fork download
copy 
  1. import java.util.*;
  2. import java.util.stream.Collectors;
  3. import java.util.stream.IntStream;
  4.  
  5. public class Main {
  6.     public static void main(final String[] args) {
  7.         final List<Person> personsSortedByComparable = constructPersons(
  8.                 new String[]{"Clair", "Alice", "Bob", "Alice"},
  9.                 new String[]{"Clear", "Wonder", "Builder", "Ace"}
  10.         );
  11.         Collections.sort(personsSortedByComparable);
  12.         System.out.println(personsSortedByComparable);
  13.  
  14.         final List<Person> personsSortByPersonByFirstNameThenByLastNameComparator =
  15.                 constructPersons(
  16.                         new String[]{"Clair", "Alice", "Bob", "Alice"},
  17.                         new String[]{"Clear", "Wonder", "Builder", "Ace"}
  18.                 );
  19.         personsSortByPersonByFirstNameThenByLastNameComparator
  20.                 .sort(PersonByFirstNameThenByLastNameComparator.INSTANCE);
  21.         System.out.println(personsSortByPersonByFirstNameThenByLastNameComparator);
  22.  
  23.         final List<Person> personsSortByComparator = constructPersons(
  24.                 new String[]{"Clair", "Alice", "Bob", "Alice"},
  25.                 new String[]{"Clear", "Wonder", "Builder", "Ace"}
  26.         );
  27.         personsSortByComparator.sort(Comparator.comparing(Person::getFirstName)
  28.                 .thenComparing(Person::getLastName));
  29.         System.out.println(personsSortByComparator);
  30.     }
  31.  
  32.     public static List<Person> constructPersons(
  33.             final String[] firstNames,
  34.             final String[] lastNames) {
  35.         if (firstNames.length != lastNames.length) {
  36.             throw new IllegalArgumentException("firstNames and lastNames must have same length");
  37.         }
  38.         return IntStream.range(0, firstNames.length)
  39.                 .mapToObj(index -> Person.of(firstNames[index], lastNames[index]))
  40.                 .collect(Collectors.toCollection(ArrayList::new));
  41.     }
  42. }
  43.  
  44. class Person implements Comparable<Person> {
  45.     public static final String PERSON_TO_STRING_FORMAT = "{f: %s, l: %s}";
  46.  
  47.     private final String firstName;
  48.     private final String lastName;
  49.  
  50.     private Person(final String firstName, final String lastName) {
  51.         this.firstName = Objects.requireNonNull(firstName);
  52.         this.lastName = Objects.requireNonNull(lastName);
  53.     }
  54.  
  55.     public static Person of(final String firstName, final String lastName) {
  56.         return new Person(firstName, lastName);
  57.     }
  58.  
  59.     public String getFirstName() {
  60.         return firstName;
  61.     }
  62.  
  63.     public String getLastName() {
  64.         return lastName;
  65.     }
  66.  
  67.     @Override
  68.     public String toString() {
  69.         return String.format(PERSON_TO_STRING_FORMAT, getFirstName(), getLastName());
  70.     }
  71.  
  72.     @Override
  73.     public final boolean equals(Object thatObject) {
  74.         if (this == thatObject) {
  75.             return true;
  76.         }
  77.         if (thatObject == null || getClass() != thatObject.getClass()) {
  78.             return false;
  79.         }
  80.         final Person that = (Person) thatObject;
  81.         return Objects.equals(getFirstName(), that.getFirstName()) &&
  82.                 Objects.equals(getLastName(), that.getLastName());
  83.     }
  84.  
  85.     @Override
  86.     public final int hashCode() {
  87.         return Objects.hash(getFirstName(), getLastName());
  88.     }
  89.  
  90.     @Override
  91.     public final int compareTo(final Person that) {
  92.         if (Objects.equals(getFirstName(), that.getFirstName())) {
  93.             return getLastName().compareTo(that.getLastName());
  94.         }
  95.         return getFirstName().compareTo(that.getFirstName());
  96.     }
  97. }
  98.  
  99. class PersonByFirstNameThenByLastNameComparator implements Comparator<Person> {
  100.     public static final PersonByFirstNameThenByLastNameComparator INSTANCE =
  101.             new PersonByFirstNameThenByLastNameComparator();
  102.  
  103.     private PersonByFirstNameThenByLastNameComparator() {
  104.     }
  105.  
  106.     @Override
  107.     public int compare(final Person lhs, final Person rhs) {
  108.         if (Objects.equals(lhs.getFirstName(), rhs.getFirstName())) {
  109.             return lhs.getLastName().compareTo(rhs.getLastName());
  110.         }
  111.         return lhs.getFirstName().compareTo(rhs.getFirstName());
  112.     }
  113. }
Success #stdin #stdout 0.1s 35196KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
[{f: Alice, l: Ace}, {f: Alice, l: Wonder}, {f: Bob, l: Builder}, {f: Clair, l: Clear}]
[{f: Alice, l: Ace}, {f: Alice, l: Wonder}, {f: Bob, l: Builder}, {f: Clair, l: Clear}]
[{f: Alice, l: Ace}, {f: Alice, l: Wonder}, {f: Bob, l: Builder}, {f: Clair, l: Clear}]
https://ideone.com/YIebsl
language:
Java (HotSpot 12)
created:
4 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!