/*

 * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package javax.naming.ldap;

import java.io.IOException;

import com.sun.jndi.ldap.Ber;

import com.sun.jndi.ldap.BerDecoder;

/**

 * Indicates the end of a batch of search results.

 * Contains an estimate of the total number of entries in the result set

 * and an opaque cookie. The cookie must be supplied to the next search

 * operation in order to get the next batch of results.

 * <p>

 * The code sample in {@link PagedResultsControl} shows how this class may

 * be used.

 * <p>

 * This class implements the LDAPv3 Response Control for

 * paged-results as defined in

 * <a href="http://www.ietf.org/rfc/rfc2696">RFC 2696</a>.

 *

 * The control's value has the following ASN.1 definition:

 * <pre>

 *

 *     realSearchControlValue ::= SEQUENCE {

 *         size      INTEGER (0..maxInt),

 *                           -- requested page size from client

 *                           -- result set size estimate from server

 *         cookie    OCTET STRING

 *     }

 *

 * </pre>

 *

 * @since 1.5

 * @see PagedResultsControl

 * @author Vincent Ryan

 */

final public class PagedResultsResponseControl extends BasicControl {

    /**

     * The paged-results response control's assigned object identifier

     * is 1.2.840.113556.1.4.319.

     */

    public static final String OID = "1.2.840.113556.1.4.319";

    private static final long serialVersionUID = -8819778744844514666L;

    /**

     * An estimate of the number of entries in the search result.

     *

     * @serial

     */

    private int resultSize;

    /**

     * A server-generated cookie.

     *

     * @serial

     */

    private byte[] cookie;

    /**

     * Constructs a paged-results response control.

     *

     * @param   id              The control's object identifier string.

     * @param   criticality     The control's criticality.

     * @param   value           The control's ASN.1 BER encoded value.

     *                          It is not cloned - any changes to value

     *                          will affect the contents of the control.

     * @exception IOException   If an error was encountered while decoding

     *                          the control's value.

     */

    public PagedResultsResponseControl(String id, boolean criticality,

        byte[] value) throws IOException {

        super(id, criticality, value);

        // decode value

        BerDecoder ber = new BerDecoder(value, 0, value.length);

        ber.parseSeq(null);

        resultSize = ber.parseInt();

        cookie = ber.parseOctetString(Ber.ASN_OCTET_STR, null);

    }

    /**

     * Retrieves (an estimate of) the number of entries in the search result.

     *

     * @return The number of entries in the search result, or zero if unknown.

     */

    public int getResultSize() {

        return resultSize;

    }

    /**

     * Retrieves the server-generated cookie. Null is returned when there are

     * no more entries for the server to return.

     *

     * @return A possibly null server-generated cookie. It is not cloned - any

     *         changes to the cookie will update the control's state and thus

     *         are not recommended.

     */

    public byte[] getCookie() {

        if (cookie.length == 0) {

            return null;

        } else {

            return cookie;

        }

    }

}