/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
 * or http://forgerock.org/license/CDDLv1.0.html.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at legal-notices/CDDLv1_0.txt.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information:
 *      Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 *
 *      Copyright 2006-2008 Sun Microsystems, Inc.
 *      Portions Copyright 2013-2015 ForgeRock AS.
 */
package org.opends.server.replication.protocol;

import java.util.zip.DataFormatException;

/**
 * This message is used by LDAP or Replication Server that have been out of
 * credit for a while and want to check if the remote servers is able to accept
 * more messages.
 * <p>
 * A sending entity that is blocked because its send window is closed for a
 * while should create such a message to check that the window closure is valid.
 * <p>
 * An entity that received such a message should respond with a
 * {@link WindowMsg} indicating the current credit available.
 */
public class WindowProbeMsg extends ReplicationMsg
{
  /**
   * Create a new WindowProbeMsg message.
   */
  public WindowProbeMsg()
  {
  }

  /**
   * Creates a new WindowProbeMsg from its encoded form.
   *
   * @param in The byte array containing the encoded form of the
   *           WindowMessage.
   * @throws DataFormatException If the byte array does not contain a valid
   *                             encoded form of the WindowMessage.
   */
  public WindowProbeMsg(byte[] in) throws DataFormatException
  {
    // WindowProbeMsg only contains its type.
    if (in[0] != MSG_TYPE_WINDOW_PROBE)
    {
      throw new DataFormatException("input is not a valid WindowProbeMsg");
    }
  }

  /** {@inheritDoc} */
  @Override
  public byte[] getBytes(short protocolVersion)
  {
    // WindowProbeMsg only contains its type.
    return new byte[] { MSG_TYPE_WINDOW_PROBE };
  }
}