enum of Color Codes

Question

I have a Color enum :

public enum Color {
    YELLOW(0), RED(1), GREEN(2), BLUE(3), GRAY(4), CYAN(5), BLACK(6), MAGENTA(7);

    int colorCode;

    Color(int colorCode) {
        this.colorCode = colorCode;
    }

    public int getColorCode() {
        return this.colorCode;
    }

    public Color getColor(int colorCode) {
        return Color.this.colorCode;
    }
}

I want to return a Color depending of colorCode, but I got a exception

incompatibles Types int and Color

How can I solve this? Any help would be appreciated.

Solution

You can use :

public static Color getColor(int colorCode) {
    for (Color c : Color.values()) {
        if (c.getColorCode() == colorCode)
            return c;
    }
    return NOT_DEFINE;
}

Note I defined another enum NOT_DEFINE(8) in case the code not exit and return it in the end of the getColor.

---

But I would like to create a Map which hold Map<colorCode, Color> so you can get the colors easily with key without looping over the values of the enum each time

static Map<Integer, Color> mapOfColord = new HashMap<>();

static {
    Map<Integer, Color> colors = new HashMap<>();
    for (Color color : Color.values()) {
        colors.put(color.colorCode, color);
    }
    mapOfColord = Collections.unmodifiableMap(colors);
}

Or you can stick with the first method which take the key and return the Color like so :

private static Map<Integer, Color> mapOfColord = new HashMap<>();

static {
    for (Color color : Color.values()) {
        mapOfColord.put(color.colorCode, color);
    }
}

public static Color getColor(Integer key) {
    return mapOfColord.get(key);
}

So you can get the Color like this for example :

int key = 3;
Color blue = Color.mapOfColord.get(key);

Or :

Color blue = Color.getColor(key);

---

Thank you @Andy Turner for the information, I appreciate it.

Comments

[matoni]

Enums have "ordinal" number associated with each value. Ordinal corresponds to "definition index", so you can simply write Color.values()[index] to get Color at specified index.

[Andy Turner]

You should make that method static too. And in any case, you shouldn't refer to NOT_EXIST via this.

[Andy Turner]

you don't want it to be an instance method. That would mean you would need an instance of Color on which to invoke the method to get an instance of Color from an int.

[Andy Turner]

You similarly want the Map to be static, in order that you don't have an copy of that map for every enum value.

[Marten]

Thank you @YCF_L and Andy Turner it helps me a lot.

[Youcef Laidani]

@AndyTurner I can't make the Map static It will gives you illegal reference to static field from initializer

[Andy Turner]

@YCL_L given that it is a static field that you are initializing, use a static initializer.

[Youcef Laidani]

@AndyTurner Its my first time that I use that maybe thank you for teaching me that, Is that what you mean?

[Andy Turner]

@YCF_L you should also either make the map unmodifiable, or only expose a method to get the Color. Otherwise you can change the values in the map (e.g. remove them all using Color.mapOfColord.clear()).

[Youcef Laidani]

Thank you @AndyTurner for the information I really appreciate it, what should I do more :)