[HIVE-15518] Refactoring rows and range related classes to put the window type on Window

• Type: Sub-task
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 2.3.0
• Component/s: PTF-Windowing
• Assignee: Aihua Xu
• Reporter: Aihua Xu
• Created: 27/Dec/16 16:36
• Updated: 21/Jul/17 18:35
• Resolved: 04/Jan/17 16:18

Description

  /*
   * - A Window Frame that has only the /start/boundary, then it is interpreted as:
         BETWEEN <start boundary> AND CURRENT ROW
   * - A Window Specification with an Order Specification and no Window
   *   Frame is interpreted as:
         ROW BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW
   * - A Window Specification with no Order and no Window Frame is interpreted as:
         ROW BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
   */

The comments in WindowSpec above doesn't really match what it's claimed to do. Correct the comment to reduce the confusion.

Also currently the window type is specified on each BoundarySpec but makes sense to put the type (rows or range) for each window.