/*
 * 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 2013-2014 ForgeRock AS.
 */
package org.opends.server.replication.protocol;

import java.util.zip.DataFormatException;

/**
 * This message is used by LDAP server or by Replication Servers to
 * update the send window of the remote entities.
 *
 * A receiving entity should create such a message with a given credit
 * when it wants to open the send window of the remote entity.
 * A LDAP or Replication Server should increase its send window when receiving
 * such a message.
 */
public class WindowMsg extends ReplicationMsg
{
  private final int numAck;

  /**
   * Create a new WindowMsg.
   *
   * @param numAck The number of acknowledged messages.
   *               The window will be increase by this credit number.
   */
  public WindowMsg(int numAck)
  {
    this.numAck = numAck;
  }

  /**
   * Creates a new WindowMsg from its encoded form.
   *
   * @param in The byte array containing the encoded form of the
   *           WindowMsg.
   * @throws DataFormatException If the byte array does not contain a valid
   *                             encoded form of the WindowMsg.
   */
  WindowMsg(byte[] in) throws DataFormatException
  {
    final ByteArrayScanner scanner = new ByteArrayScanner(in);
    final byte msgType = scanner.nextByte();
    if (msgType != MSG_TYPE_WINDOW)
    {
      throw new DataFormatException("input is not a valid Window Message");
    }

    numAck = scanner.nextIntUTF8();
  }

  /** {@inheritDoc} */
  @Override
  public byte[] getBytes(short protocolVersion)
  {
    final ByteArrayBuilder builder = new ByteArrayBuilder();
    builder.appendByte(MSG_TYPE_WINDOW);
    builder.appendIntUTF8(numAck);
    return builder.toByteArray();
  }

  /**
   * Get the number of message acknowledged by the Window message.
   *
   * @return the number of message acknowledged by the Window message.
   */
  public int getNumAck()
  {
    return numAck;
  }

  /** {@inheritDoc} */
  @Override
  public String toString()
  {
    return "WindowMsg : " + "numAck: " + numAck;
  }
}