ede3954d创建于 2021年3月5日历史提交
// reflection/PetCounter.java
// (c)2021 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
// Using instanceof
import reflection.pets.*;
import java.util.*;

public class PetCounter {
  static class Counter extends HashMap<String,Integer> {
    public void count(String type) {
      Integer quantity = get(type);
      if(quantity == null)
        put(type, 1);
      else
        put(type, quantity + 1);
    }
  }
  private Counter counter = new Counter();
  private void countPet(Pet 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");
  }
  public void count(Creator creator) {
    creator.stream().limit(20)
      .forEach(pet -> countPet(pet));
    System.out.println();
    System.out.println(counter);
  }
  public static void main(String[] args) {
    new PetCounter().count(new ForNamePetCreator());
  }
}
/* 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}
*/