1 /*
   2  * Copyright (c) 2015, 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 8072726
  27  * @summary Tests for Enumeration-to-Iterator conversion.
  28  * @run testng EnumerationAsIterator
  29  */
  30 
  31 import java.util.*;
  32 
  33 import org.testng.annotations.Test;
  34 import static org.testng.Assert.*;
  35 
  36 @Test
  37 public class EnumerationAsIterator {
  38     public void emptyHasNext() {
  39         Iterator<Object> it = Collections.emptyEnumeration().asIterator();
  40         assertFalse(it.hasNext());
  41     }
  42 
  43     @Test(expectedExceptions = {NoSuchElementException.class})
  44     public void emptyNextThrows() {
  45         Iterator<Object> it = Collections.emptyEnumeration().asIterator();
  46         Object o = it.next();
  47         fail("NoSuchElementException should have been thrown");
  48     }
  49 
  50     private List<String> copy(List<String> input) {
  51         List<String> output = new ArrayList<>();
  52         Collections.enumeration(input)
  53                    .asIterator()
  54                    .forEachRemaining(output::add);
  55         return output;
  56     }
  57 
  58     public void copyZero() {
  59         assertEquals(copy(Collections.emptyList()), Collections.emptyList());
  60     }
  61 
  62     public void copyOne() {
  63         assertEquals(copy(Collections.singletonList("a")),
  64                           Collections.singletonList("a"));
  65     }
  66 
  67     public void copyMany() {
  68         List<String> input = Arrays.asList("a", "b", "c");
  69         assertEquals(copy(input), input);
  70     }
  71 
  72     public void repeatedCalls() {
  73         Iterator<String> iter = new Vector<>(Arrays.asList("a", "b", "c"))
  74             .elements().asIterator();
  75         assertTrue(iter.hasNext());
  76         assertTrue(iter.hasNext());
  77         assertEquals(iter.next(), "a");
  78         assertEquals(iter.next(), "b");
  79         assertEquals(iter.next(), "c");
  80         assertFalse(iter.hasNext());
  81         assertFalse(iter.hasNext());
  82     }
  83 }