ConcurrentHashMap examples

winterbe · winterbe · commit 780bfa667269 · 2015-05-04T09:00:45.000+02:00
diff --git a/src/com/winterbe/java8/samples/concurrent/ConcurrentHashMap1.java b/src/com/winterbe/java8/samples/concurrent/ConcurrentHashMap1.java
@@ -0,0 +1,33 @@
+package com.winterbe.java8.samples.concurrent;
+
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ForkJoinPool;
+
+/**
+ * @author Benjamin Winterberg
+ */
+public class ConcurrentHashMap1 {
+
+    public static void main(String[] args) {
+        testForEach();
+    }
+
+    private static void testForEach() {
+        ConcurrentHashMap<String, String> map = new ConcurrentHashMap<>();
+        map.putIfAbsent("foo", "bar");
+        map.putIfAbsent("han", "solo");
+        map.putIfAbsent("r2", "d2");
+        map.putIfAbsent("c3", "p0");
+
+
+//        map.forEach((key, value) -> System.out.printf("key: %s; value: %s\n", key, value));
+
+        System.out.println("Parallelism: " + ForkJoinPool.getCommonPoolParallelism());
+
+        map.forEach(1, (key, value) -> System.out.printf("key: %s; value: %s; thread: %s\n", key, value, Thread.currentThread().getName()));
+//        map.forEach(5, (key, value) -> System.out.printf("key: %s; value: %s; thread: %s\n", key, value, Thread.currentThread().getName()));
+
+        System.out.println(map.mappingCount());
+    }
+
+}
