394 lines
16 KiB
Java
394 lines
16 KiB
Java
/*
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* Copyright (c) 2013, 2017, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/**
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* @test
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* @bug 8171826
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* @summary Comparator default method tests
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* @run testng BasicTest
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*/
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import org.testng.annotations.Test;
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import java.util.Collections;
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import java.util.Comparator;
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import java.util.function.Function;
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import java.util.function.ToDoubleFunction;
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import java.util.function.ToIntFunction;
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import java.util.function.ToLongFunction;
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import static org.testng.Assert.*;
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@Test(groups = "unit")
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public class BasicTest {
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private static class Thing {
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public final int intField;
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public final long longField;
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public final double doubleField;
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public final String stringField;
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private Thing(int intField, long longField, double doubleField, String stringField) {
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this.intField = intField;
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this.longField = longField;
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this.doubleField = doubleField;
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this.stringField = stringField;
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}
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public int getIntField() {
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return intField;
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}
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public long getLongField() {
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return longField;
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}
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public double getDoubleField() {
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return doubleField;
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}
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public String getStringField() {
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return stringField;
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}
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}
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private final int[] intValues = { -2, -2, -1, -1, 0, 0, 1, 1, 2, 2 };
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private final long[] longValues = { -2, -2, -1, -1, 0, 0, 1, 1, 2, 2 };
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private final double[] doubleValues = { -2, -2, -1, -1, 0, 0, 1, 1, 2, 2 };
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private final String[] stringValues = { "a", "a", "b", "b", "c", "c", "d", "d", "e", "e" };
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private final int[] comparisons = { 0, -1, 0, -1, 0, -1, 0, -1, 0 };
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private<T> void assertComparisons(T[] things, Comparator<T> comp, int[] comparisons) {
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for (int i=0; i<comparisons.length; i++) {
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assertEquals(comparisons.length + 1, things.length);
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assertEquals(comparisons[i], comp.compare(things[i], things[i+1]));
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assertEquals(-comparisons[i], comp.compare(things[i+1], things[i]));
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}
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}
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public void testIntComparator() {
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Thing[] things = new Thing[intValues.length];
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for (int i=0; i<intValues.length; i++)
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things[i] = new Thing(intValues[i], 0L, 0.0, null);
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Comparator<Thing> comp = Comparator.comparingInt(new ToIntFunction<Thing>() {
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@Override
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public int applyAsInt(Thing thing) {
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return thing.getIntField();
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}
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});
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assertComparisons(things, comp, comparisons);
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}
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public void testLongComparator() {
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Thing[] things = new Thing[longValues.length];
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for (int i=0; i<longValues.length; i++)
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things[i] = new Thing(0, longValues[i], 0.0, null);
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Comparator<Thing> comp = Comparator.comparingLong(new ToLongFunction<Thing>() {
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@Override
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public long applyAsLong(Thing thing) {
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return thing.getLongField();
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}
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});
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assertComparisons(things, comp, comparisons);
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}
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public void testDoubleComparator() {
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Thing[] things = new Thing[doubleValues.length];
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for (int i=0; i<doubleValues.length; i++)
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things[i] = new Thing(0, 0L, doubleValues[i], null);
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Comparator<Thing> comp = Comparator.comparingDouble(new ToDoubleFunction<Thing>() {
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@Override
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public double applyAsDouble(Thing thing) {
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return thing.getDoubleField();
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}
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});
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assertComparisons(things, comp, comparisons);
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}
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public void testComparing() {
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Thing[] things = new Thing[doubleValues.length];
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for (int i=0; i<doubleValues.length; i++)
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things[i] = new Thing(0, 0L, 0.0, stringValues[i]);
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Comparator<Thing> comp = Comparator.comparing(new Function<Thing, String>() {
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@Override
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public String apply(Thing thing) {
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return thing.getStringField();
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}
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});
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assertComparisons(things, comp, comparisons);
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}
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public void testNaturalOrderComparator() {
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Comparator<String> comp = Comparator.naturalOrder();
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assertComparisons(stringValues, comp, comparisons);
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}
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public void testReverseComparator() {
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Comparator<String> cmpr = Comparator.reverseOrder();
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Comparator<String> cmp = cmpr.reversed();
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assertEquals(cmp.reversed(), cmpr);
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assertEquals(0, cmp.compare("a", "a"));
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assertEquals(0, cmpr.compare("a", "a"));
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assertTrue(cmp.compare("a", "b") < 0);
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assertTrue(cmpr.compare("a", "b") > 0);
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assertTrue(cmp.compare("b", "a") > 0);
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assertTrue(cmpr.compare("b", "a") < 0);
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}
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public void testReverseComparator2() {
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Comparator<String> cmp = (s1, s2) -> s1.length() - s2.length();
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Comparator<String> cmpr = cmp.reversed();
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assertEquals(cmpr.reversed(), cmp);
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assertEquals(0, cmp.compare("abc", "def"));
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assertEquals(0, cmpr.compare("abc", "def"));
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assertTrue(cmp.compare("abcd", "def") > 0);
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assertTrue(cmpr.compare("abcd", "def") < 0);
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assertTrue(cmp.compare("abc", "defg") < 0);
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assertTrue(cmpr.compare("abc", "defg") > 0);
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}
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private <T> void assertComparison(Comparator<T> cmp, T less, T greater) {
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assertTrue(cmp.compare(less, greater) < 0, "less");
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assertTrue(cmp.compare(less, less) == 0, "equal");
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assertTrue(cmp.compare(greater, greater) == 0, "equal");
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assertTrue(cmp.compare(greater, less) > 0, "greater");
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}
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private static class People {
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final String firstName;
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final String lastName;
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final int age;
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People(String first, String last, int age) {
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firstName = first;
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lastName = last;
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this.age = age;
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}
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String getFirstName() { return firstName; }
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String getLastName() { return lastName; }
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int getAge() { return age; }
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long getAgeAsLong() { return (long) age; };
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double getAgeAsDouble() { return (double) age; };
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}
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private final People people[] = {
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new People("John", "Doe", 34),
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new People("Mary", "Doe", 30),
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new People("Maria", "Doe", 14),
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new People("Jonah", "Doe", 10),
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new People("John", "Cook", 54),
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new People("Mary", "Cook", 50),
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new People("Mary", null, 25),
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new People("John", null, 27)
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};
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public void testComparatorDefaultMethods() {
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Comparator<People> cmp = Comparator.comparing(People::getFirstName);
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Comparator<People> cmp2 = Comparator.comparing(People::getLastName);
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// reverseOrder
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assertComparison(cmp.reversed(), people[1], people[0]);
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// thenComparing(Comparator)
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assertComparison(cmp.thenComparing(cmp2), people[0], people[1]);
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assertComparison(cmp.thenComparing(cmp2), people[4], people[0]);
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// thenComparing(Function)
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assertComparison(cmp.thenComparing(People::getLastName), people[0], people[1]);
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assertComparison(cmp.thenComparing(People::getLastName), people[4], people[0]);
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// thenComparing(ToIntFunction)
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assertComparison(cmp.thenComparingInt(People::getAge), people[0], people[1]);
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assertComparison(cmp.thenComparingInt(People::getAge), people[1], people[5]);
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// thenComparing(ToLongFunction)
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assertComparison(cmp.thenComparingLong(People::getAgeAsLong), people[0], people[1]);
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assertComparison(cmp.thenComparingLong(People::getAgeAsLong), people[1], people[5]);
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// thenComparing(ToDoubleFunction)
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assertComparison(cmp.thenComparingDouble(People::getAgeAsDouble), people[0], people[1]);
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assertComparison(cmp.thenComparingDouble(People::getAgeAsDouble), people[1], people[5]);
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}
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public void testNullsFirst() {
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Comparator<String> strcmp = Comparator.nullsFirst(Comparator.naturalOrder());
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Comparator<People> cmp = Comparator.comparing(People::getLastName, strcmp)
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.thenComparing(People::getFirstName, strcmp);
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// Mary.null vs Mary.Cook - solve by last name
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assertComparison(cmp, people[6], people[5]);
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// John.null vs Mary.null - solve by first name
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assertComparison(cmp, people[7], people[6]);
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// More than one thenComparing
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strcmp = Comparator.nullsFirst(Comparator.comparingInt(String::length)
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.thenComparing(String.CASE_INSENSITIVE_ORDER));
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assertComparison(strcmp, null, "abc");
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assertComparison(strcmp, "ab", "abc");
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assertComparison(strcmp, "abc", "def");
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assertEquals(0, strcmp.compare("abc", "ABC"));
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// Ensure reverse still handle null properly
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Comparator<String> strcmp2 = strcmp.reversed().thenComparing(Comparator.naturalOrder());
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assertComparison(strcmp2, "abc", null);
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assertComparison(strcmp2, "abc", "ab");
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assertComparison(strcmp2, "def", "abc");
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assertComparison(strcmp2, "ABC", "abc");
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// Considering non-null values to be equal
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Comparator<String> blind = Comparator.nullsFirst(null);
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assertComparison(blind, null, "abc");
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assertEquals(0, blind.compare("abc", "def"));
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// reverse still consider non-null values to be equal
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strcmp = blind.reversed();
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assertComparison(strcmp, "abc", null);
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assertEquals(0, strcmp.compare("abc", "def"));
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// chain with another comparator to compare non-nulls
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strcmp = blind.thenComparing(Comparator.naturalOrder());
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assertComparison(strcmp, null, "abc");
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assertComparison(strcmp, "abc", "def");
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}
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public void testNullsLast() {
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Comparator<String> strcmp = Comparator.nullsLast(Comparator.naturalOrder());
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Comparator<People> cmp = Comparator.comparing(People::getLastName, strcmp)
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.thenComparing(People::getFirstName, strcmp);
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// Mary.null vs Mary.Cook - solve by last name
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assertComparison(cmp, people[5], people[6]);
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// John.null vs Mary.null - solve by first name
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assertComparison(cmp, people[7], people[6]);
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// More than one thenComparing
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strcmp = Comparator.nullsLast(Comparator.comparingInt(String::length)
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.thenComparing(String.CASE_INSENSITIVE_ORDER));
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assertComparison(strcmp, "abc", null);
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assertComparison(strcmp, "ab", "abc");
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assertComparison(strcmp, "abc", "def");
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// Ensure reverse still handle null properly
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Comparator<String> strcmp2 = strcmp.reversed().thenComparing(Comparator.naturalOrder());
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assertComparison(strcmp2, null, "abc");
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assertComparison(strcmp2, "abc", "ab");
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assertComparison(strcmp2, "def", "abc");
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assertComparison(strcmp2, "ABC", "abc");
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// Considering non-null values to be equal
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Comparator<String> blind = Comparator.nullsLast(null);
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assertComparison(blind, "abc", null);
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assertEquals(0, blind.compare("abc", "def"));
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// reverse still consider non-null values to be equal
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strcmp = blind.reversed();
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assertComparison(strcmp, null, "abc");
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assertEquals(0, strcmp.compare("abc", "def"));
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// chain with another comparator to compare non-nulls
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strcmp = blind.thenComparing(Comparator.naturalOrder());
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assertComparison(strcmp, "abc", null);
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assertComparison(strcmp, "abc", "def");
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}
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public void testComposeComparator() {
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// Longer string in front
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Comparator<String> first = (s1, s2) -> s2.length() - s1.length();
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Comparator<String> second = Comparator.naturalOrder();
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Comparator<String> composed = first.thenComparing(second);
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assertTrue(composed.compare("abcdefg", "abcdef") < 0);
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assertTrue(composed.compare("abcdef", "abcdefg") > 0);
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assertTrue(composed.compare("abcdef", "abcdef") == 0);
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assertTrue(composed.compare("abcdef", "ghijkl") < 0);
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assertTrue(composed.compare("ghijkl", "abcdefg") > 0);
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}
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public void testNulls() {
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try {
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Comparator.<String>naturalOrder().compare("abc", (String) null);
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fail("expected NPE with naturalOrder");
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} catch (NullPointerException npe) {}
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try {
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Comparator.<String>naturalOrder().compare((String) null, "abc");
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fail("expected NPE with naturalOrder");
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} catch (NullPointerException npe) {}
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try {
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Comparator.<String>reverseOrder().compare("abc", (String) null);
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fail("expected NPE with naturalOrder");
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} catch (NullPointerException npe) {}
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try {
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Comparator.<String>reverseOrder().compare((String) null, "abc");
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fail("expected NPE with naturalOrder");
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} catch (NullPointerException npe) {}
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try {
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Comparator<People> cmp = Comparator.comparing(null, Comparator.<String>naturalOrder());
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fail("comparing(null, cmp) should throw NPE");
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} catch (NullPointerException npe) {}
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try {
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Comparator<People> cmp = Comparator.comparing(People::getFirstName, null);
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fail("comparing(f, null) should throw NPE");
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} catch (NullPointerException npe) {}
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try {
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Comparator<People> cmp = Comparator.comparing(null);
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fail("comparing(null) should throw NPE");
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} catch (NullPointerException npe) {}
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try {
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Comparator<People> cmp = Comparator.comparingInt(null);
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fail("comparing(null) should throw NPE");
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} catch (NullPointerException npe) {}
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try {
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Comparator<People> cmp = Comparator.comparingLong(null);
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fail("comparing(null) should throw NPE");
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} catch (NullPointerException npe) {}
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try {
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Comparator<People> cmp = Comparator.comparingDouble(null);
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fail("comparing(null) should throw NPE");
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} catch (NullPointerException npe) {}
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}
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public void testNaturalAndReverseIdentity() {
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var naturalOrder = Comparator.<String>naturalOrder();
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var reverseOrder = Comparator.<String>reverseOrder();
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assertEquals(
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naturalOrder,
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Collections.reverseOrder(reverseOrder),
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"Comparator.naturalOrder() and Collections.reverseOrder(Comparator.reverseOrder()) not equal");
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assertEquals(
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reverseOrder,
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Collections.reverseOrder(naturalOrder),
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"Comparator.reverseOrder() and Collections.reverseOrder(Comparator.naturalOrder()) not equal");
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assertEquals(
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naturalOrder.reversed(),
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reverseOrder,
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"Comparator.naturalOrder().reversed() amd Comparator.reverseOrder() not equal");
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assertEquals(
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reverseOrder.reversed(),
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naturalOrder,
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"Comparator.reverseOrder().reversed() and Comparator.naturalOrder() not equal");
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}
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}
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