(Java) Do you have any idea how to tag the customer? I need to read the data from a csv file and update it after flagging a customer.

Doesn't matter which data file to save the data in. I need to be able to query the data later on.

You are developing a simplified contact tracing system for COVID-19. The three (3) main roles in the system are listed below: 1) Customer - a customer has name, phone, and status. A customer can: a) Register an account in the system. b) Sign in the system c) Check-in a shop d) View the history of the shops he/she visited e) View his/her status. A customer status can have 3 possible values: Normal, Case, Close. i. Normal - The customer is normal. ii. Case - The customer is a case of COVID-19 positive. iii. Close - The customer is a close contact of a case. For simplicity, a close contact is anyone who checks in the same shop within one-hour range (inclusive) with a case. The seconds in check-in time are ignored. For example, if a case checks in a shop today at 12pm, then: A customer who checks in yesterday is not a close contact. A customer who checks in today at 10.59am is not a close contact A customer who checks in today at 11am is a close contact. A customer who checks in today at 1pm is a close contact. A customer who checks in today at 1.01pm is not a close contact. 2) Shop - A shop has name, phone, status, and manager. A shop status can have 2 possible values: Normal, Case. 3) Admin - a government agency who can: a) View the details of all customers, the details of all shops, the master visit history. b) Flag (change status) a customer. When a customer is flagged as a Case, the system shall automatically flag: 1. The shop as Case. ii. All close contacts as Close