@Override
 public void run() throws Exception {
   Scanner input = new Scanner(System.in);
   System.out.println("Enter Id?");
   String id = input.nextLine();
   x = X_MEM.findMemberById(id);
   address = x.getAddress();
   System.out.println("Enter address?");
   String address = input.nextLine();
   x.setAddress(address);
   System.out.println("Address updated.");
 }
 @Override
 public void undo() {
   String temp = x.getAddress();
   x.setAddress(address);
   address = temp;
 }
 @Override
 public String getLog() {
   return "Update Address " + x.getId();
 }