Simple small permission system

Permissions.java

public class Permissions
{

    public enum Permission
    {
        CREATE,
        DERP
        ;
        
        private final long val;
        
        private Permission()
        {
            this.val = 2power(this.ordinal());
        }
        
        long getValue()
        {
            return this.val;
        }
        
        private long 2power(int i)
        {
            long ret = 1;
            for(int j = 0; j < i; j++)
                ret*=2;
            return ret;
        }
    }
    
    // To save and load
    private long perm;

    public Permissions(long theirPermissionValue)
    {
        this.perm = theirPermissionValue;
    }
    
    public boolean hasPermission(Permission perm)
    {
        long i = perm.getValue();
        return (this.perm & i) == i;
    }

    public void givePermission(Permission perm)
    {
        long i = perm.getValue();
        this.perm |= i;
    }

    public void revokePermission(Permission perm)
    {
        long i = perm.getValue();
        this.perm &= ~i;
    }
}