使用Java中的接口和组合 – 使用不同变量重用代码

huangapple
go评论109阅读模式
英文:

using interface and composition in java - reuse code with different variables

问题

我在尝试重用代码时遇到了问题。
我想使用主接口和两个类，但其中一些方法具有相同的实现，因此我决定使用组合。
我的意思是，声明“a”类的实例并在方法上执行：

  1. void do_some()
  2. a.do_some()

问题是与一些数据成员相关的函数。
例如：

  1. public class Locker implements GeneralStorage {
  2.     private final int current_capacity;
  4.     public int getAvailableCapacity() {
  5.         return current_capacity;
  6.     }
  7. }
  9. public class LongTermStorage implements GeneralStorage {
  10.     private final int current_capacity;
  11.     private Locker locker = new Locker();
  13.     public int getAvailableCapacity() {
  14.         return locker.getAvailableCapacity();
  15.     }
  16. }

我应该怎么办？（我想返回LongTermStorage.current_capacity）

英文:

I have a problem during trying to do reuse code.
I want to use main interface with two classes, but some of the methods have same implements, so I decided to use compostion.
I mean, to declare instance of the "a" class and do on the method:

  1. void do_some()
  2. a.do_some()

the problem is that the function related to some data members.
for example:

  1.  public class Locker implements GeneralStorage {
  2.     private final int current_capacity;
  4.   public int getAvailableCapacity(){
  5.         return current_capacity;
  6.       }
  7. }
  9. public class LongTermStorage implements GeneralStorage {
  10.     private final int current_capacity;
  11.     private Locker locker=New Locker();
  12.        public int getAvailableCapacity(){
  13.            return locker.getAvailableCapacity

what can I do? (I want to return LongTermStorage.current_capacity)

答案1

得分: 0

你可以这样做，但最好在构造函数中为组合创建一个实例。代码如下所示：

  1. public class Locker implements GeneralStorage {
  2.   private final int current_capacity;
  4.   public int getAvailableCapacity(){
  5.     return current_capacity;
  6.   }
  7. }
  9. public class LongTermStorage implements GeneralStorage {
  10.   private Locker locker;
  12.   public LongTermStorage() {
  13.     locker = new Locker();
  14.   }
  16.   public int getAvailableCapacity(){
  17.     return locker.getAvailableCapacity();
  18.   }
  19. }

这样，你将重用 Locker 类的方法和属性。

英文:

You can do so, but it'd be better if you create an instance for composition at your constructor. So it would be like this:

  1. public class Locker implements GeneralStorage {
  2.   private final int current_capacity;
  4.   public int getAvailableCapacity(){
  5.     return current_capacity;
  6.   }
  7. }
  9. public class LongTermStorage implements GeneralStorage {
  10.   private Locker locker;
  12.   public LongTermStorage() {
  13.     locker = new Locker();
  14.   }
  16.   public int getAvailableCapacity(){
  17.     return locker.getAvailableCapacity();
  18.   }
  19. }

So, you will reuse Locker methods and also its props.

答案2

得分: 0

如果LongTermStorage是一种特殊类型的储物柜（Locker），你可以使用继承，让LongTermStorage 继承自 Locker。这样，你只需要实现那些不同的方法：

  1. public class LongTermStorage extends Locker {
  2.     // 无需实现 getAvailableCapacity()，因为从 Locker 继承的已经适用
  4.     // TODO: 实现其他 LongTermStorage 特定的功能
  5. }

隐式地，LongTermStorage 也实现了 GeneralStorage 接口，因此你可以在任何需要使用 GeneralStorage 的地方使用它。

英文:

If LongTermStorage is a special kind of Locker you can use inheritance and let LongTermStorage extend from Locker. This way you only have to implement the methods which are different:

  1. public class LongTermStorage  extends Locker {
  2.     // No need to implement getAvailableCapacity() as the one from Locker is fine
  4.     // TODO: implement other stuff specific for LongTermStorage
  5. }

Implicitly LongTermStorage also implements the GeneralStorage interface so you can use it wherever you want to use GeneralStorage

答案3

得分: 0

我不太了解Java，但请按照上面的建议进行修改：

  1. interface GeneralStorage {
  2.     void addProduct(Product product);
  3.     void removeProduct(Product product);
  4.     void close();
  5. }
  7. public class Locker implements GeneralStorage {
  8.   private Product[] products;
  10.   public void addProduct(Product product) {...};
  11.   public void removeProduct(Product product) {...};
  12.   public void close() {...};
  13. }
  15. public class LongTermStorage implements GeneralStorage {
  16.   private GeneralStorage storage;
  18.   public LongTermStorage(GeneralStorage storage) {
  19.     this.storage = storage;
  20.   }
  22.   public void addProduct(Product product) {
  23.     // some kind of logic
  24.     storage.addProduct(product);
  25.   }
  26.   public void removeProduct(Product product) {...};
  27.   public void close() {...};
  28. }
  30. GeneralStorage storage = new LongTermStorage(new Locker());

不要在构造函数中调用new来将LongTermStorage与Locker耦合在一起。

英文:

I don't know Java well, but do this instead of what was recommended above:

  1. interface GeneralStorage {
  2.     void addProduct(Product product);
  3.     void removeProduct(Product product);
  4.     void close();
  5. }
  7. public class Locker implements GeneralStorage {
  8.   private Product[] products;
  10.   public void addProduct(Product product) {...};
  11.   public void removeProduct(Product product) {...};
  12.   public void close() {...};
  13. }
  15. public class LongTermStorage implements GeneralStorage {
  16.   private GeneralStorage storage;
  18.   public LongTermStorage(GeneralStorage storage) {
  19.     this.storage = storage;
  20.   }
  21.   
  22.   public void addProduct(Product product) {
  23.     // some kind of logic
  24.     storage.addProduct(product)
  25.   };
  26.   public void removeProduct(Product product) {...};
  27.   public void close() {...};
  28. }
  30. GeneralStorage storage = new LongTermStorage(new Locker())

Don't couple LongTermStorage to Locker by calling new in the constructer.

huangapple
  • 本文由 发表于 2020年9月23日 20:03:00
  • 转载请务必保留本文链接：https://go.coder-hub.com/64027532.html
  • composition
  • design-patterns
  • interface
  • java
  • oop
匿名

发表评论

匿名网友

:?: :razz: :sad: :evil: :!: :smile: :oops: :grin: :eek: :shock: :???: :cool: :lol: :mad: :twisted: :roll: :wink: :idea: :arrow: :neutral: :cry: :mrgreen:

确定