Java抽象类或静态实用程序类设计选择 [英] Java Abstract Class or Static Utility Class Design Choice

问题描述

我正在实施一些策略（策略模式），这些策略有一些共同的行为，假设我有1个上下文和3个策略，策略中使用的一些操作是共享的，有些只需要2个其他只是其中的1个策略。

没有共享成员级别的状态，因此唯一的操作是无效的。

操作的意图是支持将状态格式化为文件，如视图助手。

选项1：制作一个AbstractStrategy类

• 我正在使用Java，这样立即
  将在
  的未来中使用此功能。


• 继承会导致。
  在山脊结构中。


• 操作将是最终的。

选项2：创建一个Util类的静态帮助器

• 灵活，但由于某种原因感觉到代码气味


• 不成立。

任何建议或偏好？

注意我正在工作的级别是策略级别，而不是上下文级别（见维基百科链接）。

解决方案

有一个原因...一个巨大的原因...在抽象类或接口上使用静态Util类。

所以你可以在以后添加更多的方法。

使用抽象类或接口，您对该类/接口的任何更改都必须在所有类中更改从它继承。如果您正在编写一个公共API，这是特别有问题的。

Java框架具有遍历整个静态方法的util类。最着名的是在 java.util 包： 集合 和 数组 。

I am implementing a few strategies (Strategy Pattern) which have some common behavior and am undecided where the common operations should live.

• Assuming I 1 context and 3 strategies, some of the operations used in the strategies are shared, some are needed only by 2 others just be 1 of the strategies.
• There is no member level state shared, therefore the only operations are effectively stateless.
• The intention of the operations are to support the formatting of state to a file, like a view helper.

Option 1: Make an AbstractStrategy class

• I'm using Java so this immediately takes away using this feature in the future.
• Inheritance tends to result. in a ridge structure.
• Operations would be final.

Option 2: Create a Util class of static helpers

• Flexible, but feels like a code smell for some reason.
• Not ridged.

Any recommendations or preferences?

Note the level I am working at is the Strategy level, not the Context level (see wikipedia link).

解决方案

There is one reason... one huge reason... to use a static Util class over an abstract class or interface.

So you can add more methods at a later date.

With an abstract class or interface, any change you make to that class/interface has to be changed in all classes that inherit from it. This is especially problematic if you're writing a public API.

The Java framework has util classes with static methods scattered throughout. The most well known ones are in the java.util package: Collections and Arrays.

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