Java接口(interface)与实现类中的构造函数

Question

我有一个关于接口(interface)的相当基本的问题，我也是个新手。我通常会使用重载的构造函数实例化我的类。我现在尝试使用接口(interface)并想知道如何填充我的构造函数。我是否可以在界面中使用类似 setSomeMethod(arguement1, argument2) 的东西来填充我的属性？

我还想指出，我正在使用带有服务注入(inject)的“Tapestry5”框架。示例

public class Main {

    @Inject
    private Bicycle bicycle;

    public Main() {
         //Not sure how to pass constructor variables in
         this.bicycle();
    }

}

界面

public interface bicycle {
   public void someMethod(String arg1, String arg2);
}

实现类

public class MountainBike implements bicycle {

   private String arg1;

   private String arg2;

   public MountainBike() {
       //Assuming there is no way to overload this constructor
   }

   public void someMethod(String arg1, String2 arg2) {
       this.arg1 = arg1;
       this.arg2 = arg2;
   }

} 

那么你如何处理扩展类呢？我不确定如何填充扩展类构造函数。

public class MountainBike extends BicycleParts implements bicycle {

   private String arg1;

   private String arg2;

   public MountainBike() {
       //Assuming there is no way to overload this constructor
       //Not sure where to put super either, but clearly won't work here. 
       //super(arg1);            
   }

   public void someMethod(String arg1, String2 arg2) {
       this.arg1 = arg1;
       this.arg2 = arg2;
       //Assuming it doesn't work outside of a constructor, so shouldn't work 
       //here either.   
       //super(arg1);
   }

} 

public class BicycleParts {

    private String arg1;

    public void BicycleParts(String arg1) {
        this.arg1 = arg1;
    }

}

提前致谢。

Answer 1

首先，您的 bicycle 方法应该使用返回类型声明:

public void someMethod(String arg1, String arg2);

接口(interface)定义了方法的契约，而不是对象的实例化方式。他们还可以定义静态变量。

要在 MountainBike 构造函数中使用 someMethod，您可以在构造函数中进行调用:

public MountainBike(String arg1, String arg2) {
   someMethod(arg1, arg2);
}

Wrt，关于扩展类的问题，super 语句必须作为构造函数中的第一个语句出现，即:

public class MegaMountainBike extends BicycleParts implements bicycle {

   public MegaMountainBike() {

      super("Comfy Saddle");
      // do other stuff
   }