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  • dynamical binding or switch/case?

    - by kingkai
    A scene like this: I've different of objects do the similar operation as respective func() implements. There're 2 kinds of solution for func_manager() to call func() according to different objects Solution 1: Use virtual function character specified in c++. func_manager works differently accroding to different object point pass in. class Object{ virtual void func() = 0; } class Object_A : public Object{ void func() {}; } class Object_B : public Object{ void func() {}; } void func_manager(Object* a) { a->func(); } Solution 2: Use plain switch/case. func_manager works differently accroding to different type pass in typedef _type_t { TYPE_A, TYPE_B }type_t; void func_by_a() { // do as func() in Object_A } void func_by_b() { // do as func() in Object_A } void func_manager(type_t type) { switch(type){ case TYPE_A: func_by_a(); break; case TYPE_B: func_by_b(); default: break; } } My Question are 2: 1. at the view point of DESIGN PATTERN, which one is better? 2. at the view point of RUNTIME EFFCIENCE, which one is better? Especailly as the kinds of Object increases, may be up to 10-15 total, which one's overhead oversteps the other? I don't know how switch/case implements innerly, just a bunch of if/else? Thanks very much!

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  • DAO design pattern and using it across multiple tables

    - by Casey
    I'm looking for feedback on the Data Access Object design pattern and using it when you have to access data across multiple tables. It seems like that pattern, which has a DAO for each table along with a Data Transfer Object (DTO) that represents a single row, isn't too useful for when dealing with data from multiple tables. I was thinking about creating a composite DAO and corresponding DTO that would return the result of, let's say performing a join on two tables. This way I can use SQL to grab all the data instead of first grabbing data from one using one DAO and than the second table using the second DAO, and than composing them together in Java. Is there a better solution? And no, I'm not able to move to Hibernate or another ORM tool at the moment. Just straight JDBC for this project.

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  • Singular method name for single object argument, plural for a list?

    - by nasufara
    I'm having a problem with naming a method for a database application. In my Database instance, I have a method that can remove an Agreement object from the database. However, I want to be able to remove multiple Agreements at once, to be able to use transactions. The problem is that I also have an overload to remove a single Agreement object. Essentially, my structure is like this: public class Database { // ... public void RemoveAgreement(Agreement a) { // ... } public void RemoveAgreement(IEnumerable<Agreement> agreements) { // ... } } But this can be confusing, as the overload with the list of Agreements has a singular name, despite being inherently plural. My question is, how should I structure this? Should I have two overloads with the name RemoveAgreement(), or RemoveAgreements()? Or should I use two separate methods, instead of overloads? Thanks.

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  • A good approach to db planing for reporting service

    - by Itay Moav
    The scenario: Big system (~200 tables). 60,000 users. Complex reports that will require me to do multiple queries for each report and even those will be complex queries with inner queries all over the place + some processing in PHP. I have seen an approach, which I am not sure about: Having one centralized, de-normalized, table that registers any activity in the system which is reportable. This table will hold mostly foreign keys, so she should be fairly compact and fast. So, for example (My system is a virtual learning management system), A user enrolls to course, the table stores the user id, date, course id, organization id, activity type (enrollment). Of course I also store this data in a normalized DB, which the actual application uses. Pros I see: easy, maintainable queries and code to process data and fast retrieval. Cons: there is a danger of the de-normalized table to be out of sync with the real DB. Is this approach worth considering, or (preferably from experience) is total $#%#%t?

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  • YAGNI and database creation scripts

    - by Daniel Straight
    Right now, I have code which creates the database (just a few CREATE queries on a SQLite database) in my main database access class. This seems unnecessary as I have no intention of ever using the code. I would just need it if something went wrong and I needed to recreate the database. Should I... Leave things as they are, even though the database creation code is about a quarter of my file size. Move the database-creation code to a separate script. It's likely I'll be running it manually if I ever need to run it again anyway, and that would put it out-of-sight-out-of-mind while working on the main code. Delete the database-creation code and rely on revision control if I ever find myself needing it again.

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  • QuestionOrAnswer model?

    - by Mark
    My site has Listings. Users can ask Questions about listings, and the author of the listing can respond with an Answer. However, the Answer might need clarification, so I've made them recursive (you can "answer" an answer). So how do I set up the database? The way I have it now looks like this (in Django-style models): class QuestionOrAnswer(Model): user = ForeignKey(User, related_name='questions') listing = ForeignKey(Listing, related_name='questions') parent = models.ForeignKey('self', null=True, blank=True, related_name='children') message = TextField() But what bugs me is that listing is now an attribute of the answers as well (it doesn't need to be). What happens if the database gets mangled and an answer belongs to a different listing than its parent question? That just doesn't make any sense. We can separate it with polymorphism: QuestionOrAnswer user message created updated Question(QuestionOrAnswer) shipment Answer(QuestionOrAnswer) parent = ForeignKey(QuestionOrAnswer) And that ought to work, but now ever question and answer is split into 2 tables. Is it worth this overhead for clearly defined models?

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  • P/Invoke or C++/CLI for wrapping a C library

    - by Ian G
    Have a moderate size (40-odd function) C API that needs to be called from a C# project. The functions logically break up to form a few classes that will be API presented to the rest of the project. Are there any objective reasons to prefer P/Invoke or C++/CLI for the interoperability underneath that API, in terms of robustness, maintainability, deployment, ...? The issues I could think of that might be, but aren't problematic are: C++/CLI will require an separate assembly, the P/Invoke classes can be in the main assembly. (We've already got multiple assemblies and there'll be the C dlls anyway so not a major issue). Performance doesn't seem differ noticeable between the two methods. Issues that I'm not sure about are: My feeling is C++/CLI will be easier to debug if there's inter-op problem, is this true? Language familiarity enough people know C# and C++ but knowledge of details of C++/CLI are rarer here. Anything else?

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  • Java Code Formating

    - by the qwerty
    I'm using FreeMarker to generate java code, but as most of it is dynamically generated it's difficult to control the code formation. I want to get code well formatted. Does anyone knows a lib or something like a pretty printer for java code?

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  • Passing objects by reference or not in C#

    - by Piku
    Suppose I have a class like this: public class ThingManager { List<SomeClass> ItemList; public void AddToList (SomeClass Item) { ItemList.Add(Item); } public void ProcessListItems() { // go through list one item at a time, get item from list, // modify item according to class' purpose } } Assume "SomeClass" is a fairly large class containing methods and members that are quite complex (List<s and arrays, for example) and that there may be a large quantity of them, so not copying vast amounts of data around the program is important. Should the "AddToList" method have "ref" in it or not? And why? It's like trying to learn pointers in C all over again ;-) (which is probably why I am getting confused, I'm trying to relate these to pointers. In C it'd be "SomeClass *Item" and a list of "SomeClass *" variables)

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  • Some good websites to learn about JavaScript and programming architecture?

    - by Jack Roscoe
    I'm not sure if 'architecture' is the correct term, but I've been looking for some articles online which talk about programming design and more about how best to use languages such as JavaScript in a code design sense rather than the actual syntax itself. I have found many websites but a lot seem to be very out dated, and I'm not sure what developments have taken place with JavaScript over the years so do not know how old is too old. If anybody could suggest some great websites, or maybe specific articles you think would be useful, that would be highly appreciated. I am a beginner programmer currently using JavaScript with XML and of course HTML & CSS, and I'm currently trying to get further into and learn more about web development.

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  • PHP MVC: How to implement an effective Controller/View Association like ZendFramework guys do!

    - by Navi
    Hi, I am making my own PHP-MVC framework. i have a question regarding Controller and View Association. I love the way Zend framework uses view within Controller as follow: $this->view->data = 'Data here'; so it can be used in view as follow: echo $this->data; I am wondering how can i implement this association. I want to remove codes between /** **/ and want to replace with some magic functions. My codes for controller as as follow: class UserController extends Controller{ /************************************/ public function __construct(){ $this->view = new View(); $this->view->setLayout( 'home' ); } function __destruct(){ $this->view->render(); } /************************************/ public function index(){ $this->redirect('user/login'); } public function login(){ } public function register(){ } public function forgotPassword(){ } } Thanks and best regards, -Navi

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  • Create swipe controlled simple flipbook style animation in ObjC

    - by eco_bach
    Hi I am a beginner in Obj C development, though quite experienced (over 10 years) with other ECMAscript based languages and OOP development. I want to build a simple flipbook style animation, controlled through swiping motion. I'm sure extremely simple for any advanced ObjC coders. Can anyone with extensive ObjC-CocoaTouch experience give me some higher level recommendations? ie, 1 -general application design, should I start with a simple view based application, or navigation based or? 2 -should I use 3rd party animation frameworks such as Cocos2D, or stick with built in classes and methods? 3 -if using built in methods, classes, what is the recommended way of achieving a animation, that will be controlled via swipe and touch gestures? 4 -I want to eventually have multiple 'flipbooks' that I can 'instantly' swap with one another, ie to give the net effect of an object changing color, etc, but not sure how to approach this from a memory management point of view, related to #1 above Except for point 3 above, I'm not expecting any actual code examples. Just general guidelines to follow and perhaps, what are some next steps I should take in my goal as an ObjC code samurai.

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  • How to best launch C++ application from web page

    - by JB
    I guess there are two parts to this question, one technical and one best practice for security and doing things "right". I'm working on a little game using C++ / directx but I would like to be able to launch it from a web page by someone clicking on a link on that page. Ideally I would like the first time they clicked for it to launch an installer downloads and installs the game on their machine, and then the next time to launch an application which updates the game from a web site if it's old and then launches it. I have no problems with the expected security popups and questions the first time it runs. I want people to be certain what they are installing and understand what they are doing. But it would be nice if once it is installed they could run it with the minimum of fuss. My question then is what technologies I could use to do this? I'm thinking that it would need a browser plugin and an activex control so that first time you'd install that, and subsequently the control/plugin would be able to launch the game. I'm not sure that under newer browser secuity models that a plugin would have the permissions to be able to run an installer though or silently invoke applications on the client machine even if they are already installed. Is there a more sensible way to achive what I want to achieve? And I'm worried about the security aspects too. I want this to be convenient for users but I of course want to do it "right". I know this can be done as I've seen several mmorpg type games that launch in this way from the browser now but it's not entirely clear to me how they've done it.

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  • WCF Best Practice for "Overloaded" methods

    - by Nate Bross
    What is the best practice for emulating overloaded methods over WCF? Typically I might write an interface like this interface IInterface { MyType ReadMyType(int id); IEnumerable<MyType> ReadMyType(String name); IEnumerable<MyType> ReadMyType(String name, int maxResults); } What would this interface look like after you converted it to WCF?

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  • What is the best practice in regards to building composite dtos off of an aggregate root with domain

    - by Chance
    I'm trying to figure out the best approach/practice for assembling a composite data transfer object off of an aggregate root and would love to hear people's thoughts on this. For example, lets say I have a root that has a few domain objects as children. I want to assemble a specific view dto, based on some business logic, that either has attributes or full dto's of it's objects. What I'm struggling with is trying to figure out where that assembly should happen. I can see it going on the domain object of the aggregate root as there is some business logic associated with it. The benefits of this approach from what I've deduced thus far is that it should reduce the inevitable business logic from bleeding outisde of the domain object. It also allows for private methods that take care of tasks that could become more complex from an external builder. The downsides being that the domain object becomes much more entrenched in the application's workflow and represents much more than just the domain object. It also could become very large in the scenario where you need multiple composite Dtos. Alternatively, I could also see it belonging to some form of transfer object assembler where there is a builder for each domain object. The domain objects would still be responsible for GetDto() and UpdateFromDto(dto). Outside of that, the builder would handle the construction and deconstruction of composite dtos. The downside is kind of mentioned above, where I fear this will easily lead to developers unfamiliar with DDD bleeding a ton of business logic into the assembler which is what I want to desperately avoid. Any thoughts would be greatly apperciated.

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  • DRYing up Rails Views with Nested Resources

    - by viatropos
    What is your solution to the problem if you have a model that is both not-nested and nested, such as products: a "Product" can belong_to say an "Event", and a Product can also just be independent. This means I can have routes like this: map.resources :products # /products map.resources :events do |event| event.resources :products # /events/1/products end How do you handle that in your views properly? Note: this is for an admin panel. I want to be able to have a "Create Event" page, with a side panel for creating tickets (Product), forms, and checking who's rsvp'd. So you'd click on the "Event Tickets" side panel button, and it'd take you to /events/my-new-event/tickets. But there's also a root "Products" tab for the admin panel, which could list tickets and other random products. The 'tickets' and 'products' views look 90% the same, but the tickets will have some info about the event it belongs to. It seems like I'd have to have views like this: products/index.haml products/show.haml events/products/index.haml events/products/show.haml But that doesn't seem DRY. Or I could have conditionals checking to see if the product had an Event (@product.event.nil?), but then the views would be hard to understand. How do you deal with these situations? Thanks so much.

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  • creational pattern for instances depending on multiple subclass instances

    - by markusw
    I have a problem, for that I was not able to identify a suitable design pattern. I want to create instances depending on a given type that has been passed to a factory method. What I am doing until now is the following: T create(SuperType x) { if (x instanceof SubType1) { // do some stuff and return a new SubType extends T } else if (x instanceof SubType2) { // do some stuff and return a new SubType extends T } else if ... } else { throw new UnSupportedOperationException("nothing defined for " + x); } } It seems not to be best pratice for me. Has anybody an idea how to solve this in a better way?

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  • How should Application.Run() be called for the main presenter a MVP WinForms app?

    - by Mr Roys
    I'm learning to apply MVP to a simple WinForms app (only one form) in C# and encountered an issue while creating the main presenter in static void Main(). Is it a good idea to expose a View from the Presenter in order to supply it as a parameter to Application.Run()? Currently, I've implemented an approach which allows me to not expose the View as a property of Presenter: static void Main() { IView view = new View(); Model model = new Model(); Presenter presenter = new Presenter(view, model); presenter.Start(); Application.Run(); } The Start and Stop methods in Presenter: public void Start() { view.Start(); } public void Stop() { view.Stop(); } The Start and Stop methods in View (a Windows Form): public void Start() { this.Show(); } public void Stop() { // only way to close a message loop called // via Application.Run(); without a Form parameter Application.Exit(); } The Application.Exit() call seems like an inelegant way to close the Form (and the application). The other alternative would be to expose the View as a public property of the Presenter in order to call Application.Run() with a Form parameter. static void Main() { IView view = new View(); Model model = new Model(); Presenter presenter = new Presenter(view, model); Application.Run(presenter.View); } The Start and Stop methods in Presenter remain the same. An additional property is added to return the View as a Form: public void Start() { view.Start(); } public void Stop() { view.Stop(); } // New property to return view as a Form for Application.Run(Form form); public System.Windows.Form View { get { return view as Form(); } } The Start and Stop methods in View (a Windows Form) would then be written as below: public void Start() { this.Show(); } public void Stop() { this.Close(); } Could anyone suggest which is the better approach and why? Or there even better ways to resolve this issue?

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  • How do I know if I'm being truly clever and not just "clever"?

    - by Covar
    If there's one thing I've learned from programming is that there are clever solutions to problems, and then there are "clever" solutions to problems. One is an intelligent solution to a difficult problem that results in improved efficiency and a better way to to do something and the other will wind up on The Daily WTF, and result in headaches and pain for anyone else involved. My question is how do you distinguish between one and the other? How do you figure out if you've over thought the solution? How do you stop yourself from throwing away truly clever solutions, thinking they were "clever"?

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  • Is it OK to put link to SO questions in a program comments?

    - by WizardOfOdds
    In quite some codebase you can see comments stating things like: // Workaround for defect 'xxx', (See bug 1434594 on Sun's bugparade) So I've got a few questions, but they're all related. Is it OK to put link to SO questions in a program's comments: // We're now mapping from the "sorted-on column" to original indices. // // There's apparently no easy way to do this in Java, so we're // re-inventing a wheel. // // (see why here, in SO question: http://stackoverflow.com/questions/951848) Do you do it? And what are the drawbacks in doing so? (see my first comment for a terrible drawback)

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  • Why is debugging better in an IDE?

    - by Bill Karwin
    I've been a software developer for over twenty years, programming in C, Perl, SQL, Java, PHP, JavaScript, and recently Python. I've never had a problem I could not debug using some careful thought, and well-placed debugging print statements. I respect that many people say that my techniques are primitive, and using a real debugger in an IDE is much better. Yet from my observation, IDE users don't appear to debug faster or more successfully than I can, using my stone knives and bear skins. I'm sincerely open to learning the right tools, I've just never been shown a compelling advantage to using visual debuggers. Moreover, I have never read a tutorial or book that showed how to debug effectively using an IDE, beyond the basics of how to set breakpoints and display the contents of variables. What am I missing? What makes IDE debugging tools so much more effective than thoughtful use of diagnostic print statements? Can you suggest resources (tutorials, books, screencasts) that show the finer techniques of IDE debugging? Sweet answers! Thanks much to everyone for taking the time. Very illuminating. I voted up many, and voted none down. Some notable points: Debuggers can help me do ad hoc inspection or alteration of variables, code, or any other aspect of the runtime environment, whereas manual debugging requires me to stop, edit, and re-execute the application (possibly requiring recompilation). Debuggers can attach to a running process or use a crash dump, whereas with manual debugging, "steps to reproduce" a defect are necessary. Debuggers can display complex data structures, multi-threaded environments, or full runtime stacks easily and in a more readable manner. Debuggers offer many ways to reduce the time and repetitive work to do almost any debugging tasks. Visual debuggers and console debuggers are both useful, and have many features in common. A visual debugger integrated into an IDE also gives you convenient access to smart editing and all the other features of the IDE, in a single integrated development environment (hence the name).

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  • What is the best way to manage application screens in SWT?

    - by parxier
    I'm creating a standalone SWT desktop application that has around 10 different screens (few wizards, help, forms, etc). Some elements on screen don't change at all (like header, background, etc) and there is a working area that changes depending on what is clicked, etc. What is the best way to manage application screens? Do I need to create all screen at startup and then show/hide them depending on what is clicked? Or do I need to create those screens dynamically? Also, I couldn't find any way to show/hide a Composite, do I need to dispose it and then create again? What is the best practice? I'm new to SWT developing outside of Eclipse so any help would be beneficial.

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  • MyController class must produce class according to the enum type.

    - by programmerist
    GenoTipController must produce class according to the enum type. i have 3 class: _Company,_Muayene,_Radyoloji. Also i have CompanyView Class GetPersonel method. if you look GenoTipController my codes need refactoring. Can you understand me? i need a class according to ewnum type must me produce class. For example; case DataModelType.Radyoloji it must return radyoloji= new Radyoloji . Everything must be one switch case? public class GenoTipController { public _Company GenerateCompany(DataModelType modeltype) { _Company company = null; switch (modeltype) { case DataModelType.Radyoloji: break; case DataModelType.Satis: break; case DataModelType.Muayene: break; case DataModelType.Company: company = new Company(); break; default: break; } return company; } public _Muayene GenerateMuayene(DataModelType modeltype) { _Muayene muayene = null; switch (modeltype) { case DataModelType.Radyoloji: break; case DataModelType.Satis: break; case DataModelType.Muayene: muayene = new Muayene(); break; case DataModelType.Company: break; default: break; } return muayene; } public _Radyoloji GenerateRadyoloji(DataModelType modeltype) { _Radyoloji radyoloji = null; switch (modeltype) { case DataModelType.Radyoloji: radyoloji = new Radyoloji(); break; case DataModelType.Satis: break; case DataModelType.Muayene: break; case DataModelType.Company: break; default: break; } return radyoloji; } } public class CompanyView { public static List GetPersonel() { GenoTipController controller = new GenoTipController(); _Company company = controller.GenerateCompany(DataModelType.Company); return company.GetPersonel(); } } public enum DataModelType { Radyoloji, Satis, Muayene, Company } }

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