1 /*
2 * Copyright (c) 2012, 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 8009736 8010279
27 * @run testng EntryComparators
28 */
29 import java.util.function.Function;
30 import java.util.Comparator;
31 import java.util.AbstractMap;
32 import java.util.Map;
33 import org.testng.annotations.Test;
34
35 import static org.testng.Assert.assertTrue;
36 import static org.testng.Assert.fail;
37
38 /**
39 * Unit tests for Map.Entry.comparing
40 */
41 @Test(groups = "unit")
42 public class EntryComparators {
43
44 private <K, V> void assertPairComparison(K k1, V v1, K k2, V v2,
45 Comparator<Map.Entry<K, V>> ck,
46 Comparator<Map.Entry<K, V>> cv) {
47 final Map.Entry<K, V> p11 = new AbstractMap.SimpleImmutableEntry<>(k1, v1);
48 final Map.Entry<K, V> p12 = new AbstractMap.SimpleImmutableEntry<>(k1, v2);
49 final Map.Entry<K, V> p21 = new AbstractMap.SimpleImmutableEntry<>(k2, v1);
50 final Map.Entry<K, V> p22 = new AbstractMap.SimpleImmutableEntry<>(k2, v2);
51
52 assertTrue(ck.compare(p11, p11) == 0);
53 assertTrue(ck.compare(p12, p11) == 0);
54 assertTrue(ck.compare(p11, p12) == 0);
55 assertTrue(ck.compare(p12, p22) < 0);
56 assertTrue(ck.compare(p12, p21) < 0);
57 assertTrue(ck.compare(p21, p11) > 0);
58 assertTrue(ck.compare(p21, p12) > 0);
59
60 assertTrue(cv.compare(p11, p11) == 0);
61 assertTrue(cv.compare(p12, p11) > 0);
62 assertTrue(cv.compare(p11, p12) < 0);
63 assertTrue(cv.compare(p12, p22) == 0);
64 assertTrue(cv.compare(p12, p21) > 0);
65 assertTrue(cv.compare(p21, p11) == 0);
66 assertTrue(cv.compare(p21, p12) < 0);
67
68 Comparator<Map.Entry<K, V>> cmp = ck.thenComparing(cv);
69 assertTrue(cmp.compare(p11, p11) == 0);
70 assertTrue(cmp.compare(p12, p11) > 0);
71 assertTrue(cmp.compare(p11, p12) < 0);
72 assertTrue(cmp.compare(p12, p22) < 0);
73 assertTrue(cmp.compare(p12, p21) < 0);
74 assertTrue(cmp.compare(p21, p11) > 0);
75 assertTrue(cmp.compare(p21, p12) > 0);
76
77 cmp = cv.thenComparing(ck);
78 assertTrue(cmp.compare(p11, p11) == 0);
79 assertTrue(cmp.compare(p12, p11) > 0);
80 assertTrue(cmp.compare(p11, p12) < 0);
81 assertTrue(cmp.compare(p12, p22) < 0);
82 assertTrue(cmp.compare(p12, p21) > 0);
83 assertTrue(cmp.compare(p21, p11) > 0);
84 assertTrue(cmp.compare(p21, p12) < 0);
85 }
86
87 public void testKVComparables() {
88 assertPairComparison(1, "ABC", 2, "XYZ",
89 Map.Entry.<Integer, String>comparingByKey(),
90 Map.Entry.<Integer, String>comparingByValue());
91 }
92
93 private static class People {
94 final String firstName;
95 final String lastName;
96 final int age;
97
98 People(String first, String last, int age) {
99 firstName = first;
100 lastName = last;
101 this.age = age;
102 }
103
104 String getFirstName() { return firstName; }
105 String getLastName() { return lastName; }
106 int getAge() { return age; }
107 }
108
109 private final People people[] = {
110 new People("John", "Doe", 34),
111 new People("Mary", "Doe", 30),
112 };
113
114 public void testKVComparators() {
115 // Comparator<People> cmp = Comparator.naturalOrder(); // Should fail to compiler as People is not comparable
116 // We can use simple comparator, but those have been tested above.
117 // Thus choose to do compose for some level of interation.
118 Comparator<People> cmp1 = Comparator.comparing((Function<People, String>) People::getFirstName);
119 Comparator<People> cmp2 = Comparator.comparing((Function<People, String>) People::getLastName);
120 Comparator<People> cmp = cmp1.thenComparing(cmp2);
121
122 assertPairComparison(people[0], people[0], people[1], people[1],
123 Map.Entry.<People, People>comparingByKey(cmp),
124 Map.Entry.<People, People>comparingByValue(cmp));
125
126 }
127
128 public void testNulls() {
129 try {
130 Comparator<Map.Entry<String, String>> cmp = Map.Entry.comparingByKey(null);
131 fail("comparingByKey(null) should throw NPE");
132 } catch (NullPointerException npe) {}
133
134 try {
135 Comparator<Map.Entry<String, String>> cmp = Map.Entry.comparingByValue(null);
136 fail("comparingByValue(null) should throw NPE");
137 } catch (NullPointerException npe) {}
138 }
139 }