Qoida tariqasida, antipatternlar quyidagi turlarga bo'linadi:
- Arxitektura antipatternlari - tizim strukturasini loyihalashda paydo bo'ladigan me'moriy antipatternlar (odatda me'mor tomonidan).
- Management Anti Pattern - odatda turli menejerlar (yoki menejerlar guruhlari) duch keladigan boshqaruv sohasidagi antipatternlar.
- Development Anti Pattern - antipatternlar oddiy dasturchilar tizimni yozishda paydo bo'ladigan rivojlanish muammolari.
1. Analitik falaj
Tahlil falaji klassik tashkiliy anti-naqsh hisoblanadi. Bu rejalashtirishda vaziyatni ortiqcha tahlil qilishni o'z ichiga oladi, shunda hech qanday qaror yoki harakat amalga oshirilmaydi, bu esa rivojlanishni falaj qiladi. Bu ko'pincha maqsad mukammallikka erishish va tahlil davrini to'liq yakunlash bo'lganda sodir bo'ladi. Ushbu anti-naqsh aylana bo'ylab yurish (yopiq halqa turi), batafsil modellarni qayta ko'rib chiqish va yaratish bilan tavsiflanadi, bu esa o'z navbatida ish jarayoniga xalaqit beradi. Masalan, siz quyidagi narsalarni bashorat qilmoqchisiz: agar foydalanuvchi to'satdan o'z ismining to'rtinchi va beshinchi harflari asosida xodimlar ro'yxatini tuzmoqchi bo'lsa, shu jumladan, ro'yxatda ular ish vaqti orasida eng ko'p ish vaqtini ajratgan loyihalarni yaratmoqchi bo'lsa-chi? Oldingi to'rt yil ichida Yangi yil va sakkizinchi mart? Aslini olganda, bu tahlilning haddan tashqari ko'pligi. Yaxshi real hayot misoli tahlil falaji Kodakni bankrotlikka olib keldi . Mana tahlil falajiga qarshi kurashish uchun bir nechta kichik maslahatlar:- Uzoq muddatli maqsadni qaror qabul qilish uchun mayoq sifatida belgilashingiz kerak, shunda siz qabul qilgan har bir qaror sizni maqsadingizga yaqinlashtiradi va vaqtni belgilashga majburlamaydi.
- E'tiboringizni mayda-chuyda narsalarga qaratmang (nega hayotingizdagi so'nggisi bo'lganidek, kichik nuance haqida qaror qabul qilasiz?)
- Qaror qabul qilish muddatini belgilang.
- Vazifani mukammal bajarishga urinmang: buni juda yaxshi bajarish yaxshiroqdir.
2. Xudo qarshi
Ilohiy ob'ekt - bu juda ko'p turli xil funktsiyalarning haddan tashqari kontsentratsiyasini tavsiflovchi anti-naqsh, katta hajmdagi turli xil ma'lumotlarni (ilova atrofida aylanadigan ob'ekt) saqlash. Keling, kichik bir misol keltiraylik:public class SomeUserGodObject {
private static final String FIND_ALL_USERS_EN = "SELECT id, email, phone, first_name_en, access_counter, middle_name_en, last_name_en, created_date FROM users;
private static final String FIND_BY_ID = "SELECT id, email, phone, first_name_en, access_counter, middle_name_en, last_name_en, created_date FROM users WHERE id = ?";
private static final String FIND_ALL_CUSTOMERS = "SELECT id, u.email, u.phone, u.first_name_en, u.middle_name_en, u.last_name_en, u.created_date" +
" WHERE u.id IN (SELECT up.user_id FROM user_permissions up WHERE up.permission_id = ?)";
private static final String FIND_BY_EMAIL = "SELECT id, email, phone, first_name_en, access_counter, middle_name_en, last_name_en, created_dateFROM users WHERE email = ?";
private static final String LIMIT_OFFSET = " LIMIT ? OFFSET ?";
private static final String ORDER = " ORDER BY ISNULL(last_name_en), last_name_en, ISNULL(first_name_en), first_name_en, ISNULL(last_name_ru), " +
"last_name_ru, ISNULL(first_name_ru), first_name_ru";
private static final String CREATE_USER_EN = "INSERT INTO users(id, phone, email, first_name_en, middle_name_en, last_name_en, created_date) " +
"VALUES (?, ?, ?, ?, ?, ?, ?)";
private static final String FIND_ID_BY_LANG_CODE = "SELECT id FROM languages WHERE lang_code = ?";
........
private final JdbcTemplate jdbcTemplate;
private Map<String, String> firstName;
private Map<String, String> middleName;
private Map<String, String> lastName;
private List<Long> permission;
........
@Override
public List<User> findAllEnCustomers(Long permissionId) {
return jdbcTemplate.query( FIND_ALL_CUSTOMERS + ORDER, userRowMapper(), permissionId);
}
@Override
public List<User> findAllEn() {
return jdbcTemplate.query(FIND_ALL_USERS_EN + ORDER, userRowMapper());
}
@Override
public Optional<List<User>> findAllEnByEmail(String email) {
var query = FIND_ALL_USERS_EN + FIND_BY_EMAIL + ORDER;
return Optional.ofNullable(jdbcTemplate.query(query, userRowMapper(), email));
}
.............
private List<User> findAllWithoutPageEn(Long permissionId, Type type) {
switch (type) {
case USERS:
return findAllEnUsers(permissionId);
case CUSTOMERS:
return findAllEnCustomers(permissionId);
default:
return findAllEn();
}
}
..............…
private RowMapper<User> userRowMapperEn() {
return (rs, rowNum) ->
User.builder()
.id(rs.getLong("id"))
.email(rs.getString("email"))
.accessFailed(rs.getInt("access_counter"))
.createdDate(rs.getObject("created_date", LocalDateTime.class))
.firstName(rs.getString("first_name_en"))
.middleName(rs.getString("middle_name_en"))
.lastName(rs.getString("last_name_en"))
.phone(rs.getString("phone"))
.build();
}
}
findAllWithoutPageEnbiznes mantig'i bilan fasad usulini ham ko'ramiz. Bunday ilohiy ob'ekt juda katta va qo'llab-quvvatlash uchun noqulay bo'ladi. Biz har bir kod bo'lagida u bilan shug'ullanishimiz kerak: tizimdagi ko'plab tugunlar unga tayanadi va unga mahkam bog'langan. Bunday kodni saqlash tobora qiyinlashib bormoqda. Bunday hollarda uni alohida sinflarga bo'lish kerak, ularning har biri faqat bitta maqsadga (maqsadga) ega bo'ladi. Ushbu misolda siz uni dao sinfiga bo'lishingiz mumkin:
public class UserDaoImpl {
private static final String FIND_ALL_USERS_EN = "SELECT id, email, phone, first_name_en, access_counter, middle_name_en, last_name_en, created_date FROM users;
private static final String FIND_BY_ID = "SELECT id, email, phone, first_name_en, access_counter, middle_name_en, last_name_en, created_date FROM users WHERE id = ?";
........
private final JdbcTemplate jdbcTemplate;
........
@Override
public List<User> findAllEnCustomers(Long permissionId) {
return jdbcTemplate.query(FIND_ALL_CUSTOMERS + ORDER, userRowMapper(), permissionId);
}
@Override
public List<User> findAllEn() {
return jdbcTemplate.query(FIND_ALL_USERS_EN + ORDER, userRowMapper());
}
........
}public class UserInfo {
private Map<String, String> firstName;
…..
public Map<String, String> getFirstName() {
return firstName;
}
public void setFirstName(Map<String, String> firstName) {
this.firstName = firstName;
}
....private List<User> findAllWithoutPageEn(Long permissionId, Type type) {
switch (type) {
case USERS:
return findAllEnUsers(permissionId);
case CUSTOMERS:
return findAllEnCustomers(permissionId);
default:
return findAllEn();
}
}3.Singleton
Singleton - bu bitta tarmoqli ilovada ba'zi bir sinfning bitta nusxasi bo'lishini kafolatlaydigan va ushbu ob'ektga global kirish nuqtasini ta'minlaydigan eng oddiy naqsh. Bu haqda ko'proq ma'lumotni shu yerda o'qishingiz mumkin . Lekin bu naqshmi yoki antipatternmi?
Keling, ushbu shablonning kamchiliklarini ko'rib chiqaylik:
-
Global davlat. Biz sinf misoliga kirganda, biz bu sinfning hozirgi holatini yoki uni kim va qachon o'zgartirganini bilmaymiz va bu holat biz kutgandek bo'lmasligi mumkin. Boshqacha qilib aytganda, singleton bilan ishlashning to'g'riligi unga qo'ng'iroqlar tartibiga bog'liq bo'lib, bu quyi tizimlarning bir-biriga bog'liq bo'lishiga olib keladi va natijada rivojlanishning murakkabligini jiddiy ravishda oshiradi.
-
Singleton SOLID tamoyillaridan birini - Yagona javobgarlik printsipini buzadi - Singleton klassi o'zining bevosita majburiyatlarini bajarishdan tashqari, uning nusxalari sonini ham nazorat qiladi.
-
Oddiy sinfning singletonga bog'liqligi sinf interfeysida ko'rinmaydi. Odatda singlning namunasi usul parametrlarida o'tkazilmaydi, lekin
getInstance()sinfning singletonga bog'liqligini aniqlash uchun to'g'ridan-to'g'ri orqali olinadi, shuning uchun siz har bir usulning amalga oshirilishini chuqur o'rganishingiz kerak - oddiygina ommaviy ko'rish. ob'ektning shartnomasi etarli emas.Singletonning mavjudligi umuman dasturning sinovdan o'tish qobiliyatini va xususan, singletondan foydalanadigan sinflarni kamaytiradi. Birinchidan, siz Singleton o'rniga Mock ob'ektini qo'ya olmaysiz, ikkinchidan, agar singleton o'z holatini o'zgartirish uchun interfeysga ega bo'lsa, testlar bir-biriga bog'liq bo'ladi.
Boshqacha qilib aytganda, singleton ulanishni oshiradi va yuqorida aytilganlarning barchasi ulanishning kuchayishi natijasidan boshqa narsa emas.
Va agar siz bu haqda o'ylab ko'rsangiz, singletondan foydalanishdan qochish mumkin. Masalan, ob'ektning nusxalari sonini nazorat qilish uchun har xil turdagi zavodlardan foydalanish juda mumkin (va zarur).
Eng katta xavf - bu butun dastur arxitekturasini singletonlar asosida qurishga urinishda. Ushbu yondashuv uchun juda ko'p ajoyib alternativalar mavjud. Eng muhim misol - Bahor, ya'ni uning IoC konteynerlari: u erda xizmatlarni yaratishni nazorat qilish muammosi tabiiy ravishda hal qilinadi, chunki ular aslida "steroidlar zavodlari".
Endi bu mavzu bo'yicha juda ko'p holivar bor, shuning uchun singlning naqsh yoki antipattern ekanligini siz hal qilishingiz kerak.
Va biz bu haqda to'xtalmaymiz va bugungi kunning so'nggi dizayn namunasiga o'tamiz - poltergeist.
4. Poltergeist
Poltergeist - bu foydali bo'lmagan sinf antipattern bo'lib, u boshqa sinf usullarini chaqirish uchun ishlatiladi yoki shunchaki keraksiz abstraktsiya qatlamini qo'shadi. Antipattern davlatdan mahrum bo'lgan qisqa muddatli ob'ektlar shaklida o'zini namoyon qiladi. Ushbu ob'ektlar ko'pincha boshqa, bardoshli ob'ektlarni ishga tushirish uchun ishlatiladi.public class UserManager {
private UserService service;
public UserManager(UserService userService) {
service = userService;
}
User createUser(User user) {
return service.create(user);
}
Long findAllUsers(){
return service.findAll().size();
}
String findEmailById(Long id) {
return service.findById(id).getEmail();}
User findUserByEmail(String email) {
return service.findByEmail(email);
}
User deleteUserById(Long id) {
return service.delete(id);
}
}5. Qattiq kod
Shunday qilib, biz bu dahshatli so'zga - qattiq kodga keldik. Ushbu antipatternning mohiyati shundaki, kod ma'lum bir apparat konfiguratsiyasi va/yoki tizim muhiti bilan mustahkam bog'langan, bu esa uni boshqa konfiguratsiyalarga o'tkazishni juda qiyinlashtiradi. Ushbu antipattern sehrli raqamlar bilan chambarchas bog'liq (ular ko'pincha bir-biriga bog'langan). Misol:public Connection buildConnection() throws Exception {
Class.forName("com.mysql.cj.jdbc.Driver");
connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/someDb?characterEncoding=UTF-8&characterSetResults=UTF-8&serverTimezone=UTC", "user01", "12345qwert");
return connection;
}spring:
datasource:
jdbc-url:jdbc:mysql://localhost:3306/someDb?characterEncoding=UTF-8
driver-class-name: com.mysql.cj.jdbc.Driver
username: user01
password: 12345qwert6. Qayiq langari
Antipatternlar kontekstidagi qayiq langari, ba'zi optimallashtirish yoki qayta ishlashdan keyin qolgan tizimning foydalanilmagan qismlarini saqlashni anglatadi. Bundan tashqari, kodning ba'zi qismlari, agar siz ularni qayta ishlatishingiz kerak bo'lsa, "kelajak uchun" qoldirilishi mumkin. Bu aslida kodni axlat qutisiga aylantiradi.
Misol:
public User update(Long id, User request) {
User user = mergeUser(findById(id), request);
return userDAO.update(user);
}
private User mergeUser(User findUser, User requestUser) {
return new User(
findUser.getId(),
requestUser.getEmail() != null ? requestUser.getEmail() : findUser.getEmail(),
requestUser.getFirstName() != null ? requestUser.getFirstName() : findUser.getFirstNameRu(),
requestUser.getMiddleName() != null ? requestUser.getMiddleName() : findUser.getMiddleNameRu(),
requestUser.getLastName() != null ? requestUser.getLastName() : findUser.getLastNameEn(),
requestUser.getPhone() != null ? requestUser.getPhone() : findUser.getPhone());
}public User update(Long id, User request) {
return userDAO.update(user);
}mergeUseru endi ishlatilmaydi va uni o'chirish juda achinarli: agar u (yoki uning g'oyasi) hali ham foydali bo'lsa-chi? Bunday kod faqat tizimlarni murakkablashtiradi va chalkashtirib yuboradi, aslida hech qanday amaliy ahamiyatga ega emas. Shuni unutmasligimiz kerakki, "o'lik qismlar" bo'lgan bunday kodni boshqa loyihaga ketganingizda hamkasbingizga o'tkazish qiyin bo'ladi. Qayiq langarlari bilan ishlashning eng yaxshi usuli - bu kodni qayta tiklash, ya'ni kodning ushbu bo'limlarini o'chirish (afsuski, afsuski). Shuningdek, rivojlanishni rejalashtirishda siz bunday langarlarning paydo bo'lishini hisobga olishingiz kerak (quyruqlarni tozalash uchun vaqt ajrating).
7.Ob'ekt axlatxonasi
Ushbu antipatternni tasvirlash uchun avvalo ob'ekt bilan tanishishingiz kerak hovuz naqsh . Ob'ektlar hovuzi (resurslar hovuzi) generativ dizayn naqshidir , ishga tushirilgan va foydalanishga tayyor ob'ektlar to'plami. Ilova ob'ektni talab qilganda, u yangidan yaratilmaydi, balki shu hovuzdan olinadi. Ob'ekt endi kerak bo'lmaganda, u yo'q qilinmaydi, balki hovuzga qaytariladi. Odatda har safar yaratish uchun resurs talab qiladigan og'ir ob'ektlar uchun ishlatiladi, masalan, ma'lumotlar bazasi ulanishi. Keling, misol uchun kichik va oddiy misolni ko'rib chiqaylik. Shunday qilib, bizda ushbu naqshni ifodalovchi sinf mavjud:class ReusablePool {
private static ReusablePool pool;
private List<Resource> list = new LinkedList<>();
private ReusablePool() {
for (int i = 0; i < 3; i++)
list.add(new Resource());
}
public static ReusablePool getInstance() {
if (pool == null) {
pool = new ReusablePool();
}
return pool;
}
public Resource acquireResource() {
if (list.size() == 0) {
return new Resource();
} else {
Resource r = list.get(0);
list.remove(r);
return r;
}
}
public void releaseResource(Resource r) {
list.add(r);
}
}Resource, konstruktorda sukut bo'yicha hovuz 4 nusxa bilan to'ldiriladi; bunday ob'ekt olinganda, u hovuzdan chiqariladi (agar u yo'q bo'lsa, u yaratiladi va darhol beriladi) va oxirida ob'ektni qaytarib qo'yish usuli mavjud. Ob'ektlar Resourcequyidagicha ko'rinadi:
public class Resource {
private Map<String, String> patterns;
public Resource() {
patterns = new HashMap<>();
patterns.put("заместитель", "https://studfile.net/preview/3676297/page:3/");
patterns.put("мост", "https://studfile.net/preview/3676297/page:4/");
patterns.put("фасад", "https://studfile.net/preview/3676297/page:5/");
patterns.put("строитель", "https://studfile.net/preview/3676297/page:6/#16");
}
public Map<String, String> getPatterns() {
return patterns;
}
public void setPatterns(Map<String, String> patterns) {
this.patterns = patterns;
}
}main:
class SomeMain {
public static void main(String[] args) {
ReusablePool pool = ReusablePool.getInstance();
Resource firstResource = pool.acquireResource();
Map<String, String> firstPatterns = firstResource.getPatterns();
// ......Howим-то образом используем нашу мапу.....
pool.releaseResource(firstResource);
Resource secondResource = pool.acquireResource();
Map<String, String> secondPatterns = firstResource.getPatterns();
// ......Howим-то образом используем нашу мапу.....
pool.releaseResource(secondResource);
Resource thirdResource = pool.acquireResource();
Map<String, String> thirdPatterns = firstResource.getPatterns();
// ......Howим-то образом используем нашу мапу.....
pool.releaseResource(thirdResource);
}
}main:
Resource fourthResource = pool.acquireResource();
Map<String, String> fourthPatterns = firstResource.getPatterns();
// ......Howим-то образом используем нашу мапу.....
fourthPatterns.clear();
firstPatterns.put("first","blablabla");
firstPatterns.put("second","blablabla");
firstPatterns.put("third","blablabla");
firstPatterns.put("fourth","blablabla");
pool.releaseResource(fourthResource);public Resource() {
patterns = new HashMap<>();
patterns.put("заместитель", "https://studfile.net/preview/3676297/page:3/");
patterns.put("мост", "https://studfile.net/preview/3676297/page:4/");
patterns.put("фасад", "https://studfile.net/preview/3676297/page:5/");
patterns.put("строитель", "https://studfile.net/preview/3676297/page:6/#16");
patterns = Collections.unmodifiableMap(patterns);
}
Shu bilan maqolaning birinchi qismi nihoyasiga yetdi: davom etish .
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