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 2011-2-10)
   */
  package com.alibaba.cobar.parser.ast.fragment.tableref;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  import com.alibaba.cobar.parser.ast.ASTNode;
  import com.alibaba.cobar.parser.visitor.SQLASTVisitor;
  
  /**
   * @author <a href="mailto:shuo.qius@alibaba-inc.com">QIU Shuo</a>
   */
  public class IndexHint implements ASTNode {
      public static enum IndexAction {
          USE,
          IGNORE,
          FORCE
      }
  
      public static enum IndexType {
          INDEX,
          KEY
      }
  
      public static enum IndexScope {
          /** not specified */
          ALL,
          JOIN,
          GROUP_BY,
          ORDER_BY
      }
  
      private final IndexAction action;
      private final IndexType type;
      private final IndexScope scope;
      private final List<String> indexList;
  
      public IndexHint(IndexAction action, IndexType type, IndexScope scope, List<String> indexList) {
          super();
          if (action == null)
              throw new IllegalArgumentException("index hint action is null");
          if (type == null)
              throw new IllegalArgumentException("index hint type is null");
          if (scope == null)
              throw new IllegalArgumentException("index hint scope is null");
          this.action = action;
          this.type = type;
          this.scope = scope;
          if (indexList == null || indexList.isEmpty()) {
              this.indexList = Collections.emptyList();
          } else if (indexList instanceof ArrayList) {
              this.indexList = indexList;
          } else {
              this.indexList = new ArrayList<String>(indexList);
          }
      }
  
      public IndexAction getAction() {
          return action;
      }
  
      public IndexType getType() {
          return type;
      }
  
      public IndexScope getScope() {
          return scope;
      }
  
      public List<String> getIndexList() {
          return indexList;
      }
  
      @Override
      public void accept(SQLASTVisitor visitor) {
          visitor.visit(this);
      }
  }
  