How to compare objects by multiple fields

Question

Assume you have some objects which have several fields they can be compared by:

public class Person {

    private String firstName;
    private String lastN         


        

Answer 1

Following blog given good chained Comparator example

http://www.codejava.net/java-core/collections/sorting-a-list-by-multiple-attributes-example

import java.util.Arrays;
import java.util.Comparator;
import java.util.List;

/**
 * This is a chained comparator that is used to sort a list by multiple
 * attributes by chaining a sequence of comparators of individual fields
 * together.
 *
 */
public class EmployeeChainedComparator implements Comparator {

    private List> listComparators;

    @SafeVarargs
    public EmployeeChainedComparator(Comparator... comparators) {
        this.listComparators = Arrays.asList(comparators);
    }

    @Override
    public int compare(Employee emp1, Employee emp2) {
        for (Comparator comparator : listComparators) {
            int result = comparator.compare(emp1, emp2);
            if (result != 0) {
                return result;
            }
        }
        return 0;
    }
}

Calling Comparator:

Collections.sort(listEmployees, new EmployeeChainedComparator(
                new EmployeeJobTitleComparator(),
                new EmployeeAgeComparator(),
                new EmployeeSalaryComparator())
        );