Java sort multiple fields using Comparator.

Sort multiple fields using Comparator:

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

class SortByAnimalName implements Comparator<Animal> {

@Override
public int compare(Animal o1, Animal o2) {
return o1.name.compareTo(o2.name);
}
}

class SortByAnimalColor implements Comparator<Animal> {

@Override
public int compare(Animal o1, Animal o2) {
return o1.color.compareTo(o2.color);
}
}

class SortByAnimalWeight implements Comparator<Animal> {

@Override
public int compare(Animal o1, Animal o2) {
if (o1.weight > o2.weight) {
return 1;
}
if (o1.weight < o2.weight) {
return -1;
}
return 0;
}
}

class SortByAllAnimal implements Comparator<Animal> {

List<Comparator<Animal>> allFields;

@SafeVarargs
SortByAllAnimal(Comparator<Animal>... allSort) {
this.allFields = Arrays.asList(allSort);

}
@Override
public int compare(Animal o1, Animal o2) {
for (Comparator<Animal> x : allFields) {
int res = x.compare(o1, o2);
if (res != 0) {
return res;
}
}
return 0;
}
}

class Animal {
String color;
String name;
int weight;

Animal(String c, String n, int w) {
this.color = c;
this.name = n;
this.weight = w;
}
@Override
public String toString() {
return this.color + " " + this.name + " " + this.weight;
}
}

public class SortMultipleDataByComparator{
public static void main(String[] args) {
List<Animal> l = new ArrayList<Animal>();
Animal a1 = new Animal("black", "dog", 20);
Animal a2 = new Animal("white", "cat", 15);
Animal a3 = new Animal("black", "elephant", 120);
Animal a4 = new Animal("white", "horse", 80);
l.add(a1);
l.add(a2);
l.add(a3);
l.add(a4);
System.out.println(l);
System.out.println("------------------------------------");
Collections.sort(l,
new SortByAllAnimal(new SortByAnimalColor(), new SortByAnimalName(), new SortByAnimalWeight()));

System.out.println(l);
}
}

---

Output:

[black dog 20, white cat 15, black elephant 120, white horse 80]
------------------------------------
[black dog 20, black elephant 120, white cat 15, white horse 80]