public JoinType flip() {
      switch (this) {
        case INNER:
          return INNER;
        case FULL:
          return FULL;
        case LEFT:
          return RIGHT;
        case RIGHT:
          return LEFT;
        default:
      }
      throw new IllegalArgumentException("Unsupported join type: " + this);
    }
@return a new JoinNode with the flipped attributes
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/relational/planner/node/JoinNode.java