recurring event logic

Question

I\'m working on a Groovy/Java calendar-type application that allows the user to enter events with a start date and an optional recurrence. If it\'s a recurring event, it may

Answer 1

I am not very familiar with Groovy library but since Groovy is running on JVM we then I suppose you should be able to use Java / Scala library as well.

What you need here is a professional schedule generation library like Lamma(http://lamma.io) instead of a general purpose date time library like Joda.

    // monthly on a date of the month that corresponds to the start date
    // output: [Date(2014,6,10), Date(2014,7,10), Date(2014,8,10), Date(2014,9,10), Date(2014,10,10)]
    System.out.println(Dates.from(2014, 6, 10).to(2014, 10, 10).byMonth().build());

    // weekly on a day of the week of that corresponds to the start date
    // output: [Date(2014,6,10), Date(2014,6,17), Date(2014,6,24), Date(2014,7,1), Date(2014,7,8)]
    System.out.println(Dates.from(2014, 6, 10).to(2014, 7, 10).byWeek().build());

    // every 2 weeks on a day of the week of that corresponds to the start date
    // output: [Date(2014,6,10), Date(2014,6,24), Date(2014,7,8)]
    System.out.println(Dates.from(2014, 6, 10).to(2014, 7, 10).byWeeks(2).build());

    // edge cases are handled properly, for example, leap day
    // output: [Date(2012,2,29), Date(2013,2,28), Date(2014,2,28), Date(2015,2,28), Date(2016,2,29)]
    System.out.println(Dates.from(2012, 2, 29).to(2016, 2, 29).byYear().build());