interface enum and updates

gudii9
gudii9 used Ask the Experts™
on
It’s a very bad idea to create an interface which is solely for declaring some constants without any methods. Here’s such an interface:
1
2
3
4
5
public interface Color {
    public static final int RED = 0xff0000;
    public static final int BLACK = 0x000000;
    public static final int WHITE = 0xffffff;
}
It’s because the purpose of interfaces is for inheritance and polymorphism, not for static stuffs like that. So the best practice recommends us to use an enum instead. For example:
1
2
3
public enum Color {
    BLACK, WHITE, RED
}
In case the color code does matter, we can update the enum like this:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
public enum Color {
 
    BLACK(0x000000),
    WHITE(0xffffff),
    RED(0xff0000);
 
    private int code;
 
    Color(int code) {
        this.code = code;
    }
 
    public int getCode() {
        return this.code;
    }
}

Open in new window


what is the meaning of color code does not matter and updating like below?

In case the color code does matter, we can update the enum like this:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
public enum Color {
 
    BLACK(0x000000),
    WHITE(0xffffff),
    RED(0xff0000);
 
    private int code;
 
    Color(int code) {
        this.code = code;
    }
 
    public int getCode() {
        return this.code;
    }
}

Open in new window

https://www.codejava.net/coding/10-java-core-best-practices-every-java-programmer-should-know

when we create special AppConstants class?
can there be interface just for constants?
please advise
Comment
Watch Question

Do more with

Expert Office
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
Consulting
Distinguished Expert 2017
Commented:
Hi,

Maybe take a look at the Services Locator design pattern.

Do more with

Expert Office
Submit tech questions to Ask the Experts™ at any time to receive solutions, advice, and new ideas from leading industry professionals.

Start 7-Day Free Trial