4.1 java

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.Objects;
import java.util.Scanner;
record Student (String name, int group, int number, int day, int month, int year, String sex) {}
public class College {
    static Scanner scanner = new Scanner(System.in);
    public static int n = 0;
    public static boolean exit = false;
    public static Student[] arrayOfRecords = new Student[0];
    // тут костыльно реализовано, потому я дебил и не знал,
    // что динамических массивов в jave, как это устроено в delphi, не существует
    // надо было юзать arraylist, но тогда надо переписывать много кода(
    public static Student[] tempArray = new Student[0];

    public static void main (String[] args) throws IOException {
        System.out.println("The program is a college student database.");
        while (!exit) {
            showInfo();
            chooseAction();
        }
    }
    public static void showInfo () {
        System.out.println("1 - add record");
        System.out.println("2 - show sorted records");
        System.out.println("3 - show all records");
        System.out.println("4 - delete record");
        System.out.println("5 - edit record");
        System.out.println("6 - open record from file");
        System.out.println("7 - save record in file");
        System.out.println("8 - exit");
    }

    public static void chooseAction () throws IOException {
        int chose;
        boolean isIncorrect;
        final int MAX = 8;
        System.out.println("Please, choose:");
        do {
            chose = inputData();
            isIncorrect = false;
            if ((chose > MAX) || (chose < 1)) {
                isIncorrect = true;
                System.out.println("Please enter the correct function number.");
            }
        } while (isIncorrect);

        switch (chose) {
            case 1 -> addRecord();
            case 2 -> sortRecords();
            case 3 -> showRecords();
            case 4 -> deleteRecord();
            case 5 -> editRecord();
            case 6 -> openFile();
            case 7 -> saveData();
            case 8 -> exit = true;
        }
    }

    public static void editRecord () {
        System.out.println("Specify the number of the student you want to edit:");
        int number;
        boolean isIncorrect;
        do {
            number = inputData();
            isIncorrect = false;
            if ((number > n) || (number < 1)){
                isIncorrect = true;
                System.out.println("Please enter the number of an existing student:");
            }
        } while (isIncorrect);

        int data; // что мы хотим редактировать, какую позицию
        final int MAX = 7;
        System.out.println("Select what you want to edit:");
        System.out.println("1 - surname");
        System.out.println("2 - group");
        System.out.println("3 - number in logbook");
        System.out.println("4 - day (of birthday)");
        System.out.println("5 - month (of birthday)");
        System.out.println("6 - year (of birthday)");
        System.out.println("7 - sex");
        do {
            data = inputData();
            isIncorrect = false;
            if ((data > MAX) || (data < 1)){
                isIncorrect = true;
                System.out.println("Please enter the number of an existing position.");
            }
        } while (isIncorrect);
        number--;
        String name = arrayOfRecords[number].name();
        int group = arrayOfRecords[number].group();
        int numberInList = arrayOfRecords[number].number();
        int day = arrayOfRecords[number].day();
        int month = arrayOfRecords[number].month();
        int year = arrayOfRecords[number].year();
        String sex = arrayOfRecords[number].sex();

        switch (data) {
            case 1 -> name = inputName();
            case 2 -> group = inputGroup();
            case 3 -> numberInList = inputNumber();
            case 4 -> day = inputDay();
            case 5 -> month = inputMonth();
            case 6 -> year = inputYear();
            case 7 -> sex = inputSex();
        }
        arrayOfRecords[number] = new Student(name, group, numberInList, day, month, year, sex);
        System.out.println("Ready!");
        System.out.println();
    }

    public static void addRecord () {
        String name, sex;
        int group, number, day, month, year;
        name = inputName();
        sex = inputSex();
        group = inputGroup();
        number = inputNumber();
        day = inputDay();
        month = inputMonth();
        year = inputYear();
        if (checkRepeats(name, group, number, day, month, year, sex)) {
            tempArray = arrayOfRecords;
            arrayOfRecords = new Student[n + 1];
            System.arraycopy(tempArray, 0, arrayOfRecords, 0, tempArray.length);
            arrayOfRecords[n] = new Student(name, group, number, day, month, year, sex);
            n++;
            System.out.println("Ready!");
            System.out.println();
        }
    }

    public static void showRecords () {
        String ANSI_YELLOW = "\u001B[33m";
        String ANSI_RESET = "\u001B[0m";
        if (n > 0) {
            for (int i = 0; i < arrayOfRecords.length; i++) {
                System.out.println(ANSI_YELLOW + "Student " + (i + 1) + ":");
                System.out.println("Surname: " + arrayOfRecords[i].name());
                System.out.println("Sex: " + arrayOfRecords[i].sex());
                System.out.println("Group: " + arrayOfRecords[i].group());
                System.out.println("Number in logbook: " + arrayOfRecords[i].number());
                System.out.println("Birthday: " + arrayOfRecords[i].day() + "." + arrayOfRecords[i].month() + "." + arrayOfRecords[i].year() + ANSI_RESET);
                System.out.println();
            }
            System.out.println();
        }
        else {
            System.out.println(ANSI_YELLOW + "The list of students is empty..." + ANSI_RESET);
        }
    }

    public static void deleteRecord () {
        if (!(arrayOfRecords.length == 0)) {
            String ANSI_RED = "\u001B[31m";
            String ANSI_RESET = "\u001B[0m";
            System.out.println("Specify the number of the student you want to delete:");
            int number;
            boolean isIncorrect;
            do {
                number = inputData();
                isIncorrect = false;
                if ((number > n) || (number < 1)) {
                    isIncorrect = true;
                    System.out.println("Please enter the number of an existing student");
                }
            } while (isIncorrect);
            number--;
            System.out.println(ANSI_RED + "Do you want to remove the student " + arrayOfRecords[number].name() + " ?");
            System.out.println("Write \"yes\" if yes. Write \"no\" if no." + ANSI_RESET);
            String answer;
            do {
                isIncorrect = false;
                answer = scanner.nextLine();
                if (answer.equals("yes") || answer.equals("Yes")) {
                    if (number < (arrayOfRecords.length - 1)) {
                        for (int i = number; i < (arrayOfRecords.length - 1); i++) {   // вот тут может быть что-то не так
                            arrayOfRecords[i] = arrayOfRecords[i + 1];
                        }
                    }
                    tempArray = arrayOfRecords;
                    arrayOfRecords = new Student[n - 1];
                    System.arraycopy(tempArray, 0, arrayOfRecords, 0, arrayOfRecords.length);
                    n--;
                } else if (answer.equals("no") || answer.equals("No")) {
                    deleteRecord();
                } else {
                    isIncorrect = true;
                    System.out.println("Please enter \"yes\" or \"no.\"");
                }
            } while (isIncorrect);
            System.out.println("Ready!" + ANSI_RESET);
            System.out.println();
        } else {
            System.out.println("List is empty, impossible to delete someone.");
        }
    }

    public static boolean isAdult (int i) {
        boolean isYoung = true;
        GregorianCalendar gcalendar = new GregorianCalendar();
        int currYear = gcalendar.get(Calendar.YEAR);
        int currMonth = gcalendar.get(Calendar.MONTH);
        int currDay = gcalendar.get(Calendar.DAY_OF_MONTH);
        if (arrayOfRecords[i].year() < (currYear - 18))
            isYoung = false;
        if (arrayOfRecords[i].year() == (currYear - 18) && (arrayOfRecords[i].month() < (currMonth)))
            isYoung = false;
        if ((arrayOfRecords[i].year() == (currYear - 18)) && (arrayOfRecords[i].month() == currMonth) && (arrayOfRecords[i].day() <= currDay))
            isYoung = false;
        return isYoung;
    }

    public static void sortRecords () {
        Student min;
        if (arrayOfRecords.length > 1) {  //сортиро4ка по номерам группы (по возрастанию)
            Student[] arrayForSort = arrayOfRecords;

            for (int i = 0; i < (arrayForSort.length - 1); i++) {
                if (isAdult(i)) {
                    for (int j = i + 1; j < (arrayForSort.length); j++) {
                        if (arrayForSort[j].group() < arrayForSort[i].group()) {
                            min = arrayForSort[j];
                            arrayForSort[j] = arrayForSort[i];
                            arrayForSort[i] = min;
                        }
                    }
                }
            }

            for (int i = 0; i < (arrayForSort.length - 1); i++) {
                if (isAdult(i)) {
                    for (int j = i + 1; j < (arrayForSort.length); j++) {
                        if ((arrayForSort[j].number() < arrayForSort[i].number()) && (arrayForSort[j].group() == arrayForSort[i].group())) {
                            min = arrayForSort[j];
                            arrayForSort[j] = arrayForSort[i];
                            arrayForSort[i] = min;
                        }
                    }
                }
            }

            String ANSI_YELLOW = "\u001B[33m";
            String ANSI_RESET = "\u001B[0m";
            int k = 0;
            for (int i = 0; i < arrayForSort.length; i++) {
                if (isAdult(i)) {
                    System.out.println(ANSI_YELLOW + "Student " + (k + 1) + ":");
                    System.out.println("Surname: " + arrayForSort[i].name());
                    System.out.println("Sex: " + arrayForSort[i].sex());
                    System.out.println("Group: " + arrayForSort[i].group());
                    System.out.println("Number in logbook: " + arrayForSort[i].number());
                    System.out.println("Birthday: " + arrayForSort[i].day() + "." + arrayForSort[i].month() + "." + arrayForSort[i].year() + ANSI_RESET);
                    System.out.println();
                    k++;
                }
            }
            System.out.println();
        }else{
            System.out.println("Sorting needs in at least 2 students.");
        }
    }

    public static String inputName () {
        System.out.println("Enter a student's surname:");
        boolean isIncorrect;
        String str;
        do {
            isIncorrect = false;
            str = inputString();
            if (!checkName(str))
                isIncorrect = true;
        }while (isIncorrect);
        return str;
    }

    public static boolean checkName (String str) {
        final int MAX = 30;
        boolean isOK = true;
        if ((str.length() < 1) || (str.length() > MAX)) {
            isOK = false;
            System.out.println("The length of the surname should not exceed " + MAX + " characters");
        }
        return isOK;
    }

    private static String inputSex() {
        int sex = 0;
        boolean isIncorrect;
        final int MIN_NUM = 1;
        final int MAX_NUM = 3;
        System.out.println("Enter 1, if the student is male.");
        System.out.println("Enter 2, if the student is female.");
        System.out.println("Enter 3, if the student is non-binary person.");
        do {
            isIncorrect = false;
            try {
                sex = Integer.parseInt(scanner.nextLine());
            } catch (Exception e) {
                isIncorrect = true;
                System.out.println("Please, enter a number.");
            }
            if (!isIncorrect && (sex < MIN_NUM || sex > MAX_NUM)) {
                System.out.println("Enter a valid value. Repeat the entry.");
                isIncorrect = true;
            }
            if (!isIncorrect && (sex == 3)) {
                isIncorrect = true;
                System.out.println("Once all the genders came into the bar and said: \"We'll have a table for two\"");
                System.out.println("P.S. There are only two genders at our college. Repeat the entry.");
            }
        } while (isIncorrect);
        switch (sex) {
            case 1 -> {
                return "Male";
            }
            case 2 -> {
                return "Female";
            }
        }
        return "";
    }

    public static boolean checkSex (String str) { // это только для файлов, в консоли - своя проверка
        boolean isCorrect = str.equals("Female") || str.equals("Male") || str.equals("female") || str.equals("male");
        if (!isCorrect) {
            System.out.println("Incorrect data. Field \"sex\" should contain either \"Male\" or \"Female\"");
        }
        return isCorrect;
    }

    public static String inputString () {
        String str;
        boolean isIncorrect;
        do {
            isIncorrect = false;
            str = scanner.nextLine();
            for (int i = 0; i < str.length(); i++) {
                if ((str.charAt(i) < (int)'A') || (str.charAt(i) > (int)'z')) {
                    if (str.charAt(i) != (int)' ') {
                        isIncorrect = true;
                        System.out.println("Please enter a string consisting of Latin characters");
                        break;
                    }
                }
            }
        } while (isIncorrect);
        return str;
    }

    public static int inputGroup () {
        boolean isIncorrect;
        int group;
        System.out.println("Enter the student's group number. Length - no more than 8 digits.");
        final int MAX = 99999999;
        do {
            isIncorrect = false;
            group = inputData();
            if (group > MAX) {
                System.out.println("Group number - no more than 8 digits.");
                isIncorrect = true;
            }
        }while (isIncorrect);
        return group;
    }

    public static boolean checkGroup (String strGroup) {
        boolean isIncorrect;
        int group = 0;
        final int MIN_SIZE = 1;
        final int MAX_SIZE = 99999999;
        isIncorrect = false;
        try {
            group = Integer.parseInt(strGroup);
        } catch (Exception e) {
            isIncorrect = true;
            System.out.println("Please enter an integer number");
        }
        if ((group < MIN_SIZE || group > MAX_SIZE) && !isIncorrect) {
            System.out.println("Please enter a positive number (no longer than 8) symbols");
            isIncorrect = true;
        }
        return !isIncorrect;
    }

    private static int inputData() {
        int n = 0;
        boolean isIncorrect;
        final int MIN_SIZE = 1;
        do {
            isIncorrect = false;
            try {
                n = Integer.parseInt(scanner.nextLine());
            } catch (Exception e) {
                isIncorrect = true;
                System.out.println("Please enter an integer number");
            }
            if (n < MIN_SIZE && !isIncorrect) {
                System.out.println("Please enter a positive number");
                isIncorrect = true;
            }
        } while (isIncorrect);
        return n;
    }

    public static int inputNumber () {
        boolean isIncorrect;
        int number;
        System.out.println("Enter the number of the student in the log list (not more than 40).");
        final int MAX = 40;
        do {
            isIncorrect = false;
            number = inputData();
            if (number > MAX) {
                System.out.println("Student number - a number not to exceed 40");
                isIncorrect = true;
            }
        }while (isIncorrect);
        return number;
    }

    public static boolean checkNumber (String strNum) {
        boolean isIncorrect;
        int number = 0;
        final int MIN_SIZE = 1;
        final int MAX_SIZE = 40;
        isIncorrect = false;
        try {
            number = Integer.parseInt(strNum);
        } catch (Exception e) {
            isIncorrect = true;
            System.out.println("Please enter an integer number");
        }
        if ((number < MIN_SIZE || number > MAX_SIZE) && !isIncorrect) {
            System.out.println("Please enter a number in range [1..40]");
            isIncorrect = true;
        }
        return !isIncorrect;
    }


    public static int inputDay () {
        boolean isIncorrect;
        int day;
        System.out.println("Enter day of birthday:");
        final int MAX = 31;
        do {
            isIncorrect = false;
            day = inputData();
            if (day > MAX) {
                System.out.println("Range: 1..31");
                isIncorrect = true;
            }
        }while (isIncorrect);
        return day;
    }

    public static boolean checkDay (String strDay) {
        boolean isIncorrect;
        int day = 0;
        final int MIN_SIZE = 1;
        final int MAX_SIZE = 31;
        isIncorrect = false;
        try {
            day = Integer.parseInt(strDay);
        } catch (Exception e) {
            isIncorrect = true;
            System.out.println("Please enter an integer number");
        }
        if ((day < MIN_SIZE || day > MAX_SIZE) && !isIncorrect) {
            System.out.println("Please enter a number in range [1..31]");
            isIncorrect = true;
        }
        return !isIncorrect;
    }


    public static int inputMonth () {
        boolean isIncorrect;
        int month;
        System.out.println("Enter month of birthday:");
        final int MAX = 12;
        do {
            isIncorrect = false;
            month = inputData();
            if (month > MAX) {
                System.out.println("Range: 1..12");
                isIncorrect = true;
            }
        }while (isIncorrect);
        return month;
    }

    public static boolean checkMonth (String strMonth) {
        boolean isIncorrect;
        int month = 0;
        final int MIN_SIZE = 1;
        final int MAX_SIZE = 12;
        isIncorrect = false;
        try {
            month = Integer.parseInt(strMonth);
        } catch (Exception e) {
            isIncorrect = true;
            System.out.println("Please enter an integer number");
        }
        if ((month < MIN_SIZE || month > MAX_SIZE) && !isIncorrect) {
            System.out.println("Please enter a number in range [1..12]");
            isIncorrect = true;
        }
        return !isIncorrect;
    }

    public static int inputYear () {
        boolean isIncorrect;
        int year;
        GregorianCalendar gcalendar = new GregorianCalendar();
        int currYear = gcalendar.get(Calendar.YEAR);
        System.out.println("Enter year of birthday:");
        final int MIN_YEAR = 1900;
        do {
            isIncorrect = false;
            year = inputData();
            if (year > currYear || year < MIN_YEAR) {
                System.out.println("Range: 1900..current year");
                isIncorrect = true;
            }
        }while (isIncorrect);
        return year;
    }

    public static boolean checkYear (String strYear) {
        boolean isIncorrect;
        int year = 0;
        GregorianCalendar gcalendar = new GregorianCalendar();
        int currYear = gcalendar.get(Calendar.YEAR);
        final int MIN_SIZE = 1900;
        isIncorrect = false;
        try {
            year = Integer.parseInt(strYear);
        } catch (Exception e) {
            isIncorrect = true;
            System.out.println("Please enter an integer number");
        }
        if ((year < MIN_SIZE || year > currYear) && !isIncorrect) {
            System.out.println("Please enter a number in range [1900..current year]");
            isIncorrect = true;
        }
        return !isIncorrect;
    }


    private static String inputFilePath() {
        String path;
        boolean isIncorrect;
        do {
            isIncorrect = false;
            System.out.println("Input file path:");
            path = scanner.nextLine();
            File file = new File(path);
            if (!file.exists()) {
                System.out.println("Wrong way to file.");
                isIncorrect = true;
            }
            if (!file.canRead() && file.exists()) {
                System.out.println("Impossible to read a file.");
                isIncorrect = true;
            }
            if (!file.canWrite() && file.canRead()) {
                System.out.println("Impossible to write a file.");
                isIncorrect = true;
            }
        } while (isIncorrect);
        return path;
    }

    public static boolean checkRepeats(String name, int group, int number, int day, int month, int year, String sex) {
        boolean isCorrect = true;
        if (Objects.equals(sex, "male"))
            sex = "Male";
        if (Objects.equals(sex, "female"))
            sex = "Female";
        if(arrayOfRecords.length > 0) {
            for (Student arrayOfRecord : arrayOfRecords) {
                if ((name.equals(arrayOfRecord.name())) && (group == arrayOfRecord.group()) &&
                        (number == (arrayOfRecord.number())) && (day == arrayOfRecord.day()) &&
                        (month == arrayOfRecord.month()) && (year == arrayOfRecord.year()) &&
                        (sex.equals(arrayOfRecord.sex()))) {
                    isCorrect = false;
                    System.out.println("Such an entry already exists.");
                    break;
                }
            }
        }
        return isCorrect;
    }

     private static boolean checkDataCorrectness(String str) {
        boolean isCorrect = true;
        boolean isCorrectName, isCorrectGroup, isCorrectNumber, isCorrectSex, isCorrectDay, isCorrectMonth, isCorrectYear;
        String[] chr;
         chr = str.split(" ");
         if (chr.length > 7) {
             System.out.println("Too many characteristics in string.");
             isCorrect = false;
         } else {
             isCorrectName = checkName(chr[0]);
             if (!isCorrectName) {
                 isCorrect = false;
             }
             isCorrectSex = checkSex(chr[6]);
             if (!isCorrectSex) {
                 isCorrect = false;
             }
             isCorrectGroup = checkGroup(chr[1]);
             if (!isCorrectGroup) {
                 isCorrect = false;
             }
             isCorrectNumber = checkNumber(chr[2]);
             if (!isCorrectNumber) {
                 isCorrect = false;
             }
             isCorrectDay = checkDay(chr[3]);
             if (!isCorrectDay) {
                 isCorrect = false;
             }
             isCorrectMonth = checkMonth(chr[4]);
             if (!isCorrectMonth) {
                 isCorrect = false;
             }
             isCorrectYear = checkYear(chr[5]);
             if (!isCorrectYear) {
                 isCorrect = false;
             }
         }
        return isCorrect;
    }


    public static void openFile () {
        System.out.println("Example of string with info about student:");
        System.out.println("Name - Group - Number in list - Day (of birthday) - Month (of birthday) - Year (of birthday) - Sex");
        System.out.println("P.S. after every position expected only space ");
        String path = inputFilePath();
        String str;
        boolean isIncorrect = true;
        String[] mas;
        try {
            Scanner fileReader = new Scanner(new File(path));
            while((fileReader.hasNext()) && isIncorrect) {
                str = fileReader.nextLine();
                isIncorrect = checkDataCorrectness(str);
                if (isIncorrect) {
                    mas = str.split(" ");
                    int group = Integer.parseInt(mas[1]);
                    int number = Integer.parseInt(mas[2]);
                    int day = Integer.parseInt(mas[3]);
                    int month = Integer.parseInt(mas[4]);
                    int year = Integer.parseInt(mas[5]);
                    if (Objects.equals(mas[6], "male"))
                        mas[6] = "Male";
                    if (Objects.equals(mas[6], "female"))
                        mas[6] = "Female";
                    if (Objects.equals(mas[6], "male"))
                        mas[6] = "Male";
                    isIncorrect = checkRepeats(mas[0], group, number, day, month, year, mas[6]);
                    if (isIncorrect){
                        tempArray = arrayOfRecords;
                        arrayOfRecords = new Student[n + 1];
                        System.arraycopy(tempArray, 0, arrayOfRecords, 0, tempArray.length);
                        arrayOfRecords[n] = new Student(mas[0], group, number, day, month, year, mas[6]);
                        n++;
                    }
                } else {
                    System.out.println("Such a record already exists.");
                }
            }
            if (isIncorrect)
                System.out.println("Ready!");
        } catch (Exception q) {
            System.out.println("Something went wrong, check file.");
        }
    }

    private static void saveData() throws IOException {
        if (arrayOfRecords.length > 0) {
            String path = inputFilePath();
            FileWriter writer = new FileWriter(path);
            for (Student arrayOfRecord : arrayOfRecords) {
                writer.write(arrayOfRecord.name() + " " + arrayOfRecord.group() + " " +
                        arrayOfRecord.number() + " " + arrayOfRecord.day() + " " + arrayOfRecord.month()
                        + " " + arrayOfRecord.year() + " " + arrayOfRecord.sex());
                writer.write("\n");
            }
            writer.close();
            System.out.println("Ready!");
        } else
            System.out.println("There is nothing to save, bro.");
    }
}