How to limit integer values obtained from user at the runtime in java ?

I wanted to get the mobile number from the user in java using scanner. When the user enters the number, he/she shouldn't be able to enter when the limit exceeds 10. Could anyone share how ?

long mobNo;
     Scanner s=new Scanner(System.in);
     mobNo=s.nextLong();
      int length = (int)(Math.log10(mobNo)+1);
     if(length==10)
         System.out.println("Successfully entered !");
     else
         System.out.println("Enter only 10 digits");