content: /*
   * Copyright 1999-2012 Alibaba Group.
   *  
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *  
   *      http://www.apache.org/licenses/LICENSE-2.0
   *  
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.alibaba.cobar.jdbc.packet;
  
  import com.alibaba.cobar.jdbc.util.MySQLMessage;
  
  /**
   * From server to client after command, if no error and result set -- that is,
   * if the command was a query which returned a result set. The Result Set Header
   * Packet is the first of several, possibly many, packets that the server sends
   * for result sets. The order of packets for a result set is:
   * 
   * <pre>
   * (Result Set Header Packet)   the number of columns
   * (Field Packets)              column descriptors
   * (EOF Packet)                 marker: end of Field Packets
   * (Row Data Packets)           row contents
   * (EOF Packet)                 marker: end of Data Packets
   * 
   * Bytes                        Name
   * -----                        ----
   * 1-9   (Length-Coded-Binary)  field_count
   * 1-9   (Length-Coded-Binary)  extra
   * 
   * @see http://forge.mysql.com/wiki/MySQL_Internals_ClientServer_Protocol#Result_Set_Header_Packet
   * </pre>
   * 
   * @author xianmao.hexm 2010-7-22 下午05:59:55
   */
  public class ResultSetHeaderPacket extends MySQLPacket {
  
      public int fieldCount;
      public long extra;
  
      public void read(BinaryPacket data) {
          this.packetLength = data.packetLength;
          this.packetId = data.packetId;
          MySQLMessage mm = new MySQLMessage(data.value);
          this.fieldCount = (int) mm.readLength();
          if (mm.hasRemaining()) {
              this.extra = mm.readLength();
          }
      }
  
      @Override
      protected String packetInfo() {
          return "MySQL ResultSetHeader Packet";
      }
  
  }
  