UML的基础元件之架构元件(一)


Structural Things
Structural things
are the nouns of UML models. These are the mostly static parts of a model, representing elements that are either conceptual or physical. Collectively the
structural things are called classifiers.

架构元件是UML模型的名称．它们是模型最静态的部分，体现的是概念上的元素或物理上的元素．架构元件统称为分类器．

A
class is a description of a set of objects that share
the same attributes, operations, relationships, and semantics. A class
implements one or more interfaces.　Graphically, a class is rendered as a rectangle, usually including its name, attributes, and operations,

类描述对象集，对象集拥有同样的属性，操作，关联和语义．类实现一个或更多的接口．类生动地以一个矩形框呈现，通常包含它的名称，属性和操作．

An
interface is a collection of operations that specify
a service of a class or component. An interface therefore describes the externally visible behavior of that element. An interface might represent the complete behavior of a class or component or only a part of that behavior. An interface defines a set of operation
specifications (that is, their signatures) but never a set of operation implementations. The declaration of an interface looks like a class with the keyword <<interface>> above the name; attributes are not relevant, except sometimes to show constants. An interface
rarely stands alone, however. An interface provided by a class to the outside world is shown as a small circle attached to the class box by a line. An interface required by a class from some other class is shown as a small semicircle attached to the class
box by a line.

接口是操作的集合，用来列举类或者组件提供的服务．因为接口描述元素对外可见的行为．接口也许表现类或组件的完整行为，或者仅表现它们的部分行为．接口只定义一组操作的规格(即它们的特征)，而不会定义这组操作怎么实现．接口的声明与类相似，只是在名称上面多了一个<<接口>>标识；除了有时显示常量外，没有相关的属性．而且接口很少单独画出，通常还需要画出接口的输入与输出，类的输出接口由一个小圆圈将类与外部世界相连．类的输入接口由一个小半圆与其它类相连．