How to convert one enum to another enum in java?

Question

I have;

public enum Detailed {     PASSED, INPROCESS, ERROR1, ERROR2, ERROR3; } 

and need to convert it to the following;

public enum Simple {     DONE, RUNNING, ERROR; } 

So first PASSED->DONE and INPROCESS->RUNNING, but all errors should be: ERROR. Obviously it is possible to write cases for all values, but there may be a better solution?

Answer 1

Personally I would just create a Map<Detailed, Simple> and do it explicitly - or even use a switch statement, potentially.

Another alternative would be to pass the mapping into the constructor - you could only do it one way round, of course:

public enum Detailed {     PASSED(Simple.DONE),     INPROCESS(Simple.RUNNING),     ERROR1(Simple.ERROR),     ERROR2(Simple.ERROR),     ERROR3(Simple.ERROR);      private final Simple simple;      private Detailed(Simple simple) {         this.simple = simple;     }      public Simple toSimple() {         return simple;     } } 

(I find this simpler than Ted's approach of using polymorphism, as we're not really trying to provide different behaviour - just a different simple mapping.)

While you could potentially do something cunning with the ordinal value, it would be much less obvious, and take more code - I don't think there'd be any benefit.