外文翻譯--軟件體系結(jié)構(gòu)的現(xiàn)狀及發(fā)展方向

1、<p><b>　　英文原文</b></p><p>　　The current situation of the system structure of the software and developing direction</p><p>　　In the article of " concept of system structure o

2、f the software ", we speak of from the crisis of the software, have explained origin , defines and the function in the project of the software is developed of the system structure of the software. Then, how is the c

3、urrent situation of the system structure of software at present? What is the development trend of the system structure of software? This is the content that this text will introduce. At present, in the system structure o

4、f the software i</p><p>　　Since later stage of 1990s, the research of the system structure of the software has become a focus . The masses of software worker realize software system great meaning and it that

5、 structure study design the importance developed to the software system already, have launched a lot of research and practice work.</p><p>　　Is it watch to come by system current situation that structure stu

6、dy from software, present research and to software system description of structure, come to say to still stay on the basis of the thing that it is not formalized to a great extent. Teacher , framework of software , lack

7、essential tool still, the tool should explicit describe, have formalized tool of independent character.</p><p>　　At present among the in common use software development approach, it is it use formalized pict

8、ure and text non- usually to describe, can't describe the interface between the components of existence that the system expects , can't describe the meaning of different systematic association relation of composi

9、tion . Difficult to understand developer , let alone use for analysing its characteristics , such as consistency and integrality ,etc..is studied Component of system nearly by one when describin</p><p>　　Sof

10、tware system structure is it remain in formalized block diagram stage non- only to study, it has been already difficult to meet the needs of further development. For support based on system structure development , need f

11、ormalized modeling symbol , system analysis and developing instrument that structure prove. Is it watch to come from software system current situation that structure study, in field this there are progress recently, a re

12、presentative one Mellon of American Carnegie university a</p><p>　　Study primary problem of the system structure of the software is how to express the system structure of the software, namely what system str

13、ucture modeling to the software. According to the difference of emphasis points of modeling , can divide the model of the system structure of the software into 5 kinds : Structure model, frame model, dynamic model, cours

14、e model and function model. In these 5 models, the most frequently used one is the structure model and dynamic model.</p><p>　　This is a most ocular , most general modeling method . The method portray the st

15、ructure with system component , attachment and other concepts of structure, and is it is it reflect important semanteme content of system to come through structure to try hard, including systematic disposition , restrain

16、t , implicit assumed conditions , style , nature . The core to study structure model is that the system structure describes languages.</p><p>　　The frame model is similar to structure model, but it does not

17、lay particular emphasis on describing the detail of the structure and laying particular emphasis on the structure of the whole even more very much. Frame model regard some special problems as goal set up only mainly to m

18、eet structure of question this.</p><p>　　Dynamic model to structure or frame supplement of model , study behavior nature of " big particle " of system. For example, describe systematic deconfigurat

19、ion or evolution. The trends may mean the disposition , setting-up of the systematic ensemble architecture or remove the course of the communication passway or calculation . This kind of system is often encouraging type.

20、</p><p>　　Study the step and course with systematic structure in course model. Therefore the structure is a result of following some course scripts.</p><p>　　Model this think system structure to

21、 make up by one group function component according to the level, the lower floor provides service to the upper strata . It can be regarded as a kind of special frame model. Having their own strong points each in these 5

22、kinds of models, perhaps unify 5 kinds of models together organically, form one intact model it comes to be system structure suitable to portray software. For example Kruchten propose one visual angle model of " 4+1

23、 " in 1995. " 4+1 " model inc</p><p>　　end user:Function requirementprogrammer:SoftWare Management</p><p>　　system integrated person:capability extending 、thuoughput </p>

24、<p>　　etc.. system process person:system topology、installtion、communication etc..</p><p>　　" 4+1 " model is as Fig.</p><p>　　Software development model cross over whole software

25、 system develop, operate, all work and structure frame of task implemented to maintain of life cycle, provide the relation that software development moves about between every stages. At present, the common software devel

26、opment model can roughly be divided into three kinds: </p><p>　　Waterfall model if the demand of the software is totally confirmed .</p><p>　　Progressive development model adopted when software

27、development can only offer the basic demand at initial stage, for instance spiral model ,etc.. </p><p>　　Based on formalization development approach to vary models.</p><p>　　All development appr

28、oaches are to solve the demand and disparity while realizing. But three software development model of kind these there are all kinds of defects , can't well support the development course based on system structure of

29、 the software . So, researchers have done certain work in developing the software development model based on system structure. For example, in order to express the life cycle of the system structure vividly, Zhou YingXin

30、 Dr. of Beijing University of Post & Telecom</p><p>　　Software system development of structure large-scale software key link that system develops . The system structure has essential function in the deve

31、lopment of the production line of the software, in producing , because of same software system structure , can is it have different a lot of system of function to establish in the development. Share system structure and

32、a group of reusable components between the software product clans, can increase the soft project and reduce developing and safeguar</p><p>　　At present, the system structure is still a very new research fiel

33、d, its concept is still quite fuzzy . But software system structure regard as soft project a component of field, having already obtained considerable development, the ones that have been designed with researchers by most

34、 software systems are paid attention to. Whether software system structure active research direction include at present. (1)Research of the system structure form foundation of the software; (2)Study the new special</p

35、><p>　　In between software engineer and software description and understanding ability of system of raising, though the system structure of the software describes that plays an important role, these abstract de

36、scription is usually non- formalized and random one. System structural design frequently difficult to understand , difficult to is it carry on formalized analysis and simulation to suitable for, lack corresponding suppor

37、t tool help framework teacher finish the design work. For solve the problem, </p><p>　　ADL is this language, the systematic framework teacher can exploit the characteristic offered by its institute and carry

38、 on the systematic concept system structure modeling of the software . ADL has offered the concrete grammar and portrayed the concept frame of the system structure. ADLs makes the systematic developer able to well descri

39、be the system structure that they design, in order to exchange with people , can analyse a lot of instances with the tool that is offered .</p><p>　　The purpose of this kind of description language is to off

40、er a kind of standardized system structure to describe, thus make the automation of the system structure analyse that is possible. Researchers have already designed nearly 20 kinds of ADLs, the more powerful one is C2 ,

41、UniCon , MetaH , Aesop , SADL , Rapide , Wright ,etc.. Language these can go on to system structure connector the first abstract, at the same time , still can describe the reciprocation between the structure of the model

42、 a</p><p>　　Work of in this respect to obtain of different system structure principle , arrangement and classification of mode among software development practice software engineer mainly. For example to sof

43、tware system structure classification and comparison of style , describe to the system structure that the synthesis of the language is analysed etc.. So far as at present, domestic study on system structure of the softwa

44、re concentrate on to software system arrangement of special knowledge of structure ma</p><p>　　Recently , develop specific field is it offer for products reusable frame pay close attention to the thing day b

45、y day to go. Develop it because of such an idea in these: Can draw common respect of relevant system, in order to can through low to afford to become copy. The common example has: </p><p>　　The standard of t

46、he compiling device is resolved . This method can make an undergraduate construct a new language compiling system within one term . </p><p>　　Standardized communication agreement. This piece can make produce

47、r through in to is it drive each other to provide service on being abstract different levels. </p><p>　　The fourth generation of language. Utilize 4GL to develop the normal form in common use of commercial i

48、nformation processing. </p><p>　　Software system structure make one understand systematic component and frame of the relation between the they, especially those attribute of crossing over time and realizing

49、all the time. This piece understand and systematic synthesis very much necessary future to now systematic analysis. Under analysing and supporting, the system structure catches domain knowledge and real unanimity, promot

50、e the implementation of the assessment and component designed, reduce emulation and construct the prototyp</p><p>　　Is it make system structure design of magnitude understand , realize better to show to syst

51、em formalization of reasoning of structural design. Purpose of it some experience and method of design come out to summarize summarize , summarize in the course of practising to designer, structure of system,, thus form

52、a formalized description , form certain theoretical foundation (in order to replace the present research not accurate). Propose some formalized mechanism already, course algebra for instanc</p><p>　　Predict

53、the quality of the software through analysing, establish , choose , assess the system structure different from comparing through analysing. For example, ATAM (Architectural Tradeoff Analysis Method ) method that Kazman ,

54、etc. were put forward in 2000. ATAM method can announce how about structure satisfied with the specific quality demands system (such as the performance and alterability), and has offered the method to analyse reciprocati

55、on between the quality demand. Use ATAM method appra</p><p>　　Existing ADLs mostly correlate with field , is unfavorable to the explanation to different domain system structure. But these ADLs to different f

56、ieldses are very much the same in some aspects, cause the redundancy of resources. In fact, most ADLs common concepts with a series of. How stand up synthetically with one public form various kinds of language, is it can

57、 exchange various kinds of system structure describe message to make, it will be the system structure research of the software and one </p><p>　　Software system structural design since as a part of soft proj

58、ect, computer of it auxiliary to realize means quite important. We should develop some software tool is it realize system description of structure and analyse to come, the developing stage changes tools, the automatic co

59、nversion of the achievement by realizing stage, for example, change demand specifications into component wait for automatically. Little about research results of this at present, can apply to actual project develop too&l

60、t;/p><p>　　Software scale of system become more and more heavy nowadays, have more and more more complicated structures even, the large quantity of system structured from scratch at the same time is reducing sh

61、arply, therefore a lot of are leaving over the system and is being utilized progressively . From leave over systems soft ware code and system collect structure information , through describe , unify , not abstract , vagu

62、e generalization punish with instance ,etc., can summarize the systematic system </p><p><b>　　中文譯文</b></p><p>　　軟件體系結(jié)構(gòu)的現(xiàn)狀及發(fā)展方向</p><p>　　在《軟件體系結(jié)構(gòu)的概念》一文中，我們從軟件危機(jī)談起，闡述了軟件體系

63、結(jié)構(gòu)的起源、定義及其在軟件項(xiàng)目開發(fā)中的作用。那么，目前軟件體系結(jié)構(gòu)的現(xiàn)狀如何呢？軟件體系結(jié)構(gòu)的發(fā)展趨勢又是什么呢？這就是本文要介紹的內(nèi)容。</p><p>　　目前，軟件體系結(jié)構(gòu)尚處在迅速發(fā)展之中，越來越多的研究人員正在把注意力投向軟件體系結(jié)構(gòu)的研究。用于對軟件體系進(jìn)行規(guī)格描述的模型、標(biāo)記法和工具仍很不正規(guī)。盡管這些不正規(guī)的模型是有用的，為使之更為精確和健壯，在很多方面的研究工作還需要繼續(xù)進(jìn)行。 </p&g

64、t;<p>　　關(guān)于軟件體系結(jié)構(gòu)的研究工作主要在國外展開的，國內(nèi)到目前為止對于軟件體系結(jié)構(gòu)的研究尚處在起步階段。軟件體系結(jié)構(gòu)在國內(nèi)未引起人們廣泛注意的原因主要有兩點(diǎn)： </p><p>　　軟件體系結(jié)構(gòu)從表面上看起來是一個老話題，似乎沒有新東西。</p><p>　　與國外相比，國內(nèi)對大型和超大型復(fù)雜軟件系統(tǒng)開發(fā)的經(jīng)歷相對較少，對軟件危機(jī)的災(zāi)難性體會沒有國外深刻，因而對軟件體

65、系結(jié)構(gòu)研究的重要性和必要性的認(rèn)識還不很充分。</p><p>　　自20世紀(jì)90年代后期以來，軟件體系結(jié)構(gòu)的研究成為一個熱點(diǎn)。廣大軟件工作者已經(jīng)認(rèn)識到軟件體系結(jié)構(gòu)研究的重大意義和它對軟件系統(tǒng)設(shè)計(jì)開發(fā)的重要性，開展了很多研究和實(shí)踐工作。 </p><p>　　從軟件體系結(jié)構(gòu)研究的現(xiàn)狀來看，當(dāng)前的研究和對軟件體系結(jié)構(gòu)的描述，在很大程度上來說還停留在非形式化的基礎(chǔ)上。軟件構(gòu)架師仍然缺乏必要的工具

66、，這種工具應(yīng)該是顯式描述的、有獨(dú)立性的形式化工具。</p><p>　　在目前通用的軟件開發(fā)方法中，其描述通常是用非形式化的圖和文本，不能描述系統(tǒng)期望的存在于構(gòu)件之間的接口，不能描述不同的組成系統(tǒng)的組合關(guān)系的意義。難以被開發(fā)人員理解，更不能用來分析其一致性和完整性等特性。</p><p>　　當(dāng)一個軟件系統(tǒng)中的構(gòu)件之間幾乎以一種非形式化的方法描述時，系統(tǒng)的重用性也會受到影響，在設(shè)計(jì)一個系統(tǒng)

67、結(jié)構(gòu)過程中的努力很難移植到另一個系統(tǒng)中去。對系統(tǒng)構(gòu)件和連接關(guān)系的結(jié)構(gòu)化假設(shè)沒有得到顯式的、形式化的描述時，把這樣的系統(tǒng)構(gòu)件移植到另一個系統(tǒng)中去將是有風(fēng)險的，甚至是不可能的。 </p><p>　　軟件體系結(jié)構(gòu)研究如果僅僅停留在非形式化的框圖階段，已經(jīng)難以適應(yīng)進(jìn)一步發(fā)展的需要。為支持基于體系結(jié)構(gòu)的開發(fā)，需要有形式化建模符號、體系結(jié)構(gòu)說明的分析與開發(fā)工具。從軟件體系結(jié)構(gòu)研究的現(xiàn)狀來看，在這一領(lǐng)域近來已經(jīng)有不少進(jìn)展，其

68、中比較有代表性的是美國卡耐基梅隆大學(xué)（Carnegie Mellon University）的Robert J．A11en于l997年提出的Wright系統(tǒng)。Wright是-種結(jié)構(gòu)描述語言，該語言基于一種形式化的、抽象的系統(tǒng)模型，為描述和分析軟件體系結(jié)構(gòu)和結(jié)構(gòu)化方法提供了一種實(shí)用的工具。Wright主要側(cè)重于描述系統(tǒng)的軟件構(gòu)件和連接的結(jié)構(gòu)、配置和方法。它使用顯式的、獨(dú)立的連接模型來作為交互的方式，這使得該系統(tǒng)可以用邏輯謂詞符號系統(tǒng)，而不

69、依賴特定的系統(tǒng)實(shí)例來描述系統(tǒng)的抽象行為。該系統(tǒng)還可以通過一組靜態(tài)檢查來判斷系統(tǒng)結(jié)構(gòu)規(guī)格說明的一致性和完整性。從這些特性的分析來說，Wright系統(tǒng)的確適用于對大型系統(tǒng)的描述和分析。</p><p>　　研究軟件體系結(jié)構(gòu)的首要問題是如何表示軟件體系結(jié)構(gòu)，即如何對軟件體系結(jié)構(gòu)建模。根據(jù)建模的側(cè)重點(diǎn)的不同，可以將軟件體系結(jié)構(gòu)的模型分為5種：結(jié)構(gòu)模型、框架模型、動態(tài)模型、過程模型和功能模型。在這5個模型中，最常用的是結(jié)構(gòu)

70、模型和動態(tài)模型。</p><p><b>　　結(jié)構(gòu)模型</b></p><p>　　這是一個最直觀、最普遍的建模方法。這種方法以體系結(jié)構(gòu)的構(gòu)件、連接件和其他概念來刻畫結(jié)構(gòu)，并力圖通過結(jié)構(gòu)來反映系統(tǒng)的重要語義內(nèi)容，包括系統(tǒng)的配置、約束、隱含的假設(shè)條件、風(fēng)格、性質(zhì)。研究結(jié)構(gòu)模型的核心是體系結(jié)構(gòu)描述語言。</p><p>　　框架模型框架模型與結(jié)構(gòu)模

71、型類似，但它不太側(cè)重描述結(jié)構(gòu)的細(xì)節(jié)而更側(cè)重于整體的框架模型主要以一些特殊的問題為目標(biāo)建立只針對和適應(yīng)該問題的結(jié)構(gòu)。 </p><p><b>　　動態(tài)模型</b></p><p>　　動態(tài)模型是對結(jié)構(gòu)或框架模型的補(bǔ)充，研究系統(tǒng)的"大顆粒"的行為性質(zhì)。例如，描述系統(tǒng)的重新配置或演化。動態(tài)可能指系統(tǒng)總體結(jié)構(gòu)的配置、建立或拆除通信通道或計(jì)算的過程。這類系

72、統(tǒng)常是激勵型的。</p><p>　　過程模型過程模型研究構(gòu)造系統(tǒng)的步驟和過程。因而結(jié)構(gòu)是遵循某些過程腳本的結(jié)果。 </p><p>　　該模型認(rèn)為體系結(jié)構(gòu)是由一組功能構(gòu)件按層次組成，下層向上層提供服務(wù)。它可以看作是一種特殊的框架模型。這5種模型各有所長，也許將5種模型有機(jī)地統(tǒng)一在一起，形成一個完整的模型來刻畫軟件體系結(jié)構(gòu)更合適。例如，Kruchten在1995年提出了一個"4+

73、1"的視角模型。"4+1"模型從5個不同的視角包括邏輯視角、過程視角、物理視角、開發(fā)視角和場景視角來描述軟件體系結(jié)構(gòu)。每一個視角只關(guān)心系統(tǒng)的一個側(cè)面，5個視角結(jié)合在一起才能夠反映系統(tǒng)的軟件體系結(jié)構(gòu)的全部內(nèi)容。"4+1"模型如圖1所示。</p><p>　　圖1 "4+1"模型</p><p>　　軟件開發(fā)模型是跨越整個軟

74、件生存周期的系統(tǒng)開發(fā)、運(yùn)行、維護(hù)所實(shí)施的全部工作和任務(wù)的結(jié)構(gòu)框架，給出了軟件開發(fā)活動各階段之間的關(guān)系。目前，常見的軟件開發(fā)模型大致可分為三種類型:</p><p>　　以軟件需求完全確定為前提的瀑布模型。</p><p>　　在軟件開發(fā)初始階段只能提供基本需求時采用的漸進(jìn)式開發(fā)模型,如螺旋模型等。以形式化開發(fā)方法為基礎(chǔ)的變換模型。</p><p>　　所有開發(fā)方法都

75、是要解決需求與實(shí)現(xiàn)之間的差距。但是，這三種類型的軟件開發(fā)模型都存在這樣或那樣的缺陷，不能很好地支持基于軟件體系結(jié)構(gòu)的開發(fā)過程。因此，研究人員在發(fā)展基于體系結(jié)構(gòu)的軟件開發(fā)模型方面做了一定的工作。例如，為了形象地表示體系結(jié)構(gòu)的生命周期，北京郵電大學(xué)的周瑩新博士建立了一個軟件體系結(jié)構(gòu)的生命周期模型。 </p><p>　　軟件體系結(jié)構(gòu)的開發(fā)是大型軟件系統(tǒng)開發(fā)的關(guān)鍵環(huán)節(jié)。體系結(jié)構(gòu)在軟件生產(chǎn)線的開發(fā)中具有至關(guān)重要的作用，在

76、這種開發(fā)生產(chǎn)中，基于同一個軟件體系結(jié)構(gòu)，可以創(chuàng)建具有不同功能的多個系統(tǒng)。在軟件產(chǎn)品族之間共享體系結(jié)構(gòu)和一組可重用的構(gòu)件，可以增加軟件工程和降低開發(fā)和維護(hù)成本。 一個產(chǎn)品線代表著一組具有公共的系統(tǒng)需求集的軟件系統(tǒng)，它們都是根據(jù)基本的用戶需求對標(biāo)準(zhǔn)的產(chǎn)品線構(gòu)架進(jìn)行定制，將可重用構(gòu)件與系統(tǒng)獨(dú)有的部分集成而得到的。采用軟件生產(chǎn)線式模式進(jìn)行軟件生產(chǎn)，將產(chǎn)生巨型編程企業(yè)。但目前生產(chǎn)的軟件產(chǎn)品族大部分是處于同一領(lǐng)域的。</p>

77、<p>　　當(dāng)前，體系結(jié)構(gòu)仍是一個非常新的研究領(lǐng)域，其概念還相當(dāng)模糊。但軟件體系結(jié)構(gòu)作為軟件工程領(lǐng)域中的一個組成部分，已經(jīng)取得了長足的發(fā)展，受到大多數(shù)軟件系統(tǒng)設(shè)計(jì)和研究人員的重視。</p><p>　　軟件體系結(jié)構(gòu)目前較活躍的研究方向包括：軟件體系結(jié)構(gòu)形式基礎(chǔ)的研究；針對軟件體系結(jié)構(gòu)描述中特有的問題研究新的專門的高級語言；建立用于度量和評價軟件體系結(jié)構(gòu)的模型和方法；建立面向?qū)ｉT領(lǐng)域的軟件體系結(jié)構(gòu)范型庫。

78、把軟件體系結(jié)構(gòu)從目前的直覺和經(jīng)驗(yàn)狀態(tài)過渡到理論。</p><p>　　在提高軟件工程師對軟件系統(tǒng)的描述和理解能力中，雖然軟件體系結(jié)構(gòu)描述起著重要作用，但這些抽象的描述通常是非形式化的和隨意的。體系結(jié)構(gòu)設(shè)計(jì)經(jīng)常難以理解，難以適于進(jìn)行形式化分析和模擬，缺乏相應(yīng)的支持工具幫助構(gòu)架師完成設(shè)計(jì)工作。為了解決這個問題，用于描述和推理的形式化語言得以發(fā)展，這些語言就叫做體系結(jié)構(gòu)描述語言（Architecture Descrip

79、tion Language）, ADLs尋求增加軟件體系結(jié)構(gòu)設(shè)計(jì)的可理解性和重用性。</p><p>　　ADL是這樣一種語言，系統(tǒng)構(gòu)架師可以利用它所提供的特性進(jìn)行軟件系統(tǒng)概念體系結(jié)構(gòu)建模。ADL提供了具體的語法與刻畫體系結(jié)構(gòu)的概念框架。ADLs使得系統(tǒng)開發(fā)者能夠很好地描述他們設(shè)計(jì)的體系結(jié)構(gòu)，以便與人交流，能夠用提供的工具對許多實(shí)例進(jìn)行分析。</p><p>　　這種描述語言的目的就是提供

80、一種規(guī)范化的體系結(jié)構(gòu)描述，從而使得體系結(jié)構(gòu)的自動化分析變得可能。研究人員已經(jīng)設(shè)計(jì)出了近二十種ADLs，比較有影響力的有C2、UniCon、MetaH、Aesop、SADL、Rapide、Wright等。這些語言能夠?qū)w系結(jié)構(gòu)連接器進(jìn)行第一級抽象，同時還能描述模型的結(jié)構(gòu)和內(nèi)部構(gòu)件之間的交互作用，并且還引入了一些新的系統(tǒng)分析模式。</p><p>　　這方面的工作主要是對軟件工程師在軟件開發(fā)實(shí)踐中得來的各種體系結(jié)構(gòu)的

81、原則、模式的整理和分類。例如，對軟件體系結(jié)構(gòu)風(fēng)格的分類和比較，對體系結(jié)構(gòu)描述語言的綜合分析等。就目前看來，國內(nèi)對軟件體系結(jié)構(gòu)的研究主要集中在對軟件體系結(jié)構(gòu)的專門知識的整理上。</p><p>　　最近，開發(fā)特定的領(lǐng)域去為產(chǎn)品提供可重用框架日益受到關(guān)注。這些開發(fā)基于這樣的想法：可以提取相關(guān)系統(tǒng)中的共同方面，以便可以通過低成本地把這些共同的設(shè)計(jì)實(shí)例化來構(gòu)筑新系統(tǒng)。常見的例子有：</p><p>

82、;　　編譯器的標(biāo)準(zhǔn)分解。這個方法可以使一個本科生在一個學(xué)期時間內(nèi)構(gòu)造一個新的語言編譯系統(tǒng)。</p><p>　　標(biāo)準(zhǔn)化的通訊協(xié)議。這個可以使廠家通過在不同層次的抽象上提供服務(wù)來互相操縱。第四代語言。利用4GL開發(fā)出商務(wù)信息處理的通用范式。用戶界面工具和框架。這個方法為開發(fā)者提供了一個可重用框架以及象菜單、對話框這樣的可重用構(gòu)件的集合。</p><p>　　軟件體系結(jié)構(gòu)充當(dāng)一個理解系統(tǒng)構(gòu)件和

83、它們之間關(guān)系的框架，特別是那些始終跨越時間和實(shí)現(xiàn)的屬性。這個理解對于現(xiàn)在系統(tǒng)的分析和未來系統(tǒng)的綜合很有必要。在分析和支持下，體系結(jié)構(gòu)抓住領(lǐng)域知識和實(shí)際的一致，促進(jìn)設(shè)計(jì)的評估和構(gòu)件的實(shí)施，減少仿真和構(gòu)造原型。在綜合的支持下，體系結(jié)構(gòu)提供了建立系列產(chǎn)品的基礎(chǔ)，以可預(yù)測的方式利用領(lǐng)域知識構(gòu)造和維護(hù)模塊、子系統(tǒng)和系統(tǒng)。 </p><p>　　對體系結(jié)構(gòu)設(shè)計(jì)的推理的形式化表示使得體系結(jié)構(gòu)級的設(shè)計(jì)更好地被理解、被實(shí)現(xiàn)。它的目

84、的是對體系結(jié)構(gòu)設(shè)計(jì)人員在實(shí)踐過程中總結(jié)出來的一些設(shè)計(jì)的經(jīng)驗(yàn)和方法加以總結(jié)、概括，從而形成一個形式化的描述，形成一定的理論基礎(chǔ)(以代替當(dāng)前的不精確的研究)。已提出一些形式化機(jī)制，如過程代數(shù)、偏序集合、化學(xué)抽象機(jī)等。希望對系統(tǒng)的非功能特性如性能、可維護(hù)性等給出形式特征，同時給出軟件體系結(jié)構(gòu)的理論。</p><p>　　通過分析來預(yù)見軟件的質(zhì)量，通過分析來創(chuàng)建、選擇、評估與比較不同的體系結(jié)構(gòu)。例如，Kazman等人在2

85、000年提出的ATAM（Architectural Tradeoff Analysis Method）方法。ATAM方法不但能夠揭示體系結(jié)構(gòu)如何滿足特定的質(zhì)量需求（例如性能和可修改性），而且還提供了分析這些質(zhì)量需求之間交互作用的方法。使用ATAM方法評價一個軟件體系結(jié)構(gòu)的目的是理解體系結(jié)構(gòu)設(shè)計(jì)滿足系統(tǒng)質(zhì)量需求的結(jié)果。采用ATAM方法的步驟如圖3所示，限于篇幅，在此不再詳細(xì)介紹具體步驟，有興趣的讀者可查閱有關(guān)ATAM方法的文獻(xiàn)。</

86、p><p>　　現(xiàn)有的ADLs大多是與領(lǐng)域相關(guān)的，所以不利于對不同領(lǐng)域體系結(jié)構(gòu)的說明。但這些針對不同領(lǐng)域的ADLs在某些方面又大同小異，造成資源的冗余。其實(shí)，大多數(shù)ADLs具有一系列的共同概念。如何用一種公共形式把各種語言綜合起來，使得能夠交換各種體系結(jié)構(gòu)描述信息，將是今后軟件體系結(jié)構(gòu)研究和實(shí)踐的重點(diǎn)之一。</p><p>　　軟件體系結(jié)構(gòu)設(shè)計(jì)既然作為軟件工程的一部分，它的計(jì)算機(jī)輔助實(shí)現(xiàn)手段是

87、相當(dāng)重要的。我們應(yīng)當(dāng)開發(fā)出一些軟件工具來實(shí)現(xiàn)體系結(jié)構(gòu)的描述和分析，開發(fā)階段轉(zhuǎn)換工具，以實(shí)現(xiàn)階段成果的自動轉(zhuǎn)換，例如，把需求規(guī)格說明自動轉(zhuǎn)換為構(gòu)件等。目前關(guān)于這方面的研究成果很少，特別是可以應(yīng)用到實(shí)際項(xiàng)目開發(fā)中的工具和環(huán)境就更少。</p><p>　　當(dāng)今軟件系統(tǒng)的規(guī)模變得越來越大，結(jié)構(gòu)也越來越復(fù)雜，同時從頭開始構(gòu)建的大系統(tǒng)數(shù)量在急劇地減少，因而很多遺留系統(tǒng)正在被逐步地利用。從遺留系統(tǒng)軟件代碼和系統(tǒng)中抽取結(jié)構(gòu)信息，

88、經(jīng)過描述、統(tǒng)一、抽象、一般化與實(shí)例化等處理，可總結(jié)出系統(tǒng)的體系結(jié)構(gòu)。</p><p>　　在這種情況下，軟件再工程變得越來越重要，因?yàn)樗峁┝艘粭l把遺留系統(tǒng)轉(zhuǎn)換為可進(jìn)化系統(tǒng)的現(xiàn)實(shí)可行的途徑，是一種可以改進(jìn)人們對軟件的理解和改進(jìn)軟件本身的活動。這類研究的目的是為一些特定的應(yīng)用領(lǐng)域的軟件系統(tǒng)提供一些體系結(jié)構(gòu)框架，如控制系統(tǒng)、移動機(jī)器人和用戶接口界面等。通過這些框架可以很方便地構(gòu)造一個新的軟件系統(tǒng)。</p>