/* * Copyright (c) 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. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * 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 * @summary Comparator API narrowing type test * @run testng TypeTest */ import java.util.function.Function; import java.util.Map; import java.util.TreeMap; import java.util.Comparator; import org.testng.annotations.Test; @Test(groups = "unit") public class TypeTest { static class Person { String name; static Comparator C = (p1, p2) -> p1.name.compareTo(p2.name); Person(String name) { this.name = name; } String getName() { return name; } } static class Employee extends Person { int id; static Comparator C = (e1, e2) -> e1.id - e2.id; Employee(int id, String name) { super(name); this.id = id; } } static class Manager extends Employee { long reports; static Comparator C = (e1, e2) -> (int) (e1.reports - e2.reports); Manager(String name, int id, long reports) { super(id, name); this.reports = reports; } } static void assertOrder(T o1, T o2, Comparator cmp) { if (cmp.compare(o1, o2) > 0) { System.out.println("Fail!!"); } if (cmp.compare(o1, o2) == 0) { System.out.println("Equal!!"); } } public static void main(String[] args) { Manager m1 = new Manager("Manager", 2, 2000); Manager m2 = new Manager("Manager", 4, 1300); // Comparator tmp = Person.C; // Comparator cmp = Employee.C.thenComparing(Person.C); Comparator cmp = Employee.C.thenComparing(Person.C); assertOrder(m1, m2, Employee.C.thenComparing(Person.C)); assertOrder(m1, m2, cmp); assertOrder(m1, new Employee(1, "Z"), Person.C); assertOrder(new Employee(1, "Z"), m2, Employee.C); assertOrder(m1, m2, Comparator.comparing(Employee::getName, String.CASE_INSENSITIVE_ORDER)); Map map = new TreeMap<>(); map.entrySet().stream().sorted(Map.Entry.comparingByKey(String.CASE_INSENSITIVE_ORDER)); } }