Passing Array Constant to enum Constructor [duplicate]

Question

Java enum lets you pass arguments to the constructor, but I can't seem to pass an array. For instance, the following code compiles with out error:

enum Color {
    RED(255,0,0),
    GREEN(0,255,0),
    BLUE(0,0,255);

    int[] rgb;

    Color(int r, int g, int b) {
        rgb[0] = r;
        rgb[1] = g;
        rgb[2] = b;
    }
}

But if this same data is passed in as an array constant, the code will not compile:

enum Color {
    RED({255,0,0}),
    GREEN({0,255,0}),
    BLUE({0,0,255});

    int[] rgb;

    Color(int[] rgb) {
        this.rgb = rgb;
    }
}

I have also tried variations of creating a new int[] array, like:

...
RED(new int[]{255,0,0}),
...

with no luck. I think the problem lies in passing an array constant. I'm not sure if it is a simple syntax that needs to be corrected or if there is an underlying problem with passing this type of data. Thanks in advance.

RED(new int[]{255,0,0}) should work fine, although @Mark Peters's solution is ideal. — Priyal
– Priyal, Commented Aug 3, 2016 at 9:49

Mark Peters · Accepted Answer · 2014-05-26 05:23:56Z

7

You can't use the literal form here, because that syntax is only allowed in the declaration of the variable. But you could use the varargs syntactic sugar, which is actually shorter.

enum Color {
    RED(255,0,0),
    GREEN(0,255,0),
    BLUE(0,0,255);

    int[] rgb;

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

And contrary to what you have said, RED(new int[]{255, 0, 0}) works just fine.

edited May 26, 2014 at 5:23

answered May 26, 2014 at 5:18

Mark Peters

81.3k17 gold badges163 silver badges196 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Cory N. Over a year ago

Thanks. I only tried the new int[] for a single line, which is why it didn't work. When I replaced all three lines, it did however work. Good point about the varags.

John Over a year ago

Varargs won't work for more than one array at the end of the arg list; in that case, array constructor new T[] is helpful. Therefore, can we say that the syntax is allowed as a literal argument to the enum element?

Collectives™ on Stack Overflow

Passing Array Constant to enum Constructor [duplicate]

1 Answer 1

2 Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Linked

Related