Java Reference
In-Depth Information
return getClass() == comparator.getClass();
}
}
Directory "TrySortingWithComparator"
Just to make it more interesting and to demonstrate that it's this comparator and not the
compareTo()
method in the
Person
class that's being used by the
sort()
method, this comparator establishes a des-
cending sequence of
Person
objects. By switching the sign of the value that the
compareTo()
method
returns, you invert the sort order. Thus, sorting using this comparator sorts
Person
objects in descending
alphabetical order by surname and then by first name within surname.
You can try this out with the following program:
import java.util.Arrays;
public class TrySortingWithComparator {
public static void main(String[] args) {
Person[] authors = {
new Person("Danielle", "Steel"),
new Person("John",
"Grisham"),
new Person("Tom", "Clancy"),
new Person("Christina",
"Schwartz"),
new Person("Patricia", "Cornwell"), new Person("Bill", "Bryson")
};
System.out.println("Original order:");
for(Person author : authors) {
System.out.println(author);
}
Arrays.sort(authors, new ComparePersons()); // Sort using
comparator
System.out.println("\nOrder after sorting using comparator:");
for(Person author : authors) {
System.out.println(author);
}
Arrays.sort(authors);
// Sort using
compareTo() method
System.out.println("\nOrder after sorting using compareTo()
method:");
for(Person author : authors) {
System.out.println(author);
}
}
