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简介: Agile Modeling and eXtreme Programming (XP) 敏捷建模和极限编程(XP) Agile Modeling (AM) is a practices-based software process whose...
Agile Modeling and eXtreme Programming (XP)

Agile Modeling (AM) is a practices-based software process whose scope is to describe how to model and document in an effective and agile manner.  On the AM home page I state that one of the goals of AM is to address the issue of how to apply modeling techniques on software projects taking an agile approach such as eXtreme Programming (XP),  Dynamic Systems Development Method (DSDM), and Scrum to name a few.  Because the scope of XP is much greater than that of AM, XP covers the full development lifecycle, it is a candidate "base process" into which the techniques of AM may be tailored.  Furthermore, although XP clearly includes modeling as part of its process it is not as explicit about how to do so as many developers would prefer.  Hence an opportunity for AM.  Luckily XP, like AM, is also an agile practices-based methodology which makes the conceptual fit between the two methods much easier than between AM and a process such as the Rational Unified Process (RUP) the topic of the article Agile Modeling and the Unified Process.  


Table of Contents

Setting the record straight
XP and AM?  
AM throughout the XP lifecycle 
How do you make this work?  

1. Setting The Record Straight

There are several common misconceptions that people seem to have regarding modeling on an XP project.  The three most common misconceptions are that you don’t model on an XP project, that you don’t document on an XP project, or that if you do model your only options are the modeling artifacts of the UML.  I’ll address these misconceptions in turn in this section, but first I want to explore why they occur so that you can recognize other misconceptions when they arise.  From what I can gather based on the conversations on the AM mailing list the source of these misconceptions is often the result of one or more of the following:

有几个常见的误解,人们似乎已经对一个XP项目的建模。 3种最常见的误解是,你没有建模在一个XP的项目上,你不记录在一个XP项目上,或者说,如果你做模型的唯一的选择是UML的建模构件。我会在本节轮流来处理这些误解,但首先我想探讨他们为什么会发生的,以便在他们出现时你可以认出其他误解。从我收集的基础上在AM的谈话邮件列表列出这些误解的根源往往是一个或多个以下的结果:

Second-hand knowledge of XP.  The Internet is a major source of information for many developers, in particular newsgroups and emails from colleagues.  As people learn a new technique they often join a newsgroup or mailing list, such as the extremeprogramming list, and start monitoring the group/list.  Someone will post something, which may not be accurate, and many people will accept it as official, particularly when they haven’t had an opportunity yet to try it out for themselves.  Don’t believe everything that you hear.  

Questionable sources of information regarding XP.  It’s often hard to determine the quality of published material, be it electronic or printed form.  Sometimes honest mistakes are made, that’s happened to me more than once, and sometimes people publish misleading information on purpose.  When you’re just learning a new subject you often cannot distinguish between high-quality sources of information and questionable ones.  If you base your understanding on questionable sources it is very easy to get the wrong idea about XP. 

Difficulty seeing beyond their current environment.  Many developers find themselves in less-than-ideal environments.  XP requires you to adopt practices that are often foreign to your current environment, pair programming and test-first development are new to most organizations, and sometimes these practices simply aren’t feasible to adopt.  If you cannot adopt the practice of pair programming then XP isn’t going to work for you, but instead of proclaiming that XP doesn’t work in their environment many people will instead proclaim that XP doesn’t work at all.  The reality is that XP does in fact work in the right situations, it is just that your situation may not be one of the right ones.

Too much focus on the word “extreme”.  XP’s name is both one of its greatest strengths its greatest weaknesses.  Because of the name when some people hear XP’s advice to travel light, to reduce the amount of documentation that you create and maintain, that they instead translate it to “create no documentation at all”.  That’s extreme, right?  Or they’ll hear XP’s advice to use simple modeling techniques such as user stories and CRC cards and somehow translate that advice to “you don’t model at all.”  That’s extreme, right?  Sigh.
过多集中于“极限”的字。 XP的名字,既是其最大的优点,亦是其最大的弱点之一。因为当一些人听到XP的意见来轻装上阵,以减少您所创建和维护的文档的数量,,他们反而把它翻译为“根本不用创建文档”。这就是极限,对吗?或者他们会听到XP的意见去一些简单的建模技术,比如用户故事和CRC卡(注:Class类别, Responsibility责任, Collaborator辅助者),或者换种方式说“你根本不必建模”这就是极限,对吗?哎.

In this section I will set the record straight regarding the three most common issues concerning modeling and XP:

  Modeling is Part of XP  
  Documentation happens 
  XP and the UML?

1.1 Modeling is Part of XP
1.1 建模是XP的一部分

User stories are a fundamental aspect of XP and artifacts such as Class Responsibility Collaborator (CRC) cards are common to XP efforts.  User stories provide a high-level overview of the requirements for a system -- they are reminders to have a conversation with your project stakeholders regarding their requirements -- and are used to as a primary input into estimating and scheduling, and drive the development of acceptance test cases.   CRC cards are used to explore structure, perhaps for conceptual modeling to understand the problem domain or for design to work through the structure of your software.  User stories and CRC cards are both models, see the Artifacts for AM article, so therefore modeling is clearly a part of XP.  XP developers will also create sketches, often on a whiteboard or a piece of paper, whenever user stories and CRC cards aren’t the best option.  In Extreme Programming Explained, the first book written about XP, Kent Beck includes hand-drawn sketches of class diagrams and other free-form diagrams.  In fact, in the second edition he includes a mind map in the inside cover overviewing XP. The bottom line is that modeling is a fundamental aspect of XP, something that I explore in detail in this article.
用户故事是XP和加工品的基本方面,如类责任合作者(CRC)卡对XP的努力来说是很普遍的。用户故事为一个系统需求提供了高层次的概述 - 他们有一个与您的项目利益相关者对他们的要求谈话提醒 - 被用来作为主要输入到估计和调度,并推动发展验收测试用例。 CRC卡是用来探讨结构,也许是为概念建模的理解问题域,或通过你的软件的结构来设计工作。用户故事和CRC卡都是模型,请参阅我的文章的加工品,因此建模显然是一个XP的一部分。 每当用户故事和CRC卡是不是最好的选择,XP的开发者也将创建草图,经常在白板上或一块纸上。在极限编程已说明过的,关于XP编写的第一本书,Kent Beck包括类图和其他自由形式的图的手绘草图。事实上,他在第二版包括在里面覆盖概览XP的脑海映像。底线是,建模是一个XP的基本方面,我在这篇文章中详细探讨。

1.2 Documentation Happens
1.2 建立文档的发生

Documentation is also an important part of XP.  Ron Jeffries offers the following advice:

“Outside your extreme programming project, you will probably need documentation: by all means, write it.  Inside your project, there is so much verbal communication that you may need very little else.  Trust yourselves to know the difference.” 

There are several interesting implications of that statement.  First and foremost, the XP community recognizes that documentation should be produced for people external to your team, people that AM would term project stakeholders.  Second, it points out that verbal communication between team members reduces the need for documentation within the team.  This is the result of project team members being co-located, making communication easier, as well as aspects of XP such as Pair Programming and Collective Ownership that promote communication between developers.  As I discuss in the article on Communication documentation is only one form of communication, one that is typically the least effective, that can be easily replaced by more effective techniques such as face-to-face communication.  Third, it recognizes that sometimes you do in fact need internal documentation for your team.  This is consistent with the advice presented in Extreme Programming Installed where the authors point out that information resulting from conversations with your project stakeholders regarding user stories are captured as additional documentation attached to the card.  More on this in the Section A Closer Look At the XP Lifecycle.  Fourth, it suggests that XP team members should know when documentation is required and be allowed to act accordingly.  Fifth, it implies that you should trust the team and give them control over their own destiny.  This can be hard in many organizations.  If the team is untrustworthy then you have a serious problem that needs to be dealt with, this is true regardless of whether they are following XP, or if they are trustworthy but your organizational culture doesn’t allow you to act based on that trust then once again you have a serious problem to deal with.  Another problem is that when you are an outsider to an XP team, when you haven’t been actively involved in the conversations and interactions that have replaced the need for documentation, that it appears that there isn’t enough documentation.  When this is the case, instead of forcing the team to write documentation instead invest the time to determine if they need the documentation that you believe is missing – suggest the documentation to the team, and if there is an actual need for it then they’ll create it.  As Ron Jeffries likes to say, “It’s called Extreme Programming not stupid programming”.  Finally, the most important implication for XP teams is that if you need documentation then write it.




另一个问题是,当你是一个XP团队,局外人当你有没有积极参与谈话相互作用,已经取代了对文档的需要,似乎没有足够的文件。何时这种情况下,而不是迫使团队写文档,而不是投资,如果他们需要时间来确定您认为是文件丢失 - 建议文档队,如果有实际需要为它然后,他们将创建它。正如罗恩·杰弗里斯喜欢说,“这就是所谓的极限编程没有愚蠢的编程”。


The need for documentation on an XP project is reduced by several of its practices.  First, because of test-first development and a focus on acceptance testing there is always a working test suite that shows that your system works and fulfills the requirements implemented to that point.  For the developers, these tests act as significant documentation because it shows how the code actually works.  When you think about it, this makes a lot of sense.  When you are learning something new do you prefer to read a bunch of documentation or do you look for source code samples?  Many developers prefer to start at source code samples, and the test suite provides these samples.  Second, XP’s focus on simplicity and practice of refactoring result in very clean and clear code.  If the code is already easy to understand, why invest a lot of time writing documentation to help you to understand it?  This applies to both internal and external documentation – why add comments to code that is already clear and unambiguous?  If the code isn’t so, then refactor it to improve its quality or as a last resort write documentation.  Even though some development environments make it easy to include documentation in your code, Java’s Javadoc utility is such an example, you only want to invest in documentation when it makes sense to do so and not just because it is easy.
第二,XP的非常干净,清晰的代码重构结果的简单和实践上的焦点。如果代码已经是很容易理解,为什么投资了很多时间写文档,以帮助你了解它吗?这适用于内部和外部的文件 - 为什么添加代码,已经是明确和毫不含糊的意见?如果代码是不是这样,然后重构它,以提高其质量或作为最后的手段写文件。即使一些开发环境中可以很容易包括在您的代码中的文档,Java的javadoc工具是一个这样的例子,你只希望在文档中进行投资时是有意义的这样做,不仅因为它很容易。

What confuses many people regarding XP and documentation is that XP doesn’t specify potential documents to create during development.  This is unlike the RUP which suggests a slew of potential project artifacts.  Instead, the suggestion is to work together with your project stakeholders in an environment of rapid feedback and trust them to determine the things that they need, not just documents but any type of project enhancements.  Once again, you need to have the courage to trust the people involved with the project.  In the article Agile Documentation I discuss a collection of documents that you may choose to create and provide advice for when to consider creating them.

One of the greatest misunderstandings people have about XP regards concept of traveling light – many people believe that it means you don’t create any documentation, but nothing could be further from the truth.  What traveling light actually means is that you create just enough models and documentation, too little or too much puts you at risk.  As I suggest in Agile Documentation a good rule of thumb to ensure that you’re traveling light is that you shouldn’t create a model or document until you actually need it – creating either thing too early puts you at risk of wasting your time working on something you don’t actually need yet. 
一个最大的误解,人们对XP有一个轻装上阵的概念 - 许多人认为,这意味着你不创建任何文件,但没有可能进一步从真相。轻装上阵,实际上是指的是你创建只是足够模型和文件,太少或太多置于风险之中。我建议在敏捷文档的一个很好的经验规则,以确保你轻装上阵,你不应该创建一个模型或文件,直到你真正需要它 - 创造任何东西,过早让你在浪费你的时间工作的风险你但实际上并不需要。

An important thing to understand about documentation on an XP project is that it is a business decision, not a technical one.  This is consistent with AM’s philosophy regarding documentation, discussed in Agile Documentation.  Jeffries says it best:

“If there is a need for a document, the customer should request the document in the same way that she would request a feature: with a story card.  The team will estimate the cost of the document, and the customer may schedule it in any iteration she wishes.”

1.3 XP and The UML
1.3 极限编程和统一建模语言?

See the article XP and the UML?  Clearly the Wrong Question to be Asking

2. AM and XP?
2. AM和XP?

AM should be tailored into an existing, full lifecycle methodology, in order to improve its approach to modeling.  Because modeling is clearly a part of XP, see above, the potential exists for AM to add value to an XP project.  This assumes of course that there is possible to tailor AM into XP, I believe it is and argue so below, and that you can do so without detracting from what currently exists within XP.  In particular, XP’s practices of refactoring and test-first development clearly do a very good job of filling in for two critical goals – promoting clean design and thinking through your design before writing code – that are typically associated with traditional modeling processes.  My experience is that both refactoring and test-first development are complementary to AM and arguably enablers of several AM practices, as I argue below.  In this section I explore the following issues:
AM应调整到一个现有的,完整的生命周期方法,以改善其建模方法。因为模型显然是一个XP的一部分,见上面,存在潜在AM添加一个XP项目的价值。这当然假设是有可能进入XP定制AM,我相信这是认为这样下面,你可以做而不减损目前在XP中存在。特别是,重构和测试优先发展的XP的做法显然填补两个关键目标的一个非常好的工作 - 促进您的设计,编写代码之前,洁净的设计与思考 - 通常与传统的建模过程。我的经验是,重构和测试优先发展是相辅相成的,我可以说是几个AM做法引擎,我认为以下。在本节中,我探讨了以下问题:

  The potential fit between AM and XP 
  Refactoring and AM  
  Test-first development and AM  
  Which AM practices to adopt? 

2.1 The Potential Fit Between AM and XP
2.1 AM和XP之间的潜在适合

A critical issue that must be addressed is how well AM fits with XP.  Table 1 lists the practices of AM and either maps them to existing principles or practices of XP or discusses the potential fit of the AM practice when it is not explicitly a part of XP.  Because XP was used as a foundation for AM many of the practices map straight to XP.  However, because AM’s focus is on modeling several practices are clearly new, hence the potential for AM to bring value to an XP project.

Table 1. Applicability of AM Practices on an XP Project.


AM Practice


Fit With XP


Active Stakeholder Participation


This practice is simply a new take on XP’s On-Site Customer practice.  AM uses the term project stakeholder in place of customer and focuses on the concept of their active participation, hence Active Stakeholder Participation and not On-Site Stakeholder.


Apply Modeling Standards


This is the AM version of XP’s Coding Standards practice.


Apply Patterns Gently


This practice reflects the YAGNI principle to the effective application of patterns within your system, in conformance to XP’s practice of Simple Design.


Apply the Right Artifact(s)


This practice is not explicitly described by XP principles and practices although is very much aligned with XP philosophies of “if you need it do it” and using the most appropriate tool or technique for the job at hand.


Collective Ownership


AM has adopted XP’s Collective Ownership practice.


Create Several Models in Parallel


This is a modeling-specific practice.  XP developers can clearly work on several models – such as CRC cards, acceptance test cases, and sketches – if they choose to do so.

这是一个建模的具体实践。 XP开发人员可以清楚地工作的几种模式 - 如CRC卡,接受测试的情况下,和草图 - 如果他们选择这样做。

Create Simple Content


This is complementary XP’s Simple Design practice that advises to keep your models as simple as possible.


Depict Models Simply


This is complementary XP’s Simple Design practice that suggests that your models do not need to be fancy to be effective, perfect examples of which are CRC cards and user stories.


Discard Temporary Models


This practice reflects XP’s Travel Light principle, which AM has adopted, explicitly advising you to dispose of models that you no longer need.


Display Models Publicly


This practice reflects XP’s (and AM’s) value of Communication, principle of Open & Honest Communication (adopted by AM), and reflects its practice of Collective Ownership.


Formalize Contract Models


This practice is not currently reflected within XP, well perhaps in its “if you need to then do it” philosophy.  This practice was included in AM to provide guidance for how to deal with the very common situation of integrating with other systems.


Iterate to Another Artifact


This practice explicitly states, in a general form, the practice of XP developers to iterate between working on various artifacts such as source code, CRC cards, and tests.


Model in Small Increments


This practice supports XP’s iterative and increment approach to development.  Both XP and AM prefer an emergent approach to development and not a big design up front (BDUF) approach. 

这种做法,支持XP的迭代和递增的发展方针。 XP和AM都喜欢发展的应急办法,不是前面的大设计(BDUF)方法。

Model With Others


This is the AM version of XP’s Pair Programming practice.


Prove it With Code


This is the AM version of XP’s Concrete Experiments principle.  In fact, it was originally called Concrete Experiments although was renamed when it was evolved into a practice.


Reuse Existing Resources


This concept is not explicitly included in XP, although it clearly isn’t excluded either.  XP developers are practical, if there is something available that can be appropriately reused then they will likely choose to do so.

这个概念没有明确包括在XP中,虽然这显然是不排除。 XP的开发是可行的,如果有东西可用可适当重用,那么他们很可能会选择这样做。

Single Source Information
The goal of storing information in a single place reflects the XP concept of traveling light.

Update Only When it Hurts


This practice reflects AM and XP’s Travel Light principle, advising that you should only update an artifact only when you desperately need to.


Use the Simplest Tools


This practice reflects AM and XP’s Assume Simplicity principle and is consistent with XP’s preference for low-tech tools such as index cards for modeling.


The fact that AM’s practices are complementary to XP isn’t sufficient; there should also be a philosophical alignment between the two methodologies as well.  I believe that there is.  First, AM has adopted the four values of XP – Courage, Simplicity, Communication, and Feedback – and added a fifth one, Humility, one that is clearly compatible with XP.  Second, the principles of AM are closely aligned with those of XP.  Nine of eighteen are adopted directly from XP, and the remaining ones – Software is Your Primary Goal, Enabling the Next Effort is Your Secondary Goal, Model With a Purpose, Multiple Models, Content is More Important Than Representation, Everyone Can Learn From Everyone Else, and maximize stakeholder ROI – are clearly compatible with XP’s philosophies.  The three modeling-specific principles may cause a hard-core XP developer to pause for a moment, but on reflection should not prove arguable.  Model With a Purpose advises that you shouldn’t work on a model without good cause, Multiple Models says that you have a wide range of techniques available to you that you may choose to apply (including but not limited to CRC cards, user stories, and the diagrams of the UML).

事实上,AM的做法是相辅相成的XP是不够的,以及两者之间的方法也应该是一个有哲学对齐。我相信有。首先,AM已通过XP的四个价值观 - 勇气,简单,沟通,反馈 - 增加了五分之一,谦逊,一个显然是与XP兼容。

第二,AM的原则与XP中的密切配合。八九十是通过直接从XP,其余的 - 软件是你的首要目标,使下一步的努力是你的第二个目标,模型的目的,多种模式,内容更重要比表示,每个人都可以学习别人和最大化利益相关者的投资回报率 - 显然是与兼容XP的理念。三种建模的具体原则可能会导致暂停硬核XP片刻开发的,但反思不应该证明值得商榷。模型有目的的建议,你不应该无正当理由工作模型,多模型,说你有一个广泛的技术提供给您,您可以选择适用于(包括但不限于CRC卡,用户故事,和UML的图)。

2.2 Refactoring and AM

Refactoring is a technique to restructure code in a disciplined way, a technique that is a fundamental practice of XP.  The basic idea is that you make small changes to your code, called refactorings, to support new requirements and/or to keep your design as simple as possible.  The advantage of refactoring is that it enables programmers to safely and easily evolve their code to fulfill new requirements or to improve its quality.

Is refactoring compatible with AM?  Yes.  Refactoring is a coding technique whereas AM does not address programming-related issues, therefore there is no technical overlap between the two.  What about a conceptual overlap?  AM address design modeling and refactoring addresses design improvement of source code.  This begs the question “What do you do when you have an existing design model and you refactor your code?”  Although it’s an interesting question, the real issue is that you have two artifacts, a design model and source code, that describe the design of your system.  One has changed, the source code, now you need to decide whether or not you wish to update the model.  The way that you originally arrived at the model is irrelevant to this issue, you could have gotten there because you took an AM approach to develop it, you could have taken a BDUF approach, or you could adopted an existing model and are coding to it (for example, several organizations have developed persistence frameworks based on the design that I present at http://www.ambysoft.com/persistenceLayer.html).  The issue is irrelevant of the type of design model, be it a UML class diagram, CRC cards, a physical data model, or a procedural structure chart.  The good news is that AM provides advice for how to deal with such a situation, in particular the practice Discard Temporary Models suggests that you should consider whether you really need the design model and then if not get rid of it and the practice Update Only When it Hurts suggests that it’s often reasonable to have artifacts such as the design model and the code out of sync.

So how do you apply AM and refactoring together?  Simple.  Apply AM practices as appropriate when you are modeling, use those models as input into your programming efforts, and refactor your code as you normally would have.  If you discover that you need to attempt a major refactoring, get the team together to discuss it, modeling whenever appropriate, then approach the major refactoring as you would have in the past: as a collection of small refactorings. 


Modeling tools that reverse-engineer your code can prove valuable when you are refactoring code, particularly when you are unfamiliar with that code. Many developers think visually, they grasp information communicated via pictures more readily than they do information communicated textually, so CASE tools that quickly import a bit of code and create diagrams from them can be very useful.  It's quite common for CASE tools to import object-oriented source code, perhaps written in Java or C++, and generate UML class diagrams that show the static structure of the code and UML sequence diagrams that depict its dynamic nature.  These diagrams can be used to quickly understand the existing code, the first step in refactoring it.
建模工具,逆向工程的代码可以被证明是有价值的,当你重构代码,尤其是当你不熟悉的代码。许多开发商认为,在视觉上,他们掌握更容易比他们传达文本信息,通过图片传达的信息,因此CASE工具,快速导入的代码位,并从他们创建图表是非常有用的。CASE工具导入Java编写的面向对象的源代码,也许这是相当普遍的或C + +,生成UML类图显示的代码和UML序列图的描绘,其动态性质的静态结构。这些图可用于快速理解现有的代码,在重构的第一步。

2.3 Test-First Development and AM
2.3 测试先行的开发和AM

Test-first development is a development practice where you work in very short cycles where you consider a test, write the test and business code for it, get it to work, then continue.  These tests are collected into a development integration testing suite that must be successfully run whenever code is submitted into your shared repository.  This practice is integral to XP.

Is test-first development compatible with AM?  Yes.  Like refactoring, test-first development is more of a coding practice so there is little opportunity for technical overlap.  However, there is room for conceptual overlap because test-first development clearly delves into the realm of detailed design since it provides developers with an opportunity to think through their code before they write it (as well as important feedback regarding their code).  If you’ve chosen to do a little modeling before writing your code, perhaps to think through an issue larger than a single test case, then that’s okay.  In fact, it may even make your test-first development efforts easier, because you've thought things through better.  

How do you apply AM within a test-first development environment?  As with refactoring, simply apply AM practices as appropriate when you are modeling, use those models as input into your programming efforts, and iterate between modeling, testing, and programming as needed.  For more details, read the AMDD article.

2.4 Which AM Practices to Adopt?
2.4 采用哪种AM实践?

Only the ones that add value to what your team is trying to accomplish.  Ideally that will at least be the core practices of AM, therefore it would be fair to claim that you are in fact “doing AM”, and perhaps even adopt the supplementary practices as well.  It is important to note that your goal isn’t simply to be able to say that you’re agile modeling, it is to improve your productivity as software developers.

3. AM Throughout the XP Lifecycle
3. AM贯穿整个XP的生命周期 

To explain how the practices of AM can be applied on an XP I will work through a portion of the SWA Online Case Study and show how  modeling is used throughout the XP lifecycle in the article AM and XP: AM Throughout the XP Lifecycle. 

4. How Do You Make This Work?
4. 你如何做这项工作?

How should you approach modeling during development on an XP project?  Beck suggests that you should apply the XP practice of Small Initial Investment and draw a few pictures at a time.  He states that the XP strategy is that anyone can design with pictures all they want, but as soon as a question is raised that can be answered with code then the designers must turn to code for the answer.  In other works you should then seek Rapid Feedback to discover whether your pictures are on target by following the AM practice Prove it With Code.

When should you consider modeling during development on an XP project?  Whenever creating a model is more effective that writing code.  In other words, follow the AM principle maximize stakeholder ROI and the AM practice Apply the Right Artifact(s).

How should you model?  Follow AM’s practice Use the Simplest Tools and prefer tools such as index cards, whiteboards, and Post It notes over more complicated CASE tools.  Simple tools tend to promote interaction and communication, two factors that are critical to your success.  Although XP favors the use of index cards to record user stories, CRC models, and story tasks there is nothing wrong with using a CASE tool as long as its use provides positive value to your effort.

How should you document?  XP teams prefer to write clean, easy-to-understand source code – their philosophy is that only the source code is in sync with the source code.  However, remember that AM’s principle Model With A Purpose states that you should understand the needs of a model/document’s audience.  If the audience for documentation is your system’s users or your senior management then clean source code isn’t going to do it, instead you will need to develop external documentation for this audience.  Your stakeholders should request this documentation and should understand the costs involved, one of which is the fact that any time you spend writing documentation isn’t spent writing software, and be willing to accept those costs.
你应该如何记录?XP团队喜欢写干净,易于理解的源代码 - 他们的理念是,只有源代码是在与源代码同步。但是,请记住,我的原则与目的国模型,你应该了解模型/文档的观众的需求。如果观众文件系统的用户或高级管理人员,然后干净的源代码不打算这样做,而不是你将需要开发这个观众的外部文档。你的利益攸关方应请求这个文件,并应了解所涉及的费用,其中之一是没有花任何时间花在编写文档编写软件,并愿意接受这些费用的事实。

XP developers need to recognize that you can model on an XP project, that modeling is in fact a part of XP already with its existing application of user stories and CRC cards.  More importantly, XP developers must abandon any preconceived notions that they may have about modeling - that big modeling up front (BMUF) is the only approach to modeling, that models are permanent documents that must always be updated, that you need to use complex CASE tools to model, and that the UML defines the only models available to you - and approach modeling from a new perspective.  One such perspective was presented in this article, that you can tailor Agile Modeling (AM) into a software process based on eXtreme Programming (XP) and still remain effective as software developers.
XP开发人员需要认识到,你可以模拟一个XP项目,该模型实际上是一个XP的一部分已经与现有的应用程序其用户故事和CRC卡。更重要的是,XP的开发必须摒弃任何先入为主的观念,他们可能有大约建模 - 大,前面建模(BMUF)的模型,模型是必须始终更新的永久文件是唯一的办法,你需要使用复杂的情况下工具的UML模型,并定义唯一的车型为您提供 - 从一个新的视角和方法建模。这样一个观点,在这篇文章中,你可以定制敏捷建模(AM)到极限编程(XP)的基础上,仍然有效的软件开发商的软件过程。

Reference sit: http://www.agilemodeling.com/essays/agileModelingXP.htm


版权声明:本文为博主chszs的原创文章,未经博主允许不得转载。 https://blog.csdn.net/chszs/article/details/1921224 面向概念...
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