1 /*
 2  * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 4  *
 5  * This code is free software; you can redistribute it and/or modify it
 6  * under the terms of the GNU General Public License version 2 only, as
 7  * published by the Free Software Foundation.
 8  *
 9  * This code is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * version 2 for more details (a copy is included in the LICENSE file that
13  * accompanied this code).
14  *
15  * You should have received a copy of the GNU General Public License version
16  * 2 along with this work; if not, write to the Free Software Foundation,
17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18  *
19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20  * or visit www.oracle.com if you need additional information or have any
21  * questions.
22  */
23 
24 /*
25  * @test
26  * @bug 8024500 8166446
27  * @run testng SingletonIterator
28  */
29 
30 import java.util.Collections;
31 import java.util.Iterator;
32 import java.util.NoSuchElementException;
33 import java.util.concurrent.atomic.AtomicInteger;
34 import org.testng.annotations.Test;
35 
36 import static org.testng.Assert.assertEquals;
37 import static org.testng.Assert.assertFalse;
38 import static org.testng.Assert.fail;
39 
40 @Test(groups = "unit")
41 public class SingletonIterator {
42     static void assertIteratorExhausted(Iterator<?> it) {
43         assertFalse(it.hasNext());
44         try {
45             it.next();
46             fail("should have thrown NoSuchElementException");
47         } catch (NoSuchElementException success) { }
48         it.forEachRemaining(e -> { throw new AssertionError("action called incorrectly"); });
49     }
50 
51     public void testForEachRemaining() {
52         Iterator<String> it = Collections.singleton("TheOne").iterator();
53         AtomicInteger cnt = new AtomicInteger(0);
54 
55         it.forEachRemaining(s -> {
56             assertEquals("TheOne", s);
57             cnt.incrementAndGet();
58         });
59 
60         assertEquals(cnt.get(), 1);
61         assertIteratorExhausted(it);
62     }
63 
64     static class SingletonException extends RuntimeException { }
65 
66     public void testThrowFromForEachRemaining() {
67         Iterator<String> it = Collections.singleton("TheOne").iterator();
68 
69         try {
70             it.forEachRemaining(s -> { throw new SingletonException(); });
71         } catch (SingletonException ignore) { }
72 
73         assertIteratorExhausted(it);
74     }
75 }