--- jsr166/src/test/tck/CountedCompleterTest.java	2015/10/18 19:33:21	1.27
+++ jsr166/src/test/tck/CountedCompleterTest.java	2016/08/29 19:13:16	1.28
@@ -13,9 +13,12 @@ import java.util.concurrent.CountedCompl
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ForkJoinPool;
 import java.util.concurrent.ForkJoinTask;
+import java.util.concurrent.ThreadLocalRandom;
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.BiConsumer;
+import java.util.function.Consumer;
 
 import junit.framework.Test;
 import junit.framework.TestSuite;
@@ -1842,4 +1845,115 @@ public class CountedCompleterTest extend
         testInvokeOnPool(singletonPool(), a);
     }
 
+    /** CountedCompleter class javadoc code sample, version 1. */
+    public static <E> void forEach1(E[] array, Consumer<E> action) {
+        class Task extends CountedCompleter<Void> {
+            final int lo, hi;
+            Task(Task parent, int lo, int hi) {
+                super(parent); this.lo = lo; this.hi = hi;
+            }
+
+            public void compute() {
+                if (hi - lo >= 2) {
+                    int mid = (lo + hi) >>> 1;
+                    // must set pending count before fork
+                    setPendingCount(2);
+                    new Task(this, mid, hi).fork(); // right child
+                    new Task(this, lo, mid).fork(); // left child
+                }
+                else if (hi > lo)
+                    action.accept(array[lo]);
+                tryComplete();
+            }
+        }
+        new Task(null, 0, array.length).invoke();
+    }
+
+    /** CountedCompleter class javadoc code sample, version 2. */
+    public static <E> void forEach2(E[] array, Consumer<E> action) {
+        class Task extends CountedCompleter<Void> {
+            final int lo, hi;
+            Task(Task parent, int lo, int hi) {
+                super(parent); this.lo = lo; this.hi = hi;
+            }
+
+            public void compute() {
+                if (hi - lo >= 2) {
+                    int mid = (lo + hi) >>> 1;
+                    setPendingCount(1); // not off by one !
+                    new Task(this, mid, hi).fork(); // right child
+                    new Task(this, lo, mid).compute(); // direct invoke
+                } else {
+                    if (hi > lo)
+                        action.accept(array[lo]);
+                    tryComplete();
+                }
+            }
+        }
+        new Task(null, 0, array.length).invoke();
+    }
+
+    /** CountedCompleter class javadoc code sample, version 3. */
+    public static <E> void forEach3(E[] array, Consumer<E> action) {
+        class Task extends CountedCompleter<Void> {
+            final int lo, hi;
+            Task(Task parent, int lo, int hi) {
+                super(parent); this.lo = lo; this.hi = hi;
+            }
+
+            public void compute() {
+                int n = hi - lo;
+                for (; n >= 2; n /= 2) {
+                    addToPendingCount(1);
+                    new Task(this, lo + n/2, lo + n).fork();
+                }
+                if (n > 0)
+                    action.accept(array[lo]);
+                propagateCompletion();
+            }
+        }
+        new Task(null, 0, array.length).invoke();
+    }
+
+    /** CountedCompleter class javadoc code sample, version 4. */
+    public static <E> void forEach4(E[] array, Consumer<E> action) {
+        class Task extends CountedCompleter<Void> {
+            final int lo, hi;
+            Task(Task parent, int lo, int hi) {
+                super(parent, 31 - Integer.numberOfLeadingZeros(hi - lo));
+                this.lo = lo; this.hi = hi;
+            }
+
+            public void compute() {
+                for (int n = hi - lo; n >= 2; n /= 2)
+                    new Task(this, lo + n/2, lo + n).fork();
+                action.accept(array[lo]);
+                propagateCompletion();
+            }
+        }
+        if (array.length > 0)
+            new Task(null, 0, array.length).invoke();
+    }
+
+    void testRecursiveDecomposition(
+        BiConsumer<Integer[], Consumer<Integer>> action) {
+        int n = ThreadLocalRandom.current().nextInt(8);
+        Integer[] a = new Integer[n];
+        for (int i = 0; i < n; i++) a[i] = i + 1;
+        AtomicInteger ai = new AtomicInteger(0);
+        action.accept(a, (x) -> ai.addAndGet(x));
+        assertEquals(n * (n + 1) / 2, ai.get());
+    }
+
+    /**
+     * Variants of divide-by-two recursive decomposition into leaf tasks,
+     * as described in the CountedCompleter class javadoc code samples
+     */
+    public void testRecursiveDecomposition() {
+        testRecursiveDecomposition(CountedCompleterTest::forEach1);
+        testRecursiveDecomposition(CountedCompleterTest::forEach2);
+        testRecursiveDecomposition(CountedCompleterTest::forEach3);
+        testRecursiveDecomposition(CountedCompleterTest::forEach4);
+    }
+
 }