1 /*
   2  * Copyright (c) 2003, 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
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  23 
  24 /*
  25  * @test
  26  * @bug     4339792
  27  * @summary Basic test for Collections.disjoint
  28  * @author  Josh Bloch
  29  * @key randomness
  30  */
  31 
  32 import java.util.*;
  33 
  34 public class Disjoint {
  35     final static int N = 20;
  36 
  37     public static void main(String args[]) {
  38         // Make an array of lists each of which shares a single element
  39         // with its "neighbors," and no elements with other lists in the array
  40         Random rnd = new Random();
  41         List[] lists = new List[N];
  42         int x = 0;
  43         for (int i = 0; i < N; i++) {
  44             int size = rnd.nextInt(10) + 2;
  45             List<Integer> list = new ArrayList<Integer>(size);
  46             for (int j = 1; j < size; j++)
  47                 list.add(x++);
  48             list.add(x);
  49             Collections.shuffle(list);
  50 
  51             lists[i] = list;
  52         }
  53 
  54         for (int i = 0; i < N; i++) {
  55             for (int j = 0; j < N; j++) {
  56                 boolean disjoint = (Math.abs(i - j) > 1);
  57                 List<Integer> a = (List<Integer>) lists[i];
  58                 List<Integer> b = (List<Integer>) lists[j];
  59 
  60                 if (Collections.disjoint(a, b) != disjoint)
  61                     throw new RuntimeException("A: " + i + ", " + j);
  62                 if (Collections.disjoint(new HashSet<Integer>(a), b)
  63                     != disjoint)
  64                     throw new RuntimeException("B: " + i + ", " + j);
  65                 if (Collections.disjoint(new HashSet<Integer>(a),
  66                                          new HashSet<Integer>(b)) != disjoint)
  67                     throw new RuntimeException("C: " + i + ", " + j);
  68             }
  69         }
  70     }
  71 }