content: /*
   * Copyright 1999-2017 Alibaba Group Holding Ltd.
   *
   * 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.druid.sql.visitor;
  
  import com.alibaba.druid.sql.visitor.functions.Function;
  
  import java.util.List;
  
  public interface SQLEvalVisitor extends SQLASTVisitor {
      public static final String EVAL_VALUE = "eval.value";
      public static final String EVAL_EXPR = "eval.expr";
      public static final Object EVAL_ERROR = new Object();
      public static final Object EVAL_VALUE_COUNT = new Object();
      public static final Object EVAL_VALUE_NULL = new Object();
  
      Function getFunction(String funcName);
  
      void registerFunction(String funcName, Function function);
  
      void unregisterFunction(String funcName);
  
      List<Object> getParameters();
  
      void setParameters(List<Object> parameters);
  
      int incrementAndGetVariantIndex();
  
      boolean isMarkVariantIndex();
  
      void setMarkVariantIndex(boolean markVariantIndex);
  }
  