        BERInteger num = (BERInteger)s.elementAt(1);
		_changeNumber = num.getValue();
	    }
	}
	if (s.size() > 2) {
	    BERInteger num = (BERInteger)s.elementAt(2);
  	    _changeNumber = num.getValue();
	}
    }
  
    /**
     * Sets the change number (which identifies the record of the change
     * in the server's change log) in this "entry change notification"
     * control.
     * @param num change number to set
     * @see org.ietf.ldap.controls.LDAPEntryChangeControl#getChangeNumber
     */
    public void setChangeNumber(int num) {
        _changeNumber = num;
    }

    /**
     * Sets the change type (which identifies the type of change
     * that occurred) in this "entry change notification" control.
     * @param num change type to set. This can be one of
     * the following values:
     * <P>
     *
     * <UL>
     * <LI><CODE>LDAPPersistSearchControl.ADD</CODE> (a new entry was
     * added to the directory)
     * <LI><CODE>LDAPPersistSearchControl.DELETE</CODE> (an entry was
     * removed from the directory)
     * <LI><CODE>LDAPPersistSearchControl.MODIFY</CODE> (an entry was
     * modified)
     * <LI><CODE>LDAPPersistSearchControl.MODDN</CODE> (an entry was
     * renamed)
     * </UL>
     * <P>
     *
     * @see org.ietf.ldap.controls.LDAPEntryChangeControl#getChangeType
     */
    public void setChangeType(int num) {
        _changeTypes = num;
    }

    /**
     * Sets the previous DN of the entry (if the entry was renamed)
     * in the "entry change notification control".
     * @param dn the previous distinguished name of the entry
     * @see org.ietf.ldap.controls.LDAPEntryChangeControl#getPreviousDN
     */
    public void setPreviousDN(String dn) {
        _previousDN = dn;
    }

    /**
     * Gets the change number, which identifies the record of the change
     * in the server's change log.
     * @return change number identifying the change made.
     * @see org.ietf.ldap.controls.LDAPEntryChangeControl#setChangeNumber
     */
    public int getChangeNumber() {
        return _changeNumber;
    }

    /**
     * Gets the change type, which identifies the type of change
     * that occurred.
     * @return change type identifying the type of change that
     * occurred.  This can be one of the following values:
     * <P>
     *
     * <UL>
     * <LI><CODE>LDAPPersistSearchControl.ADD</CODE> (a new entry was
     * added to the directory)
     * <LI><CODE>LDAPPersistSearchControl.DELETE</CODE> (an entry was
     * removed from the directory)
     * <LI><CODE>LDAPPersistSearchControl.MODIFY</CODE> (an entry was
     * modified)
     * <LI><CODE>LDAPPersistSearchControl.MODDN</CODE> (an entry was
     * renamed)
     * </UL>
     * <P>
     *
     * @see org.ietf.ldap.controls.LDAPEntryChangeControl#setChangeType
     */
    public int getChangeType() {
        return _changeTypes;
    }

    /**
     * Gets the previous DN of the entry (if the entry was renamed).
     * @return the previous distinguished name of the entry.
     * @see org.ietf.ldap.controls.LDAPEntryChangeControl#setPreviousDN
     */
    public String getPreviousDN() {
        return _previousDN;
    }

    public String toString() {
         StringBuffer sb = new StringBuffer("{EntryChangedCtrl:");
        
        sb.append(" isCritical=");
        sb.append(isCritical());
        
        sb.append(" changeTypes=");
        sb.append(LDAPPersistSearchControl.typesToString(_changeTypes));
        
        sb.append(" previousDN=");
        sb.append(_previousDN);
        
        sb.append(" changeNumber=");
        sb.append(_changeNumber);

        sb.append("}");

        return sb.toString();
    }

    private int _changeNumber = -1;
    private int _changeTypes = -1;
    private String _previousDN = null;
    public final static String ENTRYCHANGED = "2.16.840.1.113730.3.4.7";

}