Generalize logic for calendar booking expansion

• Type: Technical Task
• Status: Closed
• Resolution: Fixed
• Affects Version/s: None
• Fix Version/s: 6.2.X EE, 7.0.0 M1
• Component/s: Calendar
• Labels: None
• Branch Version/s:
  6.2.x
• Backported to Branch:
  Committed
• Git Pull Request: https://github.com/brianchandotcom/liferay-plugins/pull/3408

Currently, RecurrenceUtil.expandCalendarBooking(CalendarBooking, long, long, int) returns all instances of an event happening in a time interval up to a maximum number. This works well for retrieving events to be displayed; however, for solving LPS-47404 we also need to get the n-th instance regardless of when it happens.

RecurrenceUtil.expandCalendarBooking() does not solve this problem well but most of its algorithm would be repeated in a RecurrenceUtil.getCalendarBookingInstance() method. For this reason, it is necessary to isolate this more general part of the algorithm so it can be used on both methods.

Steps to reproduce

• None: this ticket is not testable by QA.