Question

I have the following enum in a Java class:

public enum Resolution {
    RES_32 (32),
    RES_64 (64);
    private final int asInt;
    private Resolution(int asInt) {
        this.asInt = asInt;
    }
};

I have more classes that need a similar kind of enum, with the same asInt property and the same constructor, but with different constants. So, in another class, I need the following enum:

public enum Resolution {
    RES_32 (32),
    RES_64 (64),
    RES_128 (128);
    private final int asInt;
    private Resolution(int asInt) {
        this.asInt = asInt;
    }
};

If this was a class, I could use inheritance to not repeat the code in the constructor (and would likely have made a getter for that asInt property). What can I do in order to stop repeating myself each time I need such a Resolution enum? Ideally, I would like to just specify the constants for each Resolution, and to have the constructor and property kept.

Answer 1

EnumSet may be helpful in this context. Given the following,

public enum Resolution {

    RES_32(32),
    RES_64(64),
    RES_128(128),
    RES_256(256);

    public static Set<Resolution> deluxe = EnumSet.allOf(Resolution.class);
    public static Set<Resolution> typical = EnumSet.range(RES_64, RES_128);
    public static Set<Resolution> ecomomy = EnumSet.of(RES_32);

    private final int asInt;

    private Resolution(int asInt) {
        this.asInt = asInt;
    }
};

Suitably named sets may be used as shown below.

for (Resolution r : Resolution.deluxe) {
    System.out.println(r.asInt);
}