BAEL-1473 (#3477)

* BAEL-1473 Intoduction to Spliterator in Java

* BAEL-1473 - Replace .out with logger.info

* removed log

* BAEL-1473 - added test-cases

* modify test-cases

core-java-8/src/main/java/com/baeldung/spliteratorAPI/Executor.java

@@ -1,45 +1,19 @@
 package com.baeldung.spliteratorAPI;
 
-import java.util.Arrays;
 import java.util.List;
-import java.util.Spliterator;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
 import java.util.stream.Collectors;
-import java.util.stream.IntStream;
 import java.util.stream.Stream;
-import java.util.stream.StreamSupport;
 
 public class Executor {
-	public void executeCustomSpliterator() {
-        Article article = new Article(Arrays.asList(new Author("Ahmad", 0), new Author("Eugen", 0), new Author("Alice", 1), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1),
-            new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0),
-            new Author("Alice", 1), new Author("Mike", 0), new Author("Michał", 0), new Author("Loredana", 1)), 0);
-        Stream<Author> stream = IntStream.range(0, article.getListOfAuthors()
-            .size())
-            .mapToObj(article.getListOfAuthors()::get);
-        System.out.println("count= " + countAutors(stream.parallel()));
-        Spliterator<Author> spliterator = new RelatedAuthorSpliterator(article.getListOfAuthors());
-        Stream<Author> stream2 = StreamSupport.stream(spliterator, true);
-        System.out.println("count= " + countAutors(stream2.parallel()));
-    }
 
-    public void executeSpliterator() {
+	public static int countAutors(Stream<Author> stream) {
-        Spliterator<Article> split1 = generateElements().spliterator();
+		RelatedAuthorCounter wordCounter = stream.reduce(new RelatedAuthorCounter(0, true),
-        Spliterator<Article> split2 = split1.trySplit();
+				RelatedAuthorCounter::accumulate, RelatedAuthorCounter::combine);
-        ExecutorService service = Executors.newCachedThreadPool();
+		return wordCounter.getCounter();
-        service.execute(new Task(split1));
+	}
-        service.execute(new Task(split2));
-    }
 
-    private static int countAutors(Stream<Author> stream) {
+	public static List<Article> generateElements() {
-        RelatedAuthorCounter wordCounter = stream.reduce(new RelatedAuthorCounter(0, true), RelatedAuthorCounter::accumulate, RelatedAuthorCounter::combine);
+		return Stream.generate(() -> new Article("Java")).limit(35000).collect(Collectors.toList());
-        return wordCounter.getCounter();
+	}
-    }
 
-    private List<Article> generateElements() {
+}
-        return Stream.generate(() -> new Article("Java"))
-            .limit(35000)
-            .collect(Collectors.toList());
-    }
-}

core-java-8/src/main/java/com/baeldung/spliteratorAPI/Task.java

@@ -1,8 +1,9 @@
 package com.baeldung.spliteratorAPI;
 
 import java.util.Spliterator;
+import java.util.concurrent.Callable;
 
-public class Task implements Runnable {
+public class Task implements Callable<String> {
     private Spliterator<Article> spliterator;
     private final static String SUFFIX = "- published by Baeldung";
 
@@ -11,7 +12,7 @@ public class Task implements Runnable {
     }
 
     @Override
-    public void run() {
+    public String call() {
         int current = 0;
         while (spliterator.tryAdvance(article -> {
             article.setName(article.getName()
@@ -20,7 +21,7 @@ public class Task implements Runnable {
             current++;
         }
         ;
-        System.out.println(Thread.currentThread()
+        return Thread.currentThread()
-            .getName() + ":" + current);
+            .getName() + ":" + current;
     }
 }

core-java-8/src/test/java/com/baeldung/spliteratorAPI/ExecutorTest.java

@@ -0,0 +1,44 @@
+package com.baeldung.spliteratorAPI;
+
+import java.util.Arrays;
+import java.util.Spliterator;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+import static org.assertj.core.api.Assertions.*;
+import org.junit.Before;
+import org.junit.Test;
+
+public class ExecutorTest {
+	Article article;
+	Stream<Author> stream;
+	Spliterator<Author> spliterator;
+	Spliterator<Article> split1;
+	Spliterator<Article> split2;
+
+	@Before
+	public void init() {
+		article = new Article(Arrays.asList(new Author("Ahmad", 0), new Author("Eugen", 0), new Author("Alice", 1),
+				new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0),
+				new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0),
+				new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1),
+				new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1),
+				new Author("Mike", 0), new Author("Michał", 0), new Author("Loredana", 1)), 0);
+		stream = article.getListOfAuthors().stream();
+		split1 = Executor.generateElements().spliterator();
+		split2 = split1.trySplit();
+		spliterator = new RelatedAuthorSpliterator(article.getListOfAuthors());
+	}
+
+	@Test
+	public void givenAstreamOfAuthors_whenProcessedInParallelWithCustomSpliterator_coubtProducessRightOutput() {
+		Stream<Author> stream2 = StreamSupport.stream(spliterator, true);
+		assertThat(Executor.countAutors(stream2.parallel())).isEqualTo(9);
+	}
+
+	@Test
+	public void givenSpliterator_whenAppliedToAListOfArticle_thenSplittedInHalf() {
+		assertThat(new Task(split1).call()).containsSequence(Executor.generateElements().size() / 2 + "");
+		assertThat(new Task(split2).call()).containsSequence(Executor.generateElements().size() / 2 + "");
+	}
+}