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.heartbeat;
  
  import com.alibaba.cobar.config.ErrorCode;
  import com.alibaba.cobar.exception.HeartbeatException;
  import com.alibaba.cobar.net.handler.BackendAsyncHandler;
  import com.alibaba.cobar.net.mysql.EOFPacket;
  import com.alibaba.cobar.net.mysql.ErrorPacket;
  import com.alibaba.cobar.net.mysql.OkPacket;
  
  /**
   * @author xianmao.hexm
   */
  public class MySQLDetectorHandler extends BackendAsyncHandler {
      private static final int RESULT_STATUS_INIT = 0;
      private static final int RESULT_STATUS_HEADER = 1;
      private static final int RESULT_STATUS_FIELD_EOF = 2;
  
      private final MySQLDetector source;
      private volatile int resultStatus;
  
      public MySQLDetectorHandler(MySQLDetector source) {
          this.source = source;
          this.resultStatus = RESULT_STATUS_INIT;
      }
  
      @Override
      public void handle(byte[] data) {
          offerData(data, source.getProcessor().getExecutor());
      }
  
      @Override
      protected void offerDataError() {
          dataQueue.clear();
          resultStatus = RESULT_STATUS_INIT;
          throw new HeartbeatException("offer data error!");
      }
  
      @Override
      protected void handleData(byte[] data) {
          switch (resultStatus) {
          case RESULT_STATUS_INIT:
              switch (data[4]) {
              case OkPacket.FIELD_COUNT:
                  handleOkPacket();
                  break;
              case ErrorPacket.FIELD_COUNT:
                  handleErrorPacket(data);
                  break;
              default:
                  resultStatus = RESULT_STATUS_HEADER;
              }
              break;
          case RESULT_STATUS_HEADER:
              switch (data[4]) {
              case ErrorPacket.FIELD_COUNT:
                  resultStatus = RESULT_STATUS_INIT;
                  handleErrorPacket(data);
                  break;
              case EOFPacket.FIELD_COUNT:
                  resultStatus = RESULT_STATUS_FIELD_EOF;
                  break;
              }
              break;
          case RESULT_STATUS_FIELD_EOF:
              switch (data[4]) {
              case ErrorPacket.FIELD_COUNT:
                  resultStatus = RESULT_STATUS_INIT;
                  handleErrorPacket(data);
                  break;
              case EOFPacket.FIELD_COUNT:
                  resultStatus = RESULT_STATUS_INIT;
                  handleRowEofPacket();
                  break;
              }
              break;
          default:
              throw new HeartbeatException("unknown status!");
          }
      }
  
      @Override
      protected void handleDataError(Throwable t) {
          dataQueue.clear();
          resultStatus = RESULT_STATUS_INIT;
          source.error(ErrorCode.ERR_HANDLE_DATA, t);
      }
  
      /**
       * OK数据包处理
       */
      private void handleOkPacket() {
          source.getHeartbeat().setResult(MySQLHeartbeat.OK_STATUS, source, false);
      }
  
      /**
       * ERROR数据包处理
       */
      private void handleErrorPacket(byte[] data) {
          ErrorPacket err = new ErrorPacket();
          err.read(data);
          throw new HeartbeatException(new String(err.message));
      }
  
      /**
       * 行数据包结束处理
       */
      private void handleRowEofPacket() {
          source.getHeartbeat().setResult(MySQLHeartbeat.OK_STATUS, source, false);
      }
  
  }
  