Java枚举作为BigInteger值

Question

I have Enumeration classes in my application and I am using this enumerations to compare value of BigIntegers like this:

if (user.getObjId.equals(RoleEnum.ADMIN.getValue())) {
    //something happens
}

The question is, can I modify this enumeration class to use it without calling getValue() method, as shown in following code sample?

if (user.getObjId.equals(RoleEnum.ADMIN)) {
    //something happens
}

Here is my Enumeration class:

public enum RoleEnum {
    ADMIN(1), USER(2);
    private final BigInteger value;

    private RoleEnum(int value) {
        this.value = BigInteger.valueOf(value);
    }

    public BigInteger getValue() {
        return value;
    }
}

Answer 1

the idea behind BigInteger is that you can work with numbers that are so big you can just type in a numeric way on the IDE...

you should do:

ADMIN("1"), USER("2");
private RoleEnum(String value) {
    this.value = BigInteger.valueOf(value);

Answer 2

The answer to your question is simply 'No'.

It all depends on the equals method of the objectId. You can not override the equals method of the enum, but you could possibly override/declare the equals method on the objectId (it's hard to say from the information you provided).

The implementation of the equals method can then check for the type of the parameter to be of the enum type, and in that case, compare the values. For example:

public boolean equals(Object o){
   if(o instanceof RoleEnum){
      return this.value.equals(((RoleEnum)o).getValue());
   }
   ...
}

But I assume, your objId is of type BigInteger, so you cant override the equals method. In that case, the answer is as mention above: 'No'

Answer 3

If something's not very neat refactor out a method so it looks neat again (especially if it happens in more than one place):

if (user.isRole(RoleEnum.ADMIN))

on User (I'm assuming the name of the type of user ):

public boolean isRole(RoleEnum role) {
    return getObjId.equals(role.getValue());
}

Or if it's not not possible to modify User or reference the enum from there, then maybe a static:

public final class UserHelpers {

    private UserHelpers(){}

    public static boolean userIsRole(User user, RoleEnum role) {
        return user.getObjId.equals(role.getValue());
    }
}

Usage:

if (UserHelpers.userIsRole(user, RoleEnum.ADMIN))

Or with the static imported:

if (userIsRole(user, RoleEnum.ADMIN))