在Java bean中声明枚举变量

Question

I need to declare an enum variable as a class member and need to define a setter and getter for that like a java bean. something like this -

public class Vehicle {
 private String id;
 private String name;
 enum color {
   RED, GREEN, ANY;
 }
 // setter and getters
} 

Now, I want to set color property as red, green or any from some other class and want to make decisions accordingly.

Answer 1

The enum will have to be made public to be seen by the outside world:

public class Vehicle {
     private String id;
     private String name;

     public enum Color {
       RED, GREEN, ANY;
     };

     private Color color;    

     public Color getColor(){
        return color; 
     }

     public void setColor(Color color){
         this.color = color;
     }   

    } 

Then from outside the package you can do:

vehicle.setColor(Vehicle.Color.GREEN);

if you only need to use Vehicle.Color inside the same package as Vehicle you may remove the public from the enum declaration.

Answer 2

If you want to work with your color enum, you have to share its declaration more widely than you're doing. The simplest might be to put public in front of enum color in Vehicle.

Next, you need to declare a field of the enum's type. I suggest you change the name of the enum from color to Color , because it's basically a class anyway. Then you can declare a field: private Color color among with your other fields.

To use the enum and especially its constants from another class, you need to be aware that the enum is nested in Vehicle. You need to qualify all names, so:

Vehicle.Color myColor = Vehicle.Color.RED;

Bakkal has kindly written code to demonstrate much of what I was talking about. See his answer for details!