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 2011-5-10)
   */
  package com.alibaba.cobar.parser.ast.fragment.tableref;
  
  import com.alibaba.cobar.parser.ast.ASTNode;
  
  /**
   * @author <a href="mailto:shuo.qius@alibaba-inc.com">QIU Shuo</a>
   */
  public interface TableReference extends ASTNode {
      int PRECEDENCE_REFS = 0;
      int PRECEDENCE_JOIN = 1;
      int PRECEDENCE_FACTOR = 2;
  
      /**
       * remove last condition element is success
       * 
       * @return {@link java.util.List List&lt;String&gt;} or
       *         {@link com.alibaba.cobar.parser.ast.expression.Expression
       *         Expression}. null if last condition element cannot be removed.
       */
      Object removeLastConditionElement();
  
      /**
       * @return true if and only if there is one table (not subquery) in table
       *         reference
       */
      public boolean isSingleTable();
  
      /**
       * @return precedences are defined in {@link TableReference}
       */
      int getPrecedence();
  }
  