Java 如何在 UML 类图中表示回调

How to represent Callback in UML Class Diagram

提问by Nandhan

I have an Interface say

我有一个接口说

Interface ICallback {
    public void informFunction();
}

I have a Class say:

我有一个班级说：

Class Implementation implements ICallback {

   public Implementation() {
      new AnotherImplementation(this);
   }

   @override
   public void informFunction() {
      // do something
   }

}

Now consider a class where in the instance of Class Implementation is passed as a interface and is used to make a callback.

现在考虑一个类，其中在类实现的实例中作为接口传递并用于进行回调。

Class AnotherImplementation {
   public ICallback mCallback;

   public AnotherImplementation(ICallback callback) {
      mCallback = callback;
   }

   public void testFunction() {
     mCallback.informFunction();  // Callback
   }
}

Now I want to know how I can design a UML Class Diagram. Most importantly I need to know how to represent Callback Functionality that will happen in the Class AnotherImplementation :: testFunction().

现在我想知道如何设计 UML 类图。最重要的是，我需要知道如何表示将在 AnotherImplementation :: testFunction() 类中发生的回调功能。

采纳答案by nakosspy

Your code is represented in the following class diagram:

您的代码在以下类图中表示：

It represents the relationships between the classes:

它表示类之间的关系：

• Implementationimplements ICallback
• Implementationdepends on AnotherImplementation(it creates one in its constructor)
• AnotherImplementationhas a ICallback(named mCallback)

• Implementation工具 ICallback
• Implementation取决于AnotherImplementation（它在其构造函数中创建一个）
• AnotherImplementation有一个ICallback（名为 mCallback）

A class diagram does not represent method functionality. Method functionality is visualized with a sequence or a Collaboration diagram.

类图不表示方法功能。方法功能通过序列或协作图进行可视化。

In your example, the sequence diagram for testFucntion()is very simple:

在您的示例中，序列图testFucntion()非常简单：

Note that the Implementationclass does not show in the sequence diagram. This happens because the mCallbackmember is declared as ICallback. It could be anything that implements the ICallbackinterface.

请注意，Implementation该类未显示在序列图中。发生这种情况是因为该mCallback成员被声明为ICallback. 它可以是任何实现ICallback接口的东西。

I think that the more interesting question is how to visualize the method that triggers the callback. You don't mention which method of Implementationcalls the testFunction()of AnotherImplementation, so I guess that this happens inside the constructor of Implementation. I created the following sequence diagram for this constructor:

我认为更有趣的问题是如何可视化触发回调的方法。你没有提到Implementation调用testFunction()of 的哪个方法AnotherImplementation，所以我猜这发生在Implementation. 我为此构造函数创建了以下序列图：

Here you can see:

在这里你可以看到：

1. Implementationcreates the AnotherImplementation
2. Implementationinvokes testFunctionon AnotherImplementation
3. AnotherImplementationinvokes informFunctionon Implementation

1. Implementation创建 AnotherImplementation
2. Implementation所调用testFunction的AnotherImplementation
3. AnotherImplementation所调用informFunction的Implementation