共享一个场法

Question

类

我有对象 类现在我想从我怎样才能避免重新创建方法，只是容器类

class Container 
{ 
    Box box1 = new Box(); 
    Toy toy1 = new Toy(); 
    public void open() 
    { 
     box1.open(); 
    } 
    public void play() 
    { 
     toy1.play(); 
    } 
} 

外面打电话从盒和玩具对象的功能与Container类共享方法。 我不能使用继承，因为我有2个或更多的对象。

Answer 1

你可以这样做，如下所示。

public interface ToyInterface { 
    public void play(); 
} 

public class Toy implements ToyInterface { 
    @Override 
    public void play() { 
     System.out.println("Play toy"); 
    } 
} 

public interface BoxInterface { 
    public void open(); 
} 

public class Box implements BoxInterface { 
    @Override 
    public void open() { 
     System.out.println("open box"); 
    } 
} 

public class Container implements ToyInterface, BoxInterface { 
    private BoxInterface box; 
    private ToyInterface toy; 

    public Container() { 
     box = new Box(); 
     toy = new Toy(); 
    } 

    public BoxInterface getBox() { 
     return box; 
    } 

    public ToyInterface getToy() { 
     return toy; 
    } 

    @Override 
    public void play() { 
     System.out.println("play container"); 
     this.toy.play(); 
    } 

    @Override 
    public void open() { 
     System.out.println("open container"); 
     this.box.open(); 
    } 
} 

然后，您可以访问Container和Box之外的方法。

Container container = new Container(); 
container.open(); 
container.getBox().open(); 

container.play(); 
container.getToy().play(); 

Answer 2

做这样的：

main或究竟在哪儿你初始化Container同时通过对象它

public static void main(String args[]){ 
    Box box1 = new Box(); 
    Toy toy1 = new Toy(); 
    Container c = new Container(box1, toy1); 
    box1.open(); 
    toy1.play(); 
    //or pass both object where ever you want without recreating them 
} 

class Container { 
    Box box1 = new Box(); 
    Toy toy1 = new Toy(); 

    public Container(Box box1, Toy toy1){ 
     this.box1 = box1; 
     this.toy1 = toy1; 
    } 
} 

UPDATE：现在按照你的需要以下解决方案，但我也不喜欢这样做：

class Container 
{ 
    public Box box1 = new Box(); // should not be public but as your needs 
    public Toy toy1 = new Toy(); // should not be public but as your needs 
} 
container.box1.open(); 
container.toy1.play();