Timofey Pletnev

homesystem/HomeTask.java

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+package dev.timatifey.homesystem;
+
+
+public class HomeTask {
+
+    int id;
+    int studentId;
+    long deadlineTimestamp;
+
+    Status status;
+    int score;
+
+    int inspectorId;
+
+    HomeTask(int id, int studentId, long deadlineTimestamp) {
+        this.id = id;
+        this.studentId = studentId;
+        this.status = Status.NEED_VERIFY;
+        this.deadlineTimestamp = deadlineTimestamp;
+    }
+
+
+    public enum Status {
+        NEED_VERIFY,
+        VERIFIED
+    }
+}

homesystem/Inspector.java

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+package dev.timatifey.homesystem;
+
+
+public class Inspector extends Thread {
+
+    int id;
+    private final VerifySystem verifySystem;
+
+    public Inspector(int id, VerifySystem verifySystem) {
+        this.id = id;
+        this.verifySystem = verifySystem;
+    }
+
+    @Override
+    public void run() {
+        while (true) {
+            try {
+                verifySystem.verifyTask(id);
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        }
+    }
+}
+

homesystem/Simulation.java

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+package dev.timatifey.homesystem;
+
+import java.util.Random;
+
+public class Simulation {
+
+    public static void main(String[] args) throws InterruptedException {
+        VerifySystem verifySystem = new VerifySystem();
+        Random random = new Random();
+        for (int i = 0; i < 5; i++) {
+            Inspector inspector = new Inspector(i, verifySystem);
+            inspector.start();
+        }
+
+        for (int i = 0; i < 100; i++) {
+            Student student = new Student(i, verifySystem);
+
+            long currentTime = System.currentTimeMillis();
+            long taskTime = random.nextLong(1000000);
+            HomeTask task = new HomeTask(i, student.id, currentTime + taskTime);
+
+            student.sendTaskOnVerify(task);
+            student.start();
+        }
+
+    }
+}

homesystem/Student.java

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+package dev.timatifey.homesystem;
+
+public class Student extends Thread {
+
+    int id;
+    private final VerifySystem verifySystem;
+
+    public Student(int id, VerifySystem verifySystem) {
+        this.id = id;
+        this.verifySystem = verifySystem;
+    }
+
+    public void sendTaskOnVerify(HomeTask task) throws InterruptedException {
+        Thread.sleep(2000);
+        long currentTime = System.currentTimeMillis();
+        verifySystem.addTask(id, task, currentTime);
+    }
+
+    @Override
+    public void run() {
+        while (true) {
+            HomeTask task = verifySystem.checkTask(id);
+            if (task != null) {
+                System.out.printf("Student checked task. Student = %d Task = %d Score = %d%n", id, task.id, task.score);
+                break;
+            }
+        }
+    }
+}

homesystem/VerifySystem.java

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+package dev.timatifey.homesystem;
+
+import java.util.Comparator;
+import java.util.Map;
+import java.util.Random;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.PriorityBlockingQueue;
+
+public class VerifySystem {
+
+    private final int CAPACITY = 11;
+    private final BlockingQueue<HomeTask> tasks = new PriorityBlockingQueue<>(CAPACITY, new TasksComparator());
+    private final Map<Integer, HomeTask> verifiedTasks = new ConcurrentHashMap<>();
+    private final Random random = new Random();
+
+    public void addTask(int studentId, HomeTask task, long sendTimestamp) {
+        System.out.println("Got task " + task.id + " from student " + studentId + " at time " + sendTimestamp);
+        tasks.add(task);
+    }
+
+    public void verifyTask(int inspectorId) throws InterruptedException {
+        HomeTask task = tasks.take();
+
+        Thread.sleep(random.nextInt(5000));
+        task.status = HomeTask.Status.VERIFIED;
+        task.inspectorId = inspectorId;
+        task.score = random.nextInt(100);
+
+        System.out.printf("Inspector verified task. Inspector = %d Task = %d Score = %d%n", inspectorId, task.id, task.score);
+
+        verifiedTasks.put(task.studentId, task);
+    }
+
+    public HomeTask checkTask(int studentId) {
+        HomeTask task = verifiedTasks.get(studentId);
+        return task;
+    }
+
+    private class TasksComparator implements Comparator<HomeTask> {
+
+        @Override
+        public int compare(HomeTask o1, HomeTask o2) {
+            boolean firstMorePriority = (o1.deadlineTimestamp > o2.deadlineTimestamp) || (o1.id < o2.id);
+            return firstMorePriority ? 1 : 0;
+        }
+    }
+
+}