Question

After doing some research, I see since java 1.5 it is preferable to manage constants (or key properties) in enum which are declared in a “constant” class.

I’d like to know what is the proper way to implement these enum to get as simple as possible the value of an element of an enum whatever its type.

Example : is it possible to have the value of “Constant.Messages.WARNING” where Messages is :

public enum Messages {

    WARNING("main.message.warning")

}

Thank you.

Answer 1

You can customize enums as other classes in Java with few exceptions.

I’ll use the same example, but it uses toString without getMessage, so you can use enums in those places where toString is called (for example, in System.out.println or any logging methods).

public enum Messages
{
    WARNING("main.message.warning"),
    ERROR("main.message.error");

    private final String message;

    // Parameters to the enum constructors are the ones in the enum "definition"
    Messages(final string message)
    {
        this.message = message;
    }

    @Override
    public String toString()
    {
        return message;
    }
}