Loro-lorone nggawe cara nata urutan objek, nanging beda caranya: Comparable nggawe urutan alami kelas (dileksani dening kelas dhéwé), dene Comparator nggawe urutan lan dumunung njabane (obyek kapisah). Piline gumantung apa urutane iku kekarepan atawa kebantuane.
public class Person implements Comparable<Person> {
private String name;
private int age;
@Override
public int compareTo(Person other) { // defines THE natural order
return Integer.compare(this.age, other.age); // by age
}
// return: negative if this < other, 0 if equal, positive if this > other
}
List<Person> people = ...;
Collections.sort(people); // uses compareTo — sorts by age (the natural order)
Comparable manggon ing jero kelas liwat compareTo(), nggawe urutane tunggal lan baku. Dienggo kanthi otomatis dening Collections.sort, TreeSet, TreeMap, lan sapanunggale.
// define orderings OUTSIDE the class — as many as you need
Comparator<Person> byName = (a, b) -> a.getName().compareTo(b.getName());
Comparator<Person> byAge = Comparator.comparingInt(Person::getAge);
people.sort(byName); // sort by name
people.sort(byAge.reversed()); // by age, descending
Comparator minangka obyek kapisah, ngandakake kowe bisa nggawe pirang-pirang urutan béda kanggo kelas sing padha tanpa ngobah-obah.
Comparator<Person> comp = Comparator
.comparing(Person::getLastName) // primary: last name
.thenComparing(Person::getFirstName) // tie-break: first name
.thenComparingInt(Person::getAge) // then: age
.reversed(); // reverse the whole thing
people.sort(comp);
Metode gaya builder comparing/thenComparing gawe urutan multi-lapangan kang rumit dadi ringkas lan gampang diaggo.
Comparable → the class has ONE obvious natural order (numbers by value, strings
alphabetically, dates chronologically); you own the class
Comparator → you need MULTIPLE orderings, situational/custom ordering, OR you
can't modify the class (e.g. sorting a third-party type differently)
Nata urutan obyek iku keperluwan terusan — mba-mba senarahing, nganggo TreeSet/TreeMap, panggihake min/max.
Ngerteni bedane Comparable lawan Comparator nggawe kowe bisa milih kanthi bener: Comparable kanggo urutan kekarepan tunggal kelas (candraka ing kelas, dienggo baku), Comparator kanggo keluwesen pirang-pirang urutan utawa urutan njéwantah (mba-mba data sing sama miturut lapangan béda, utawa nata jinis kang ora kowe kontrol).
API Comparator luwes modern (comparing/thenComparing/reversed) gawe urutan multi-tingkat dadi ayu.
Domèn loro-lorone — lan kapan saben-e cocok — iku penting kanggo manggon karo struktur data kang kasor-urut-an lan iku topik praktis lan pagowan kang kerep ana ing Java.