OCL对类A的操作和类B的属性的写约束 [英] OCL write constraint on an operation of class A and attribute of class B

问题描述

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我想知道OCL是否允许以下​​操作.

I would like to know if OCL allows the following.

想象一下下面的UML图.

Imagine the following UML diagram.

如何使用ocl建模:只有当他来自国家名称'ABCD'且该国家的人口> = 1000000时，他才能喝Water()"

How to use ocl to model: "a person can drinkWater() only if he is from country name 'ABCD'" AND if the population of the country is >= 1000000"

当然，这个例子纯粹是虚构的.

Of course, the example is purely fictive.

================                  ================
|    Person    |                  |    Country   |
|--------------|                  |--------------|
|- name        |------------------|- id          |
|- age         |                  |- name        |
|--------------|                  |- population  |
|+ drinkWater()|                  ================
|+ drinkBeer() |                  
================                   

推荐答案

您将需要命名Country的角色(在Person中创建一个命名属性).因此，我们将其命名为country.当然可以照常使用":

You will need to name the role of Country (create a named attribute inside Person). So let's name that country. This of course can be used "as usual":

context Person::drinkWater()
pre Enough: self.country.name == "ABCD" and self.country.population >= 1000000

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