Java 11 migration: patterns (t-v) (#1085)

* Moves visitor pattern to java 11

* Moves value-object pattern to java 11

* Moves unit-of-work pattern to java 11

* Moves typeobjectpattern pattern to java 11

* Moves twin pattern to java 11

* Moves trampoline pattern to java 11

* Moves tolerant-reader pattern to java 11

* Moves tls pattern to java 11

* Moves throttling pattern to java 11

* Moves thread-pool pattern to java 11

* Moves template-method pattern to java 11

thread-pool/src/main/java/com/iluwatar/threadpool/App.java

@@ -56,7 +56,7 @@ public class App {
     LOGGER.info("Program started");
 
     // Create a list of tasks to be executed
-    List<Task> tasks = List.of(
+    var tasks = List.of(
         new PotatoPeelingTask(3),
         new PotatoPeelingTask(6),
         new CoffeeMakingTask(2),
@@ -82,10 +82,7 @@ public class App {
     // Allocate new worker for each task
     // The worker is executed when a thread becomes
     // available in the thread pool
-    for (int i = 0; i < tasks.size(); i++) {
-      var worker = new Worker(tasks.get(i));
-      executor.execute(worker);
-    }
+    tasks.stream().map(Worker::new).forEach(executor::execute);
     // All tasks were executed, now shutdown
     executor.shutdown();
     while (!executor.isTerminated()) {

thread-pool/src/test/java/com/iluwatar/threadpool/AppTest.java

@@ -27,15 +27,13 @@ import org.junit.jupiter.api.Test;
 
 /**
  * Application test
- * 
- * @author ilkka
  *
+ * @author ilkka
  */
 public class AppTest {
 
   @Test
   public void test() {
-    String[] args = {};
-    App.main(args);
+    App.main(new String[]{});
   }
 }

thread-pool/src/test/java/com/iluwatar/threadpool/TaskTest.java

@@ -23,27 +23,25 @@
 
 package com.iluwatar.threadpool;
 
-import org.junit.jupiter.api.Test;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Objects;
-import java.util.concurrent.Callable;
-import java.util.concurrent.ExecutionException;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-import java.util.concurrent.Future;
-import java.util.function.IntFunction;
-import java.util.stream.Collectors;
-
 import static java.time.Duration.ofMillis;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTimeout;
 
+import java.util.ArrayList;
+import java.util.Objects;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.function.IntFunction;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import org.junit.jupiter.api.Test;
+
 /**
- * Date: 12/30/15 - 18:22 PM
- * Test for Tasks using a Thread Pool
+ * Date: 12/30/15 - 18:22 PM Test for Tasks using a Thread Pool
+ *
  * @param <T> Type of Task
  * @author Jeroen Meulemeester
  */
@@ -87,14 +85,13 @@ public abstract class TaskTest<T extends Task> {
   @Test
   public void testIdGeneration() throws Exception {
     assertTimeout(ofMillis(10000), () -> {
-      final ExecutorService service = Executors.newFixedThreadPool(THREAD_COUNT);
+      final var service = Executors.newFixedThreadPool(THREAD_COUNT);
 
-      final List<Callable<Integer>> tasks = new ArrayList<>();
-      for (int i = 0; i < TASK_COUNT; i++) {
-        tasks.add(() -> factory.apply(1).getId());
-      }
+      final var tasks = IntStream.range(0, TASK_COUNT)
+          .<Callable<Integer>>mapToObj(i -> () -> factory.apply(1).getId())
+          .collect(Collectors.toCollection(ArrayList::new));
 
-      final List<Integer> ids = service.invokeAll(tasks)
+      final var ids = service.invokeAll(tasks)
           .stream()
           .map(TaskTest::get)
           .filter(Objects::nonNull)
@@ -102,7 +99,7 @@ public abstract class TaskTest<T extends Task> {
 
       service.shutdownNow();
 
-      final long uniqueIdCount = ids.stream()
+      final var uniqueIdCount = ids.stream()
           .distinct()
           .count();
 
@@ -117,7 +114,7 @@ public abstract class TaskTest<T extends Task> {
    */
   @Test
   public void testTimeMs() {
-    for (int i = 0; i < 10; i++) {
+    for (var i = 0; i < 10; i++) {
       assertEquals(this.expectedExecutionTime * i, this.factory.apply(i).getTimeMs());
     }
   }

thread-pool/src/test/java/com/iluwatar/threadpool/WorkerTest.java

@@ -23,13 +23,13 @@
 
 package com.iluwatar.threadpool;
 
-import org.junit.jupiter.api.Test;
-
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
 import static org.mockito.Mockito.verifyZeroInteractions;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * Date: 12/30/15 - 18:21 PM
  *
@@ -42,8 +42,8 @@ public class WorkerTest {
    */
   @Test
   public void testRun() {
-    final Task task = mock(Task.class);
-    final Worker worker = new Worker(task);
+    final var task = mock(Task.class);
+    final var worker = new Worker(task);
     verifyZeroInteractions(task);
 
     worker.run();