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.manager.parser;
  
  import com.alibaba.cobar.parser.util.ParseUtil;
  
  /**
   * @author xianmao.hexm
   */
  public final class ManagerParseRollback {
  
      public static final int OTHER = -1;
      public static final int CONFIG = 1;
      public static final int ROUTE = 2;
      public static final int USER = 3;
  
      public static int parse(String stmt, int offset) {
          int i = offset;
          for (; i < stmt.length(); i++) {
              switch (stmt.charAt(i)) {
              case ' ':
                  continue;
              case '/':
              case '#':
                  i = ParseUtil.comment(stmt, i);
                  continue;
              case '@':
                  return rollback2Check(stmt, i);
              default:
                  return OTHER;
              }
          }
          return OTHER;
      }
  
      static int rollback2Check(String stmt, int offset) {
          if (stmt.length() > ++offset && stmt.charAt(offset) == '@') {
              if (stmt.length() > ++offset) {
                  switch (stmt.charAt(offset)) {
                  case 'C':
                  case 'c':
                      return rollback2CCheck(stmt, offset);
                  case 'R':
                  case 'r':
                      return rollback2RCheck(stmt, offset);
                  case 'U':
                  case 'u':
                      return rollback2UCheck(stmt, offset);
                  default:
                      return OTHER;
                  }
              }
          }
          return OTHER;
      }
  
      // ROLLBACK @@CONFIG
      static int rollback2CCheck(String stmt, int offset) {
          if (stmt.length() > offset + 5) {
              char c1 = stmt.charAt(++offset);
              char c2 = stmt.charAt(++offset);
              char c3 = stmt.charAt(++offset);
              char c4 = stmt.charAt(++offset);
              char c5 = stmt.charAt(++offset);
              if ((c1 == 'O' || c1 == 'o') && (c2 == 'N' || c2 == 'n') && (c3 == 'F' || c3 == 'f')
                      && (c4 == 'I' || c4 == 'i') && (c5 == 'G' || c5 == 'g')) {
                  if (stmt.length() > ++offset && stmt.charAt(offset) != ' ') {
                      return OTHER;
                  }
                  return CONFIG;
              }
          }
          return OTHER;
      }
  
      // ROLLBACK @@ROUTE
      static int rollback2RCheck(String stmt, int offset) {
          if (stmt.length() > offset + 4) {
              char c1 = stmt.charAt(++offset);
              char c2 = stmt.charAt(++offset);
              char c3 = stmt.charAt(++offset);
              char c4 = stmt.charAt(++offset);
              if ((c1 == 'O' || c1 == 'o') && (c2 == 'U' || c2 == 'u') && (c3 == 'T' || c3 == 't')
                      && (c4 == 'E' || c4 == 'e')) {
                  if (stmt.length() > ++offset && stmt.charAt(offset) != ' ') {
                      return OTHER;
                  }
                  return ROUTE;
              }
          }
          return OTHER;
      }
  
      // ROLLBACK @@USER
      static int rollback2UCheck(String stmt, int offset) {
          if (stmt.length() > offset + 3) {
              char c1 = stmt.charAt(++offset);
              char c2 = stmt.charAt(++offset);
              char c3 = stmt.charAt(++offset);
              if ((c1 == 'S' || c1 == 's') && (c2 == 'E' || c2 == 'e') && (c3 == 'R' || c3 == 'r')) {
                  if (stmt.length() > ++offset && stmt.charAt(offset) != ' ') {
                      return OTHER;
                  }
                  return USER;
              }
          }
          return OTHER;
      }
  
  }
  