我正在为下周的面向对象编程考试做一些复习,遇到了一个问题。问题基本上是给出狗和跳蚤之间双向关联的例子。到目前为止,我有一只有跳蚤的狗。我卡在的部分是,“修改狗类,使得狗对象最多只能持有5个跳蚤对象(如果有超过5个跳蚤,则打印“你的狗有太多的跳蚤!”)。这是我的代码:
Dog.java
import java.util.ArrayList;
public class Dog {
private String name;
private int age;
private String address;
ArrayList<Flea> fleas = new ArrayList<Flea>(); {
if(fleas.size() > 5) {
System.out.println("This dog has too many fleas!");
}
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public void hostFlea(Flea flea) {
fleas.add(flea);
}
public ArrayList<Flea> getDogFlea() {
return fleas;
}
public String toString() {
return name + " the Dog (aged " + age + ") has fleas. \nThey are: " + fleas + ".";
}
}
Flea.java
public class Flea {
private String name;
private int age;
public Flea (String name, int age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String toString() {
return name + " (aged " + age + ")";
}
}
Test.java
public class Test {
public static void main(String[] args) {
Dog dog = new Dog();
dog.setName("Freddy");
dog.setAddress("Cork");
dog.setAge(5);
Flea flea1 = new Flea("John", 1);
dog.hostFlea(flea1);
Flea flea2 = new Flea("Patrick", 3);
dog.hostFlea(flea2);
Flea flea3 = new Flea("Alan", 7);
dog.hostFlea(flea3);
Flea flea4 = new Flea("Steven", 2);
dog.hostFlea(flea4);
Flea flea5 = new Flea("Charles", 5);
dog.hostFlea(flea5);
Flea flea6 = new Flea("Derek", 1);
dog.hostFlea(flea6);
Flea flea7 = new Flea("Kevin", 8);
dog.hostFlea(flea7);
System.out.println(dog);
}
}
控制台:
5岁的狗弗雷迪有跳蚤。 它们是:[1岁的约翰,3岁的帕特里克,7岁的艾伦,2岁的史蒂文,5岁的查尔斯,1岁的德里克,8岁的凯文]。
hostFlea
方法的定义是什么? - Nate Barbettini