OnJava8-Examples/typeinfo/PetCount.java

// typeinfo/PetCount.java
// <20>2016 MindView LLC: see Copyright.txt
// Using instanceof.
import typeinfo.pets.*;
import java.util.*;

public class PetCount {
  static class PetCounter extends HashMap<String,Integer> {
    public void count(String type) {
      Integer quantity = get(type);
      if(quantity == null)
        put(type, 1);
      else
        put(type, quantity + 1);
    }
  }
  public static void
  countPets(PetCreator creator) {
    PetCounter counter= new PetCounter();
    for(Pet pet : creator.createArray(20)) {
      // List each individual pet:
      System.out.print(pet.getClass().getSimpleName() + " ");
      if(pet instanceof Pet)
        counter.count("Pet");
      if(pet instanceof Dog)
        counter.count("Dog");
      if(pet instanceof Mutt)
        counter.count("Mutt");
      if(pet instanceof Pug)
        counter.count("Pug");
      if(pet instanceof Cat)
        counter.count("Cat");
      if(pet instanceof EgyptianMau)
        counter.count("EgyptianMau");
      if(pet instanceof Manx)
        counter.count("Manx");
      if(pet instanceof Cymric)
        counter.count("Cymric");
      if(pet instanceof Rodent)
        counter.count("Rodent");
      if(pet instanceof Rat)
        counter.count("Rat");
      if(pet instanceof Mouse)
        counter.count("Mouse");
      if(pet instanceof Hamster)
        counter.count("Hamster");
    }
    // Show the counts:
    System.out.println();
    System.out.println(counter);
  }
  public static void main(String[] args) {
    countPets(new ForNameCreator());
  }
}
/* Output:
Rat Manx Cymric Mutt Pug Cymric Pug Manx Cymric Rat
EgyptianMau Hamster EgyptianMau Mutt Mutt Cymric Mouse Pug
Mouse Cymric
{EgyptianMau=2, Pug=3, Rat=2, Cymric=5, Mouse=2, Cat=9,
Manx=7, Rodent=5, Mutt=3, Dog=6, Pet=20, Hamster=1}
*/