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:

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Answer 1

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);

Answer 2

Even better:

enum choices {
   a1, a2, b1, b2;

  public static boolean contains(String s)
  {
      for(choices choice:values())
           if (choice.name().equals(s)) 
              return true;
      return false;
  } 

};

Answer 3

This one works for me:

Arrays.asList(YourEnum.values()).toString().contains("valueToCheck");

Answer 4

Few assumptions:
1) No try/catch, as it is exceptional flow control
2) 'contains' method has to be quick, as it usually runs several times.
3) Space is not limited (common for ordinary solutions)

import java.util.HashSet;
import java.util.Set;

enum Choices {
    a1, a2, b1, b2;

    private static Set<String> _values = new HashSet<>();

    // O(n) - runs once
    static{
        for (Choices choice : Choices.values()) {
            _values.add(choice.name());
        }
    }

    // O(1) - runs several times
    public static boolean contains(String value){
        return _values.contains(value);
    }
}

Answer 5

com.google.common.collect.Sets.newHashSet(MyEnum.values()).contains("myValue")

Answer 6

Use the Apache commons lang3 lib instead

 EnumUtils.isValidEnum(MyEnum.class, myValue)