Java: Hệ thống quản lý số điện thoại

Solution cho bài tập: Bài tập 1 - Bài tập phần Abstract class & Interface

Interface Phone (file Phone.java):

package baitap1abstractvainterface;

public abstract class Phone {
  abstract void insertPhone(String name, String phone);

  abstract void removePhone(String name);

  abstract void updatePhone(String name, String newPhone);

  abstract void searchPhone(String name);

  abstract void sort();
}

Class PhoneBook (file PhoneBook.java):

package baitap1abstractvainterface;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

public class PhoneBook extends Phone {

  ArrayList<String> PhoneList = new ArrayList();

  @Override
  void insertPhone(String name, String phone) {
    boolean timThay = false;
    for (String s : PhoneList) {
      if (s.contains(name)) {
        timThay = true;
        if (!s.contains(phone)) {
          s += " : " + phone;
        } else {
          System.out.println("Danh bạ này đã có sẵn");
        }
      }
    }
    if (!timThay) {
      PhoneList.add(name + "," + phone);
    }
  }

  @Override
  void removePhone(String name) {
    boolean searched = false;
    for (String s : PhoneList) {
      if (name.equals(s.substring(0, s.indexOf(",")))) {
        searched = true;
        PhoneList.remove(s);
        System.out.println("Removed");
        break;
      }
    }
    if (!searched) System.out.println("Not found person with name: " + name);
  }

  @Override
  void updatePhone(String name, String newPhone) {
    String s = name;
    s = s.substring(0, s.indexOf(",")); //bỏ số điện thoại cũ (chỉ giữ lại tên)
    PhoneList.set(PhoneList.indexOf(s), s + "," + newPhone); //đưa sdt mới vào
    System.out.println("Updated");
  }

  @Override
  void searchPhone(String name) {
    boolean searched = false;
    for (String s : PhoneList) {
      if (s.contains(name)) {
        searched = true;
        System.out.println(s.toString());
        break;
      }
    }
    if (!searched) System.out.println("Not found person");
  }

  @Override
  void sort() {
    if (PhoneList.size() == 0) System.out.println("PhoneList is empty");
    else {
      //Sắp xếp tăng dần theo tên
      Collections.sort(PhoneList, new Comparator<String>() {
        @Override
        public int compare(String s, String t1) {
          return s.compareTo(t1);
        }
      });
      System.out.println("Sort Ascending by name:");
      for (String s : PhoneList) {
        System.out.println(s);
      }
      //Sắp xếp giảm dần theo tên
      Collections.sort(PhoneList, new Comparator<String>() {
        @Override
        public int compare(String s, String t1) {
          return t1.compareTo(s);
        }
      });
      System.out.println("Sort Descending by name:");
      for (String s : PhoneList) {
        System.out.println(s);
      }
    }
  }
}

Class ManagePhoneBook (file ManagePhoneBook.java):

package baitap1abstractvainterface;

import java.util.Scanner;

public class ManagePhoneBook {
  static PhoneBook pb = new PhoneBook();
  static Scanner scanner = new Scanner(System.in);
  static String name, phone;

  static void menu() {
    System.out.println("PHONEBOOK MANAGEMENT SYSTEM");
    System.out.println("1. Insert phone");
    System.out.println("2. Remove phone");
    System.out.println("3. Update phone");
    System.out.println("4. Search phone");
    System.out.println("5. Sort");
    System.out.println("6. Exit");
  }

  public static void main(String[] args) {
    menu();
    while (true) {
      System.out.print("Please choose an option: ");
      switch (scanner.nextInt()) {
        case 1:
          insertPhone();
          break;
        case 2:
          removePhone();
        case 3:
          updatePhone();
          break;
        case 4:
          searchPhone();
          break;
        case 5:
          sortPhone();
          break;
        case 6:
          return;
      }
    }
  }

  private static void removePhone() {
    scanner.nextLine();
    System.out.print("Input name of person you want to remove: ");
    name = scanner.nextLine();
    pb.removePhone(name);
  }

  private static void searchPhone() {
    scanner.nextLine();
    System.out.print("Please input name of person you want to search the phone: ");
    name = scanner.nextLine();
    pb.searchPhone(name);
  }

  private static void updatePhone() {
    boolean searched = false;
    scanner.nextLine();
    System.out.print("Input name of person you want to update: ");
    name = scanner.nextLine();
    for (String s : pb.PhoneList) {
      if (name.equals(s.substring(0, s.indexOf(",")))) {
        searched = true;
        System.out.print("Input phone number you want to update: ");
        phone = scanner.nextLine();
        pb.updatePhone(name, phone);
        break;
      }
    }
    if (!searched) System.out.println("Not found person with name is: " + name);
  }

  private static void sortPhone() {
    pb.sort();
  }

  private static void insertPhone() {
    scanner.nextLine();
    System.out.print("Input name: ");
    name = scanner.nextLine();
    System.out.print("Input phone: ");
    phone = scanner.nextLine();
    pb.insertPhone(name, phone);
  }
}