Conveniently map between enum and int / String

Question

When working with variables/parameters that can only take a finite number of values, I try to always use Java\'s enum, as in

public enum BonusT         


        

Answer 1

If you have a class Car

public class Car {
    private Color externalColor;
}

And the property Color is a class

@Data
public class Color {
    private Integer id;
    private String name;
}

And you want to convert Color to an Enum

public class CarDTO {
    private ColorEnum externalColor;
}

Simply add a method in Color class to convert Color in ColorEnum

@Data
public class Color {
    private Integer id;
    private String name;

    public ColorEnum getEnum(){
        ColorEnum.getById(id);
    }
}

and inside ColorEnum implements the method getById()

public enum ColorEnum {
...
    public static ColorEnum getById(int id) {
        for(ColorEnum e : values()) {
            if(e.id==id) 
                return e;
        }
    }
}

Now you can use a classMap

private MapperFactory factory = new DefaultMapperFactory.Builder().build();
...
factory.classMap(Car.class, CarDTO.class)
    .fieldAToB("externalColor.enum","externalColor")
    .byDefault()
    .register();
...
CarDTO dto = mapper.map(car, CarDTO.class);