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 2011-1-21)
   */
  package com.alibaba.cobar.parser.ast.expression.primary;
  
  import java.util.Map;
  
  import com.alibaba.cobar.parser.visitor.SQLASTVisitor;
  
  /**
   * <code>'?'</code>
   * 
   * @author <a href="mailto:shuo.qius@alibaba-inc.com">QIU Shuo</a>
   */
  public class ParamMarker extends PrimaryExpression {
      private final int paramIndex;
  
      /**
       * @param paramIndex start from 1
       */
      public ParamMarker(int paramIndex) {
          this.paramIndex = paramIndex;
      }
  
      /**
       * @return start from 1
       */
      public int getParamIndex() {
          return paramIndex;
      }
  
      @Override
      public int hashCode() {
          return paramIndex;
      }
  
      @Override
      public boolean equals(Object obj) {
          if (obj == this)
              return true;
          if (obj instanceof ParamMarker) {
              ParamMarker that = (ParamMarker) obj;
              return this.paramIndex == that.paramIndex;
          }
          return false;
      }
  
      @Override
      public Object evaluationInternal(Map<? extends Object, ? extends Object> parameters) {
          return parameters.get(paramIndex);
      }
  
      @Override
      public void accept(SQLASTVisitor visitor) {
          visitor.visit(this);
      }
  }
  