/*
 * The contents of this file are subject to the terms of the Common Development and
 * Distribution License (the License). You may not use this file except in compliance with the
 * License.
 *
 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
 * specific language governing permission and limitations under the License.
 *
 * When distributing Covered Software, include this CDDL Header Notice in each file and include
 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
 * Header, with the fields enclosed by brackets [] replaced by your own identifying
 * information: "Portions Copyright [year] [name of copyright owner]".
 *
 * 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 };
  }
}