Semaphore example

Author: winterbe

src/com/winterbe/java8/samples/concurrent/Semaphore2.java

@@ -0,0 +1,44 @@
+package com.winterbe.java8.samples.concurrent;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Semaphore;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.IntStream;
+
+/**
+ * @author Benjamin Winterberg
+ */
+public class Semaphore2 {
+
+ private static Semaphore semaphore = new Semaphore(5);
+
+ public static void main(String[] args) {
+ ExecutorService executor = Executors.newFixedThreadPool(10);
+
+ IntStream.range(0, 10)
+ .forEach(i -> executor.submit(Semaphore2::doWork));
+
+ ConcurrentUtils.stop(executor);
+ }
+
+ private static void doWork() {
+ boolean permit = false;
+ try {
+ permit = semaphore.tryAcquire(1, TimeUnit.SECONDS);
+ if (permit) {
+ System.out.println("Semaphore acquired");
+ ConcurrentUtils.sleep(5);
+ } else {
+ System.out.println("Could not acquire semaphore");
+ }
+ } catch (InterruptedException e) {
+ throw new IllegalStateException(e);
+ } finally {
+ if (permit) {
+ semaphore.release();
+ }
+ }
+ }
+
+}