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 5018254 27 * @summary Test null-allowing Comparators 28 * @author Martin Buchholz 29 */ 30 31import java.util.*; 32import java.util.concurrent.*; 33 34public class NullAtEnd { 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) 53 passed++; 54 else 55 fail(msg); 56 } 57 58 static void check(boolean condition) { 59 check(condition, "Assertion failure"); 60 } 61 62 private static boolean eq(Object x, Object y) { 63 return x == null ? y == null : x.equals(y); 64 } 65 66 private static final Comparator<String> NULL_AT_END 67 = new Comparator<>() { 68 /** 69 * Allows for nulls. Null is greater than anything non-null. 70 */ 71 public int compare(String x, String y) { 72 if (x == null && y == null) return 0; 73 if (x == null && y != null) return 1; 74 if (x != null && y == null) return -1; 75 return x.compareTo(y); 76 } 77 }; 78 79 public static void main(String[] args) { 80 try { 81 SortedMap<String,String> m1 = new TreeMap<>(NULL_AT_END); 82 check(eq(m1.put("a", "a"), null)); 83 check(eq(m1.put("b", "b"), null)); 84 check(eq(m1.put("c", "c"), null)); 85 check(eq(m1.put(null, "d"), null)); 86 87 SortedMap<String,String> m2 = new TreeMap<>(m1); 88 89 check(eq(m1.lastKey(), null)); 90 check(eq(m1.get(m1.lastKey()), "d")); 91 check(eq(m1.remove(m1.lastKey()), "d")); 92 check(eq(m1.lastKey(), "c")); 93 94 check(eq(m2.entrySet().toString(), "[a=a, b=b, c=c, null=d]")); 95 96 SortedMap<String,String> m3 = m2.tailMap("b"); 97 98 check(eq(m3.lastKey(), null)); 99 check(eq(m3.get(m3.lastKey()), "d")); 100 check(eq(m3.remove(m3.lastKey()), "d")); 101 check(eq(m3.lastKey(), "c")); 102 103 } catch (Throwable t) { unexpected(t); } 104 105 System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed); 106 if (failed > 0) throw new Error("Some tests failed"); 107 } 108} 109