Java: Check if enum contains a given string?

Question

Here\'s my problem - I\'m looking for (if it even exists) the enum equivalent of ArrayList.contains();.

Here\'s a sample of my code problem:

<         


        

Answer 1

This should do it:

public static boolean contains(String test) {

    for (Choice c : Choice.values()) {
        if (c.name().equals(test)) {
            return true;
        }
    }

    return false;
}

This way means you do not have to worry about adding additional enum values later, they are all checked.

Edit: If the enum is very large you could stick the values in a HashSet:

public static HashSet<String> getEnums() {

  HashSet<String> values = new HashSet<String>();

  for (Choice c : Choice.values()) {
      values.add(c.name());
  }

  return values;
}

Then you can just do: values.contains("your string") which returns true or false.

Answer 2

You can use valueOf("a1") if you want to look up by String

Answer 3

Guavas Enums could be your friend

Like e.g. this:

enum MyData {
    ONE,
    TWO
}

@Test
public void test() {

    if (!Enums.getIfPresent(MyData.class, "THREE").isPresent()) {
        System.out.println("THREE is not here");
    }
}

Answer 4

You can first convert the enum to List and then use list contains method

enum Choices{A1, A2, B1, B2};

List choices = Arrays.asList(Choices.values());

//compare with enum value 
if(choices.contains(Choices.A1)){
   //do something
}

//compare with String value
if(choices.contains(Choices.valueOf("A1"))){
   //do something
}

Answer 5

I created the next class for this validation

public class EnumUtils {

    public static boolean isPresent(Enum enumArray[], String name) {
        for (Enum element: enumArray ) {
            if(element.toString().equals(name))
                return true;
        }
        return false;
    }

}

example of usage :

public ArrivalEnum findArrivalEnum(String name) {

    if (!EnumUtils.isPresent(ArrivalEnum.values(), name))
        throw new EnumConstantNotPresentException(ArrivalEnum.class,"Arrival value must be 'FROM_AIRPORT' or 'TO_AIRPORT' ");

    return ArrivalEnum.valueOf(name);
}

Answer 6

If you are Using Java 8 or above, you can do this :

boolean isPresent(String testString){
      return Stream.of(Choices.values()).map(Enum::name).collect(Collectors.toSet()).contains(testString);
}