猫狗队列

public class Pet { private String type; public Pet(String type) { this.type = type; } public String getPetType() { return this.type; } } public class Dog extends Pet { public Dog() { super("dog"); } } public class Cat extends Pet { public Cat() { super("cat"); } }
实现一种狗猫队列的结构，要求如下： 用户可以调用add方法将cat类或dog类的 实例放入队列中； 用户可以调用pollAll方法，将队列中所有的实例按照进队列 的先后顺序依次弹出； 用户可以调用pollDog方法，将队列中dog类的实例按照 进队列的先后顺序依次弹出； 用户可以调用pollCat方法，将队列中cat类的实 例按照进队列的先后顺序依次弹出； 用户可以调用isEmpty方法，检查队列中是 否还有dog或cat的实例； 用户可以调用isDogEmpty方法，检查队列中是否有dog 类的实例； 用户可以调用isCatEmpty方法，检查队列中是否有cat类的实例

package my_basic.class_3;

import java.util.LinkedList;
import java.util.Queue;

/*猫狗队列*/
public class Code_04_CatDogQueue {
    public static class Pet{
        private String type;

        public Pet(String type) {
            this.type = type;
        }
        public  String getPetType() {
            return this.type;
        }
    }
    public static class Dog extends Pet{
        public Dog() {
            super("dog");
        }
    }
    public static class Cat extends Pet{
        public Cat() {
            super("cat");
        }
    }
    
    public static class PetEnterQueue{
        private Pet pet;
        private Integer count;
        
        public PetEnterQueue(Pet pet, Integer count) {
            this.pet = pet;
            this.count = count;
        }
        public Pet getPet() {
            return pet;
        }
        
        public Integer getCount() {
            return count;
        }
    }
    
    public static class DogCatQueue{
        private Queue<PetEnterQueue> dogQ;
        private Queue<PetEnterQueue> catQ;
        private int count =0 ;
        
        
        public DogCatQueue() {
            super();
            this.dogQ = new LinkedList<PetEnterQueue>();
            this.catQ = new LinkedList<PetEnterQueue>();
            this.count = 0;
        }
        
        public void add(Pet pet) {
            if (pet.getPetType().equals("dog")) {
                this.dogQ.add(new PetEnterQueue(pet, this.count++));
            }else if (pet.getPetType().equals("cat")) {
                this.catQ.add(new PetEnterQueue(pet, count++));
            }else {
                throw new IllegalArgumentException("不是猫或狗");
            }
        }
        public Pet pollAll() {
            if (!dogQ.isEmpty() && !catQ.isEmpty()) {
                if (this.dogQ.peek().getCount() < this.catQ.peek().getCount()) {
                    return dogQ.poll().getPet();
                }else {
                    return catQ.poll().getPet();
                }
            }else if (!dogQ.isEmpty()) {
                return dogQ.poll().getPet();
            }else if (!catQ.isEmpty()) {
                return catQ.poll().getPet();
            }else {
                throw new RuntimeException("queue is empty!");
            }
        }
        public Pet pollDog() {
            if (!isDogEmpty()) {
                return dogQ.poll().getPet();
            }
            throw new RuntimeException("dogQ is empty!" );
        }
        public Pet pollCat() {
            if (!isCatEmpty()) {
                return catQ.poll().getPet();
            }
            throw new RuntimeException("dogQ is empty!" );
        }
        public boolean isEmpty() {
            return (dogQ.isEmpty() && catQ.isEmpty())? true : false;
        }
        public boolean isDogEmpty() {
            return dogQ.isEmpty();
        }
        public boolean isCatEmpty() {
            return catQ.isEmpty();
        }
        
    }
    
    /*for test*/
    public static void main(String[] args) {
        DogCatQueue test = new DogCatQueue();

        Pet dog1 = new Dog();
        Pet cat1 = new Cat();
        Pet dog2 = new Dog();
        Pet cat2 = new Cat();
        Pet dog3 = new Dog();
        Pet cat3 = new Cat();

        test.add(dog1);
        test.add(cat1);
        test.add(dog2);
        test.add(cat2);
        test.add(dog3);
        test.add(cat3);

        test.add(dog1);
        test.add(cat1);
        test.add(dog2);
        test.add(cat2);
        test.add(dog3);
        test.add(cat3);

        test.add(dog1);
        test.add(cat1);
        test.add(dog2);
        test.add(cat2);
        test.add(dog3);
        test.add(cat3);
        while (!test.isDogEmpty()) {
            System.out.println(test.pollDog().getPetType());
        }
        while (!test.isEmpty()) {
            System.out.println(test.pollAll().getPetType());
        }
    }

}