抽象類

package com.hdy.test9;
abstract class Animal {
  private String name;
  Animal(String name) {this.name = name;}
  /*
  public void enjoy(){
    System.out.println("叫聲......");//這個方法，要被重寫，因此父類沒有必要去實現
    //定義爲抽象方法，那麼類也就成爲了抽象類
  }
  */
  public abstract void enjoy();
}

abstract class Cat extends Animal {
  private String eyesColor;
  Cat(String n,String c) {super(n); eyesColor = c;}
 
  /*public void enjoy() {
    System.out.println("貓叫聲......");
  }*/
  //原則上Cat必須要實現抽象父類的所有方法，但是也可以交給Cat的子類去實現，或者Cat實現不了
  public abstract void enjoy();
 
}

class Dog extends Animal {
  private String furColor;
  Dog(String n,String c) {super(n); furColor = c;}
 
  public void enjoy() {
    System.out.println("狗叫聲......");
  }
}

class Bird extends Animal {
  Bird() {
    super("bird");
  }
  public void enjoy() {
    System.out.println("鳥叫聲......");
  }
}

class Lady {
    private String name;
    private Animal pet;
    Lady(String name,Animal pet) {
        this.name = name; this.pet = pet;
    }
    public void myPetEnjoy(){pet.enjoy();}
}

public class Test {
    public static void main(String args[]){
      //  Cat c = new Cat("catname","blue");抽象類不能被new
        Dog d = new Dog("dogname","black");
        Bird b = new Bird();
        //Lady l1 = new Lady("l1",c);
        Lady l2 = new Lady("l2",d);
        Lady l3 = new Lady("l3",b);
       //l1.myPetEnjoy();
        l2.myPetEnjoy();
        l3.myPetEnjoy();
    }
}