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  • byte + byte = int... why?

    - by Robert C. Cartaino
    Looking at this C# code... byte x = 1; byte y = 2; byte z = x + y; // ERROR: Cannot implicitly convert type 'int' to 'byte' The result of any math performed on byte (or short) types is implicitly cast back to an integer. The solution is to explicitly cast the result back to a byte, so... byte z = (byte)(x + y); // works What I am wondering is why? Is it architectural? Philosophical? We have: int + int = int long + long = long float + float = float double + double = double So why not: byte + byte = byte short + short = short ? A bit of background: I am performing a long list of calculations on "small numbers" (i.e. < 8) and storing the intermediate results in a large array. Using a byte array (instead of an int array) is faster (because of cache hits). But the extensive byte-casts spread through the code make it that much more unreadable.

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  • How important is the website logo on a page?

    - by meo
    I have stopped to insert "img" tags for the logo of the page. Because its not an image that is part of the content, its a design element but its still a information I want to have control over. So I just write the title in a "a" element as display: block, overflow: hidden and I push the text out with some padding. I think thats a good solution for SEO because you are keeping control of how important the logo should be on a page. But now my dilemma is starting. How important is the logo of a page? "A list apart" puts the logo in a h1 element. But is the logo really that important? On article pages you have two H1 elements (the logo and the title of the article) Most of the sites just use a img balbal /a, but I don't like this solution. Because I just want to use img for images that are part of the content... Its kinda philosophical question, I hope you can give me some input or some articles to read about that...

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  • Updating a composite primary key

    - by VBCSharp
    I am struggling with the philosophical discussions about whether or not to use composite primary keys on my SQL Server database. I have always used the surrogate keys in the past and I am challenging myself by leaving my comfort zone to try something different. I have read many discussion but can't come to any kind of solution yet. The struggle I am having is when I have to update a record with the composite PK. For example, the record in questions is like this: ContactID, RoleID, EffectiveDate, TerminationDT. The PK in this case is the ContactID, RoleID, and EffectiveDate. TerminationDT can be null. If in my UI, the user changes the RoleID and then I need to update the record. Using the surrogate key I can do an Update Table Set RoleID = 1 WHERE surrogateID = Z. However, using the Composite Key way, once one of the fields in the composite key changes I have no way to reference the old record to update it without now maintaining somewhere in the UI a reference to the old values. I do not bind datasources in my UI. I open a connection, get the data and store it in a bucket, then close the connection. What are everyone's opinions? Thanks.

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  • Best way to design a class in python

    - by Fraz
    So, this is more like a philosophical question for someone who is trying to understand classes. Most of time, how i use class is actually a very bad way to use it. I think of a lot of functions and after a time just indent the code and makes it a class and replacing few stuff with self.variable if a variable is repeated a lot. (I know its bad practise) But anyways... What i am asking is: class FooBar: def __init__(self,foo,bar): self._foo = foo self._bar = bar self.ans = self.__execute() def __execute(self): return something(self._foo, self._bar) Now there are many ways to do this: class FooBar: def __init__(self,foo): self._foo = foo def execute(self,bar): return something(self._foo, bar) Can you suggest which one is bad and which one is worse? or any other way to do this. This is just a toy example (offcourse). I mean, there is no need to have a class here if there is one function.. but lets say in __execute something() calls a whole set of other methods.. ?? Thanks

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  • What are good examples of perfectly acceptable approaches to development that are NOT test driven development (TDD)?

    - by markbruns
    The TDD cycle is test, code, refactor, (repeat) and then ship. TDD implies development that is driven by testing, specifically that means understanding requirements and then writing tests first before developing or writing code. My natural inclination is a philosophical bias in favor of TDD; I would like to be convinced that there are other approaches that now work well or even better than TDD so I have asked this question. What are examples of perfectly acceptable approaches that NOT test driven development? I can think of plenty approaches that are not TDD but could be a lot more trouble than what they are worth ... it's not moral judgement, it's just that they are cost more than they are worth ... the following are simply examples of things that might be ok as learning exercises, but approaches I'd find to be NOT acceptable in serious production and NOT TDD might include: Inspecting quality into your product -- Focusing efforts on developing a proficiency in testing/QA can be problematic, especially if you don't work on the requirements and development side first ... symptom of this include bug triaging where the developers have so many different bugs to deal with it, it is necessary to employ a form of triage -- each development cycle gets worse and worse, programmers work more and more hours, sleep less and less, struggle to keep going in death march until they are consumed. Superstition ... believing in things that you don't understand -- this would involve borrowing code that you believe has been proven or tested from somewhere, e.g. legacy code, a magic code starter wizard or an open source project, and you go forward hacking up a storm of modifications, sliding FaceBook Connect into your the user interface, inventing some new magic features on the fly (e.g. a mashup using the Twitter API, GoogleMaps API and maybe Zappos API), showing off your cool new "product" to a few people and then writing up a simple "specification" and list of "test cases" and turning that over to Mechanical Turk for testing.

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  • What's a good way to organize a large collection of personal scripts using git?

    - by spooky note
    I have a large collection of my personal scripts that I would like to start versioning using Git. I've previously organized my code as follows: ~/code/python/projects/ (for large stuff, each project contained in an individual folder) ~/code/python/scripts/ (single file scripts all contained in this directory) ~/code/python/sandbox/ (my testing area) ~/code/python/docs/ (downloaded documentation) ~/code/java/... (as above) Now i'm going to start versioning my code using git, so that I can have history and backup all my code to a remote server. I know if I were using SVN I would just keep my entire "~/code/" directory in a large repository, but I understand this is not a good way to do things with Git. Most info I've seen online suggests keeping all my project folders in a single place (as in, no separate directories for python or java) with each project containing it's own git repository, and simply having a "snippets" directory containing all single-file scripts/experiments that can be converted into projects at a later date. But I'm not sure how I feel about consolidating all of my code directories into one area. Is there a good way to keep my separate code directories intact, or is it not worth the effort? Maybe I'm just attached to the separate code directories because I've never known anything else... Also (as a side note), I'd like to quickly be able to see a chronological history of all my projects and scripts. So I can see which projects I created most recently. I used to do this by keeping a number at the beginning of all my projects, 002project, 003project. Is there automatic or easy way to do this in git without having to add a number to all of the project names? I'm open to any practical or philosophical code organizing advice you have. Thanks!!!

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  • nothrow or exception ?

    - by Muggen
    I am a student and I have small knowledge on C++, which I try to expand. This is more of a philosophical question.. I am not trying to implement something. Since #include <new> //... T * t = new (std::nothrow) T(); if(t) { //... } //... Will hide the Exception, and since dealing with Exceptions is heavier compared to a simple if(t), why isn't the normal new T() not considered less good practice, considering we will have to use try-catch() to check if a simple allocation succeeded (and if we don't, just watch the program die)?? What are the benefits (if any) of the normal new allocation compared to using a nothrow new? Exception's overhead in that case is insignificant ? Also, Assume that an allocation fails (eg. no memory exists in the system). Is there anything the program can do in that situation, or just fail gracefully. There is no way to find free memory on the heap, when all is reserved, is there? Incase an allocation fails, and an std::bad_alloc is thrown, how can we assume that since there is not enough memory to allocate an object (Eg. a new int), there will be enough memory to store an exception ?? Thanks for your time. I hope the question is in line with the rules.

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  • Oracle OpenWorld Preview: Let's Get Social and Interactive

    - by Christie Flanagan
    Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} On this blog, we often write about getting social and interactive.  Usually, we’re talking about how to create a social business or how to make the customer experience more social and interactive.  Today’s topic is about getting social and interactive as well. But this time we’re talking about getting social and interactive the old fashioned way, face-to-face at Oracle OpenWorld with fellow Oracle WebCenter customers, partners and experts and the broader Oracle community.  Here are some great ways to get social at OpenWorld outside of the exhibition halls and meeting rooms: Oracle OpenWorld Welcome Reception - Sponsored by FujitsuSunday, September 30, 7:00 p.m.–8:30 p.m.Yerba Buena Gardens & Howard Street Tent You’ll definitely want to attend the Opening Ceremonies for Oracle OpenWorld 2012 on Sunday, September 30. Centered in Yerba Buena Gardens (YBG) and shimmying out to other venues, the Opening Ceremonies are not to be missed. Join other attendees for great food and drink, energizing music, networking opportunities, and more. While you’re at YBG (home of ORACLE TEAM USA’s America’s Cup Pavilion), be sure to meet the sailors who will be defending the 34th America’s Cup in 2013. Get a good look at the 161-year old Trophy itself—the oldest trophy still being contested in international sport. And at the AC72 boat display, view a model of the largest wingsail ever built. Oracle WebCenter Customer Appreciation ReceptionTuesday, October 2, 6:30 p.m.—9:30 p.m.The Palace Hotel, Rallston BallroomThose Oracle WebCenter customers who’ve RSVP’d to attend the Oracle WebCenter Customer Appreciation Reception shouldn’t miss this private cocktail reception at one of San Francisco’s finest hotels. Sponsored by Oracle WebCenter partners Fishbowl Solutions, Fujitsu, Keste, Mythics, Redstone Content Solutions, TEAM Informatics, and TekStream, this evening will provide plenty of time to interact with other WebCenter customers, partners and employees over hors d'oeuvres and cocktails. Oracle Appreciation Event – Sponsored by CSC, Fujitsu and IntelWednesday, October 3, 7:30 p.m.—1:00 a.m.Treasure Island, San Francisco On Wednesday night October 3, Treasure Island will be engineered to rock as the Oracle Appreciation Event gets revved up and attendees get rolling. As always at the Oracle Appreciation Event, there will be unlimited refreshments, fun and games, the most awesome views of San Francisco from just about anywhere, and top notch entertainment.  Past performers read like a veritable who’s who of the rock and roll elite. Join us—it's our way of saying thanks to you for supporting Oracle and our flagship conference. Complimentary shuttle service to and from Treasure Island will be provided, so all you have to worry about is having a rocking night of your own. Oracle OpenWorld Music FestivalSeptember 30-October 4, Check schedule for venues and times.Oracle presents the first annual Oracle OpenWorld Musical Festival, featuring some of today’s breakthrough musicians from around the country and the world including Macy Gray, Joss Stone, Jimmy Cliff and The Hives. It’s five nights of back-to-back performances in the heart of San Francisco. Registered Oracle conference attendees get free admission, so remember your badge when you head to a show. With limited space at some venues, these concerts are first-come, first-served. So mark your calendars and get ready for the music to begin. See you there!I hope this give you an idea of the many opportunities to socialize and interact with the Oracle community at OpenWorld, and if you’re a music lover like me, you’re in for a special treat as we debut our first annual Oracle OpenWorld Music Festival.  Check out the links below for more information on these events and the many featured performers: Reflections from the Young Prisms A Brief Soul Session with Joss Stone Mixing It Up with Blues Mix Red Meat’s Music is Rare and Well Done The English Beat’s Dave Wakeling Gets Philosophical Top Ten Reasons to Attend the Oracle Appreciation Event There’s Magic in the Air, There’ll Be Music Everywhere Looking forward to seeing you at OpenWorld!

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  • How to Work Around Limitations in Generic Type Constraints in C#?

    - by Jose
    Okay I'm looking for some input, I'm pretty sure this is not currently supported in .NET 3.5 but here goes. I want to require a generic type passed into my class to have a constructor like this: new(IDictionary<string,object>) so the class would look like this public MyClass<T> where T : new(IDictionary<string,object>) { T CreateObject(IDictionary<string,object> values) { return new T(values); } } But the compiler doesn't support this, it doesn't really know what I'm asking. Some of you might ask, why do you want to do this? Well I'm working on a pet project of an ORM so I get values from the DB and then create the object and load the values. I thought it would be cleaner to allow the object just create itself with the values I give it. As far as I can tell I have two options: 1) Use reflection(which I'm trying to avoid) to grab the PropertyInfo[] array and then use that to load the values. 2) require T to support an interface like so: public interface ILoadValues { void LoadValues(IDictionary values); } and then do this public MyClass<T> where T:new(),ILoadValues { T CreateObject(IDictionary<string,object> values) { T obj = new T(); obj.LoadValues(values); return obj; } } The problem I have with the interface I guess is philosophical, I don't really want to expose a public method for people to load the values. Using the constructor the idea was that if I had an object like this namespace DataSource.Data { public class User { protected internal User(IDictionary<string,object> values) { //Initialize } } } As long as the MyClass<T> was in the same assembly the constructor would be available. I personally think that the Type constraint in my opinion should ask (Do I have access to this constructor? I do, great!) Anyways any input is welcome.

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  • Generic Type constraint in .net

    - by Jose
    Okay I'm looking for some input, I'm pretty sure this is not currently supported in .NET 3.5 but here goes. I want to require a generic type passed into my class to have a constructor like this: new(IDictionary<string,object>) so the class would look like this public MyClass<T> where T : new(IDictionary<string,object>) { T CreateObject(IDictionary<string,object> values) { return new T(values); } } But the compiler doesn't support this, it doesn't really know what I'm asking. Some of you might ask, why do you want to do this? Well I'm working on a pet project of an ORM so I get values from the DB and then create the object and load the values. I thought it would be cleaner to allow the object just create itself with the values I give it. As far as I can tell I have two options: 1) Use reflection(which I'm trying to avoid) to grab the PropertyInfo[] array and then use that to load the values. 2) require T to support an interface like so: public interface ILoadValues { void LoadValues(IDictionary values); } and then do this public MyClass<T> where T:new(),ILoadValues { T CreateObject(IDictionary<string,object> values) { T obj = new T(); obj.LoadValues(values); return obj; } } The problem I have with the interface I guess is philosophical, I don't really want to expose a public method for people to load the values. Using the constructor the idea was that if I had an object like this namespace DataSource.Data { public class User { protected internal User(IDictionary<string,object> values) { //Initialize } } } As long as the MyClass<T> was in the same assembly the constructor would be available. I personally think that the Type constraint in my opinion should ask (Do I have access to this constructor? I do, great!) Anyways any input is welcome.

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  • The Sensemaking Spectrum for Business Analytics: Translating from Data to Business Through Analysis

    - by Joe Lamantia
    One of the most compelling outcomes of our strategic research efforts over the past several years is a growing vocabulary that articulates our cumulative understanding of the deep structure of the domains of discovery and business analytics. Modes are one example of the deep structure we’ve found.  After looking at discovery activities across a very wide range of industries, question types, business needs, and problem solving approaches, we've identified distinct and recurring kinds of sensemaking activity, independent of context.  We label these activities Modes: Explore, compare, and comprehend are three of the nine recognizable modes.  Modes describe *how* people go about realizing insights.  (Read more about the programmatic research and formal academic grounding and discussion of the modes here: https://www.researchgate.net/publication/235971352_A_Taxonomy_of_Enterprise_Search_and_Discovery) By analogy to languages, modes are the 'verbs' of discovery activity.  When applied to the practical questions of product strategy and development, the modes of discovery allow one to identify what kinds of analytical activity a product, platform, or solution needs to support across a spread of usage scenarios, and then make concrete and well-informed decisions about every aspect of the solution, from high-level capabilities, to which specific types of information visualizations better enable these scenarios for the types of data users will analyze. The modes are a powerful generative tool for product making, but if you've spent time with young children, or had a really bad hangover (or both at the same time...), you understand the difficult of communicating using only verbs.  So I'm happy to share that we've found traction on another facet of the deep structure of discovery and business analytics.  Continuing the language analogy, we've identified some of the ‘nouns’ in the language of discovery: specifically, the consistently recurring aspects of a business that people are looking for insight into.  We call these discovery Subjects, since they identify *what* people focus on during discovery efforts, rather than *how* they go about discovery as with the Modes. Defining the collection of Subjects people repeatedly focus on allows us to understand and articulate sense making needs and activity in more specific, consistent, and complete fashion.  In combination with the Modes, we can use Subjects to concretely identify and define scenarios that describe people’s analytical needs and goals.  For example, a scenario such as ‘Explore [a Mode] the attrition rates [a Measure, one type of Subject] of our largest customers [Entities, another type of Subject] clearly captures the nature of the activity — exploration of trends vs. deep analysis of underlying factors — and the central focus — attrition rates for customers above a certain set of size criteria — from which follow many of the specifics needed to address this scenario in terms of data, analytical tools, and methods. We can also use Subjects to translate effectively between the different perspectives that shape discovery efforts, reducing ambiguity and increasing impact on both sides the perspective divide.  For example, from the language of business, which often motivates analytical work by asking questions in business terms, to the perspective of analysis.  The question posed to a Data Scientist or analyst may be something like “Why are sales of our new kinds of potato chips to our largest customers fluctuating unexpectedly this year?” or “Where can innovate, by expanding our product portfolio to meet unmet needs?”.  Analysts translate questions and beliefs like these into one or more empirical discovery efforts that more formally and granularly indicate the plan, methods, tools, and desired outcomes of analysis.  From the perspective of analysis this second question might become, “Which customer needs of type ‘A', identified and measured in terms of ‘B’, that are not directly or indirectly addressed by any of our current products, offer 'X' potential for ‘Y' positive return on the investment ‘Z' required to launch a new offering, in time frame ‘W’?  And how do these compare to each other?”.  Translation also happens from the perspective of analysis to the perspective of data; in terms of availability, quality, completeness, format, volume, etc. By implication, we are proposing that most working organizations — small and large, for profit and non-profit, domestic and international, and in the majority of industries — can be described for analytical purposes using this collection of Subjects.  This is a bold claim, but simplified articulation of complexity is one of the primary goals of sensemaking frameworks such as this one.  (And, yes, this is in fact a framework for making sense of sensemaking as a category of activity - but we’re not considering the recursive aspects of this exercise at the moment.) Compellingly, we can place the collection of subjects on a single continuum — we call it the Sensemaking Spectrum — that simply and coherently illustrates some of the most important relationships between the different types of Subjects, and also illuminates several of the fundamental dynamics shaping business analytics as a domain.  As a corollary, the Sensemaking Spectrum also suggests innovation opportunities for products and services related to business analytics. The first illustration below shows Subjects arrayed along the Sensemaking Spectrum; the second illustration presents examples of each kind of Subject.  Subjects appear in colors ranging from blue to reddish-orange, reflecting their place along the Spectrum, which indicates whether a Subject addresses more the viewpoint of systems and data (Data centric and blue), or people (User centric and orange).  This axis is shown explicitly above the Spectrum.  Annotations suggest how Subjects align with the three significant perspectives of Data, Analysis, and Business that shape business analytics activity.  This rendering makes explicit the translation and bridging function of Analysts as a role, and analysis as an activity. Subjects are best understood as fuzzy categories [http://georgelakoff.files.wordpress.com/2011/01/hedges-a-study-in-meaning-criteria-and-the-logic-of-fuzzy-concepts-journal-of-philosophical-logic-2-lakoff-19731.pdf], rather than tightly defined buckets.  For each Subject, we suggest some of the most common examples: Entities may be physical things such as named products, or locations (a building, or a city); they could be Concepts, such as satisfaction; or they could be Relationships between entities, such as the variety of possible connections that define linkage in social networks.  Likewise, Events may indicate a time and place in the dictionary sense; or they may be Transactions involving named entities; or take the form of Signals, such as ‘some Measure had some value at some time’ - what many enterprises understand as alerts.   The central story of the Spectrum is that though consumers of analytical insights (represented here by the Business perspective) need to work in terms of Subjects that are directly meaningful to their perspective — such as Themes, Plans, and Goals — the working realities of data (condition, structure, availability, completeness, cost) and the changing nature of most discovery efforts make direct engagement with source data in this fashion impossible.  Accordingly, business analytics as a domain is structured around the fundamental assumption that sense making depends on analytical transformation of data.  Analytical activity incrementally synthesizes more complex and larger scope Subjects from data in its starting condition, accumulating insight (and value) by moving through a progression of stages in which increasingly meaningful Subjects are iteratively synthesized from the data, and recombined with other Subjects.  The end goal of  ‘laddering’ successive transformations is to enable sense making from the business perspective, rather than the analytical perspective.Synthesis through laddering is typically accomplished by specialized Analysts using dedicated tools and methods. Beginning with some motivating question such as seeking opportunities to increase the efficiency (a Theme) of fulfillment processes to reach some level of profitability by the end of the year (Plan), Analysts will iteratively wrangle and transform source data Records, Values and Attributes into recognizable Entities, such as Products, that can be combined with Measures or other data into the Events (shipment of orders) that indicate the workings of the business.  More complex Subjects (to the right of the Spectrum) are composed of or make reference to less complex Subjects: a business Process such as Fulfillment will include Activities such as confirming, packing, and then shipping orders.  These Activities occur within or are conducted by organizational units such as teams of staff or partner firms (Networks), composed of Entities which are structured via Relationships, such as supplier and buyer.  The fulfillment process will involve other types of Entities, such as the products or services the business provides.  The success of the fulfillment process overall may be judged according to a sophisticated operating efficiency Model, which includes tiered Measures of business activity and health for the transactions and activities included.  All of this may be interpreted through an understanding of the operational domain of the businesses supply chain (a Domain).   We'll discuss the Spectrum in more depth in succeeding posts.

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  • IOC Container Handling State Params in Non-Default Constructor

    - by Mystagogue
    For the purpose of this discussion, there are two kinds of parameters an object constructor might take: state dependency or service dependency. Supplying a service dependency with an IOC container is easy: DI takes over. But in contrast, state dependencies are usually only known to the client. That is, the object requestor. It turns out that having a client supply the state params through an IOC Container is quite painful. I will show several different ways to do this, all of which have big problems, and ask the community if there is another option I'm missing. Let's begin: Before I added an IOC container to my project code, I started with a class like this: class Foobar { //parameters are state dependencies, not service dependencies public Foobar(string alpha, int omega){...}; //...other stuff } I decide to add a Logger service depdendency to the Foobar class, which perhaps I'll provide through DI: class Foobar { public Foobar(string alpha, int omega, ILogger log){...}; //...other stuff } But then I'm also told I need to make class Foobar itself "swappable." That is, I'm required to service-locate a Foobar instance. I add a new interface into the mix: class Foobar : IFoobar { public Foobar(string alpha, int omega, ILogger log){...}; //...other stuff } When I make the service locator call, it will DI the ILogger service dependency for me. Unfortunately the same is not true of the state dependencies Alpha and Omega. Some containers offer a syntax to address this: //Unity 2.0 pseudo-ish code: myContainer.Resolve<IFoobar>( new parameterOverride[] { {"alpha", "one"}, {"omega",2} } ); I like the feature, but I don't like that it is untyped and not evident to the developer what parameters must be passed (via intellisense, etc). So I look at another solution: //This is a "boiler plate" heavy approach! class Foobar : IFoobar { public Foobar (string alpha, int omega){...}; //...stuff } class FoobarFactory : IFoobarFactory { public IFoobar IFoobarFactory.Create(string alpha, int omega){ return new Foobar(alpha, omega); } } //fetch it... myContainer.Resolve<IFoobarFactory>().Create("one", 2); The above solves the type-safety and intellisense problem, but it (1) forced class Foobar to fetch an ILogger through a service locator rather than DI and (2) it requires me to make a bunch of boiler-plate (XXXFactory, IXXXFactory) for all varieties of Foobar implementations I might use. Should I decide to go with a pure service locator approach, it may not be a problem. But I still can't stand all the boiler-plate needed to make this work. So then I try this: //code named "concrete creator" class Foobar : IFoobar { public Foobar(string alpha, int omega, ILogger log){...}; static IFoobar Create(string alpha, int omega){ //unity 2.0 pseudo-ish code. Assume a common //service locator, or singleton holds the container... return Container.Resolve<IFoobar>( new parameterOverride[] {{"alpha", alpha},{"omega", omega} } ); } //Get my instance: Foobar.Create("alpha",2); I actually don't mind that I'm using the concrete "Foobar" class to create an IFoobar. It represents a base concept that I don't expect to change in my code. I also don't mind the lack of type-safety in the static "Create", because it is now encapsulated. My intellisense is working too! Any concrete instance made this way will ignore the supplied state params if they don't apply (a Unity 2.0 behavior). Perhaps a different concrete implementation "FooFoobar" might have a formal arg name mismatch, but I'm still pretty happy with it. But the big problem with this approach is that it only works effectively with Unity 2.0 (a mismatched parameter in Structure Map will throw an exception). So it is good only if I stay with Unity. The problem is, I'm beginning to like Structure Map a lot more. So now I go onto yet another option: class Foobar : IFoobar, IFoobarInit { public Foobar(ILogger log){...}; public IFoobar IFoobarInit.Initialize(string alpha, int omega){ this.alpha = alpha; this.omega = omega; return this; } } //now create it... IFoobar foo = myContainer.resolve<IFoobarInit>().Initialize("one", 2) Now with this I've got a somewhat nice compromise with the other approaches: (1) My arguments are type-safe / intellisense aware (2) I have a choice of fetching the ILogger via DI (shown above) or service locator, (3) there is no need to make one or more seperate concrete FoobarFactory classes (contrast with the verbose "boiler-plate" example code earlier), and (4) it reasonably upholds the principle "make interfaces easy to use correctly, and hard to use incorrectly." At least it arguably is no worse than the alternatives previously discussed. One acceptance barrier yet remains: I also want to apply "design by contract." Every sample I presented was intentionally favoring constructor injection (for state dependencies) because I want to preserve "invariant" support as most commonly practiced. Namely, the invariant is established when the constructor completes. In the sample above, the invarient is not established when object construction completes. As long as I'm doing home-grown "design by contract" I could just tell developers not to test the invariant until the Initialize(...) method is called. But more to the point, when .net 4.0 comes out I want to use its "code contract" support for design by contract. From what I read, it will not be compatible with this last approach. Curses! Of course it also occurs to me that my entire philosophy is off. Perhaps I'd be told that conjuring a Foobar : IFoobar via a service locator implies that it is a service - and services only have other service dependencies, they don't have state dependencies (such as the Alpha and Omega of these examples). I'm open to listening to such philosophical matters as well, but I'd also like to know what semi-authorative reference to read that would steer me down that thought path. So now I turn it to the community. What approach should I consider that I havn't yet? Must I really believe I've exhausted my options?

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  • Agile Development

    - by James Oloo Onyango
    Alot of literature has and is being written about agile developement and its surrounding philosophies. In my quest to find the best way to express the importance of agile methodologies, i have found Robert C. Martin's "A Satire Of Two Companies" to be both the most concise and thorough! Enjoy the read! Rufus Inc Project Kick Off Your name is Bob. The date is January 3, 2001, and your head still aches from the recent millennial revelry. You are sitting in a conference room with several managers and a group of your peers. You are a project team leader. Your boss is there, and he has brought along all of his team leaders. His boss called the meeting. "We have a new project to develop," says your boss's boss. Call him BB. The points in his hair are so long that they scrape the ceiling. Your boss's points are just starting to grow, but he eagerly awaits the day when he can leave Brylcream stains on the acoustic tiles. BB describes the essence of the new market they have identified and the product they want to develop to exploit this market. "We must have this new project up and working by fourth quarter October 1," BB demands. "Nothing is of higher priority, so we are cancelling your current project." The reaction in the room is stunned silence. Months of work are simply going to be thrown away. Slowly, a murmur of objection begins to circulate around the conference table.   His points give off an evil green glow as BB meets the eyes of everyone in the room. One by one, that insidious stare reduces each attendee to quivering lumps of protoplasm. It is clear that he will brook no discussion on this matter. Once silence has been restored, BB says, "We need to begin immediately. How long will it take you to do the analysis?" You raise your hand. Your boss tries to stop you, but his spitwad misses you and you are unaware of his efforts.   "Sir, we can't tell you how long the analysis will take until we have some requirements." "The requirements document won't be ready for 3 or 4 weeks," BB says, his points vibrating with frustration. "So, pretend that you have the requirements in front of you now. How long will you require for analysis?" No one breathes. Everyone looks around to see whether anyone has some idea. "If analysis goes beyond April 1, we have a problem. Can you finish the analysis by then?" Your boss visibly gathers his courage: "We'll find a way, sir!" His points grow 3 mm, and your headache increases by two Tylenol. "Good." BB smiles. "Now, how long will it take to do the design?" "Sir," you say. Your boss visibly pales. He is clearly worried that his 3 mms are at risk. "Without an analysis, it will not be possible to tell you how long design will take." BB's expression shifts beyond austere.   "PRETEND you have the analysis already!" he says, while fixing you with his vacant, beady little eyes. "How long will it take you to do the design?" Two Tylenol are not going to cut it. Your boss, in a desperate attempt to save his new growth, babbles: "Well, sir, with only six months left to complete the project, design had better take no longer than 3 months."   "I'm glad you agree, Smithers!" BB says, beaming. Your boss relaxes. He knows his points are secure. After a while, he starts lightly humming the Brylcream jingle. BB continues, "So, analysis will be complete by April 1, design will be complete by July 1, and that gives you 3 months to implement the project. This meeting is an example of how well our new consensus and empowerment policies are working. Now, get out there and start working. I'll expect to see TQM plans and QIT assignments on my desk by next week. Oh, and don't forget that your crossfunctional team meetings and reports will be needed for next month's quality audit." "Forget the Tylenol," you think to yourself as you return to your cubicle. "I need bourbon."   Visibly excited, your boss comes over to you and says, "Gosh, what a great meeting. I think we're really going to do some world shaking with this project." You nod in agreement, too disgusted to do anything else. "Oh," your boss continues, "I almost forgot." He hands you a 30-page document. "Remember that the SEI is coming to do an evaluation next week. This is the evaluation guide. You need to read through it, memorize it, and then shred it. It tells you how to answer any questions that the SEI auditors ask you. It also tells you what parts of the building you are allowed to take them to and what parts to avoid. We are determined to be a CMM level 3 organization by June!"   You and your peers start working on the analysis of the new project. This is difficult because you have no requirements. But from the 10-minute introduction given by BB on that fateful morning, you have some idea of what the product is supposed to do.   Corporate process demands that you begin by creating a use case document. You and your team begin enumerating use cases and drawing oval and stick diagrams. Philosophical debates break out among the team members. There is disagreement as to whether certain use cases should be connected with <<extends>> or <<includes>> relationships. Competing models are created, but nobody knows how to evaluate them. The debate continues, effectively paralyzing progress.   After a week, somebody finds the iceberg.com Web site, which recommends disposing entirely of <<extends>> and <<includes>> and replacing them with <<precedes>> and <<uses>>. The documents on this Web site, authored by Don Sengroiux, describes a method known as stalwart-analysis, which claims to be a step-by-step method for translating use cases into design diagrams. More competing use case models are created using this new scheme, but again, people can't agree on how to evaluate them. The thrashing continues. More and more, the use case meetings are driven by emotion rather than by reason. If it weren't for the fact that you don't have requirements, you'd be pretty upset by the lack of progress you are making. The requirements document arrives on February 15. And then again on February 20, 25, and every week thereafter. Each new version contradicts the previous one. Clearly, the marketing folks who are writing the requirements, empowered though they might be, are not finding consensus.   At the same time, several new competing use case templates have been proposed by the various team members. Each template presents its own particularly creative way of delaying progress. The debates rage on. On March 1, Prudence Putrigence, the process proctor, succeeds in integrating all the competing use case forms and templates into a single, all-encompassing form. Just the blank form is 15 pages long. She has managed to include every field that appeared on all the competing templates. She also presents a 159- page document describing how to fill out the use case form. All current use cases must be rewritten according to the new standard.   You marvel to yourself that it now requires 15 pages of fill-in-the-blank and essay questions to answer the question: What should the system do when the user presses Return? The corporate process (authored by L. E. Ott, famed author of "Holistic Analysis: A Progressive Dialectic for Software Engineers") insists that you discover all primary use cases, 87 percent of all secondary use cases, and 36.274 percent of all tertiary use cases before you can complete analysis and enter the design phase. You have no idea what a tertiary use case is. So in an attempt to meet this requirement, you try to get your use case document reviewed by the marketing department, which you hope will know what a tertiary use case is.   Unfortunately, the marketing folks are too busy with sales support to talk to you. Indeed, since the project started, you have not been able to get a single meeting with marketing, which has provided a never-ending stream of changing and contradictory requirements documents.   While one team has been spinning endlessly on the use case document, another team has been working out the domain model. Endless variations of UML documents are pouring out of this team. Every week, the model is reworked.   The team members can't decide whether to use <<interfaces>> or <<types>> in the model. A huge disagreement has been raging on the proper syntax and application of OCL. Others on the team just got back from a 5-day class on catabolism, and have been producing incredibly detailed and arcane diagrams that nobody else can fathom.   On March 27, with one week to go before analysis is to be complete, you have produced a sea of documents and diagrams but are no closer to a cogent analysis of the problem than you were on January 3. **** And then, a miracle happens.   **** On Saturday, April 1, you check your e-mail from home. You see a memo from your boss to BB. It states unequivocally that you are done with the analysis! You phone your boss and complain. "How could you have told BB that we were done with the analysis?" "Have you looked at a calendar lately?" he responds. "It's April 1!" The irony of that date does not escape you. "But we have so much more to think about. So much more to analyze! We haven't even decided whether to use <<extends>> or <<precedes>>!" "Where is your evidence that you are not done?" inquires your boss, impatiently. "Whaaa . . . ." But he cuts you off. "Analysis can go on forever; it has to be stopped at some point. And since this is the date it was scheduled to stop, it has been stopped. Now, on Monday, I want you to gather up all existing analysis materials and put them into a public folder. Release that folder to Prudence so that she can log it in the CM system by Monday afternoon. Then get busy and start designing."   As you hang up the phone, you begin to consider the benefits of keeping a bottle of bourbon in your bottom desk drawer. They threw a party to celebrate the on-time completion of the analysis phase. BB gave a colon-stirring speech on empowerment. And your boss, another 3 mm taller, congratulated his team on the incredible show of unity and teamwork. Finally, the CIO takes the stage to tell everyone that the SEI audit went very well and to thank everyone for studying and shredding the evaluation guides that were passed out. Level 3 now seems assured and will be awarded by June. (Scuttlebutt has it that managers at the level of BB and above are to receive significant bonuses once the SEI awards level 3.)   As the weeks flow by, you and your team work on the design of the system. Of course, you find that the analysis that the design is supposedly based on is flawedno, useless; no, worse than useless. But when you tell your boss that you need to go back and work some more on the analysis to shore up its weaker sections, he simply states, "The analysis phase is over. The only allowable activity is design. Now get back to it."   So, you and your team hack the design as best you can, unsure of whether the requirements have been properly analyzed. Of course, it really doesn't matter much, since the requirements document is still thrashing with weekly revisions, and the marketing department still refuses to meet with you.     The design is a nightmare. Your boss recently misread a book named The Finish Line in which the author, Mark DeThomaso, blithely suggested that design documents should be taken down to code-level detail. "If we are going to be working at that level of detail," you ask, "why don't we simply write the code instead?" "Because then you wouldn't be designing, of course. And the only allowable activity in the design phase is design!" "Besides," he continues, "we have just purchased a companywide license for Dandelion! This tool enables 'Round the Horn Engineering!' You are to transfer all design diagrams into this tool. It will automatically generate our code for us! It will also keep the design diagrams in sync with the code!" Your boss hands you a brightly colored shrinkwrapped box containing the Dandelion distribution. You accept it numbly and shuffle off to your cubicle. Twelve hours, eight crashes, one disk reformatting, and eight shots of 151 later, you finally have the tool installed on your server. You consider the week your team will lose while attending Dandelion training. Then you smile and think, "Any week I'm not here is a good week." Design diagram after design diagram is created by your team. Dandelion makes it very difficult to draw these diagrams. There are dozens and dozens of deeply nested dialog boxes with funny text fields and check boxes that must all be filled in correctly. And then there's the problem of moving classes between packages. At first, these diagram are driven from the use cases. But the requirements are changing so often that the use cases rapidly become meaningless. Debates rage about whether VISITOR or DECORATOR design patterns should be used. One developer refuses to use VISITOR in any form, claiming that it's not a properly object-oriented construct. Someone refuses to use multiple inheritance, since it is the spawn of the devil. Review meetings rapidly degenerate into debates about the meaning of object orientation, the definition of analysis versus design, or when to use aggregation versus association. Midway through the design cycle, the marketing folks announce that they have rethought the focus of the system. Their new requirements document is completely restructured. They have eliminated several major feature areas and replaced them with feature areas that they anticipate customer surveys will show to be more appropriate. You tell your boss that these changes mean that you need to reanalyze and redesign much of the system. But he says, "The analysis phase is system. But he says, "The analysis phase is over. The only allowable activity is design. Now get back to it."   You suggest that it might be better to create a simple prototype to show to the marketing folks and even some potential customers. But your boss says, "The analysis phase is over. The only allowable activity is design. Now get back to it." Hack, hack, hack, hack. You try to create some kind of a design document that might reflect the new requirements documents. However, the revolution of the requirements has not caused them to stop thrashing. Indeed, if anything, the wild oscillations of the requirements document have only increased in frequency and amplitude.   You slog your way through them.   On June 15, the Dandelion database gets corrupted. Apparently, the corruption has been progressive. Small errors in the DB accumulated over the months into bigger and bigger errors. Eventually, the CASE tool just stopped working. Of course, the slowly encroaching corruption is present on all the backups. Calls to the Dandelion technical support line go unanswered for several days. Finally, you receive a brief e-mail from Dandelion, informing you that this is a known problem and that the solution is to purchase the new version, which they promise will be ready some time next quarter, and then reenter all the diagrams by hand.   ****   Then, on July 1 another miracle happens! You are done with the design!   Rather than go to your boss and complain, you stock your middle desk drawer with some vodka.   **** They threw a party to celebrate the on-time completion of the design phase and their graduation to CMM level 3. This time, you find BB's speech so stirring that you have to use the restroom before it begins. New banners and plaques are all over your workplace. They show pictures of eagles and mountain climbers, and they talk about teamwork and empowerment. They read better after a few scotches. That reminds you that you need to clear out your file cabinet to make room for the brandy. You and your team begin to code. But you rapidly discover that the design is lacking in some significant areas. Actually, it's lacking any significance at all. You convene a design session in one of the conference rooms to try to work through some of the nastier problems. But your boss catches you at it and disbands the meeting, saying, "The design phase is over. The only allowable activity is coding. Now get back to it."   ****   The code generated by Dandelion is really hideous. It turns out that you and your team were using association and aggregation the wrong way, after all. All the generated code has to be edited to correct these flaws. Editing this code is extremely difficult because it has been instrumented with ugly comment blocks that have special syntax that Dandelion needs in order to keep the diagrams in sync with the code. If you accidentally alter one of these comments, the diagrams will be regenerated incorrectly. It turns out that "Round the Horn Engineering" requires an awful lot of effort. The more you try to keep the code compatible with Dandelion, the more errors Dandelion generates. In the end, you give up and decide to keep the diagrams up to date manually. A second later, you decide that there's no point in keeping the diagrams up to date at all. Besides, who has time?   Your boss hires a consultant to build tools to count the number of lines of code that are being produced. He puts a big thermometer graph on the wall with the number 1,000,000 on the top. Every day, he extends the red line to show how many lines have been added. Three days after the thermometer appears on the wall, your boss stops you in the hall. "That graph isn't growing quickly enough. We need to have a million lines done by October 1." "We aren't even sh-sh-sure that the proshect will require a m-million linezh," you blather. "We have to have a million lines done by October 1," your boss reiterates. His points have grown again, and the Grecian formula he uses on them creates an aura of authority and competence. "Are you sure your comment blocks are big enough?" Then, in a flash of managerial insight, he says, "I have it! I want you to institute a new policy among the engineers. No line of code is to be longer than 20 characters. Any such line must be split into two or more preferably more. All existing code needs to be reworked to this standard. That'll get our line count up!"   You decide not to tell him that this will require two unscheduled work months. You decide not to tell him anything at all. You decide that intravenous injections of pure ethanol are the only solution. You make the appropriate arrangements. Hack, hack, hack, and hack. You and your team madly code away. By August 1, your boss, frowning at the thermometer on the wall, institutes a mandatory 50-hour workweek.   Hack, hack, hack, and hack. By September 1st, the thermometer is at 1.2 million lines and your boss asks you to write a report describing why you exceeded the coding budget by 20 percent. He institutes mandatory Saturdays and demands that the project be brought back down to a million lines. You start a campaign of remerging lines. Hack, hack, hack, and hack. Tempers are flaring; people are quitting; QA is raining trouble reports down on you. Customers are demanding installation and user manuals; salespeople are demanding advance demonstrations for special customers; the requirements document is still thrashing, the marketing folks are complaining that the product isn't anything like they specified, and the liquor store won't accept your credit card anymore. Something has to give.    On September 15, BB calls a meeting. As he enters the room, his points are emitting clouds of steam. When he speaks, the bass overtones of his carefully manicured voice cause the pit of your stomach to roll over. "The QA manager has told me that this project has less than 50 percent of the required features implemented. He has also informed me that the system crashes all the time, yields wrong results, and is hideously slow. He has also complained that he cannot keep up with the continuous train of daily releases, each more buggy than the last!" He stops for a few seconds, visibly trying to compose himself. "The QA manager estimates that, at this rate of development, we won't be able to ship the product until December!" Actually, you think it's more like March, but you don't say anything. "December!" BB roars with such derision that people duck their heads as though he were pointing an assault rifle at them. "December is absolutely out of the question. Team leaders, I want new estimates on my desk in the morning. I am hereby mandating 65-hour work weeks until this project is complete. And it better be complete by November 1."   As he leaves the conference room, he is heard to mutter: "Empowermentbah!" * * * Your boss is bald; his points are mounted on BB's wall. The fluorescent lights reflecting off his pate momentarily dazzle you. "Do you have anything to drink?" he asks. Having just finished your last bottle of Boone's Farm, you pull a bottle of Thunderbird from your bookshelf and pour it into his coffee mug. "What's it going to take to get this project done? " he asks. "We need to freeze the requirements, analyze them, design them, and then implement them," you say callously. "By November 1?" your boss exclaims incredulously. "No way! Just get back to coding the damned thing." He storms out, scratching his vacant head.   A few days later, you find that your boss has been transferred to the corporate research division. Turnover has skyrocketed. Customers, informed at the last minute that their orders cannot be fulfilled on time, have begun to cancel their orders. Marketing is re-evaluating whether this product aligns with the overall goals of the company. Memos fly, heads roll, policies change, and things are, overall, pretty grim. Finally, by March, after far too many sixty-five hour weeks, a very shaky version of the software is ready. In the field, bug-discovery rates are high, and the technical support staff are at their wits' end, trying to cope with the complaints and demands of the irate customers. Nobody is happy.   In April, BB decides to buy his way out of the problem by licensing a product produced by Rupert Industries and redistributing it. The customers are mollified, the marketing folks are smug, and you are laid off.     Rupert Industries: Project Alpha   Your name is Robert. The date is January 3, 2001. The quiet hours spent with your family this holiday have left you refreshed and ready for work. You are sitting in a conference room with your team of professionals. The manager of the division called the meeting. "We have some ideas for a new project," says the division manager. Call him Russ. He is a high-strung British chap with more energy than a fusion reactor. He is ambitious and driven but understands the value of a team. Russ describes the essence of the new market opportunity the company has identified and introduces you to Jane, the marketing manager, who is responsible for defining the products that will address it. Addressing you, Jane says, "We'd like to start defining our first product offering as soon as possible. When can you and your team meet with me?" You reply, "We'll be done with the current iteration of our project this Friday. We can spare a few hours for you between now and then. After that, we'll take a few people from the team and dedicate them to you. We'll begin hiring their replacements and the new people for your team immediately." "Great," says Russ, "but I want you to understand that it is critical that we have something to exhibit at the trade show coming up this July. If we can't be there with something significant, we'll lose the opportunity."   "I understand," you reply. "I don't yet know what it is that you have in mind, but I'm sure we can have something by July. I just can't tell you what that something will be right now. In any case, you and Jane are going to have complete control over what we developers do, so you can rest assured that by July, you'll have the most important things that can be accomplished in that time ready to exhibit."   Russ nods in satisfaction. He knows how this works. Your team has always kept him advised and allowed him to steer their development. He has the utmost confidence that your team will work on the most important things first and will produce a high-quality product.   * * *   "So, Robert," says Jane at their first meeting, "How does your team feel about being split up?" "We'll miss working with each other," you answer, "but some of us were getting pretty tired of that last project and are looking forward to a change. So, what are you people cooking up?" Jane beams. "You know how much trouble our customers currently have . . ." And she spends a half hour or so describing the problem and possible solution. "OK, wait a second" you respond. "I need to be clear about this." And so you and Jane talk about how this system might work. Some of her ideas aren't fully formed. You suggest possible solutions. She likes some of them. You continue discussing.   During the discussion, as each new topic is addressed, Jane writes user story cards. Each card represents something that the new system has to do. The cards accumulate on the table and are spread out in front of you. Both you and Jane point at them, pick them up, and make notes on them as you discuss the stories. The cards are powerful mnemonic devices that you can use to represent complex ideas that are barely formed.   At the end of the meeting, you say, "OK, I've got a general idea of what you want. I'm going to talk to the team about it. I imagine they'll want to run some experiments with various database structures and presentation formats. Next time we meet, it'll be as a group, and we'll start identifying the most important features of the system."   A week later, your nascent team meets with Jane. They spread the existing user story cards out on the table and begin to get into some of the details of the system. The meeting is very dynamic. Jane presents the stories in the order of their importance. There is much discussion about each one. The developers are concerned about keeping the stories small enough to estimate and test. So they continually ask Jane to split one story into several smaller stories. Jane is concerned that each story have a clear business value and priority, so as she splits them, she makes sure that this stays true.   The stories accumulate on the table. Jane writes them, but the developers make notes on them as needed. Nobody tries to capture everything that is said; the cards are not meant to capture everything but are simply reminders of the conversation.   As the developers become more comfortable with the stories, they begin writing estimates on them. These estimates are crude and budgetary, but they give Jane an idea of what the story will cost.   At the end of the meeting, it is clear that many more stories could be discussed. It is also clear that the most important stories have been addressed and that they represent several months worth of work. Jane closes the meeting by taking the cards with her and promising to have a proposal for the first release in the morning.   * * *   The next morning, you reconvene the meeting. Jane chooses five cards and places them on the table. "According to your estimates, these cards represent about one perfect team-week's worth of work. The last iteration of the previous project managed to get one perfect team-week done in 3 real weeks. If we can get these five stories done in 3 weeks, we'll be able to demonstrate them to Russ. That will make him feel very comfortable about our progress." Jane is pushing it. The sheepish look on her face lets you know that she knows it too. You reply, "Jane, this is a new team, working on a new project. It's a bit presumptuous to expect that our velocity will be the same as the previous team's. However, I met with the team yesterday afternoon, and we all agreed that our initial velocity should, in fact, be set to one perfectweek for every 3 real-weeks. So you've lucked out on this one." "Just remember," you continue, "that the story estimates and the story velocity are very tentative at this point. We'll learn more when we plan the iteration and even more when we implement it."   Jane looks over her glasses at you as if to say "Who's the boss around here, anyway?" and then smiles and says, "Yeah, don't worry. I know the drill by now."Jane then puts 15 more cards on the table. She says, "If we can get all these cards done by the end of March, we can turn the system over to our beta test customers. And we'll get good feedback from them."   You reply, "OK, so we've got our first iteration defined, and we have the stories for the next three iterations after that. These four iterations will make our first release."   "So," says Jane, can you really do these five stories in the next 3 weeks?" "I don't know for sure, Jane," you reply. "Let's break them down into tasks and see what we get."   So Jane, you, and your team spend the next several hours taking each of the five stories that Jane chose for the first iteration and breaking them down into small tasks. The developers quickly realize that some of the tasks can be shared between stories and that other tasks have commonalities that can probably be taken advantage of. It is clear that potential designs are popping into the developers' heads. From time to time, they form little discussion knots and scribble UML diagrams on some cards.   Soon, the whiteboard is filled with the tasks that, once completed, will implement the five stories for this iteration. You start the sign-up process by saying, "OK, let's sign up for these tasks." "I'll take the initial database generation." Says Pete. "That's what I did on the last project, and this doesn't look very different. I estimate it at two of my perfect workdays." "OK, well, then, I'll take the login screen," says Joe. "Aw, darn," says Elaine, the junior member of the team, "I've never done a GUI, and kinda wanted to try that one."   "Ah, the impatience of youth," Joe says sagely, with a wink in your direction. "You can assist me with it, young Jedi." To Jane: "I think it'll take me about three of my perfect workdays."   One by one, the developers sign up for tasks and estimate them in terms of their own perfect workdays. Both you and Jane know that it is best to let the developers volunteer for tasks than to assign the tasks to them. You also know full well that you daren't challenge any of the developers' estimates. You know these people, and you trust them. You know that they are going to do the very best they can.   The developers know that they can't sign up for more perfect workdays than they finished in the last iteration they worked on. Once each developer has filled his or her schedule for the iteration, they stop signing up for tasks.   Eventually, all the developers have stopped signing up for tasks. But, of course, tasks are still left on the board.   "I was worried that that might happen," you say, "OK, there's only one thing to do, Jane. We've got too much to do in this iteration. What stories or tasks can we remove?" Jane sighs. She knows that this is the only option. Working overtime at the beginning of a project is insane, and projects where she's tried it have not fared well.   So Jane starts to remove the least-important functionality. "Well, we really don't need the login screen just yet. We can simply start the system in the logged-in state." "Rats!" cries Elaine. "I really wanted to do that." "Patience, grasshopper." says Joe. "Those who wait for the bees to leave the hive will not have lips too swollen to relish the honey." Elaine looks confused. Everyone looks confused. "So . . .," Jane continues, "I think we can also do away with . . ." And so, bit by bit, the list of tasks shrinks. Developers who lose a task sign up for one of the remaining ones.   The negotiation is not painless. Several times, Jane exhibits obvious frustration and impatience. Once, when tensions are especially high, Elaine volunteers, "I'll work extra hard to make up some of the missing time." You are about to correct her when, fortunately, Joe looks her in the eye and says, "When once you proceed down the dark path, forever will it dominate your destiny."   In the end, an iteration acceptable to Jane is reached. It's not what Jane wanted. Indeed, it is significantly less. But it's something the team feels that can be achieved in the next 3 weeks.   And, after all, it still addresses the most important things that Jane wanted in the iteration. "So, Jane," you say when things had quieted down a bit, "when can we expect acceptance tests from you?" Jane sighs. This is the other side of the coin. For every story the development team implements,   Jane must supply a suite of acceptance tests that prove that it works. And the team needs these long before the end of the iteration, since they will certainly point out differences in the way Jane and the developers imagine the system's behaviour.   "I'll get you some example test scripts today," Jane promises. "I'll add to them every day after that. You'll have the entire suite by the middle of the iteration."   * * *   The iteration begins on Monday morning with a flurry of Class, Responsibilities, Collaborators sessions. By midmorning, all the developers have assembled into pairs and are rapidly coding away. "And now, my young apprentice," Joe says to Elaine, "you shall learn the mysteries of test-first design!"   "Wow, that sounds pretty rad," Elaine replies. "How do you do it?" Joe beams. It's clear that he has been anticipating this moment. "OK, what does the code do right now?" "Huh?" replied Elaine, "It doesn't do anything at all; there is no code."   "So, consider our task; can you think of something the code should do?" "Sure," Elaine said with youthful assurance, "First, it should connect to the database." "And thereupon, what must needs be required to connecteth the database?" "You sure talk weird," laughed Elaine. "I think we'd have to get the database object from some registry and call the Connect() method. "Ah, astute young wizard. Thou perceives correctly that we requireth an object within which we can cacheth the database object." "Is 'cacheth' really a word?" "It is when I say it! So, what test can we write that we know the database registry should pass?" Elaine sighs. She knows she'll just have to play along. "We should be able to create a database object and pass it to the registry in a Store() method. And then we should be able to pull it out of the registry with a Get() method and make sure it's the same object." "Oh, well said, my prepubescent sprite!" "Hay!" "So, now, let's write a test function that proves your case." "But shouldn't we write the database object and registry object first?" "Ah, you've much to learn, my young impatient one. Just write the test first." "But it won't even compile!" "Are you sure? What if it did?" "Uh . . ." "Just write the test, Elaine. Trust me." And so Joe, Elaine, and all the other developers began to code their tasks, one test case at a time. The room in which they worked was abuzz with the conversations between the pairs. The murmur was punctuated by an occasional high five when a pair managed to finish a task or a difficult test case.   As development proceeded, the developers changed partners once or twice a day. Each developer got to see what all the others were doing, and so knowledge of the code spread generally throughout the team.   Whenever a pair finished something significant whether a whole task or simply an important part of a task they integrated what they had with the rest of the system. Thus, the code base grew daily, and integration difficulties were minimized.   The developers communicated with Jane on a daily basis. They'd go to her whenever they had a question about the functionality of the system or the interpretation of an acceptance test case.   Jane, good as her word, supplied the team with a steady stream of acceptance test scripts. The team read these carefully and thereby gained a much better understanding of what Jane expected the system to do. By the beginning of the second week, there was enough functionality to demonstrate to Jane. She watched eagerly as the demonstration passed test case after test case. "This is really cool," Jane said as the demonstration finally ended. "But this doesn't seem like one-third of the tasks. Is your velocity slower than anticipated?"   You grimace. You'd been waiting for a good time to mention this to Jane but now she was forcing the issue. "Yes, unfortunately, we are going more slowly than we had expected. The new application server we are using is turning out to be a pain to configure. Also, it takes forever to reboot, and we have to reboot it whenever we make even the slightest change to its configuration."   Jane eyes you with suspicion. The stress of last Monday's negotiations had still not entirely dissipated. She says, "And what does this mean to our schedule? We can't slip it again, we just can't. Russ will have a fit! He'll haul us all into the woodshed and ream us some new ones."   You look Jane right in the eyes. There's no pleasant way to give someone news like this. So you just blurt out, "Look, if things keep going like they're going, we're not going to be done with everything by next Friday. Now it's possible that we'll figure out a way to go faster. But, frankly, I wouldn't depend on that. You should start thinking about one or two tasks that could be removed from the iteration without ruining the demonstration for Russ. Come hell or high water, we are going to give that demonstration on Friday, and I don't think you want us to choose which tasks to omit."   "Aw forchrisakes!" Jane barely manages to stifle yelling that last word as she stalks away, shaking her head. Not for the first time, you say to yourself, "Nobody ever promised me project management would be easy." You are pretty sure it won't be the last time, either.   Actually, things went a bit better than you had hoped. The team did, in fact, have to drop one task from the iteration, but Jane had chosen wisely, and the demonstration for Russ went without a hitch. Russ was not impressed with the progress, but neither was he dismayed. He simply said, "This is pretty good. But remember, we have to be able to demonstrate this system at the trade show in July, and at this rate, it doesn't look like you'll have all that much to show." Jane, whose attitude had improved dramatically with the completion of the iteration, responded to Russ by saying, "Russ, this team is working hard, and well. When July comes around, I am confident that we'll have something significant to demonstrate. It won't be everything, and some of it may be smoke and mirrors, but we'll have something."   Painful though the last iteration was, it had calibrated your velocity numbers. The next iteration went much better. Not because your team got more done than in the last iteration but simply because the team didn't have to remove any tasks or stories in the middle of the iteration.   By the start of the fourth iteration, a natural rhythm has been established. Jane, you, and the team know exactly what to expect from one another. The team is running hard, but the pace is sustainable. You are confident that the team can keep up this pace for a year or more.   The number of surprises in the schedule diminishes to near zero; however, the number of surprises in the requirements does not. Jane and Russ frequently look over the growing system and make recommendations or changes to the existing functionality. But all parties realize that these changes take time and must be scheduled. So the changes do not cause anyone's expectations to be violated. In March, there is a major demonstration of the system to the board of directors. The system is very limited and is not yet in a form good enough to take to the trade show, but progress is steady, and the board is reasonably impressed.   The second release goes even more smoothly than the first. By now, the team has figured out a way to automate Jane's acceptance test scripts. The team has also refactored the design of the system to the point that it is really easy to add new features and change old ones. The second release was done by the end of June and was taken to the trade show. It had less in it than Jane and Russ would have liked, but it did demonstrate the most important features of the system. Although customers at the trade show noticed that certain features were missing, they were very impressed overall. You, Russ, and Jane all returned from the trade show with smiles on your faces. You all felt as though this project was a winner.   Indeed, many months later, you are contacted by Rufus Inc. That company had been working on a system like this for its internal operations. Rufus has canceled the development of that system after a death-march project and is negotiating to license your technology for its environment.   Indeed, things are looking up!

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