Find the remaining Enum

Question

I have the Enum A, B, C. In a method, I am given two different Enum and must return the remaining Enum.

Example: I receive A and C I must return B

The solution that I have is to use if elseif else:

private EnumABC findRemaining(EnumABC pEnum1, EnumABC pEnum2){
    if((pEnum1 == EnumABC.A || pEnum2 == EnumABC.A) 
        && (pEnum1 == EnumABC.B || pEnum2 == EnumABC.B)){
        return EnumABC.C; 
    } else
    if((pEnum1 == EnumABC.A || pEnum2 == EnumABC.A)
        && (pEnum1 == EnumABC.C || pEnum2 == EnumABC.C)){
        return EnumABC.B;
    } else{
       return EnumABC.A;
    }
}

I was wondering if there was a more readable solution then this.

Answer 1

tl;dr

enum Animal { DOG , CAT , BIRD }
EnumSet<Animal> flyingAnimals = EnumSet.complementOf ( EnumSet.of( DOG , CAT ) )

EnumSet.complementOf

You can make a Set of enum objects. Indeed, you can make a highly performant EnumSet.

enum Animal { DOG , CAT , BIRD }
EnumSet<Animal> furry = EnumSet.of( DOG , CAT ) ;

Ask for those enum objects not found in an EnumSet by calling the static method EnumSet.complementOf.

EnumSet<Animal> nonFurry = EnumSet.complementOf ( furry ) ;

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Tip: You can define an enum locally in modern Java. Ditto for interface and record.