Implemented lab 1

.gitignore

@@ -5,6 +5,7 @@ build/
 !**/src/test/**/build/
 
 ### IntelliJ IDEA ###
+.idea/
 .idea/modules.xml
 .idea/jarRepositories.xml
 .idea/compiler.xml
@@ -39,4 +40,5 @@ bin/
 .vscode/
 
 ### Mac OS ###
-.DS_Store
+.DS_Store
+/.idea/

README.md

@@ -29,4 +29,21 @@
 * Использование системы сборки Gradle
 * Код должен быть отлажен и протестирован
 
-# Дедлайн 08.10.2025 23:59
+# Дедлайн 08.10.2025 23:59
+
+Решение:
+
+Для предотвращения deadlockа пронумеруем ложки от 0 до n - 1. 
+Сначала программист будет дожидаться ложки с меньшим номером, затем с большим.
+
+Официанты будут реализованы как пул потоков в ExecutorService. 
+При запросе еды программист блокируется, пока ему ее не принесут. 
+Полученная future вернет true, если еда была выдана, и false, если она закончилась. 
+При false поток программиста завершает работу.
+
+Step 1 - без приоритетов
+
+
+Step 2 - с приоритетами:
+
+Когда программист поел, у его соседей повышается приоритет, а свой сбрасывается. Если сосед с высшим приоритетом ждет ложку, текущий программист не имеет права ее брать. 

build.gradle.kts

@@ -1,5 +1,6 @@
 plugins {
     id("java")
+    id("io.freefair.lombok") version "9.1.0"
 }
 
 group = "org.labs"
@@ -16,4 +17,4 @@ dependencies {
 
 tasks.test {
     useJUnitPlatform()
-}
+}

results.txt

@@ -0,0 +1,29 @@
+OrderedSpoonService + SimpleWaiterService
+Total time: 23217 ms
+Delta: 55.76%
+[8.16, 9.14, 9.35, 9.65, 10.04, 10.34, 10.9, 11.54, 12.71, 8.17]
+
+OrderedSpoonService + SimpleWaiterService (discuss time > eat time)
+Total time: 12609 ms
+Delta: 4.57%
+[9.85, 9.97, 9.88, 9.85, 9.96, 9.94, 10.22, 10.14, 10.3, 9.89]
+
+LimitedSpoonService + SimpleWaiterService
+Total time: 72404 ms
+Delta: 0.20%
+[10.0, 10.0, 9.99, 9.99, 10.0, 10.01, 10.01, 10.0, 10.0, 10.0]
+
+OrderedSpoonService + PrioritizedWaiterService (10%)
+Total time: 23475 ms
+Delta: 59.88%
+[8.11, 9.01, 9.31, 9.73, 9.94, 10.38, 10.92, 11.55, 12.95, 8.1]
+
+OrderedSpoonService + PrioritizedWaiterService (1%)
+Total time: 27421 ms
+Delta: 10.88%
+[9.28, 9.77, 9.95, 10.27, 10.29, 10.29, 10.29, 10.29, 10.29, 9.28]
+
+LimitedSpoonService + PrioritizedWaiterService (1%)
+Total time: 79718 ms
+Delta: 0.20%
+[10.0, 10.0, 10.0, 9.99, 10.01, 10.01, 10.0, 10.0, 10.0, 9.99]

src/main/java/org/labs/Cafe.java

@@ -0,0 +1,42 @@
+package org.labs;
+
+import java.util.List;
+import java.util.stream.IntStream;
+
+public class Cafe {
+
+    private final WaiterService waiterService;
+    private final List<Programmer> programmers;
+    private final List<Thread> programmerThreads;
+
+    public Cafe(CafeConfig config, WaiterService waiterService, SpoonService spoonService) {
+        this.waiterService = waiterService;
+        programmers = IntStream.range(0, config.getProgrammersNumber())
+            .mapToObj(id -> new Programmer(waiterService, spoonService, id, config))
+            .toList();
+
+        programmerThreads = programmers.stream().map(Thread::new).toList();
+    }
+
+    public void start() {
+        programmerThreads.forEach(Thread::start);
+    }
+
+    public void join() {
+        for (var p : programmerThreads) {
+            if (Thread.currentThread().isInterrupted()) {
+                p.interrupt();
+            }
+            try {
+                p.join();
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+            }
+        }
+        waiterService.shutdown();
+    }
+
+    public List<Integer> getFoodDistribution() {
+        return programmers.stream().map(Programmer::getEatenFood).toList();
+    }
+}

src/main/java/org/labs/CafeConfig.java

@@ -0,0 +1,23 @@
+package org.labs;
+
+import lombok.Builder;
+import lombok.Getter;
+
+@Getter
+@Builder
+public class CafeConfig {
+    private final int programmersNumber;
+    private final int waitersNumber;
+    private final int totalFood;
+    private final int spoonCount;
+    @Builder.Default
+    private final int minDiscussTimeInMillis = 1;
+    @Builder.Default
+    private final int maxDiscussTimeInMillis = 5;
+    @Builder.Default
+    private final int minEatTimeInMillis = 5;
+    @Builder.Default
+    private final int maxEatTimeInMillis = 10;
+    private final Integer deltaPercentage; // Optional, for PrioritizedWaiterService
+}
+

src/main/java/org/labs/LimitedSpoonService.java

@@ -0,0 +1,40 @@
+package org.labs;
+
+import java.util.List;
+import java.util.concurrent.Semaphore;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.stream.IntStream;
+
+/**
+ * Позволяет взять левую ложку n - 1 раз.
+ * Предотвращает ситуацию, когда все n программистов взяли левую ложку.
+ */
+public class LimitedSpoonService implements SpoonService {
+
+    private final int spoonCount;
+    private final List<ReentrantLock> spoonLocks;
+    private final Semaphore semaphore;
+
+    public LimitedSpoonService(int spoonCount) {
+        this.spoonCount = spoonCount;
+        this.spoonLocks = IntStream.range(0, spoonCount)
+            .mapToObj(i -> new ReentrantLock())
+            .toList();
+        this.semaphore = new Semaphore(spoonCount - 1, true);
+    }
+
+    @Override
+    public void acquireSpoons(int id) throws InterruptedException {
+        semaphore.acquire();
+        spoonLocks.get(id).lock();
+        spoonLocks.get((id + 1) % spoonCount).lock();
+    }
+
+    @Override
+    public void releaseSpoons(int id) {
+        spoonLocks.get((id + 1) % spoonCount).unlock();
+        spoonLocks.get(id).unlock();
+        semaphore.release();
+    }
+
+}

src/main/java/org/labs/Main.java

@@ -1,7 +1,170 @@
 package org.labs;
 
+import java.io.FileNotFoundException;
+import java.io.PrintWriter;
+
 public class Main {
+
+    // SpoonService:
+    //      OrderedSpoonService
+    //      LimitedSpoonService
+    // WaiterService:
+    //      SimpleWaiterService
+    //      PrioritizedWaiterService
+
     public static void main(String[] args) {
-        System.out.println("Hello, World!");
+        PrintWriter fileOut;
+        try {
+            fileOut = new PrintWriter("results.txt");
+        } catch (FileNotFoundException e) {
+            System.err.println("Failed to create results.txt: " + e.getMessage());
+            return;
+        }
+
+        fileOut.println("OrderedSpoonService + SimpleWaiterService");
+        CafeConfig config = CafeConfig.builder()
+            .programmersNumber(10)
+            .waitersNumber(4)
+            .totalFood(10000)
+            .spoonCount(10)
+            .minDiscussTimeInMillis(1)
+            .maxDiscussTimeInMillis(5)
+            .minEatTimeInMillis(5)
+            .maxEatTimeInMillis(10)
+            .build();
+        test(
+            fileOut,
+            config,
+            new OrderedSpoonService(config.getSpoonCount()),
+            new SimpleWaiterService(config.getWaitersNumber(), config.getTotalFood())
+        );
+
+
+        fileOut.println("\nOrderedSpoonService + SimpleWaiterService (discuss time > eat time)");
+        config = CafeConfig.builder()
+            .programmersNumber(10)
+            .waitersNumber(4)
+            .totalFood(10000)
+            .spoonCount(10)
+            .minDiscussTimeInMillis(5)
+            .maxDiscussTimeInMillis(10)
+            .minEatTimeInMillis(1)
+            .maxEatTimeInMillis(5)
+            .build();
+        test(
+            fileOut,
+            config,
+            new OrderedSpoonService(config.getSpoonCount()),
+            new SimpleWaiterService(config.getWaitersNumber(), config.getTotalFood())
+        );
+
+        fileOut.println("\nLimitedSpoonService + SimpleWaiterService");
+        config = CafeConfig.builder()
+            .programmersNumber(10)
+            .waitersNumber(4)
+            .totalFood(10000)
+            .spoonCount(10)
+            .minDiscussTimeInMillis(1)
+            .maxDiscussTimeInMillis(5)
+            .minEatTimeInMillis(5)
+            .maxEatTimeInMillis(10)
+            .build();
+        test(
+            fileOut,
+            config,
+            new LimitedSpoonService(config.getSpoonCount()),
+            new SimpleWaiterService(config.getWaitersNumber(), config.getTotalFood())
+        );
+
+        fileOut.println("\nOrderedSpoonService + PrioritizedWaiterService (10%)");
+        config = CafeConfig.builder()
+            .programmersNumber(10)
+            .waitersNumber(4)
+            .totalFood(10000)
+            .spoonCount(10)
+            .minDiscussTimeInMillis(1)
+            .maxDiscussTimeInMillis(5)
+            .minEatTimeInMillis(5)
+            .maxEatTimeInMillis(10)
+            .deltaPercentage(10)
+            .build();
+        test(
+            fileOut,
+            config,
+            new OrderedSpoonService(config.getSpoonCount()),
+            new PrioritizedWaiterService(config.getProgrammersNumber(), config.getWaitersNumber(), config.getTotalFood(), config.getDeltaPercentage())
+        );
+
+        fileOut.println("\nOrderedSpoonService + PrioritizedWaiterService (1%)");
+        System.out.println("OrderedSpoonService + PrioritizedWaiterService (1%)");
+        config = CafeConfig.builder()
+            .programmersNumber(10)
+            .waitersNumber(4)
+            .totalFood(10000)
+            .spoonCount(10)
+            .minDiscussTimeInMillis(1)
+            .maxDiscussTimeInMillis(5)
+            .minEatTimeInMillis(5)
+            .maxEatTimeInMillis(10)
+            .deltaPercentage(1)
+            .build();
+        test(
+            fileOut,
+            config,
+            new OrderedSpoonService(config.getSpoonCount()),
+            new PrioritizedWaiterService(config.getProgrammersNumber(), config.getWaitersNumber(), config.getTotalFood(), config.getDeltaPercentage())
+        );
+
+        fileOut.println("\nLimitedSpoonService + PrioritizedWaiterService (1%)");
+        config = CafeConfig.builder()
+            .programmersNumber(10)
+            .waitersNumber(4)
+            .totalFood(10000)
+            .spoonCount(10)
+            .minDiscussTimeInMillis(1)
+            .maxDiscussTimeInMillis(5)
+            .minEatTimeInMillis(5)
+            .maxEatTimeInMillis(10)
+            .deltaPercentage(1)
+            .build();
+        test(
+            fileOut,
+            config,
+            new LimitedSpoonService(config.getSpoonCount()),
+            new PrioritizedWaiterService(config.getProgrammersNumber(), config.getWaitersNumber(), config.getTotalFood(), config.getDeltaPercentage())
+        );
+
+        fileOut.close();
+    }
+
+    private static void test(
+        PrintWriter fileOut,
+        CafeConfig config,
+        SpoonService spoonService,
+        WaiterService waiterService
+    ) {
+        Cafe cafe = new Cafe(config, waiterService, spoonService);
+
+        long startTime = System.currentTimeMillis();
+
+        cafe.start();
+        cafe.join();
+
+        long endTime = System.currentTimeMillis();
+
+        long totalTime = endTime - startTime;
+
+        var distribution = cafe.getFoodDistribution();
+        var sum = distribution.stream().mapToInt(Integer::intValue).sum();
+        var percentage = distribution.stream().map(value -> 100.0 * value / sum).toList();
+        var minFood = distribution.stream().min(Integer::compare).get();
+        var maxFood = distribution.stream().max(Integer::compare).get();
+        var delta = 100.0 * (maxFood - minFood) / minFood;
+
+        fileOut.println("Total time: " + totalTime + " ms");
+        fileOut.printf("Delta: %.2f", delta);
+        fileOut.println("%");
+        fileOut.println(percentage);
+        fileOut.flush();
     }
-}
+}