CODEWITHSUNDEEP
javaenums
Bonk
Bonk

Reputation: 1949

enum as storage?

I have a large enum declared in my class

public enum CarMaker{
        Honda,
        Toyota,
        Sony,
        ...;

        public CarMaker at(int index){ //a method to retrieve enum by index
                CarMaker[] retval = this.values();
                return retval[index];
        }
        public final SomeObj val; //a value associated with each enum
            //.. more custom functions if needed
    }

since only one instance of each CarMaker is needed, is it a bad practice if I want to use this enum as a storage (like an array but instead access each element using indices, I could use more intuitive names. Also I can have custom functions for each element)

CarMaker A = CarMaker.Honda;
CarMaker B = CarMaker.at(1); 
//Error above b/c 'at' is not a static member, can I make at a static member?

A.val = 5; 
B.val = 6; 
//Here I want A to be share data with B since both are "Honda"
//but it doesn't seem to do that yet
 System.out.println(A)
 System.out.println(B)

//Expected output:
//A: 6
//B: 6

Right now A and B seem to create their own instance of "Honda", but I want them to be shared. Is it possible?

Upvotes: 1

Views: 165

Answers (2)

Hovercraft Full Of Eels
Hovercraft Full Of Eels

Reputation: 285403

Use your enum but via composition: Create an enum of brand names, but then build your objects that need a name to hold a field of the enum.

Example

public enum CarMaker {
   Honda,
   Toyota,
   Sony,
   Olympus,
   Facebook,
   Google,
   ...
}

public class Car {
   CarMaker carMaker;
   //... etc....

   Car(CarMaker carMaker) {
      this.carMaker = carMaker;
      // ... more code
   }

   //....

Upvotes: 2

Jeffrey
Jeffrey

Reputation: 44808

enums are supposed to be immutable constants. Giving them a public, modifiable field is a horrible idea.

Upvotes: 5

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