Lock examples

Author: winterbe

src/com/winterbe/java8/samples/concurrent/Lock1.java

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+package com.winterbe.java8.samples.concurrent;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.locks.ReentrantLock;
+import java.util.stream.IntStream;
+
+/**
+ * @author Benjamin Winterberg
+ */
+public class Lock1 {
+
+ private static final int NUM_INCREMENTS = 10000;
+
+ private static ReentrantLock lock = new ReentrantLock();
+
+ private static int count = 0;
+
+ private static void increment() {
+ lock.lock();
+ try {
+ count++;
+ }
+ finally {
+ lock.unlock();
+ }
+ }
+
+ public static void main(String[] args) {
+ testLock();
+ }
+
+ private static void testLock() {
+ count = 0;
+
+ ExecutorService executor = Executors.newFixedThreadPool(2);
+
+ IntStream.range(0, NUM_INCREMENTS)
+ .forEach(i -> executor.submit(Lock1::increment));
+
+ ConcurrentUtils.stop(executor);
+
+ System.out.println(count);
+ }
+
+}

src/com/winterbe/java8/samples/concurrent/Lock2.java

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+package com.winterbe.java8.samples.concurrent;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.locks.ReentrantLock;
+
+/**
+ * @author Benjamin Winterberg
+ */
+public class Lock2 {
+
+ public static void main(String[] args) {
+ ExecutorService executor = Executors.newFixedThreadPool(2);
+
+ ReentrantLock lock = new ReentrantLock();
+
+ executor.submit(() -> {
+ lock.lock();
+ try {
+ System.out.println(lock.isLocked());
+ } finally {
+ lock.unlock();
+ }
+ });
+
+ ConcurrentUtils.stop(executor);
+ }
+
+}