How to retrieve Enum name using the id?

Question

I have the enum as:

public enum EnumStatus {

    PASSED(40L, \"Has Passed\"),
    AVERAGE(60L, \"Has Average Marks\"),
    GOOD(80L, \"Has Good         


        

Answer 1

Sometimes the enum's ordinal has a clear relationship with this kind of ids, enabling a neat way to get O(1) in these methods. In your code, it is clear that

EnumStatus.X = 40 + 20 * ordinal,

so you can leverage the static array that is generated under the hoods.

public static EnumStatus fromId(Long id) {
    int index = (id - 40L) / 20L;
    return values()[index];
}