Merge pull request mouredev#4582 from apuntesdejava/main

#26 - Java

Author: Roswell468

Roadmap/26 - SOLID SRP/java/diegosilval.java

@@ -0,0 +1,242 @@
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.function.Consumer;
+
+public interface diegosilval {
+    static void main(String... args) {
+        System.out.println("** Usando una clase para todo **");
+        var libraryUtil = new LibraryUtil();
+        libraryUtil.addUser("01", "Alex", "[email protected]");
+        libraryUtil.addUser("02", "Bob", "[email protected]");
+        libraryUtil.addUser("03", "Cark", "[email protected]");
+
+        libraryUtil.addBook("To Kill a Mockingbird", "Harper Lee", 2);
+        libraryUtil.addBook("1984", "George Orwell", 1);
+        libraryUtil.addBook("Pride and Prejudice", "Jane Austen", 0);
+
+        libraryUtil.bookBorrow("1984", "01").ifPresentOrElse(showBorrowSuccess, showBorrowFail);
+        libraryUtil.bookBorrow("To Kill a Mockingbird", "02").ifPresentOrElse(showBorrowSuccess, showBorrowFail);
+        libraryUtil.bookBorrow("1984", "03").ifPresentOrElse(showBorrowSuccess, showBorrowFail);
+
+        // Usando SRP
+        System.out.println("** Usando una clase por cada responsabilidad");
+        var usersRepository = new UsersRepository();
+        var booksRepository = new BooksRepository();
+        var srpLibraryUtil = new SrpLibraryUtil(usersRepository, booksRepository); // inyectando
+        usersRepository.addUser("01", "Alex", "[email protected]");
+        usersRepository.addUser("02", "Bob", "[email protected]");
+        usersRepository.addUser("03", "Cark", "[email protected]");
+
+        booksRepository.addBook("To Kill a Mockingbird", "Harper Lee", 2);
+        booksRepository.addBook("1984", "George Orwell", 1);
+        booksRepository.addBook("Pride and Prejudice", "Jane Austen", 0);
+
+        srpLibraryUtil.bookBorrow("1984", "01").ifPresentOrElse(showBorrowSuccess, showBorrowFail);
+        srpLibraryUtil.bookBorrow("To Kill a Mockingbird", "02").ifPresentOrElse(showBorrowSuccess, showBorrowFail);
+        srpLibraryUtil.bookBorrow("1984", "03").ifPresentOrElse(showBorrowSuccess, showBorrowFail);
+
+    }
+
+    static Consumer<BookLoan> showBorrowSuccess = (bookLoan) -> {
+        System.out.println(String.format("Se prestó correctamente %s a %s", bookLoan.getBook().getTitle(),
+                bookLoan.getUser().getName()));
+    };
+    static Runnable showBorrowFail = () -> System.err.println(
+            "El usuario no existe, el nombre del libro no existe, o no existen libros disponibles para prestar");
+
+}
+
+/**
+ * Book Class
+ */
+class Book {
+    private String title;
+    private String author;
+    private int available;
+
+    public Book() {
+    }
+
+    public Book(String title, String author, int available) {
+        this.title = title;
+        this.author = author;
+        this.available = available;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public String getAuthor() {
+        return author;
+    }
+
+    public void setAuthor(String author) {
+        this.author = author;
+    }
+
+    public int getAvailable() {
+        return available;
+    }
+
+    public void setAvailable(int available) {
+        this.available = available;
+    }
+
+    public void addAvailable(int delta) {
+        this.available += delta;
+    }
+
+    public void removeAvailable(int delta) {
+        this.available -= delta;
+    }
+
+}
+
+/**
+ * User Class
+ */
+class User {
+    private String name;
+    private String id;
+    private String email;
+
+    public User() {
+    }
+
+    public User(String name, String id, String email) {
+        this.name = name;
+        this.id = id;
+        this.email = email;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    public void setId(String id) {
+        this.id = id;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+
+}
+
+class BookLoan {
+    private final Book book;
+    private final User user;
+
+    public BookLoan(Book book, User user) {
+        this.book = book;
+        this.user = user;
+    }
+
+    public Book getBook() {
+        return book;
+    }
+
+    public User getUser() {
+        return user;
+    }
+
+}
+
+class LibraryUtil {
+    private List<Book> books = new ArrayList<>();
+    private List<User> users = new ArrayList<>();
+    private List<BookLoan> bookLoans = new ArrayList<>();
+
+    public void addBook(String title, String author, int available) {
+        books.add(new Book(title, author, available));
+    }
+
+    public void addUser(String id, String name, String email) {
+        users.add(new User(name, id, email));
+    }
+
+    public Optional<BookLoan> bookBorrow(String title, String userId) {
+        var user = users.stream().filter(aUser -> aUser.getId().equals(userId)).findFirst();
+        if (user.isEmpty())
+            return Optional.empty();
+        var book = books.stream().filter(aBook -> aBook.getTitle().equalsIgnoreCase(title)).findFirst();
+        if (book.isEmpty() || book.get().getAvailable() == 0)
+            return Optional.empty();
+        book.get().removeAvailable(1);
+        var bookLoan = new BookLoan(book.get(), user.get());
+        bookLoans.add(bookLoan);
+        return Optional.of(bookLoan);
+    }
+}
+
+/**
+ * Clase LibraryUtil aplicando SRP
+ */
+class SrpLibraryUtil {
+    private final UsersRepository usersRepository;
+    private final BooksRepository booksRepository;
+    private List<BookLoan> bookLoans = new ArrayList<>();
+
+    public SrpLibraryUtil(UsersRepository usersRepository, BooksRepository booksRepository) {
+        this.usersRepository = usersRepository;
+        this.booksRepository = booksRepository;
+    }
+
+    public Optional<BookLoan> bookBorrow(String title, String userId) {
+        var user = usersRepository.findById(userId);
+        var book = booksRepository.findByTitle(title);
+        if (user.isEmpty() || book.isEmpty())
+            return Optional.empty();
+        book.get().removeAvailable(1);
+        var bookLoan = new BookLoan(book.get(), user.get());
+        bookLoans.add(bookLoan);
+        return Optional.of(bookLoan);
+    }
+
+}
+
+/**
+ * Repositorio de usuarios
+ */
+class UsersRepository {
+    private List<User> users = new ArrayList<>();
+
+    public void addUser(String id, String name, String email) {
+        users.add(new User(name, id, email));
+    }
+
+    public Optional<User> findById(String userId) {
+        return users.stream().filter(aUser -> aUser.getId().equals(userId)).findFirst();
+    }
+}
+
+class BooksRepository {
+    private List<Book> books = new ArrayList<>();
+
+    public void addBook(String title, String author, int available) {
+        books.add(new Book(title, author, available));
+    }
+
+    public Optional<Book> findByTitle(String title) {
+        return books.stream().filter(aBook -> aBook.getTitle().equalsIgnoreCase(title) && aBook.getAvailable() > 0)
+                .findFirst();
+    }
+}