Lesson 08

src/main/java/lessons/lesson08/book/Book.java

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+package lessons.lesson08.book;
+
+public class Book {
+    String title, author, isbn;
+
+    Book(String title, String author, String isbn) {
+        this.title = title;
+        this.author = author;
+        this.isbn = isbn;
+    }
+
+    @Override
+    public String toString() {
+        return "ISBN: " + isbn + ", Title: " + title + ", Author: " + author;
+    }
+}

src/main/java/lessons/lesson08/book/Main.java

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+package lessons.lesson08.book;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class Main {
+    public static void main(String[] args) {
+        Map<String, Book> books = new HashMap<>();
+        books.put("978-1-23456-789-7", new Book("Effective Java", "Joshua Bloch", "978-1-23456-789-7"));
+        books.put("978-0-98765-432-1", new Book("Clean Code", "Robert C. Martin", "978-0-98765-432-1"));
+        books.put("978-0-12345-678-9", new Book("Java: The Complete Reference", "Herbert Schildt", "978-0-12345-678-9"));
+
+        System.out.println("Books list:");
+        for (Book b : books.values()) {
+            System.out.println(b);
+        }
+    }
+}

src/main/java/lessons/lesson08/numbers/Main.java

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+package lessons.lesson08.numbers;
+
+import java.util.*;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        System.out.println("Input numbers by tab (example: 1 2 3 45 5)");
+        System.out.print("Numbers: ");
+        String line = sc.nextLine().trim();
+        if (line.isEmpty()) {
+            System.out.println("Exit.");
+            sc.close();
+            return;
+        }
+        String[] tokens = line.split("\\s+");
+        Set<Integer> unique = new LinkedHashSet<>();
+        for (String t : tokens) {
+            try {
+                unique.add(Integer.parseInt(t));
+            } catch (NumberFormatException ignored) {
+            }
+        }
+        if (unique.isEmpty()) {
+            System.out.println("No valid numbers found");
+        } else {
+            System.out.print("Unique numbers: ");
+            boolean first = true;
+            for (int n : unique) {
+                if (!first) System.out.print(" ");
+                System.out.print(n);
+                first = false;
+            }
+            System.out.println();
+        }
+        sc.close();
+    }
+}

src/main/java/lessons/lesson08/queue/ElectronicQueue.java

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+package lessons.lesson08.queue;
+
+import java.util.ArrayDeque;
+import java.util.Queue;
+
+public class ElectronicQueue {
+    private Queue<User> queue = new ArrayDeque<>();
+    private int nextTicket = 1;
+
+    public User register(String name) {
+        User u = new User(name, nextTicket++);
+        queue.add(u);
+        return u;
+    }
+
+    public User processNext() {
+        return queue.poll();
+    }
+
+    public User peek() {
+        return queue.peek();
+    }
+}

src/main/java/lessons/lesson08/queue/QueeMain.java

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+package lessons.lesson08.queue;
+
+import java.util.*;
+
+public class QueeMain {
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        ElectronicQueue eq = new ElectronicQueue();
+
+        System.out.println("Commands: register \"name\" | process | peek | exit");
+
+        while (true) {
+            System.out.print("Operation: ");
+            String line = sc.nextLine();
+            if (line == null) break;
+            line = line.trim();
+            if (line.isEmpty()) continue;
+
+            // выход
+            if (line.equalsIgnoreCase("exit")) {
+                System.out.println("Exit.");
+                break;
+            }
+
+            // регистрация
+            if (line.toLowerCase().startsWith("register")) {
+                String name = "";
+                if (line.length() > 8) name = line.substring(8).trim();
+                // спрашиваем имя, если через команду не было написано
+                if (name.isEmpty()) {
+                    System.out.print("Name: ");
+                    name = sc.nextLine().trim();
+                }
+                if (name.isEmpty()) {
+                    System.out.println("Name is empty. Cancel");
+                    continue;
+                }
+                User u = eq.register(name);
+                System.out.println("Ticket " + u.ticket + " assigned to " + u.name);
+                continue;
+            }
+
+            if (line.equalsIgnoreCase("process")) {
+                User u = eq.processNext();
+                if (u == null) System.out.println("Queue is empty");
+                else System.out.println("Processing " + u);
+                continue;
+            }
+
+            if (line.equalsIgnoreCase("peek")) {
+                User u = eq.peek();
+                if (u == null) System.out.println("Queue is empty");
+                else System.out.println("Next: " + u);
+                continue;
+            }
+            // неизвестная команда
+            System.out.println("Unknown. Available: register, process, peek, exit");
+        }
+        sc.close();
+    }
+}
+

src/main/java/lessons/lesson08/queue/User.java

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+package lessons.lesson08.queue;
+
+public class User {
+    String name;
+    int ticket;
+
+    User(String name, int ticket) {
+        this.name = name;
+        this.ticket = ticket;
+    }
+
+    @Override
+    public String toString() {
+        return "Ticket " + ticket + ": " + name;
+    }
+}