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

One way is to define a method asSimple() in your Detailed enum:

public enum Detailed {
    PASSED {
        @Override
        Simple asSimple() {
            return DONE;
        }
    },
    INPROCESS {
        @Override
        Simple asSimple() {
            return RUNNING;
        }
    },
    ERROR1,
    ERROR2,
    ERROR3;
    public Simple asSimple() {
        return Simple.ERROR; // default mapping
    }
}

You can then simply call the method when you want to do the mapping:

Detailed code = . . .
Simple simpleCode = code.asSimple();

It has the advantage of putting the knowledge of the mapping with the Detailed enum (where perhaps it belongs). It has the disadvantage of having knowledge of Simple mixed in with the code for Detailed. This may or may not be a bad thing, depending on your system architecture.