Add OOP/Java/Assignments/FISAC/Q3.java

OOP/Java/Assignments/FISAC/Q3.java

@@ -0,0 +1,66 @@
+// Package: users
+package users;
+public class User {
+    String name;
+    int userID;
+    public User(String name, int userID) { this.name = name; this.userID = userID; }
+}
+
+// Package: books
+package books;
+public class Book {
+    String title;
+    boolean isAvailable;
+    public Book(String title) { this.title = title; this.isAvailable = true; }
+}
+
+// Package: exceptions
+package exceptions;
+public class BookNotAvailableException extends Exception {}
+public class BookNotBorrowedException extends Exception {}
+public class BookCannotBeIssued extends Exception {}
+
+// Interface LibraryOperations
+package users;
+import books.Book;
+import exceptions.*;
+interface LibraryOperations {
+    void borrowBook(Book book) throws BookNotAvailableException, BookCannotBeIssued;
+    void returnBook(Book book) throws BookNotBorrowedException;
+    int calculatePenalty(int daysLate);
+}
+
+// Class LibraryUser
+package users;
+import books.Book;
+import exceptions.*;
+public class LibraryUser extends User implements LibraryOperations {
+    public LibraryUser(String name, int userID) { super(name, userID); }
+    public void borrowBook(Book book) throws BookNotAvailableException, BookCannotBeIssued {
+        if (!book.isAvailable) throw new BookNotAvailableException();
+        book.isAvailable = false;
+    }
+    public void returnBook(Book book) throws BookNotBorrowedException {
+        if (book.isAvailable) throw new BookNotBorrowedException();
+        book.isAvailable = true;
+    }
+    public int calculatePenalty(int daysLate) { return daysLate * 2; }
+}
+
+// Main class for testing
+package main;
+import users.LibraryUser;
+import books.Book;
+import exceptions.*;
+public class Main {
+    public static void main(String[] args) {
+        LibraryUser user = new LibraryUser("Alice", 1);
+        Book book = new Book("Java Programming");
+        try {
+            user.borrowBook(book);
+            user.returnBook(book);
+        } catch (Exception e) {
+            System.out.println(e);
+        }
+    }
+}