UML基本架构建模--类的辅助信息.doc

Organizing Attributes and Operations 组织属性和操作 When drawing a class, you don’t have to show every attribute and every operation at once. In fact, in most cases, you can’t (there are too many of them to put in one figure) and you probably should not (only a subset of these attributes and operations are likely to be relevant to a specific view). For these reasons, you can elide a class, meaning that you can choose to show only some or none of a class’s attributes and operations. You can indicate that there are more attributes or properties than shown by ending each list with an ellipsis (“...”). You can also suppress the compartment entirely, in which case you can’t tell if there are any attributes or operations or how many there are. 在你画类的时候，不需要同时显示每个属性和每个操作．事实上，大多数情况下，你不能(有太多要放到一个图里)　也不想(只有一部分属性和操作似乎与指定的视图相关)这么做．由于这个原因，你可以省略一个类，这意味着你可以选择不显示或只显示类的部分属性或操作．你可以在列表末尾用一个省略号指示出更多的属性或操作．在说不清是否有属性或操作，也不知道它们有多少个的这种情况下．你也可以完全限制分隔栏． To better organize long lists of attributes and operations, you can also prefix each group with a descriptive category by using stereotypes, as shown in Figure 4-7. 比组织一长串的属性和操作列表更好的方法是，你可以通过使用模式化为每一个描述性的类别组加前缀，如图４－７显示的那样． Responsibilities 职责 A responsibility is a contract or an obligation of a class. When you create a class, you are making a statement that all objects of that class have the same kind of state and the same kind of behavior. At a more abstract level, these corresponding attributes and operations are just the features by which the class’s responsibilities are carried out. A Wall class is responsible for knowing about height, width, and thickness; a FraudAgent class, as you might find in a credit card application, is responsible for processing orders and determining if they are legitimate, suspect, or fraudulent; a TemperatureSensor class is responsible for measuring temperature and raising an alarm if the temperature reaches a certain point. 职责是一个类的契约或是义务．当你创建一个类时，你正在声明类的所有对象所拥有的一种状态和一种行为．在更抽象的层面里，类的职责被执行后显示出来的特征就是所对应的属性和操作．一个墙类的职责目的是了解