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• Multiple asserts in single test?

  - by Gern Blandston

  Let's say I want to write a function that validates an email address with a regex. I write a little test to check my function and write the actual function. Make it pass. However, I can come up with a bunch of different ways to test the same function ([email protected]; [email protected]; test.test.com, etc). Do I put all the incantations that I need to check in the same, single test with several ASSERTS or do I write a new test for every single thing I can think of? Thanks!

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• What Getters and Setters should and shouldn't do.

  - by cyclotis04

  I've run into a lot of differing opinions on Getters and Setters lately, so I figured I should make it into it's own question. A previous question of mine received an immediate comment (later deleted) that stated setters shouldn't have any side effects, and a SetProperty method would be a better choice. Indeed, this seems to be Microsoft's opinion as well. However, their properties often raise events, such as Resized when a form's Width or Height property is set. OwenP also states "you shouldn't let a property throw exceptions, properties shouldn't have side effects, order shouldn't matter, and properties should return relatively quickly." Yet Michael Stum states that exceptions should be thrown while validating data within a setter. If your setter doesn't throw an exception, how could you effectively validate data, as so many of the answers to this question suggest? What about when you need to raise an event, like nearly all of Microsoft's Control's do? Aren't you then at the mercy of whomever subscribed to your event? If their handler performs a massive amount of information, or throws an error itself, what happens to your setter? Finally, what about lazy loading within the getter? This too could violate the previous guidelines. What is acceptable to place in a getter or setter, and what should be kept in only accessor methods?

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• .Net - Whats the difference between a Session Facade and Business Delegate?

  - by KP65

  What I understand so far: Business Delegate - In the presentation tier, as an ASP component, provides an interface for ASP views to access business components without exposing their API, therefore reducing coupling between the two. Session Facade - In the business tier, as a com+ component, encapsulates business objects, provides a course grain interface for views to access business components. Reduces coupling, hides complex business component interaction from views. So what is the actual difference? They seem pretty similar to me..

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• Why is multiple inheritance not supported in most of programming language?

  - by Starx

  Why is multiple inheritance not supported in most of programming language? I could really use this feature to develop different layout of application?

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• What is the appropriate way to set a VB StringBuilder to an empty string?

  - by Wayne Werner

  I'm using VB's StringBuilder, and I was curious what is considered "best practice" for emptying the builder/setting it to a new string. Would it be something like this: Dim str As New System.Text.StringBuilder() str.Append("Some string to remove") str = new System.Text.StringBuilder() str.Append("Ahh, fresh new text!") or is there a "Better" way? Thanks

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• Dependency Injection & Singleton Design pattern

  - by SysAdmin

  How do we identify when to use dependency injection or singleton pattern. I have read in lot of websites where they say "Use Dependency injection over singleton pattern". But I am not sure if I totally agree with them. For my small or medium scale projects I definitely see the use of singleton pattern straightforward. For example Logger. I could use Logger.GetInstance().Log(...) But, instead of this, why do I need to inject every class I create, with the logger's instance?.

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• Regarding the ViewModel

  - by mizipzor

  Im struggling to understand the ViewModel part of the MVVM pattern. My current approach is to have a class, with no logic whatsoever (important), except that it implements INotifyPropertyChanged. The class is just a collection of properties, a struct if you like, describing an as small part of the data as possible. I consider this my Model. Most of the WPF code I write are settings dialogs that configure said Model. The code-behind of the dialog exposes a property which returns an instance of the Model. In the XAML code I bind to subproperties of that property, thereby binding directly to the Model's properties. Which works quite well since it implements the INotifyPropertyChanged. I consider this settings dialog the View. However, I havent really been able to figure out what in all this is the ViewModel. The articles Ive read suggests that the ViewModel should tie the View and the Model together, providing the logic the Model lacks but is still to complex to go directly into the View. Is this correct? Would, in my example, the code-behind of the settings dialog be considered the ViewModel? I just feel a bit lost and would like my peers to debunk some of my assumptions. Am I completely off track here?

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• What is the difference between the Facade and Adapter Pattern?

  - by devoured elysium

  I've been reading both definitions and they seem quite the same. Could anyone point out what are their differences? Thanks

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• DDD: Enum like entities

  - by Chris

  Hi all, I have the following DB model: **Person table** ID | Name | StateId ------------------------------ 1 Joe 1 2 Peter 1 3 John 2 **State table** ID | Desc ------------------------------ 1 Working 2 Vacation and domain model would be (simplified): public class Person { public int Id { get; } public string Name { get; set; } public State State { get; set; } } public class State { private int id; public string Name { get; set; } } The state might be used in the domain logic e.g.: if(person.State == State.Working) // some logic So from my understanding, the State acts like a value object which is used for domain logic checks. But it also needs to be present in the DB model to represent a clean ERM. So state might be extended to: public class State { private int id; public string Name { get; set; } public static State New {get {return new State([hardCodedIdHere?], [hardCodeNameHere?]);}} } But using this approach the name of the state would be hardcoded into the domain. Do you know what I mean? Is there a standard approach for such a thing? From my point of view what I am trying to do is using an object (which is persisted from the ERM design perspective) as a sort of value object within my domain. What do you think? Question update: Probably my question wasn't clear enough. What I need to know is, how I would use an entity (like the State example) that is stored in a database within my domain logic. To avoid things like: if(person.State.Id == State.Working.Id) // some logic or if(person.State.Id == WORKING_ID) // some logic

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• Undo/Redo using Memento: Stack, Queue or just LinkedList?

  - by serhio

  What is the best having when implementing Memento pattern (for Undo/Redo) in witch collection to Keep Mementos? Basically, I need this(c = change, u = undo, r = redo): 0 *c -1 0 *c -2 -1 0 *c -3 -2 -1 0 <u -2 -1 0 1 *c -3 -2 -1 0 Variants: LinkedList - possible in principle, maybe not optimized. Queue - not adapted for this task, IMO. Stack - not adapted for undo AND redo; Double Stack - maybe optimal, but can't control the undo maximum size.

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• CSS selectors : should I minimise my use of the class attribute in the HTML or optimise the speed

  - by Laurent Bourgault-Roy

  As I was working on a small website, I decided to use the PageSpeed extension to check if their was some improvement I could do to make the site load faster. However I was quite surprise when it told me that my use of CSS selector was "inefficient". I was always told that you should keep the usage of the class attribute in the HTML to a minimum, but if I understand correctly what PageSpeed tell me, it's much more efficient for the browser to match directly against a class name. It make sense to me, but it also mean that I need to put more CSS classes in my HTML. It also make my .css file a little harder to read. I usually tend to mark my CSS like this : #mainContent p.productDescription em.priceTag { ... } Which make it easy to read : I know this will affect the main content and that it affect something in a paragraph tag (so I wont start to put all sort of layout code in it) that describe a product and its something that need emphasis. However it seem I should rewrite it as .priceTag { ... } Which remove all context information about the style. And if I want to use differently formatted price tag (for example, one in a list on the sidebar and one in a paragraph), I need to use something like that .paragraphPriceTag { ... } .listPriceTag { ... } Which really annoy me since I seem to duplicate the semantic of the HTML in my classes. And that mean I can't put common style in an unqualified .priceTag { ... } and thus I need to replicate the style in both CSS rule, making it harder to make change. (Altough for that I could use multiple class selector, but IE6 dont support them) I believe making code harder to read for the sake of speed has never been really considered a very good practice . Except where it is critical, of course. This is why people use PHP/Ruby/C# etc. instead of C/assembly to code their site. It's easier to write and debug. So I was wondering if I should stick with few CSS classes and complex selector or if I should go the optimisation route and remove my fancy CSS selectors for the sake of speed? Does PageSpeed make over the top recommandation? On most modern computer, will it even make a difference?

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• Is it Bad Practice to use C++ only for the STL containers?

  - by gmatt

  First a little background ... In what follows, I use C,C++ and Java for coding (general) algorithms, not gui's and fancy program's with interfaces, but simple command line algorithms and libraries. I started out learning about programming in Java. I got pretty good with Java and I learned to use the Java containers a lot as they tend to reduce complexity of book keeping while guaranteeing great performance. I intermittently used C++, but I was definitely not as good with it as with Java and it felt cumbersome. I did not know C++ enough to work in it without having to look up every single function and so I quickly reverted back to sticking to Java as much as possible. I then made a sudden transition into cracking and hacking in assembly language, because I felt I was concentrated too much attention on a much too high level language and I needed more experience with how a CPU interacts with memory and whats really going on with the 1's and 0's. I have to admit this was one of the most educational and fun experiences I've had with computers to date. For obviously reasons, I could not use assembly language to code on a daily basis, it was mostly reserved for fun diversions. After learning more about the computer through this experience I then realized that C++ is so much closer to the "level of 1's and 0's" than Java was, but I still felt it to be incredibly obtuse, like a swiss army knife with far too many gizmos to do any one task with elegance. I decided to give plain vanilla C a try, and I quickly fell in love. It was a happy medium between simplicity and enough "micromanagent" to not abstract what is really going on. However, I did miss one thing about Java: the containers. In particular, a simple container (like the stl vector) that expands dynamically in size is incredibly useful, but quite a pain to have to implement in C every time. Hence my code currently looks like almost entirely C with containers from C++ thrown in, the only feature I use from C++. I'd like to know if its consider okay in practice to use just one feature of C++, and ignore the rest in favor of C type code?

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• Is the a pattern for iterating over lists held by a class (dynamicly typed OO languages)

  - by Roman A. Taycher

  If I have a class that holds one or several lists is it better to allow other classes to fetch those lists(with a getter) or to implement a doXList/eachXList type method for that list that take a function and call that function on each element of the list contained by that object. I wrote a program that did a ton of this and I hated passing around all these lists sometimes with method in class a calling method in class B to return lists contained in class C, B contains a C or multiple C's (note question is about dynamically typed OO languages languages like ruby or smalltalk) ex. (that came up in my program) on a Person class containing scheduling preferences and a scheduler class needing to access them.

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• Scrum backlog sizing is taking forever

  - by zachary

  I work on a huge project. While we program we end up meeting for endless backlog sizing sessions where all the developers sit down with the team and size user stories. Scrum doubters are saying that this process is taking too long and development time is being wasted. My question is how long should it take to size a user story on average? And does anyone have any tips to make these sizing sessions go quicker?

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• Get absolute (base) url in sinatra.

  - by berkes

  Right now, I do a get '/' do set :base_url, "#{request.env['rack.url_scheme']}://#{request.env['HTTP_HOST']}" # ... haml :index end to be able to use options.base_url in the HAML index.haml. But I am sure there is a far better, DRY, way of doing this. Yet I cannot see, nor find it. (I am new to Sinatra :)) Somehow, outside of get, I don't have request.env available, or so it seems. So putting it in an include did not work. How do you get your base url?

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• Doing a ajax / json add to database, and have a "wait doing operation" icon

  - by Dejan.S

  Hi. I got a part on my page I want to improve. It's a file upload that users can add their contacts from files like excel, csv & outlook. I read the contacts and place them in the database, so what I would like to do is to have a regular icon that spins while that operation is doing that, how could I do that? Ajax? I don't want progress bar for the file upload but the operation for reading the file EDIT: I want to know how to make this work with the add to database using ajax. like should I use a updatepanel? Thanks

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• Javascript clarity of purpose

  - by JesDaw

  Javascript usage has gotten remarkably more sophisticated and powerful in the past five years. One aspect of this sort of functional programming I struggle with, esp with Javascript’s peculiarities, is how to make clear either through comments or code just what is happening. Often this sort of code takes a while to decipher, even if you understand the prototypal, first-class functional Javascript way. Any thoughts or techniques for making perfectly clear what your code does and how in Javascript? I've asked this question elsewhere, but haven't gotten much response.

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• Managing libraries and imports in a programming language

  - by sub

  I've created an interpreter for a stupid programming language in C++ and the whole core structure is finished (Tokenizer, Parser, Interpreter including Symbol tables, core functions, etc.). Now I have a problem with creating and managing the function libraries for this interpreter (I'll explain what I mean with that later) So currently my core function handler is horrible: // Simplified version myLangResult SystemFunction( name, argc, argv ) { if ( name == "print" ) { if( argc < 1 ) { Error('blah'); } cout << argv[ 0 ]; } else if ( name == "input" ) { if( argc < 1 ) { Error('blah'); } string res; getline( cin, res ); SetVariable( argv[ 0 ], res ); } else if ( name == "exit ) { exit( 0 ); } And now think of each else if being 10 times more complicated and there being 25 more system functions. Unmaintainable, feels horrible, is horrible. So I thought: How to create some sort of libraries that contain all the functions and if they are imported initialize themselves and add their functions to the symbol table of the running interpreter. However this is the point where I don't really know how to go on. What I wanted to achieve is that there is e.g.: an (extern?) string library for my language, e.g.: string, and it is imported from within a program in that language, example: import string myString = "abcde" print string.at( myString, 2 ) # output: c My problems: How to separate the function libs from the core interpreter and load them? How to get all their functions into a list and add it to the symbol table when needed? What I was thinking to do: At the start of the interpreter, as all libraries are compiled with it, every single function calls something like RegisterFunction( string namespace, myLangResult (*functionPtr) ); which adds itself to a list. When import X is then called from within the language, the list built with RegisterFunction is then added to the symbol table. Disadvantages that spring to mind: All libraries are directly in the interpreter core, size grows and it will definitely slow it down.

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• How do you refer to the currently logged user in your code?

  - by Emanuil

  In other words - what would be a good name for a variable that references the currently logged user? I've come up with a few: logged_user visitor me I'm not convinced either of them is good enough though.

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• True or False: Good design calls for every table to have a primary key, if nothing else, a running i

  - by Velika

  Consider a grocery store scenario (I'm making this up) where you have FACT records that represent a sale transaction, where the columns of the Fact table include SaleItemFact Table ------------------ CustomerID ProductID Price DistributorID DateOfSale Etc Etc Etc Even if there are duplicates in the table when you consider ALL the keys, I would contend that a surrogate running numeric key (i.e. identity column) should be made up, e.g., TransactionNumber of type Integer. I can see someone arguing that a Fact table might not have a unique key (though I'd invent one and waste the 4 bytes, but how about a dimension table?

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• Tips for Using Multiple Development Systems

  - by Tim Lytle

  When I travel, I don't pack up the desktop I use in the office and take it with me. Maybe I should, but I don't. However, since I'm a contract programmer I like to be able to work wherever I am: I'm mostly thinking of web development here. Version Control goes a long way in keeping sane and working on multiple projects on multiple systems (two or three computers); however, there are the issues of: IDE settings - different display sizes mean the IDE settings can't be completely synced, if at all. Database - if the database is 'external' (even if it's running on the same system, it's not in version control), how do you maintain the needed syncs of structure. Development Stack - Some projects need non-standard extensions, libraries, etc installed. Just an overview of some of the hassle involved with developing on multiple systems. I'll probably end up asking some specific questions, but I thought a CW style tips might reveal some things I would even think to ask about. Update: I guess this would also address tips to make upgrading/replacing your development system easier (something I've just done). So, one tip per answer please, so the 'top' tips are easy to find. How do you make it easier to develop on multiple systems, or to transfer work after upgrading/replaceing a development system?

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• How to test a site rigorously?

  - by Sarfraz

  Hello, I recently created a big portal site. It's time for putting it to test. How do you guys test a site rigorously? What are the ways and tools for that? Can we sort of mimic hundreds of virtual users visiting the site to see its load handling? The test should be for both security and speed Thanks in advance.

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• Atomic operations on several transactionless external systems

  - by simendsjo

  Say you have an application connecting 3 different external systems. You need to update something in all 3. In case of a failure, you need to roll back the operations. This is not a hard thing to implement, but say operation 3 fails, and when rolling back, the rollback for operation 1 fails! Now the first external system is in an invalid state... I'm thinking a possible solution is to shut down the application and forcing a manual fix of the external system, but then again... It might already have used this information (and perhaps that's why it failed), or we might not have sufficient access. Or it might not even be a good way to rollback the action! Are there some good ways of handling such cases? EDIT: Some application details.. It's a multi user web application. Most of the work is done with scheduled jobs (through Quartz.Net), so most operations is run in it's own thread. Some user actions should trigger jobs that update several systems though. The external systems are somewhat unstable. I Was thinking of changing the application to use the Command and Unit Of Work pattern

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• Best way to create a C String

  - by Daniel

  Hello, I'm currently using char *thisvar = "stringcontenthere"; to declare a string in C.. Is this the best way to declare a string?

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• What design pattern to use for one big method calling many private methods

  - by Jeune

  I have a class that has a big method that calls on a lot of private methods. I think I want to extract those private methods into their own classes for one because they contain business logic and I think they should be public so they can be unit tested. Here's a sample of the code: public void handleRow(Object arg0) { if (continueRunning){ hashData=(HashMap<String, Object>)arg0; Long stdReportId = null; Date effDate=null; if (stdReportIds!=null){ stdReportId = stdReportIds[index]; } if (effDates!=null){ effDate = effDates[index]; } initAndPutPriceBrackets(hashData, stdReportId, effDate); putBrand(hashData,stdReportId,formHandlerFor==0?true:useLiveForFirst); putMultiLangDescriptions(hashData,stdReportId); index++; if (stdReportIds!=null && stdReportIds[0].equals(stdReportIds[1])){ continueRunning=false; } if (formHandlerFor==REPORTS){ putBeginDate(hashData,effDate,custId); } //handle logic that is related to pricemaps. lstOfData.add(hashData); } } What design pattern should I apply to this problem?

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