Getting all names in an enum as a String[]

Question

What\'s the easiest and/or shortest way possible to get the names of enum elements as an array of Strings?

What I mean by this is that if, for example,

Answer 1

Here's one-liner for any enum class:

public static String[] getNames(Class<? extends Enum<?>> e) {
    return Arrays.stream(e.getEnumConstants()).map(Enum::name).toArray(String[]::new);
}

Pre Java 8 is still a one-liner, albeit less elegant:

public static String[] getNames(Class<? extends Enum<?>> e) {
    return Arrays.toString(e.getEnumConstants()).replaceAll("^.|.$", "").split(", ");
}

That you would call like this:

String[] names = getNames(State.class); // any other enum class will work

If you just want something simple for a hard-coded enum class:

public static String[] names() {
    return Arrays.toString(State.values()).replaceAll("^.|.$", "").split(", ");
}

Answer 2

With java 8:

Arrays.stream(MyEnum.values()).map(Enum::name)
                    .collect(Collectors.toList()).toArray();

Answer 3

Something like this would do:

public static String[] names() {
  String[] names = new String[values().length];
  int index = 0;

  for (State state : values()) {
    names[index++] = state.name();
  }

  return names;
}

The documentation recommends using toString() instead of name() in most cases, but you have explicitly asked for the name here.

Answer 4

I have the same need and use a generic method (inside an ArrayUtils class):

public static <T> String[] toStringArray(T[] array) {
    String[] result=new String[array.length];
    for(int i=0; i<array.length; i++){
        result[i]=array[i].toString();
    }
    return result;
}

And just define a STATIC inside the enum...

public static final String[] NAMES = ArrayUtils.toStringArray(values());

Java enums really miss a names() and get(index) methods, they are really helpful.

Answer 5

i'd do it this way (but i'd probably make names an unmodifiable set instead of an array):

import java.util.Arrays;
enum State {
    NEW,RUNNABLE,BLOCKED,WAITING,TIMED_WAITING,TERMINATED;
    public static final String[] names=new String[values().length];
    static {
        State[] values=values();
        for(int i=0;i<values.length;i++)
            names[i]=values[i].name();
    }
}
public class So13783295 {
    public static void main(String[] args) {
        System.out.println(Arrays.asList(State.names));
    }
}

Answer 6

If you want the shortest you can try

public static String[] names() {
    String test = Arrays.toString(values());
    return text.substring(1, text.length()-1).split(", ");
}