Java: Check if enum contains a given string?

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:

enum choices {a1, a2, b1, b2};

if(choices.???(a1)}{
//do this
}

Now, I realize that an ArrayList of Strings would be the better route here but I have to run my enum contents through a switch/case elsewhere. Hence my problem.

Assuming something like this doesn't exist, how could I go about doing it?

Use the Apache commons lang3 lib instead

 EnumUtils.isValidEnum(MyEnum.class, myValue)

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.

You can use Enum.valueOf()

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

public class MainClass {
  public static void main(String args[]) {
    Choices day;

    try {
       day = Choices.valueOf("A1");
       //yes
    } catch (IllegalArgumentException ex) {  
        //nope
  }
}

If you expect the check to fail often, you might be better off using a simple loop as other have shown - if your enums contain many values, perhaps builda HashSet or similar of your enum values converted to a string and query that HashSet instead.

If you are using Java 1.8, you can choose Stream + Lambda to implement this:

public enum Period {
    DAILY, WEEKLY
};

//This is recommended
Arrays.stream(Period.values()).anyMatch((t) -> t.name().equals("DAILY1"));
//May throw java.lang.IllegalArgumentException
Arrays.stream(Period.values()).anyMatch(Period.valueOf("DAILY")::equals);

Java: Check if enum contains a given string?

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