Client.java

package org.pu.javapp.model;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.Locale;
import java.io.File;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class Client {

    private String names;
    private LocalDate registrationDate;
    private Integer numberOfPurchases;
    private Double totalPurchasedSum;
    private Integer rating;

    public Client() {}

    public Client(String names, LocalDate registrationDate, Integer numberOfPurchases, Double totalPurchasedSum, Integer rating) {
        this.names = names;
        this.registrationDate = registrationDate;
        this.numberOfPurchases = numberOfPurchases;
        this.totalPurchasedSum = totalPurchasedSum;
        this.rating = rating;
    }

    public Client(String names, String registrationDate, Integer numberOfPurchases, Double totalPurchasedSum, Integer rating) {
        DateTimeFormatter fomatter = DateTimeFormatter.ofPattern("dd.M.yyyy", Locale.ENGLISH);

        this.names = names;
        this.registrationDate = LocalDate.parse(registrationDate, fomatter);
        this.numberOfPurchases = numberOfPurchases;
        this.totalPurchasedSum = totalPurchasedSum;
        this.rating = rating;
    }

    public String getNames() {
        return names;
    }

    public void setNames(String names) {
        this.names = names;
    }

    public void setRegistrationDate(LocalDate registrationDate) {
        this.registrationDate = registrationDate;
    }

    public Integer getNumberOfPurchases() {
        return numberOfPurchases;
    }

    public void setNumberOfPurchases(Integer numberOfPurchases) {
        this.numberOfPurchases = numberOfPurchases;
    }

    public Double getTotalPurchasedSum() {
        return totalPurchasedSum;
    }

    public void setTotalPurchasedSum(Double totalPurchasedSum) {
        this.totalPurchasedSum = totalPurchasedSum;
    }

    public Integer getRating() {
        return rating;
    }

    private void calculateRating() {
        if (numberOfPurchases == 0 || numberOfPurchases < 0) {
            throw new IllegalStateException("Number of purchases not set for client");
        }

        if (numberOfPurchases >= 1 && numberOfPurchases < 100)
            rating = 1;

        if (numberOfPurchases >= 100 && numberOfPurchases < 299)
            rating = 2;

        if (numberOfPurchases >= 300 && numberOfPurchases < 499)
            rating = 3;

        if (numberOfPurchases >= 500 && numberOfPurchases < 999)
            rating = 4;

        if (numberOfPurchases >= 1000 && numberOfPurchases < 9999)
            rating = 5;
    }

    public void persistClientData(String path) throws IOException {
        File file = new File(path);
        if (!file.exists()) {
            file.createNewFile();
        }
        BufferedWriter writer = new BufferedWriter(new FileWriter(path, true));
        persistClientData(writer);
    }

    private void persistClientData(BufferedWriter writer) throws IOException {
        StringBuilder clientCsvDataBuilder = new StringBuilder();
        calculateRating();
        clientCsvDataBuilder.append(names+","+registrationDate.format(DateTimeFormatter.ofPattern("dd.M.yyyy", Locale.ENGLISH))+
                ","+numberOfPurchases+","+totalPurchasedSum+"," + getRating() +"\n");

        writer.write(clientCsvDataBuilder.toString());
        writer.close();
    }

    public String getYear() {
        return Integer.toString(registrationDate.getYear());
    }

    @Override
    public String toString() {
        return names + ", " + numberOfPurchases + ", " + String.format("%.2f",totalPurchasedSum) + ", " + registrationDate + ", " + Stream.generate(() -> "*").limit(getRating()).collect(Collectors.joining());
    }

}