generics + comparator

Box.java

package lesson7_10.generics;


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

public class Box<T extends Bird>{

    private List<T> birdsList;

    public Box() {

        birdsList = new ArrayList<T>();
    }

    public T getBird(int birdIndex) {

        return birdsList.get(birdIndex);
    }

    public List<T> getBirdsList() {

        return birdsList;
    }

    public void addBird(T bird) {

        birdsList.add(bird);
    }

    public void removeBird(T bird) {

        birdsList.remove(bird);
    }

    private class BirdsComparator implements Comparator<Bird> {

        @Override
        public int compare(Bird o1, Bird o2) {

            return o1.getName().compareTo(o2.getName());
        }
    }

    public void sortBirdsByName() {

        Collections.sort(birdsList, new BirdsComparator());
    }
}

BoxDemo.java

package lesson7_10.generics;

public class BoxDemo {

    public static void main(String[] args) {

        Box<Bird> birds = new Box<Bird>();

        Bird bird1= new Eagle();
        bird1.setName("eagle");
        Bird bird2 = new Duck();
        bird2.setName("duck");
        Bird bird3 = new Eagle();
        bird3.setName("eeagle");

        birds.addBird(bird1);
        birds.addBird(bird2);
        birds.addBird(bird3);

        for (Bird b : birds.getBirdsList()) {
            System.out.println(b.toString());
        }

        birds.sortBirdsByName();

        for (Bird b : birds.getBirdsList()) {
            System.out.println(b.toString());
        }
    }
}