/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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 org.apache.shardingsphere.sql.parser.sql.common.statement.dml;
  
  import lombok.Getter;
  import lombok.Setter;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.combine.CombineSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.item.ProjectionsSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.order.GroupBySegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.order.OrderBySegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.predicate.HavingSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.predicate.WhereSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.generic.table.TableSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.statement.AbstractSQLStatement;
  
  import java.util.Optional;
  
  /**
   * Select statement.
   */
  @Getter
  @Setter
  public abstract class SelectStatement extends AbstractSQLStatement implements DMLStatement {
      
      private ProjectionsSegment projections;
      
      private TableSegment from;
      
      private WhereSegment where;
      
      private GroupBySegment groupBy;
      
      private HavingSegment having;
      
      private OrderBySegment orderBy;
      
      private CombineSegment combine;
      
      /**
       * Get from.
       *
       * @return from table segment
       */
      public Optional<TableSegment> getFrom() {
          return Optional.ofNullable(from);
      }
      
      /**
       * Get where.
       *
       * @return where segment
       */
      public Optional<WhereSegment> getWhere() {
          return Optional.ofNullable(where);
      }
      
      /**
       * Get group by segment.
       *
       * @return group by segment
       */
      public Optional<GroupBySegment> getGroupBy() {
          return Optional.ofNullable(groupBy);
      }
      
      /**
       * Get having segment.
       *
       * @return having segment
       */
      public Optional<HavingSegment> getHaving() {
          return Optional.ofNullable(having);
      }
      
      /**
       * Get order by segment.
       *
       * @return order by segment
       */
      public Optional<OrderBySegment> getOrderBy() {
          return Optional.ofNullable(orderBy);
      }
      
      /**
      * Get combine segment.
      *
      * @return combine segment
      */
     public Optional<CombineSegment> getCombine() {
         return Optional.ofNullable(combine);
     }
 }