Enum of days in Java with Calendar

Question

I would like to know if there is an existing enum containing all the week days in Java. I'm using Calendar to treat time logic but I didn't see anything like this (I could create it myself but I 'd rather use something existing). I also saw the threeten project but it's still in alpha. Since an enum containing days of week is so trivial it's shown by sun in the enum documentation, I was thinking something may already exist. Any ideas ?

Answer 1

You want new DateFormatSymbols().getWeekdays().

Answer 2

The troublesome old date-time classes such as java.util.Calendar are now legacy, supplanted by java.time classes.

java.time.DayOfWeek enum

Java now includes the java.time.DayOfWeek enum.

Pass around objects of this enum rather than mere integers 1-7 to make your code more self-documenting, provide type-safety, and ensure a range of valid values.

invoices.printReportForDayOfWeek( DayOfWeek.MONDAY );

Numbering is 1-7 for Monday to Sunday, per ISO 8601 standard.

Get a localized name of the day by calling getDisplayName.

String output = DayOfWeek.MONDAY.getDisplayName( TextStyle.FULL , Locale.CANADA_FRENCH ) ;  // Or Locale.US, etc.

To track multiple days of the week, use an EnumSet (implementation of Set) or EnumMap (implementation of Map).

Set<DayOfWeek> weekend = EnumSet.of( DayOfWeek.SATURDAY , DayOfWeek.SUNDAY ) ;
…
Boolean todayIsWeekend = weekend.contains( LocalDate.now( ZoneId.of( "America/Montreal" ) ).getDayOfWeek() );

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the old troublesome date-time classes such as java.util.Date, .Calendar, & java.text.SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to java.time.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations.

Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport and further adapted to Android in ThreeTenABP.

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.