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1 /* |
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2 * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. |
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8 * |
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9 * This code is distributed in the hope that it will be useful, but WITHOUT |
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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12 * version 2 for more details (a copy is included in the LICENSE file that |
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13 * accompanied this code). |
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14 * |
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15 * You should have received a copy of the GNU General Public License version |
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16 * 2 along with this work; if not, write to the Free Software Foundation, |
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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18 * |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
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22 */ |
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23 |
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24 /** |
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25 * @test |
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26 * @bug 8003280 |
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27 * @summary Add lambda tests |
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28 * Test method reference with SAM interface Comparator<T> |
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29 * @compile MethodRef5.java |
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30 * @run main MethodRef5 |
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31 */ |
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32 |
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33 import java.util.Collections; |
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34 import java.util.List; |
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35 import java.util.ArrayList; |
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36 |
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37 public class MethodRef5 { |
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38 |
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39 static class Person { |
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40 |
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41 private String firstName; |
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42 private String lastName; |
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43 private int age; |
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44 |
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45 public Person() { } |
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46 |
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47 public Person(String fn, String ln, int a) { |
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48 firstName = fn; |
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49 lastName = ln; |
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50 age = a; |
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51 } |
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52 |
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53 public String getLastName() { |
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54 return lastName; |
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55 } |
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56 |
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57 public int getAge() { |
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58 return age; |
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59 } |
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60 |
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61 //the following 2 methods are signature-compatible with Comparator<Person>.compare(): |
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62 public static int compareByAge(Person a, Person b) { |
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63 return a.age - b.age; |
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64 } |
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65 |
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66 public int compareByLastName(Person a, Person b) { |
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67 return a.lastName.compareToIgnoreCase(b.lastName); |
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68 } |
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69 } |
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70 |
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71 private static void assertTrue(boolean cond) { |
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72 if (!cond) |
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73 throw new AssertionError(); |
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74 } |
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75 |
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76 public static void main(String[] args) { |
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77 |
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78 List<Person> persons = new ArrayList<Person>(); |
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79 persons.add(new Person("John", "Smith", 49)); |
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80 persons.add(new Person("Abraham", "Lincoln", 30)); |
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81 persons.add(new Person("George", "Washington", 29)); |
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82 persons.add(new Person("Peter", "Derby", 50)); |
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83 Collections.sort(persons, Person::compareByAge);//static method reference to compareByAge(Person, Person) |
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84 String age = ""; |
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85 for (Person p : persons) { |
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86 age += p.getAge() + " "; |
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87 } |
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88 assertTrue( (age.equals("29 30 49 50 ")) ); |
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89 Collections.sort(persons, new Person()::compareByLastName);//instance method reference to compareByLastName(Person, Person) |
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90 String lastName = ""; |
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91 for (Person p : persons) { |
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92 lastName += p.getLastName() + " "; |
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93 } |
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94 assertTrue( lastName.equals("Derby Lincoln Smith Washington ") ); |
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95 } |
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96 } |