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/*
* Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* @test
* @bug 8009736 8010279
* @run testng EntryComparators
*/
import java.util.function.Function;
import java.util.Comparator;
import java.util.AbstractMap;
import java.util.Map;
import org.testng.annotations.Test;
import static org.testng.Assert.assertTrue;
import static org.testng.Assert.fail;
/**
* Unit tests for Map.Entry.comparing
*/
@Test(groups = "unit")
public class EntryComparators {
private <K, V> void assertPairComparison(K k1, V v1, K k2, V v2,
Comparator<Map.Entry<K, V>> ck,
Comparator<Map.Entry<K, V>> cv) {
final Map.Entry<K, V> p11 = new AbstractMap.SimpleImmutableEntry<>(k1, v1);
final Map.Entry<K, V> p12 = new AbstractMap.SimpleImmutableEntry<>(k1, v2);
final Map.Entry<K, V> p21 = new AbstractMap.SimpleImmutableEntry<>(k2, v1);
final Map.Entry<K, V> p22 = new AbstractMap.SimpleImmutableEntry<>(k2, v2);
assertTrue(ck.compare(p11, p11) == 0);
assertTrue(ck.compare(p12, p11) == 0);
assertTrue(ck.compare(p11, p12) == 0);
assertTrue(ck.compare(p12, p22) < 0);
assertTrue(ck.compare(p12, p21) < 0);
assertTrue(ck.compare(p21, p11) > 0);
assertTrue(ck.compare(p21, p12) > 0);
assertTrue(cv.compare(p11, p11) == 0);
assertTrue(cv.compare(p12, p11) > 0);
assertTrue(cv.compare(p11, p12) < 0);
assertTrue(cv.compare(p12, p22) == 0);
assertTrue(cv.compare(p12, p21) > 0);
assertTrue(cv.compare(p21, p11) == 0);
assertTrue(cv.compare(p21, p12) < 0);
Comparator<Map.Entry<K, V>> cmp = ck.thenComparing(cv);
assertTrue(cmp.compare(p11, p11) == 0);
assertTrue(cmp.compare(p12, p11) > 0);
assertTrue(cmp.compare(p11, p12) < 0);
assertTrue(cmp.compare(p12, p22) < 0);
assertTrue(cmp.compare(p12, p21) < 0);
assertTrue(cmp.compare(p21, p11) > 0);
assertTrue(cmp.compare(p21, p12) > 0);
cmp = cv.thenComparing(ck);
assertTrue(cmp.compare(p11, p11) == 0);
assertTrue(cmp.compare(p12, p11) > 0);
assertTrue(cmp.compare(p11, p12) < 0);
assertTrue(cmp.compare(p12, p22) < 0);
assertTrue(cmp.compare(p12, p21) > 0);
assertTrue(cmp.compare(p21, p11) > 0);
assertTrue(cmp.compare(p21, p12) < 0);
}
public void testKVComparables() {
assertPairComparison(1, "ABC", 2, "XYZ",
Map.Entry.<Integer, String>comparingByKey(),
Map.Entry.<Integer, String>comparingByValue());
}
private static class People {
final String firstName;
final String lastName;
final int age;
People(String first, String last, int age) {
firstName = first;
lastName = last;
this.age = age;
}
String getFirstName() { return firstName; }
String getLastName() { return lastName; }
int getAge() { return age; }
}
private final People people[] = {
new People("John", "Doe", 34),
new People("Mary", "Doe", 30),
};
public void testKVComparators() {
// Comparator<People> cmp = Comparator.naturalOrder(); // Should fail to compiler as People is not comparable
// We can use simple comparator, but those have been tested above.
// Thus choose to do compose for some level of interation.
Comparator<People> cmp1 = Comparator.comparing(People::getFirstName);
Comparator<People> cmp2 = Comparator.comparing(People::getLastName);
Comparator<People> cmp = cmp1.thenComparing(cmp2);
assertPairComparison(people[0], people[0], people[1], people[1],
Map.Entry.<People, People>comparingByKey(cmp),
Map.Entry.<People, People>comparingByValue(cmp));
}
public void testNulls() {
try {
Comparator<Map.Entry<String, String>> cmp = Map.Entry.comparingByKey(null);
fail("comparingByKey(null) should throw NPE");
} catch (NullPointerException npe) {}
try {
Comparator<Map.Entry<String, String>> cmp = Map.Entry.comparingByValue(null);
fail("comparingByValue(null) should throw NPE");
} catch (NullPointerException npe) {}
}
}
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