How to cast an enum ordinal as a String?

Question

I need to pass the ordinal value of an enum as a parameter to a HashMap<String, String>. In other words, I want to cast an ordinal as a String.

Right now, I'm doing this:

HashMap<String, String> myHashMap = new HashMap<String, String>();
myHashMap.put("foo", String.format("%s", MyEnum.BAR.ordinal()));

Is that the best way? The .toString() method isn't available here, and (String)MyEnum.BAR.ordinal() doesn't work.

Why are you using this construct? There are a number of cleaner ways organize the code, most notably with Map<String, MyEnum>. — chrylis -cautiouslyoptimistic-
– chrylis -cautiouslyoptimistic-, Commented Sep 25, 2013 at 14:41
@chrylis That would require major refactoring and affect many other things. — Shaun Scovil
– Shaun Scovil, Commented Sep 25, 2013 at 14:43

nachokk · Accepted Answer · 2013-09-25 14:41:44Z

2

You also could use

String.valueOf()

myHashMap.put("foo", String.valueOf(MyEnum.BAR.ordinal()));

answered Sep 25, 2013 at 14:41

nachokk

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Comments

Peter Lawrey · Accepted Answer · 2013-09-25 14:41:35Z

1

The ordinal() is an internal number which could change. I suggest you just use

Map<String, String> myMap = new HashMap<>();
myMap.put("foo", MyEnum.BAR.toString());

or

Map<String, Object> myMap = new HashMap<>();
myMap.put("foo", MyEnum.BAR);

or

Map<String, MyEnum> myMap = new HashMap<>();
myMap.put("foo", MyEnum.BAR);

answered Sep 25, 2013 at 14:41

Peter Lawrey

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2 Comments

Peter Lawrey Over a year ago

@chrylis You are right, but I thought that might be too much of a change. ;)

chrylis -cautiouslyoptimistic- Over a year ago

I honestly couldn't think of any situation where it makes sense that you'd want to store a String representation and store the ordinal simultaneously... something smells with the whole API, and this is the point where I put on my refactoring boots!

Evgeniy Dorofeev · Accepted Answer · 2013-09-25 14:42:04Z

1

The best way if you used HashMap<String, Integer> and did not convert ordinal to String

answered Sep 25, 2013 at 14:42

Evgeniy Dorofeev

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Comments

Reimeus · Accepted Answer · 2013-09-25 15:04:12Z

1

You could use

myHashMap.put("foo", String.format("%d", Integer.toString(MyEnum.BAR.ordinal())));

or simply (credit @OldCurmudgeon)

myHashMap.put("foo", Integer.toString(MyEnum.BAR.ordinal()));

Disclaimer: Would have to agree with comments that using Map<String, MyEnum> is a better approach

edited Sep 25, 2013 at 15:04

answered Sep 25, 2013 at 14:39

Reimeus

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2 Comments

OldCurmudgeon Over a year ago

Or even myHashMap.put("foo", ""+ MyEnum.BAR.ordinal());

Luiggi Mendoza Over a year ago

Or even easier: myHashMap.put("foo", Integer.toString(MyEnum.BAR.ordinal()));. @OldCurmudgeon it is not a good practice convert something to String using "" + concatenation, the fact that works doesn't mean is good.

farincz · Accepted Answer · 2013-09-25 14:45:45Z

0

I guess it is better to use enum name as key

MyEnum.BAR.name()

and conversion back

MyEnum.valueOf("BAR")

answered Sep 25, 2013 at 14:45

farincz

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