英文:
Java instantiating a generic type which implements an interface
问题
我在学习Java中的面向对象编程（OOP）概念和内部类时有一个问题。
假设有一个名为CarFactory的类，它有一个buildCar()方法，返回一个Car。这个工厂会构建几个实现了Car接口的Models。
因此，我创建了一个Car接口，然后Models实现了Car接口。
如何返回一个是接口Car的Car对象？
我知道我可以实例化一个实现了Car接口的Model，但我想创建一个通用的方法，返回任何实现了Car接口的Model。
CarFactory.java
public class CarFactory {
Car buildCar() {
return new Car(); // ??? 我不能这样做
}
}
Car.java
public interface Car {
abstract class Construct {
abstract void constructCar();
}
void turn();
void stop();
void accelerate();
// ...
}
ModelExample.java
public class ModelExample implements Car {
static CarFactory factory;
public ModelExample() {
this.factory = new CarFactory();
}
class Construct extends Car.Construct {
void constructCar() {
System.out.println("Model Example constructed");
}
}
}
英文:
I got a question while studying OOP concept and inner classes in Java.
Let's say there is a class CarFactory, and it has buildCar() method that returns a Car. This factory builds several Models that implement a Car.
Therefore, I made a Car interface and the Models implement Car.
How can you return a Car that is an interface?
I know that I can instantiate a Model that implements a Car, but I want to make a general method that returns any Model that implements a Car.
CarFactory.java
public class CarFactory {
Car buildCar() {
return new Car(); // ??? I cannot do this
}
}
Car.java
public interface Car {
abstract class Construct {
abstract void constructCar();
}
void turn();
void stop();
void accelerate();
...
}
ModelExample.java
public class ModelExample implements Car {
static CarFactory factory;
public ModelExample() {
this.factory = new CarFactory();
}
class Construct extends Car.Construct {
void constructCar() {
System.out.println("Model Example constructed");
}
}
}
答案1
得分: 0
在Java中，您不能初始化接口。我建议您学习抽象工厂设计模式。
针对您的情况，您需要一个名为AbstractCarFactory的接口，其中包含一个名为buildCar的方法。然后，您可以为每种类型的汽车创建AbstractCarFactory的子类。
英文:
In Java, you cannot initialize interfaces. I suggest you study the Abstract Factory design pattern.
For your case, you would need an interface AbstractCarFactory, which contains a method Car buildCar. You can then create subclasses of the AbstractCarFactory for each type of car.
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