Java 11 migrate remaining (g,h,i) (iluwatar#1116)

* Moves game-loop to Java 11

* Moves guarded-suspension to Java 11

* Moves half-sync-half-async to Java 11

* Moves hexagonal to Java 11

* Moves intercepting-filter to Java 11

* Moves interpreter to Java 11

* Moves iterator to Java 11

game-loop/src/main/java/com/iluwatar/gameloop/GameLoop.java

@@ -70,7 +70,7 @@ public void stop() {
    * @return {@code true} if the game is running.
    */
   public boolean isGameRunning() {
-    return status == GameStatus.RUNNING ? true : false;
+    return status == GameStatus.RUNNING;
   }
 
   /**
@@ -80,7 +80,7 @@ public boolean isGameRunning() {
    */
   protected void processInput() {
     try {
-      int lag = new Random().nextInt(200) + 50;
+      var lag = new Random().nextInt(200) + 50;
       Thread.sleep(lag);
     } catch (InterruptedException e) {
       logger.error(e.getMessage());

game-loop/src/test/java/com/iluwatar/gameloop/AppTest.java

@@ -32,8 +32,7 @@ public class AppTest {
 
   @Test
   public void testMain() {
-    String[] args = {};
-    new App().main(args);
+    new App().main(new String[]{});
   }
 
 }

game-loop/src/test/java/com/iluwatar/gameloop/GameLoopTest.java

@@ -65,7 +65,7 @@ public void testStop() {
 
   @Test
   public void testIsGameRunning() {
-    Assert.assertEquals(false, gameLoop.isGameRunning());
+    Assert.assertFalse(gameLoop.isGameRunning());
   }
 
 }

guarded-suspension/src/main/java/com/iluwatar/guarded/suspension/App.java

@@ -23,7 +23,6 @@
 
 package com.iluwatar.guarded.suspension;
 
-import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 
@@ -45,14 +44,11 @@ public class App {
    * @param args - command line args
    */
   public static void main(String[] args) {
-    GuardedQueue guardedQueue = new GuardedQueue();
-    ExecutorService executorService = Executors.newFixedThreadPool(3);
+    var guardedQueue = new GuardedQueue();
+    var executorService = Executors.newFixedThreadPool(3);
 
     //here we create first thread which is supposed to get from guardedQueue
-    executorService.execute(() -> {
-          guardedQueue.get();
-        }
-    );
+    executorService.execute(guardedQueue::get);
 
     // here we wait two seconds to show that the thread which is trying
     // to get from guardedQueue will be waiting
@@ -63,10 +59,7 @@ public static void main(String[] args) {
     }
     // now we execute second thread which will put number to guardedQueue
     // and notify first thread that it could get
-    executorService.execute(() -> {
-          guardedQueue.put(20);
-        }
-    );
+    executorService.execute(() -> guardedQueue.put(20));
     executorService.shutdown();
     try {
       executorService.awaitTermination(30, TimeUnit.SECONDS);

guarded-suspension/src/test/java/com/iluwatar/guarded/suspension/GuardedQueueTest.java

@@ -23,13 +23,11 @@
 
 package com.iluwatar.guarded.suspension;
 
-import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
-import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
+import org.junit.jupiter.api.Test;
 
 /**
  * Test for Guarded Queue
@@ -39,8 +37,8 @@ public class GuardedQueueTest {
 
   @Test
   public void testGet() {
-    GuardedQueue g = new GuardedQueue();
-    ExecutorService executorService = Executors.newFixedThreadPool(2);
+    var g = new GuardedQueue();
+    var executorService = Executors.newFixedThreadPool(2);
     executorService.submit(() -> value = g.get());
     executorService.submit(() -> g.put(10));
     executorService.shutdown();
@@ -54,7 +52,7 @@ public void testGet() {
 
   @Test
   public void testPut() {
-    GuardedQueue g = new GuardedQueue();
+    var g = new GuardedQueue();
     g.put(12);
     assertEquals(Integer.valueOf(12), g.get());
   }

half-sync-half-async/src/main/java/com/iluwatar/halfsynchalfasync/App.java

@@ -70,7 +70,7 @@ public class App {
    * @param args command line args
    */
   public static void main(String[] args) {
-    AsynchronousService service = new AsynchronousService(new LinkedBlockingQueue<>());
+    var service = new AsynchronousService(new LinkedBlockingQueue<>());
     /*
      * A new task to calculate sum is received but as this is main thread, it should not block. So
      * it passes it to the asynchronous task layer to compute and proceeds with handling other

half-sync-half-async/src/test/java/com/iluwatar/halfsynchalfasync/AppTest.java

@@ -25,12 +25,8 @@
 
 import org.junit.jupiter.api.Test;
 
-import java.util.concurrent.ExecutionException;
-
 /**
- * 
  * Application test
- *
  */
 public class AppTest {
 

half-sync-half-async/src/test/java/com/iluwatar/halfsynchalfasync/AsynchronousServiceTest.java

@@ -57,13 +57,13 @@ public void setUp() {
 
   @Test
   public void testPerfectExecution() throws Exception {
-    final Object result = new Object();
+    final var result = new Object();
     when(task.call()).thenReturn(result);
     service.execute(task);
 
     verify(task, timeout(2000)).onPostCall(eq(result));
 
-    final InOrder inOrder = inOrder(task);
+    final var inOrder = inOrder(task);
     inOrder.verify(task, times(1)).onPreCall();
     inOrder.verify(task, times(1)).call();
     inOrder.verify(task, times(1)).onPostCall(eq(result));
@@ -73,13 +73,13 @@ public void testPerfectExecution() throws Exception {
 
   @Test
   public void testCallException() throws Exception {
-    final IOException exception = new IOException();
+    final var exception = new IOException();
     when(task.call()).thenThrow(exception);
     service.execute(task);
 
     verify(task, timeout(2000)).onError(eq(exception));
 
-    final InOrder inOrder = inOrder(task);
+    final var inOrder = inOrder(task);
     inOrder.verify(task, times(1)).onPreCall();
     inOrder.verify(task, times(1)).call();
     inOrder.verify(task, times(1)).onError(exception);
@@ -89,13 +89,13 @@ public void testCallException() throws Exception {
 
   @Test
   public void testPreCallException() {
-    final IllegalStateException exception = new IllegalStateException();
+    final var exception = new IllegalStateException();
     doThrow(exception).when(task).onPreCall();
     service.execute(task);
 
     verify(task, timeout(2000)).onError(eq(exception));
 
-    final InOrder inOrder = inOrder(task);
+    final var inOrder = inOrder(task);
     inOrder.verify(task, times(1)).onPreCall();
     inOrder.verify(task, times(1)).onError(exception);
 

hexagonal/src/main/java/com/iluwatar/hexagonal/App.java

@@ -24,7 +24,6 @@
 package com.iluwatar.hexagonal;
 
 import com.google.inject.Guice;
-import com.google.inject.Injector;
 import com.iluwatar.hexagonal.domain.LotteryAdministration;
 import com.iluwatar.hexagonal.domain.LotteryService;
 import com.iluwatar.hexagonal.module.LotteryTestingModule;
@@ -63,14 +62,14 @@ public class App {
    */
   public static void main(String[] args) {
 
-    Injector injector = Guice.createInjector(new LotteryTestingModule());
+    var injector = Guice.createInjector(new LotteryTestingModule());
 
     // start new lottery round
-    LotteryAdministration administration = injector.getInstance(LotteryAdministration.class);
+    var administration = injector.getInstance(LotteryAdministration.class);
     administration.resetLottery();
 
     // submit some lottery tickets
-    LotteryService service = injector.getInstance(LotteryService.class);
+    var service = injector.getInstance(LotteryService.class);
     SampleData.submitTickets(service, 20);
 
     // perform lottery

hexagonal/src/main/java/com/iluwatar/hexagonal/administration/ConsoleAdministration.java

@@ -24,7 +24,6 @@
 package com.iluwatar.hexagonal.administration;
 
 import com.google.inject.Guice;
-import com.google.inject.Injector;
 import com.iluwatar.hexagonal.domain.LotteryAdministration;
 import com.iluwatar.hexagonal.domain.LotteryService;
 import com.iluwatar.hexagonal.module.LotteryModule;
@@ -46,17 +45,16 @@ public class ConsoleAdministration {
    */
   public static void main(String[] args) {
     MongoConnectionPropertiesLoader.load();
-    Injector injector = Guice.createInjector(new LotteryModule());
-    LotteryAdministration administration = injector.getInstance(LotteryAdministration.class);
-    LotteryService service = injector.getInstance(LotteryService.class);
+    var injector = Guice.createInjector(new LotteryModule());
+    var administration = injector.getInstance(LotteryAdministration.class);
+    var service = injector.getInstance(LotteryService.class);
     SampleData.submitTickets(service, 20);
-    ConsoleAdministrationSrv consoleAdministration =
-        new ConsoleAdministrationSrvImpl(administration, LOGGER);
-    try (Scanner scanner = new Scanner(System.in)) {
-      boolean exit = false;
+    var consoleAdministration = new ConsoleAdministrationSrvImpl(administration, LOGGER);
+    try (var scanner = new Scanner(System.in)) {
+      var exit = false;
       while (!exit) {
         printMainMenu();
-        String cmd = readString(scanner);
+        var cmd = readString(scanner);
         if ("1".equals(cmd)) {
           consoleAdministration.getAllSubmittedTickets();
         } else if ("2".equals(cmd)) {

hexagonal/src/main/java/com/iluwatar/hexagonal/administration/ConsoleAdministrationSrvImpl.java

@@ -50,7 +50,7 @@ public void getAllSubmittedTickets() {
 
   @Override
   public void performLottery() {
-    LotteryNumbers numbers = administration.performLottery();
+    var numbers = administration.performLottery();
     logger.info("The winning numbers: {}", numbers.getNumbersAsString());
     logger.info("Time to reset the database for next round, eh?");
   }

hexagonal/src/main/java/com/iluwatar/hexagonal/banking/MongoBank.java

@@ -28,7 +28,6 @@
 import com.mongodb.client.MongoDatabase;
 import com.mongodb.client.model.UpdateOptions;
 import java.util.ArrayList;
-import java.util.List;
 import org.bson.Document;
 
 /**
@@ -107,30 +106,31 @@ public MongoCollection<Document> getAccountsCollection() {
 
   @Override
   public void setFunds(String bankAccount, int amount) {
-    Document search = new Document("_id", bankAccount);
-    Document update = new Document("_id", bankAccount).append("funds", amount);
-    accountsCollection
-        .updateOne(search, new Document("$set", update), new UpdateOptions().upsert(true));
+    var search = new Document("_id", bankAccount);
+    var update = new Document("_id", bankAccount).append("funds", amount);
+    var updateOptions = new UpdateOptions().upsert(true);
+    accountsCollection.updateOne(search, new Document("$set", update), updateOptions);
   }
 
   @Override
   public int getFunds(String bankAccount) {
-    Document search = new Document("_id", bankAccount);
-    List<Document> results = accountsCollection.find(search).limit(1).into(new ArrayList<>());
-    if (results.size() > 0) {
-      return results.get(0).getInteger("funds");
-    } else {
-      return 0;
-    }
+    return accountsCollection
+        .find(new Document("_id", bankAccount))
+        .limit(1)
+        .into(new ArrayList<>())
+        .stream()
+        .findFirst()
+        .map(x -> x.getInteger("funds"))
+        .orElse(0);
   }
 
   @Override
   public boolean transferFunds(int amount, String sourceAccount, String destinationAccount) {
-    int sourceFunds = getFunds(sourceAccount);
+    var sourceFunds = getFunds(sourceAccount);
     if (sourceFunds < amount) {
       return false;
     } else {
-      int destFunds = getFunds(destinationAccount);
+      var destFunds = getFunds(destinationAccount);
       setFunds(sourceAccount, sourceFunds - amount);
       setFunds(destinationAccount, destFunds + amount);
       return true;

hexagonal/src/main/java/com/iluwatar/hexagonal/database/InMemoryTicketRepository.java

@@ -38,17 +38,12 @@ public class InMemoryTicketRepository implements LotteryTicketRepository {
 
   @Override
   public Optional<LotteryTicket> findById(LotteryTicketId id) {
-    LotteryTicket ticket = tickets.get(id);
-    if (ticket == null) {
-      return Optional.empty();
-    } else {
-      return Optional.of(ticket);
-    }
+    return Optional.ofNullable(tickets.get(id));
   }
 
   @Override
   public Optional<LotteryTicketId> save(LotteryTicket ticket) {
-    LotteryTicketId id = new LotteryTicketId();
+    var id = new LotteryTicketId();
     tickets.put(id, ticket);
     return Optional.of(id);
   }