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• overriding implemented base class methods

  - by user793468

  I read somewhere that the chain of inheritance breaks when you alter a behavior from derived class. What does "altering a behavior" mean here? Is overriding an already implemented method in base class considered as "altering behavior"? Or, does the author mean altering method signatures and the output? Also, I ready Duplicating code is not a good practice, and its a maintenance nightmare. Again, does overriding an already implemented method in base class considered "Duplicating code"? If not, what would be considered as "Duplicating code"? I

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• Should a web designer know server-side coding?

  - by Rasoul Zabihi

  We're implementing an CMS based on ASP.NET MVC. Now, any designer should be able to provide themes for this CMS. But to write a theme, they need to be able to modify the generated HTML, thus the concept of View. In other words, they should be capable to either modify current views, or create new views from scratch, to fit their requirements. However, now we're not sure that we're taking the right path. Should a web designer (HTML, CSS, JavaScript + Photoshop) really know about server-side platforms like Razor or PHP, or classic ASP, or anything else?

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• Removing an element not currently in a list: ValueError?

  - by Izkata

  This is something that's bothered me for a while, and I can't figure out why anyone would ever want the language to act like this: In [1]: foo = [1, 2, 3] In [2]: foo.remove(2) ; foo # okay Out[2]: [1, 3] In [3]: foo.remove(4) ; foo # not okay? --------------------------------------------------------------------------- ValueError Traceback (most recent call last) /home/izkata/<ipython console> in <module>() ValueError: list.remove(x): x not in list If the value is already not in the list, then I'd expect a silent success. Goal already achieved. Is there any real reason this was done this way? It forces awkward code that should be much shorter: for item in items_to_remove: try: thingamabob.remove(item) except ValueError: pass Instead of simply: for item in items_to_remove: thingamabob.remove(item) As an aside, no, I can't just use set(thingamabob).difference(items_to_remove) because I do have to retain both order and duplicates.

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• best way to send messages to all subscribers with multiple subscriptions and multiple providers

  - by coding_idiot

  I'm writing an application in which - Many users can subsribe to posts made by another users. So for a single publisher there can be many subscribers. When a message is posted by an user X, all users who have subscribed to messages of User X will be sent an email. How to achieve this ? I'm thinking of using publish-subscribe pattern. And then I came through JMS. Which is the best JMS implementation to use according to your experience ? Or else what else solution do you propose to the given problem ? Shall I go for a straight-forward solution ?: User x posts a message, I find all users (from database) who subscribe to user x and then for every user, I call the sendEmail() method. [EDIT] My intention here is not to send-emails. I'm really sorry if it wasn't clear. I also have to send kind of system-notifications apart from Email to all subscribers. Right now, I've implemented the email-sending as a threadPool

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• C++: calling non-member functions with the same syntax of member ones

  - by peoro

  One thing I'd like to do in C++ is to call non-member functions with the same syntax you call member functions: class A { }; void f( A & this ) { /* ... */ } // ... A a; a.f(); // this is the same as f(a); Of course this could only work as long as f is not virtual (since it cannot appear in A's virtual table. f doesn't need to access A's non-public members. f doesn't conflict with a function declared in A (A::f). I'd like such a syntax because in my opinion it would be quite comfortable and would push good habits: calling str.strip() on a std::string (where strip is a function defined by the user) would sound a lot better than calling strip( str );. most of the times (always?) classes provide some member functions which don't require to be member (ie: are not virtual and don't use non-public members). This breaks encapsulation, but is the most practical thing to do (due to point 1). My question here is: what do you think of such feature? Do you think it would be something nice, or something that would introduce more issues than the ones it aims to solve? Could it make sense to propose such a feature to the next standard (the one after C++0x)? Of course this is just a brief description of this idea; it is not complete; we'd probably need to explicitly mark a function with a special keyword to let it work like this and many other stuff.

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• Should developers make their games easier with new versions?

  - by Gil Kalai

  It seems that the game Angry Birds is becoming gradually easier with new versions. Maybe so people get the illusion of progress and satisfaction of breaking new records? I would like to know if gradual small modifications of games to enhance the sense of improvement and learning by users is known/common/standard practice in game developing. (I don't mean to say that there is anything wrong with such a practice.)

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• Using Dynamic LINQ to get a filter for my Web API

  - by Espo

  We are considering using the Dynamic.CS linq-sample included in the "Samples" directory of visual studio 2008 for our WebAPI project to allow clients to query our data. The interface would be something like this (In addition to the normal GET-methods): public HttpResponseMessage List(string filter = null); The plan is to use the dynamic library to parse the "filter"-variable and then execute the query agains the DB. Any thoughts if this is a good idea? Is it a security problem?

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• Where to hire a scenario writer for a small interactive story game?

  - by Alexander Gladysh

  I need a scenario for a small dialog-based game / interactive story. The game would be used as an example for a middleware tool we're developing. I would like to buy an existing story (it should be dynamic of course — with branching dialogs etc.), or hire someone to write a new one. Please advise, where to go to find such person / service? We're based in Russia, so getting a talented enough native English writer locally is a bit of a problem. Update: To be extra clear: We must get all necessary rights to reuse the story and make a derived work (i.e. the game we're talking about) from it. This is a commercial product. Borrowing someone else's work at random and using it just not going to work.

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• Rails: The Law of Demeter [duplicate]

  - by user2158382

  This question already has an answer here: Rails: Law of Demeter Confusion 4 answers I am reading a book called Rails AntiPatterns and they talk about using delegation to to avoid breaking the Law of Demeter. Here is their prime example: They believe that calling something like this in the controller is bad (and I agree) @street = @invoice.customer.address.street Their proposed solution is to do the following: class Customer has_one :address belongs_to :invoice def street address.street end end class Invoice has_one :customer def customer_street customer.street end end @street = @invoice.customer_street They are stating that since you only use one dot, you are not breaking the Law of Demeter here. I think this is incorrect, because you are still going through customer to go through address to get the invoice's street. I primarily got this idea from a blog post I read: http://www.dan-manges.com/blog/37 In the blog post the prime example is class Wallet attr_accessor :cash end class Customer has_one :wallet # attribute delegation def cash @wallet.cash end end class Paperboy def collect_money(customer, due_amount) if customer.cash < due_ammount raise InsufficientFundsError else customer.cash -= due_amount @collected_amount += due_amount end end end The blog post states that although there is only one dot customer.cash instead of customer.wallet.cash, this code still violates the Law of Demeter. Now in the Paperboy collect_money method, we don't have two dots, we just have one in "customer.cash". Has this delegation solved our problem? Not at all. If we look at the behavior, a paperboy is still reaching directly into a customer's wallet to get cash out. EDIT I completely understand and agree that this is still a violation and I need to create a method in Wallet called withdraw that handles the payment for me and that I should call that method inside the Customer class. What I don't get is that according to this process, my first example still violates the Law of Demeter because Invoice is still reaching directly into Customer to get the street. Can somebody help me clear the confusion. I have been searching for the past 2 days trying to let this topic sink in, but it is still confusing.

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• How to handle monetary values in PHP and MySql?

  - by Songo

  I've inherited a huge pile of legacy code written in PHP on top of a MySQL database. The thing I noticed is that the application uses doubles for storage and manipulation of data. Now I came across of numerous posts mentioning how double are not suited for monetary operations because of the rounding errors. However, I have yet to come across a complete solution to how monetary values should be handled in PHP code and stored in a MySQL database. Is there a best practice when it comes to handling money specifically in PHP? Things I'm looking for are: How should the data be stored in the database? column type? size? How should the data be handling in normal addition, subtraction. multiplication or division? When should I round the values? How much rounding is acceptable if any? Is there a difference between handling large monetary values and low ones? Note: A VERY simplified sample code of how I might encounter money values in everyday life: $a= $_POST['price_in_dollars']; //-->(ex: 25.06) will be read as a string should it be cast to double? $b= $_POST['discount_rate'];//-->(ex: 0.35) value will always be less than 1 $valueToBeStored= $a * $b; //--> any hint here is welcomed $valueFromDatabase= $row['price']; //--> price column in database could be double, decimal,...etc. $priceToPrint=$valueFromDatabase * 0.25; //again cast needed or not? I hope you use this sample code as a means to bring out more use cases and not to take it literally of course. Bonus Question If I'm to use an ORM such as Doctrine or PROPEL, how different will it be to use money in my code.

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• Does MVC apply only to web

  - by Deeptechtons

  It is almost and instantaneous whenever I talk to developers about Model View Controller (MVC) they say you make a request to a url the server builds a entity (MODEL) and provides you with visual representation of that model. So does this mean MVC is only for the web or have I been meeting people who are just developers who employ MVC for writing web applications? Are there usages for MVC on desktop style applications? I for one am new to paradigm and would like to know of any super-set to MVC

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• Creating new games on Android and/or iPhone

  - by James Clifton

  I have a succesfull facebook poker game that is running very nicely, now some people have asked if I can port this to other platforms - mainly mobile devices (and I have been asked to make a tablet version, do I really need a seperate version?) I am currently a PHP programmer (and game designer) and I simply dont' have the time to learn Android and other languages - so I have decided to pay third parties to program them (if viable). The information I need to know is what programming language is needed for the following four devices - Android mobile phone, iPhone, iPad and tablets? Can they all run off a central sql database? If they can't then i'm not interested :( Do any of these run FLASH? Have I covered all my main bases here? For example if a person programs for a ANDROID mobile phone is that to much differant to an ANDROID tablet? They will have slightly differant graphics (because the tablet has a greater screen area might as well use it) but do they need to be started from scratch? Same goes for iPhone/iPad, do they really need to be programmed differantly if the only differance is the graphics?

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• What are some internet trends that you've noticed over the past ~10 years? [closed]

  - by Michael

  I'll give an example of one that I've noticed: the number of web sites that ask for your email address (GOOG ID, YAHOO! ID, etc.) has skyrocketed. I can come up with no legitimate reason for this other than (1) password reset [other ways to do this], or (2) to remind you that you have an account there, based upon the time of your last visit. Why does a web site need to know your email address (Google ID, etc.) if all you want to do is... download a file (no legit reason whatsoever) play a game (no legit reason whatsoever) take an IQ test or search a database (no legit reason whatsoever) watch a video or view a picture (no legit reason whatsoever) read a forum (no legit reason whatsoever) post on a forum (mildly legit reason: password reset) newsletter (only difference between a newsletter and a blog is that you're more likely to forget about the web site than you are to forget about your email address -- the majority of web sites do not send out newsletters, however, so this can't be the justification) post twitter messages or other instant messaging (mildly legit reason: password reset) buy something (mildly legit reasons: password reset + giving you a copy of a receipt that they can't delete, as receipts stored on their server can be deleted) On the other hand, I can think of plenty of very shady reasons for asking for this information: so the NSA, CIA, FBI, etc. can very easily track what you do by reading your email or asking GOOG, etc. what sites you used your GOOG ID at to use the password that you provide for your account in order to get into your email account (most people use the same password for all of their accounts), find all of your other accounts in your inbox, and then get into all of those accounts sell your email address to spammers These reasons, I believe, are why you are constantly asked to provide your email address. I can come up with no other explanations whatsoever. Question 1: Can anyone think of any legitimate or illegitimate reasons for asking for someone's email address? Question 2: What are some other interesting internet trends of the past ~10 years?

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• How to determine if class meets single responsibility principle ?

  - by user1483278

  Single Responsibility Principle is based on high cohesion principle. The difference between the two is that highly cohesive classes feature a set of responsibilities that are strongly related, while classes adhering to SRP have just one responsibility. But how do we determine whether particular class features a set of responsibilities and is thus just highly cohesive, or whether it has only one responsibility and is thus adhering to SRP? Namely, isn't it more or less subjective, since some may find class very granular ( and as such will consider a class as adhering to SRP ), while others may find it not granular enough?

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• Questioning one of the arguments for dependency injection: Why is creating an object graph hard?

  - by oberlies

  Dependency injection frameworks like Google Guice give the following motivation for their usage (source): To construct an object, you first build its dependencies. But to build each dependency, you need its dependencies, and so on. So when you build an object, you really need to build an object graph. Building object graphs by hand is labour intensive (...) and makes testing difficult. But I don't buy this argument: Even without dependency injection, I can write classes which are both easy to instantiate and convenient to test. E.g. the example from the Guice motivation page could be rewritten in the following way: class BillingService { private final CreditCardProcessor processor; private final TransactionLog transactionLog; // constructor for tests, taking all collaborators as parameters BillingService(CreditCardProcessor processor, TransactionLog transactionLog) { this.processor = processor; this.transactionLog = transactionLog; } // constructor for production, calling the (productive) constructors of the collaborators public BillingService() { this(new PaypalCreditCardProcessor(), new DatabaseTransactionLog()); } public Receipt chargeOrder(PizzaOrder order, CreditCard creditCard) { ... } } So there may be other arguments for dependency injection (which are out of scope for this question!), but easy creation of testable object graphs is not one of them, is it?

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• What are common patterns for handling possible pluralization in message properties?

  - by C. Ross

  Obviously users like to see text properly pluralized, and pluralization schemes vary in the various written languages one may encounter. When internationalizing an app, what pattern(s) are useful for handling messages with possible pluralization? What about messages with multiple possible pluralization? For example: "N review(s):" One pattern would be reviews.title.singular="{0} review:" reviews.title.singular="{0} reviews:" And this may not support all languages. Or a more complicated case: "Found M question(s) with N comment(s)." This would be difficult to support in English?

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• How to had operation with character/items on binary with concrete operations on C++?

  - by Piperoman

  I have the next problem. A item can had a lot of states: NORMAL = 0000000 DRY = 0000001 HOT = 0000010 BURNING = 0000100 WET = 0001000 COLD = 0010000 FROZEN = 0100000 POISONED= 1000000 A item can had some states at same time but not all of them Is impossible to be dry and wet at same time. If you COLD a WET item, it turns into FROZEN. If you HOT a WET item, it turns into NORMAL A item can be BURNING and POISON Etc. I have try to set binary flags to states, and use AND to set operation to combine different states, checking before if is possible or not to do it, or change to another status. Exist a concrete patron to solve this problem efficiently without had a interminable switch that check every states with everynew states? It is relative easy to check 2 different states, but if exist a third state it is not trivial to do.

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• Is it okay to showcase templates/layouts recreated in different codes in a portfolio?

  - by Souta

  I have several different templates/layouts, both simple and complex. I recreated these templates multiple times, just using different codes. (Say, a complex one was originally made in only HTML and CSS, I recreated it using HTML, Javascript, CSS, then again with a HTML and PHP concoction, and etc.) I wanted to showcase my work and skills by doing this, but I don't know if it would be okay for that all to go into a resumé/portfolio. This is why: Freelancing Does potential business really care about how their site is made, as long as it looks and functions to their liking? (As in, should I just only show the one example of each template/layout and not the multiple recreations?) Potential Hire However, if a potential employer were to stumble across my resumé/portfolio, would having the multiple recreations do any good for a career outlook? (As in, this potential employer is a company where I could be working on a team to create/develop sites and not be freelancing; would a lack of skill-shining turn this employer away because I didn't set myself apart and show that I'm not just like every other budding web designer?) Those two issues have me wondering if it is okay to have a resumé/portfolio combined for this specific reason. Or does something like this not matter to potential business (as a freelancer) because they wouldn't care either way as long as it looks and functions to their liking and therefore it is okay to showcase the recreations with the originals?

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• does class reference itself static anti pattern in prism

  - by Michael Riva

  I have an application and my desing approach look like this: class Manager { public int State; static Manager _instance = null; public static Manager Instance { get { return _instance; } set { if (_instance == value) return; _instance = value; } } public Manager() { State = 0; Instance=this; } } class Module1 { public void GetState() { Console.WriteLine(Manager.Instance.State); } } class Module2 { public void GetState() { Console.WriteLine(Manager.Instance.State); } } class Module3 { public void GetState() { Console.WriteLine(Manager.Instance.State); } } Manager class already registered in Bootstrapper like : protected override void ConfigureContainer() { base.ConfigureContainer(); Container.RegisterType<Manager>(new ContainerControlledLifetimeManager()); } protected override void InitializeModules() { Manager man= Container.Resolve<Manager>(); } Question is do I need to define my manager object as static in its field to be able to reach its state? Or this is anti pattern or bad for performance?

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• The balance between client and server functionality

  - by Eugen Martynov

  I want to bring the discussion that started in our teams and get your opinion about it. Assume we have an user account which could have different credentials for authentication and associated email to recover. An user has possibility to do signup with an email or use his social profile to complete signup process. As an Rest API from the backend to client looks like: Create account Authorise Update user data Link social account Register email Verify email In addition our BE is distributed and divided between several services/servers/clusters. So different calls are related to different end points. In case of the social sign up some of steps should be skipped or simplified. For example, with Facebook signup we could already skip email registration and verification step (we ask email permission form user), linking the social account and pre-fill user displayed name. So we proposed to have another end point which will hide/combine different calls on BE and return whole process result to the clients. The pros for this approach: No more duplication of functionality between clients Speed up the networking and user experience The cons for this approach: Additional work for backend Probably most complex scenarios in future updates I would like to get your opinion or experience with this situation. Especially if you already experienced point #2 from against reasons.

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• Should I extract specific functionality into a function and why?

  - by john smith optional

  I have a large method which does 3 tasks, each of them can be extracted into a separate function. If I'll make an additional functions for each of that tasks, will it make my code better or worse and why? Edit: Obviously, it'll make less lines of code in the main function, but there'll be additional function declarations, so my class will have additional methods, which I believe isn't good, because it'll make the class more complex. Edit2: Should I do that before I wrote all the code or should I leave it until everything is done and then extract functions?

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• Implementing new required feature after software release

  - by TiagoBrenck

  Fake Scenario There is a software that was released 1 year ago. The software is to map and register all kind of animals on our planet. When the software was released, the client only needed to know the scientific name of the animal, a flag if it is in risk of extinction and a scale of dangerous(that is a fake software and specification, I don't want to discuss this here). There are already 100.000 animals records saved on DB. New Feature One year later, the client wants a new feature. It is really important to him to know the animals classes, and this is a required field. So he asks me to put a field to input the animal class, and this field is required. Or maybe where this animal was discovered. Problem I have already 100.000 recorded animals without a class or where it was discovered, but I need to insert a new column to storage this information and this column can't be null. I don't have a default value for this situation (there isn't a default animal class or where it was discovered). I don't want to keep the requirement rule only on my software, my DB must have this requirement too(I like to keep business rules on DB too). What are the alternatives to solve this situation? I am on a situation that this new feature cannot be previewed or reviewed for the existing records. The time already passed and I can't go back on time to get it

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• Why do programming languages allow shadowing/hiding of variables and functions?

  - by Simon

  Many of the most popular programming languges (such as C++, Java, Python etc.) have the concept of hiding / shadowing of variables or functions. When I've encountered hiding or shadowing they have been the cause of hard to find bugs and I've never seen a case where I found it necessary to use these features of the languages. To me it would seem better to disallow hiding and shadowing. Does anybody know of a good use of these concepts?

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• Designing a system with different business rules for different customers

  - by user1595846

  My company is rewriting our proprietary business application. The current architecture is poorly done and inflexible. It is coded more procedural oriented as opposed to object oriented. It has become difficult to maintain. Our system is a web application written in .Net Webforms. I am considering ASP.Net MVC for the rewrite. We intend to rewrite it with a good, solid architecture with the goal of maintainability and reusable classes for some of our other systems and services. We would also like the system to be customizable for different customers in the event that we market the system. I am considering redesigning the system based on the layered architecture (Presentation, Business, Data Access layers) described in the Microsoft Patterns and Practices Application Architecture Guide. http://msdn.microsoft.com/en-us/library/ff650706.aspx Hopefully this isn't too open ended, but how would you recommend allowing for different business logic/rules for different customers? I'm aware of Windows Workflow Foundation, but from what I've read about it, it seems many business rules could be too complicated to handle there. Also, Can anyone point me to where I can download an example of a .net solution that is based on the Application Architecture Guide? I have already downloaded the Layered Architecture Solution Guidance and the Expense Sample on codeplex. I was looking for something a bit larger and more robust that I could step through the code and see how it works. If you feel there are better architectures to base our redesign on please feel free to share. I appreciate your help!

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• What is the difference between "data hiding" and "encapsulation"?

  - by Software Engeneering Learner

  I'm reading "Java concurrency in practice" and there is said: "Fortunately, the same object-oriented techniques that help you write well-organized, maintainable classes - such as encapsulation and data hiding -can also help you create thread-safe classes." The problem #1 - I never heard about data hiding and don't know what it is. The problem #2 - I always thought that encapsulation is using private vs public, and is actually the data hiding. Can you please explain what data hiding is and how it differs from encapsulation?

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