[GROOVY-4641] Defining an abstract method in enum

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.7.6
• Fix Version/s: 2.0.8, 2.1.3, 2.2.0-beta-1
• Component/s: Compiler
• Environment: Mac OS X 10.6.6; IntelliJ 10.0.1
• Assignee: Paul King
• Reporter: Benjamin Muschko
• Created: 24/Jan/11 07:58
• Updated: 12/Apr/13 16:55
• Resolved: 23/Mar/13 21:42

Description

In Java you can define abstract methods for an enum type to override it with a concrete method in a constant-specific class body (see Effective Java, 2nd Ed., page 152). When I try to do the same in Groovy I get a compilation error:

Can't have an abstract method in a non-abstract class. The class 'Day' must be declared abstract or the method 'java.lang.String getAction()' must be implemented.

This compilation error can be reproduced with this enum:

enum Day {
   SUNDAY {
      String getAction() {
         'Relax'
      }
   },
   MONDAY {
       String getAction() {
          'Work'
       }
   }

   abstract String getAction()
}

An enum in Groovy should provide the same behavior for enums as Java.