Unique enum member values

Question

My problem: I want to specify a 1 to 1 connection between two enums. basically:

enum MyEnum{

    ENUM_VALUE_1,
    ENUM_VALUE_2,
    ENUM_VALUE_3,

}

enum          


        

Answer 1

I put the "why" aside and try to answer your question:

Create a static block in MyOtherEnum that performs the check:

static{
    // This set stores all the used values
    EnumSet usedValues = EnumSet.noneOf(MyEnum.class);

    for(MyOtherEnum e : values()){
        // Value already present in the set?
        if(usedValues.contains(e.pair)) throw ...; // Duplicate 
        usedValues.add(e);
    }
}

But I have to agree with the comments: Instead of writing this check, you can also simply look at your code :).