content: /*
   * Copyright 2021-2022 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.aliyun.fastmodel.core.tree.relation;
  
  import java.util.List;
  
  import com.aliyun.fastmodel.core.tree.AbstractNode;
  import com.aliyun.fastmodel.core.tree.BaseRelation;
  import com.aliyun.fastmodel.core.tree.IAstVisitor;
  import com.aliyun.fastmodel.core.tree.Node;
  import com.aliyun.fastmodel.core.tree.NodeLocation;
  import com.aliyun.fastmodel.core.tree.relation.join.JoinCriteria;
  import com.aliyun.fastmodel.core.tree.relation.join.JoinToken;
  import com.google.common.collect.ImmutableList;
  import lombok.EqualsAndHashCode;
  import lombok.Getter;
  import lombok.ToString;
  
  /**
   * join statement
   *
   * @author panguanjing
   * @date 2020/10/20
   */
  @Getter
  @ToString
  @EqualsAndHashCode(callSuper = false)
  public class Join extends BaseRelation {
  
      /**
       * join statement
       */
      private final JoinCriteria criteria;
  
      /**
       * join的类型，包括常用的left，right等等
       */
      private final JoinToken joinToken;
  
      /**
       * 左边的表达式
       */
      private final BaseRelation left;
  
      /**
       * 右边的表达式
       */
      private final BaseRelation right;
  
      public Join(NodeLocation location,
                  JoinToken joinToken, BaseRelation left, BaseRelation right, JoinCriteria criteria) {
          super(location);
          this.criteria = criteria;
          this.joinToken = joinToken;
          this.left = left;
          this.right = right;
      }
  
      public Join(JoinToken joinToken, BaseRelation left, BaseRelation right, JoinCriteria criteria) {
          this(null, joinToken, left, right, criteria);
      }
  
      @Override
      public List<? extends Node> getChildren() {
          ImmutableList.Builder<Node> nodeBuilder = ImmutableList.builder();
          nodeBuilder.add(left);
          nodeBuilder.add(right);
          if (criteria != null) {
              List<AbstractNode> nodes = criteria.getNodes();
              nodeBuilder.addAll(nodes);
          }
          return nodeBuilder.build();
      }
  
      @Override
      public <R, C> R accept(IAstVisitor<R, C> visitor, C context) {
          return visitor.visitJoin(this, context);
      }
  }
  