ConcurrentHashMap examples

winterbe · winterbe · commit c80d39b25602 · 2015-05-07T07:20:29.000+02:00
diff --git a/src/com/winterbe/java8/samples/concurrent/ConcurrentHashMap1.java b/src/com/winterbe/java8/samples/concurrent/ConcurrentHashMap1.java
@@ -9,20 +9,64 @@
 public class ConcurrentHashMap1 {
 
     public static void main(String[] args) {
+        System.out.println("Parallelism: " + ForkJoinPool.getCommonPoolParallelism());
+
         testForEach();
+        testSearch();
+        testReduce();
     }
 
-    private static void testForEach() {
+    private static void testReduce() {
         ConcurrentHashMap<String, String> map = new ConcurrentHashMap<>();
         map.putIfAbsent("foo", "bar");
         map.putIfAbsent("han", "solo");
         map.putIfAbsent("r2", "d2");
         map.putIfAbsent("c3", "p0");
 
+        String reduced = map.reduce(1, (key, value) -> key + "=" + value,
+                (s1, s2) -> s1 + ", " + s2);
 
-//        map.forEach((key, value) -> System.out.printf("key: %s; value: %s\n", key, value));
+        System.out.println(reduced);
+    }
 
-        System.out.println("Parallelism: " + ForkJoinPool.getCommonPoolParallelism());
+    private static void testSearch() {
+        ConcurrentHashMap<String, String> map = new ConcurrentHashMap<>();
+        map.putIfAbsent("foo", "bar");
+        map.putIfAbsent("han", "solo");
+        map.putIfAbsent("r2", "d2");
+        map.putIfAbsent("c3", "p0");
+
+        System.out.println("\nsearch()\n");
+
+        String result1 = map.search(1, (key, value) -> {
+            System.out.println(Thread.currentThread().getName());
+            if (key.equals("foo") && value.equals("bar")) {
+                return "foobar";
+            }
+            return null;
+        });
+
+        System.out.println(result1);
+
+        System.out.println("\nsearchValues()\n");
+
+        String result2 = map.searchValues(1, value -> {
+            System.out.println(Thread.currentThread().getName());
+            if (value.length() > 3) {
+                return value;
+            }
+            return null;
+        });
+
+        System.out.println(result2);
+    }
+
+    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(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()));
