From 6db653621d80697ea9f0c9863f9d4897dee7a08f Mon Sep 17 00:00:00 2001
From: "Tagir F. Valeev" <tvaleev@openjdk.org>
Date: Fri, 29 Apr 2016 16:52:05 +0300
Subject: [PATCH] 8155600: Performance optimization of
Arrays.asList().iterator()
Reviewed-by: redestad, shade, plevart, attila
---
.../share/classes/java/util/Arrays.java | 31 ++++++-
jdk/test/java/util/Arrays/AsList.java | 93 +++++++++++++++++++
2 files changed, 123 insertions(+), 1 deletion(-)
create mode 100644 jdk/test/java/util/Arrays/AsList.java
diff --git a/jdk/src/java.base/share/classes/java/util/Arrays.java b/jdk/src/java.base/share/classes/java/util/Arrays.java
index cc7b19de64e..6d7e858fbed 100644
--- a/jdk/src/java.base/share/classes/java/util/Arrays.java
+++ b/jdk/src/java.base/share/classes/java/util/Arrays.java
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -4403,6 +4403,35 @@ public class Arrays {
public void sort(Comparator<? super E> c) {
Arrays.sort(a, c);
}
+
+ @Override
+ public Iterator<E> iterator() {
+ return new ArrayItr<>(a);
+ }
+ }
+
+ private static class ArrayItr<E> implements Iterator<E> {
+ private int cursor;
+ private final E[] a;
+
+ ArrayItr(E[] a) {
+ this.a = a;
+ }
+
+ @Override
+ public boolean hasNext() {
+ return cursor < a.length;
+ }
+
+ @Override
+ public E next() {
+ int i = cursor;
+ if (i >= a.length) {
+ throw new NoSuchElementException();
+ }
+ cursor = i + 1;
+ return a[i];
+ }
}
/**
diff --git a/jdk/test/java/util/Arrays/AsList.java b/jdk/test/java/util/Arrays/AsList.java
new file mode 100644
index 00000000000..c64c473a822
--- /dev/null
+++ b/jdk/test/java/util/Arrays/AsList.java
@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8155600
+ * @summary Tests for Arrays.asList()
+ * @run testng AsList
+ */
+
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import java.util.stream.IntStream;
+
+import org.testng.annotations.Test;
+import org.testng.annotations.DataProvider;
+import static org.testng.Assert.assertSame;
+import static org.testng.Assert.assertTrue;
+import static org.testng.Assert.assertFalse;
+import static org.testng.Assert.fail;
+
+public class AsList {
+ /*
+ * Iterator contract test
+ */
+ @Test(dataProvider = "Arrays")
+ public void testIterator(Object[] array) {
+ Iterator<Object> itr = Arrays.asList(array).iterator();
+ for (int i = 0; i < array.length; i++) {
+ assertTrue(itr.hasNext());
+ assertTrue(itr.hasNext()); // must be idempotent
+ assertSame(array[i], itr.next());
+ try {
+ itr.remove();
+ fail("Remove must throw");
+ } catch (UnsupportedOperationException ex) {
+ // expected
+ }
+ }
+ assertFalse(itr.hasNext());
+ for (int i = 0; i < 3; i++) {
+ assertFalse(itr.hasNext());
+ try {
+ itr.next();
+ fail("Next succeed when there's no data left");
+ } catch (NoSuchElementException ex) {
+ // expected
+ }
+ }
+ }
+
+ @DataProvider(name = "Arrays")
+ public static Object[][] arrays() {
+ Object[][] arrays = {
+ { new Object[] { } },
+ { new Object[] { 1 } },
+ { new Object[] { null } },
+ { new Object[] { null, 1 } },
+ { new Object[] { 1, null } },
+ { new Object[] { null, null } },
+ { new Object[] { null, 1, 2 } },
+ { new Object[] { 1, null, 2 } },
+ { new Object[] { 1, 2, null } },
+ { new Object[] { null, null, null } },
+ { new Object[] { 1, 2, 3, null, 4 } },
+ { new Object[] { "a", "a", "a", "a" } },
+ { IntStream.range(0, 100).boxed().toArray() }
+ };
+
+ return arrays;
+ }
+}