97 lines
3.1 KiB
Java
97 lines
3.1 KiB
Java
/*
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* Copyright (c) 2011, 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 8003280
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* @summary Add lambda tests
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* Test method reference with SAM interface Comparator<T>
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* @compile MethodRef5.java
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* @run main MethodRef5
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*/
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import java.util.Collections;
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import java.util.List;
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import java.util.ArrayList;
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public class MethodRef5 {
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static class Person {
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private String firstName;
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private String lastName;
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private int age;
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public Person() { }
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public Person(String fn, String ln, int a) {
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firstName = fn;
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lastName = ln;
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age = a;
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}
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public String getLastName() {
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return lastName;
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}
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public int getAge() {
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return age;
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}
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//the following 2 methods are signature-compatible with Comparator<Person>.compare():
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public static int compareByAge(Person a, Person b) {
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return a.age - b.age;
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}
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public int compareByLastName(Person a, Person b) {
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return a.lastName.compareToIgnoreCase(b.lastName);
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}
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}
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private static void assertTrue(boolean cond) {
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if (!cond)
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throw new AssertionError();
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}
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public static void main(String[] args) {
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List<Person> persons = new ArrayList<Person>();
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persons.add(new Person("John", "Smith", 49));
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persons.add(new Person("Abraham", "Lincoln", 30));
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persons.add(new Person("George", "Washington", 29));
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persons.add(new Person("Peter", "Derby", 50));
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Collections.sort(persons, Person::compareByAge);//static method reference to compareByAge(Person, Person)
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String age = "";
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for (Person p : persons) {
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age += p.getAge() + " ";
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}
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assertTrue( (age.equals("29 30 49 50 ")) );
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Collections.sort(persons, new Person()::compareByLastName);//instance method reference to compareByLastName(Person, Person)
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String lastName = "";
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for (Person p : persons) {
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lastName += p.getLastName() + " ";
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}
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assertTrue( lastName.equals("Derby Lincoln Smith Washington ") );
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}
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}
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