Mega Code Archive
Use Collections sort to sort custom class and user defined Comparator
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import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.ListIterator;
class Employee implements Comparable {
private String name;
private double salary;
Employee(String name, double salary) {
this.name = name;
this.salary = salary;
}
String getName() {
return name;
}
double getSalary() {
return salary;
}
public String toString() {
return "Name = " + getName() + ", Salary = " + getSalary();
}
public int compareTo(Object o) {
if (!(o instanceof Employee))
throw new ClassCastException();
Employee e = (Employee) o;
return name.compareTo(e.getName());
}
static class SalaryComparator implements Comparator {
public int compare(Object o1, Object o2) {
if (!(o1 instanceof Employee) || !(o2 instanceof Employee))
throw new ClassCastException();
Employee e1 = (Employee) o1;
Employee e2 = (Employee) o2;
return (int) (e1.getSalary() - e2.getSalary());
}
}
}
class UtilDemo4 {
public static void main(String[] args) {
String[] names = { "A", "B", "C", "D" };
double[] salaries = { 2.0, 5.0, 6.0, 4.0 };
List l = new ArrayList();
for (int i = 0; i < names.length; i++)
l.add(new Employee(names[i], salaries[i]));
Collections.sort(l);
ListIterator liter = l.listIterator();
while (liter.hasNext())
System.out.println(liter.next());
Collections.sort(l, new Employee.SalaryComparator());
liter = l.listIterator();
while (liter.hasNext())
System.out.println(liter.next());
}
}
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