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.
   */
  /**
   * (created at 2011-7-27)
   */
  package com.alibaba.cobar.parser.ast.fragment.tableref;
  
  import com.alibaba.cobar.parser.ast.expression.primary.Identifier;
  import com.alibaba.cobar.parser.ast.expression.primary.literal.LiteralString;
  
  /**
   * @author <a href="mailto:shuo.qius@alibaba-inc.com">QIU Shuo</a>
   */
  public abstract class AliasableTableReference implements TableReference {
      protected final String alias;
      protected String aliasUpEscape;
  
      public AliasableTableReference(String alias) {
          this.alias = alias;
      }
  
      /**
       * @return upper-case, empty is possible
       */
      public String getAliasUnescapeUppercase() {
          if (alias == null || alias.length() <= 0)
              return alias;
          if (aliasUpEscape != null)
              return aliasUpEscape;
  
          switch (alias.charAt(0)) {
          case '`':
              return aliasUpEscape = Identifier.unescapeName(alias, true);
          case '\'':
              return aliasUpEscape = LiteralString.getUnescapedString(alias.substring(1, alias.length() - 1), true);
          case '_':
              int ind = -1;
              for (int i = 1; i < alias.length(); ++i) {
                  if (alias.charAt(i) == '\'') {
                      ind = i;
                      break;
                  }
              }
              if (ind >= 0) {
                  LiteralString st = new LiteralString(alias.substring(0, ind), alias.substring(
                          ind + 1,
                          alias.length() - 1), false);
                  return aliasUpEscape = st.getUnescapedString(true);
              }
          default:
              return aliasUpEscape = alias.toUpperCase();
          }
      }
  
      public String getAlias() {
          return alias;
      }
  }
  