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test/jdk/java/util/Collections/NCopies.java

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   1 /*
   2  * Copyright (c) 2005, 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     6267846 6275009
  27  * @summary Test Collections.nCopies
  28  * @author  Martin Buchholz
  29  */
  30 
  31 import java.util.Collections;

  32 import java.util.List;

  33 
  34 public class NCopies {
  35     static volatile int passed = 0, failed = 0;
  36 
  37     static void fail(String msg) {
  38         failed++;
  39         new AssertionError(msg).printStackTrace();
  40     }
  41 
  42     static void pass() {
  43         passed++;
  44     }
  45 
  46     static void unexpected(Throwable t) {
  47         failed++;
  48         t.printStackTrace();
  49     }
  50 
  51     static void check(boolean condition, String msg) {
  52         if (condition)


  65             check(x.indexOf("foo") == -1);
  66             check(x.lastIndexOf("foo") == -1);
  67             check(x.toArray().length == 0);
  68             check(x.toArray().getClass() == Object[].class);
  69     }
  70 
  71     private static void checkFoos(List<String> x) {
  72             check(! x.isEmpty());
  73             check(x.indexOf(new String("foo")) == 0);
  74             check(x.lastIndexOf(new String("foo")) == x.size()-1);
  75             check(x.toArray().length == x.size());
  76             check(x.toArray().getClass() == Object[].class);
  77             String[] sa = x.toArray(new String[x.size()]);
  78             check(sa.getClass() == String[].class);
  79             check(sa[0].equals("foo"));
  80             check(sa[sa.length-1].equals("foo"));
  81             check(x.get(x.size()/2).equals("foo"));
  82             checkEmpty(x.subList(x.size()/2, x.size()/2));
  83     }
  84 

























  85     public static void main(String[] args) {
  86         try {
  87             List<String> empty = Collections.nCopies(0, "foo");
  88             checkEmpty(empty);
  89             checkEmpty(empty.subList(0,0));
  90 
  91             List<String> foos = Collections.nCopies(42, "foo");
  92             check(foos.size() == 42);
  93             checkFoos(foos.subList(foos.size()/2, foos.size()-1));


  94 
  95         } catch (Throwable t) { unexpected(t); }
  96 
  97         System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
  98         if (failed > 0) throw new Error("Some tests failed");
  99     }
 100 }
   1 /*
   2  * Copyright (c) 2005, 2018, 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     6267846 6275009
  27  * @summary Test Collections.nCopies
  28  * @author  Martin Buchholz
  29  */
  30 
  31 import java.util.Collections;
  32 import java.util.AbstractList;
  33 import java.util.List;
  34 import java.util.Objects;
  35 
  36 public class NCopies {
  37     static volatile int passed = 0, failed = 0;
  38 
  39     static void fail(String msg) {
  40         failed++;
  41         new AssertionError(msg).printStackTrace();
  42     }
  43 
  44     static void pass() {
  45         passed++;
  46     }
  47 
  48     static void unexpected(Throwable t) {
  49         failed++;
  50         t.printStackTrace();
  51     }
  52 
  53     static void check(boolean condition, String msg) {
  54         if (condition)


  67             check(x.indexOf("foo") == -1);
  68             check(x.lastIndexOf("foo") == -1);
  69             check(x.toArray().length == 0);
  70             check(x.toArray().getClass() == Object[].class);
  71     }
  72 
  73     private static void checkFoos(List<String> x) {
  74             check(! x.isEmpty());
  75             check(x.indexOf(new String("foo")) == 0);
  76             check(x.lastIndexOf(new String("foo")) == x.size()-1);
  77             check(x.toArray().length == x.size());
  78             check(x.toArray().getClass() == Object[].class);
  79             String[] sa = x.toArray(new String[x.size()]);
  80             check(sa.getClass() == String[].class);
  81             check(sa[0].equals("foo"));
  82             check(sa[sa.length-1].equals("foo"));
  83             check(x.get(x.size()/2).equals("foo"));
  84             checkEmpty(x.subList(x.size()/2, x.size()/2));
  85     }
  86     
  87     private static <T> List<T> referenceNCopies(int n, T o) {
  88         // A simplest correct implementation of nCopies to compare with the actual optimized implementation
  89         return new AbstractList<>() {
  90             public int size() { return n; }
  91 
  92             public T get(int index) {
  93                 Objects.checkIndex(index, n);
  94                 return o;
  95             }
  96         };
  97     }
  98     
  99     private static void checkHashCode() {
 100         int[] sizes = {0, 1, 2, 3, 5, 10, 31, 32, 100, 1000};
 101         String[] elements = {null, "non-null"};
 102         for (int size : sizes) {
 103             for (String element : elements) {
 104                 int expectedHashCode = referenceNCopies(size, element).hashCode();
 105                 int actualHashCode = Collections.nCopies(size, element).hashCode();
 106                 check(expectedHashCode == actualHashCode,
 107                         "Collections.nCopies(" + size + ", " + element + ").hashCode()");
 108             }
 109         }
 110     }
 111 
 112     public static void main(String[] args) {
 113         try {
 114             List<String> empty = Collections.nCopies(0, "foo");
 115             checkEmpty(empty);
 116             checkEmpty(empty.subList(0,0));
 117 
 118             List<String> foos = Collections.nCopies(42, "foo");
 119             check(foos.size() == 42);
 120             checkFoos(foos.subList(foos.size()/2, foos.size()-1));
 121 
 122             checkHashCode();
 123 
 124         } catch (Throwable t) { unexpected(t); }
 125 
 126         System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
 127         if (failed > 0) throw new Error("Some tests failed");
 128     }
 129 }
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