1/*
2 * Copyright (c) 2012, 2013, 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 */
29import java.util.function.Function;
30import java.util.Comparator;
31import java.util.AbstractMap;
32import java.util.Map;
33import org.testng.annotations.Test;
34
35import static org.testng.Assert.assertTrue;
36import static org.testng.Assert.fail;
37
38/**
39 * Unit tests for Map.Entry.comparing
40 */
41@Test(groups = "unit")
42public 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(People::getFirstName);
119        Comparator<People> cmp2 = Comparator.comparing(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}
140