RFR 8169808 Stream returning methods should specify if they are late binding

[Martin Buchholz]

On Mon, Nov 21, 2016 at 1:06 PM, Paul Sandoz <paul.sandoz at oracle.com> wrote:

>
> See the SpliteratorLateBindingFailFastTest. That could be refactored out
> as it’s conflating two concepts and is too collection/map focused.
>

Here's my own attempt, for the pending jsr166 integration:

 --- src/test/tck/Collection8Test.java 22 Nov 2016 01:08:14 -0000 1.29
+++ src/test/tck/Collection8Test.java 23 Nov 2016 00:20:43 -0000
@@ -606,6 +606,39 @@
             assertNull(future.get(0L, MILLISECONDS));
     }

+    /**
+     * Spliterators are either IMMUTABLE or truly late-binding or, if
+     * concurrent, use the same "late-binding style" of returning
+     * elements added between creation and first use.
+     */
+    public void testLateBinding() throws Throwable {
+        if (!testImplementationDetails) return;
+        // Immutable (snapshot) spliterators are exempt
+        if (impl.emptyCollection().spliterator()
+            .hasCharacteristics(Spliterator.IMMUTABLE))
+            return;
+        final Object one = impl.makeElement(1);
+        {
+            final Collection c = impl.emptyCollection();
+            final Spliterator split = c.spliterator();
+            c.add(one);
+            assertTrue(split.tryAdvance(e -> { assertSame(e, one); }));
+            assertFalse(split.tryAdvance(e -> { throw new
AssertionError(); }));
+            assertTrue(c.contains(one));
+        }
+        {
+            final AtomicLong count = new AtomicLong(0);
+            final Collection c = impl.emptyCollection();
+            final Spliterator split = c.spliterator();
+            c.add(one);
+            split.forEachRemaining(
+                e -> { assertSame(e, one); count.getAndIncrement(); });
+            assertEquals(1L, count.get());
+            assertFalse(split.tryAdvance(e -> { throw new
AssertionError(); }));
+            assertTrue(c.contains(one));
+        }
+    }
+