如何在 java 中实现接口并在抽象 class 中扩展线程

Question

我正在努力完成作业的要求..."Include at least one interface that contains at least one method that implementing classes must implement."

当我尝试实例化接口时，它说无法实例化接口。我不确定我做错了什么。

我已经尝试了几种方法让它发挥作用。

//main class
public class Main {

    /**
     * @param args
     */
    public static void main(String[] args) {

        Ford mustang = new Ford("Mustang", 135, 125);
        Chevrolet camero = new Chevrolet("Camero", 202, 100);
        Dodge challenger = new Dodge("Challenger", 203, 75);        

        Nitrous nitro = new Nitrous();//problem code

        mustang.start();
        camero.start();
        challenger.start();
    }

}

//Abstract class
public abstract class Vehicle extends Thread implements Nitrous {

    private String model;
    private int speed;
    private int boost;

    public Vehicle(String model, int speed, int boost) {
        this.model = model;
        this.speed = speed;
        this.boost = boost;
    }

    public String getmodel() {
        return model;
    }

    public void setmodel(String model) {
        this.model = model;
    }

    public int getspeed() {
        return speed;
    }

    public void setspeed(int speed) {
        this.speed = speed;
    }

    public int getboost() {
        return boost;
    }

    public void setboost(int boost) {
        this.boost = boost;
    }


    @Override
    public void run() {
        try {
            go();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    private void go() throws InterruptedException {
        int trackLength = 5000;
        int checkPointPassed = 0;
        for (int i = 0; i < trackLength; i += (speed + boost)) {
            if (checkPointPassed * 1000 < i) {
                checkPointPassed++;
                System.out.println("The " + this.model + " has passed check point " + checkPointPassed);
//              System.out.println(nos);
                Thread.sleep(10);
            }
        }
    }

}

//subclass one of three
public class Ford extends Vehicle {

    public Ford (String model, int speed, int boost) {

        super(model, speed, boost); 

    }

    @Override
    public void nos() {
        // TODO Auto-generated method stub
        System.out.println("The cars have Nitro!");
    }

}

public class Chevrolet extends Vehicle{

    public Chevrolet(String model, int speed, int boost) {
        // TODO Auto-generated constructor stub.
        super(model, speed, boost);
    }

    @Override
    public void nos() {
        // TODO Auto-generated method stub
        System.out.println("The cars have Nitro!");
    }

}

public class Dodge extends Vehicle{

    public Dodge(String model, int speed, int boost) {
        // TODO Auto-generated constructor stub
        super(model, speed, boost);
    }

    @Override
    public void nos() {
        // TODO Auto-generated method stub
        System.out.println("The cars have Nitro!");
    }

}

//Interface

public interface Nitrous {

    public void nos();
}

这是一场比赛，三辆车都有亚硝酸盐助推。我选择让 Nitrous 成为界面。您可以在我的代码中看到我尝试了不同的方法来使其工作并且 none 已经成功。我什至不知道我是否接近或远离如何做到这一点。

Answer 1

接口仅提供蓝图，说明实现它的特定 class 可以做什么。给你一个具体的例子，考虑接口 Fruit.

public interface Fruit {

  void eat();

}

现在，实例化接口没有意义，因为它只是一个抽象。但是，实际创建 class Banana 或 Apple 的对象是有意义的。而且这些都是水果，你可以吃。

for (Fruit f : fruits) {
  f.eat();
}

由于您的 Vehicle class 实现了 Nitrous，它的所有子 class 也可以分配给该特定类型，并且它们履行其合同，这是 nos().

Ford mustang = new Ford("Mustang", 135, 125);

Nitrous asNitrous = mustang; // works
mustang.nos(); // works

相关：What is the definition of an interface in object oriented programming?

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