From 0b193f4544439b88f56779911e23aef4e5337065 Mon Sep 17 00:00:00 2001
From: Abhinav Pandey <abhinavpandey312@gmail.com>
Date: Tue, 4 Jul 2023 20:07:40 +0530
Subject: [PATCH] Bael 6577 (#14260)

* BAEL-6577 - Paralellize for loops in Java

* BAEL-6577 - Paralellize for loops in Java

* BAEL-6577 - Paralellize for loops in Java - adding JMH

* BAEL-6577 - Paralellize for loops in Java - using CompletableFuture
---
 .../concurrent/parallel/Benchmark.java        | 14 ++++
 .../concurrent/parallel/Processor.java        | 73 +++++++++++++++++++
 2 files changed, 87 insertions(+)
 create mode 100644 core-java-modules/core-java-concurrency-2/src/main/java/com/baeldung/concurrent/parallel/Benchmark.java
 create mode 100644 core-java-modules/core-java-concurrency-2/src/main/java/com/baeldung/concurrent/parallel/Processor.java

diff --git a/core-java-modules/core-java-concurrency-2/src/main/java/com/baeldung/concurrent/parallel/Benchmark.java b/core-java-modules/core-java-concurrency-2/src/main/java/com/baeldung/concurrent/parallel/Benchmark.java
new file mode 100644
index 0000000000..964f6b3e3d
--- /dev/null
+++ b/core-java-modules/core-java-concurrency-2/src/main/java/com/baeldung/concurrent/parallel/Benchmark.java
@@ -0,0 +1,14 @@
+package com.baeldung.concurrent.parallel;
+
+import java.io.IOException;
+
+class Benchmark {
+
+    public static void main(String[] args) {
+        try {
+            org.openjdk.jmh.Main.main(new String[]{"com.baeldung.concurrent.parallel.Processor"});
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}
\ No newline at end of file
diff --git a/core-java-modules/core-java-concurrency-2/src/main/java/com/baeldung/concurrent/parallel/Processor.java b/core-java-modules/core-java-concurrency-2/src/main/java/com/baeldung/concurrent/parallel/Processor.java
new file mode 100644
index 0000000000..747ae568b0
--- /dev/null
+++ b/core-java-modules/core-java-concurrency-2/src/main/java/com/baeldung/concurrent/parallel/Processor.java
@@ -0,0 +1,73 @@
+package com.baeldung.concurrent.parallel;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Mode;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+public class Processor {
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    public void processSerially() throws InterruptedException {
+        for (int i = 0; i < 100; i++) {
+            Thread.sleep(10);
+        }
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    public void processParallelyWithExecutorService() throws InterruptedException {
+        ExecutorService executorService = Executors.newFixedThreadPool(10);
+        List<CompletableFuture<Void>> futures = new ArrayList<>();
+        for (int i = 0; i < 100; i++) {
+            CompletableFuture<Void> future = CompletableFuture.runAsync(() -> {
+                try {
+                    Thread.sleep(10);
+                } catch (InterruptedException e) {
+                    e.printStackTrace();
+                }
+            }, executorService);
+            futures.add(future);
+        }
+        CompletableFuture.allOf(futures.toArray(new CompletableFuture[0])).join();
+        executorService.shutdown();
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    public void processParallelyWithStream() {
+        IntStream.range(0, 100)
+          .parallel()
+          .forEach(i -> {
+              try {
+                  Thread.sleep(10);
+              } catch (InterruptedException e) {
+                  e.printStackTrace();
+              }
+          });
+    }
+
+    @Benchmark
+    @BenchmarkMode(Mode.AverageTime)
+    public void processParallelyWithStreamSupport() {
+        Iterable<Integer> iterable = () -> IntStream.range(0, 100).iterator();
+        Stream<Integer> stream = StreamSupport.stream(iterable.spliterator(), true);
+        stream.forEach(i -> {
+            try {
+                Thread.sleep(10);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        });
+    }
+}