Common Mechanisms

通用機(jī)制

The UML is made simpler by the presence of four common mechanisms that apply throughout the language: specifications, adornments, common divisions, and extensibility mechanisms. This chapter explains the use of two of these common mechanisms: adornments and extensibility mechanisms.

通過(guò)4個(gè)通用機(jī)制使得UML更簡(jiǎn)單，它們將利用遍及這門(mén)語(yǔ)言：詳述，修飾，公共部份和擴(kuò)大機(jī)制．這章講授其中兩個(gè)通用機(jī)制的用法：修飾和擴(kuò)大機(jī)制．

Notes are the most important kind of adornment that stands alone. A note is a graphical symbol for rendering constraints or comments attached to an element or a collection of elements. You use notes to attach information to a model, such as requirements, observations, reviews, and explanations.

備注是最重要的1類(lèi)修飾，需要單獨(dú)說(shuō)明．1個(gè)備注是1個(gè)表達(dá)束縛或是為1個(gè)元件或是1個(gè)元件集合附加注釋的圖形符號(hào)．你使用備注為1個(gè)模型附加信息，如需求，資料，回顧和說(shuō)明．

The UML’s extensibility mechanisms permit you to extend the language in controlled ways. These mechanisms include stereotypes, tagged values, and constraints. A stereotype extends the vocabulary of the UML, allowing you to create new kinds of building blocks that are derived from existing ones but that are specific to your problem. A tagged value extends the properties of a UML stereotype, allowing you to create new information in that element’s specification. A constraint extends the semantics of a UML building block, allowing you to add new rules or modify existing ones. You use these mechanisms to tailor the UML to the specific needs of your domain and your development culture.

UML的擴(kuò)大機(jī)制允許你在可控的方式內(nèi)擴(kuò)大這門(mén)語(yǔ)言．這些機(jī)制包括模式化，標(biāo)簽值和束縛．1個(gè)模式化是擴(kuò)大UML的辭匯表，允許你從已存在的辭匯中提取，專(zhuān)門(mén)針對(duì)你的問(wèn)題創(chuàng)建1個(gè)新的構(gòu)建塊，1個(gè)標(biāo)簽值擴(kuò)大UML模式化的特性，允許你在那個(gè)元素的規(guī)則以?xún)?nèi)創(chuàng)建1個(gè)新的信息．1個(gè)束縛擴(kuò)大UML構(gòu)建塊的語(yǔ)義，允許你增加新的規(guī)則或是修改現(xiàn)有的規(guī)則．你使用這些機(jī)制來(lái)剪裁UML以適應(yīng)你的領(lǐng)域和你的開(kāi)發(fā)習(xí)慣的需要．