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  • How bad it's have two methods with the same name but differents signatures in two classes?

    - by Super User
    I have a design problem relationated with the public interface, the names of methods and the understanding of my API and my code. I have two classes like this: class A: ... function collision(self): .... ... class B: .... function _collision(self, another_object, l, r, t, b): .... The first class have one public method named collision and the second have one private method called _collision. The two methods differs in arguments type and number. In the API _m method is private. For the example let's say that the _collision method checks if the object is colliding with another_ object with certain conditions l, r, t, b (for example, collide the left side, the right side, etc) and returns true or false according to the case. The collision method, on the other hand, resolves all the collisions of the object with other objects. The two methods have the same name because I think is better avoid overload the design with different names for methods who do almost the same think, but in distinct contexts and classes. This is clear enough to the reader or I should change the method's name?

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  • What's the best way to manage reusable classes/libraries separately?

    - by Tom
    When coding, I naturally often come up with classes or a set of classes with a high reusability. I'm looking for an easy, straight-forward way to work on them separately. I'd like to be able to easily integrate them into any project; it also should be possible to switch to a different version with as few commands as possible. Am I right with the assumption that git (or another VCS) is best suited for this? I thought of setting up local repositories for each class/project/library/plugin and then just cloning/pulling them. It would be great if I could reference those projects by name, not by the full path. Like git clone someproject. edit: To clarify, I know what VCS are about and I do use them. I'm just looking for a comfortable way to store and edit some reusable pieces of code (including unit tests) separately and to be able to include them (without the unit tests) in other projects, without having to manually copy files. Apache Maven is a good example, but I'm looking for a language-independent solution, optimally command-line-based.

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  • DB Object passing between classes singleton, static or other?

    - by Stephen
    So I'm designing a reporting system at work it's my first project written OOP and I'm stuck on the design choice for the DB class. Obviously I only want to create one instance of the DB class per-session/user and then pass it to each of the classes that need it. What I don't know it what's best practice for implementing this. Currently I have code like the following:- class db { private $user = 'USER'; private $pass = 'PASS'; private $tables = array( 'user','report', 'etc...'); function __construct(){ //SET UP CONNECTION AND TABLES } }; class report{ function __construct ($params = array(), $db, $user) { //Error checking/handling trimed //$db is the database object we created $this->db = $db; //$this->user is the user object for the logged in user $this->user = $user; $this->reportCreate(); } public function setPermission($permissionId = 1) { //Note the $this->db is this the best practise solution? $this->db->permission->find($permissionId) //Note the $this->user is this the best practise solution? $this->user->checkPermission(1) $data=array(); $this->db->reportpermission->insert($data) } };//end report I've been reading about using static classes and have just come across Singletons (though these appear to be passé already?) so what's current best practice for doing this?

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  • Dynamic Class Inheritance For PHP

    - by VirtuosiMedia
    I have a situation where I think I might need dynamic class inheritance in PHP 5.3, but the idea doesn't sit well and I'm looking for a different design pattern to solve my problem if it's possible. Use Case I have a set of DB abstraction layer classes that dynamically compiles SQL queries, with one DAL class for each DB type (MySQL, MsSQL, Oracle, etc.). Each table in the database has its own class that extends the appropriate DAL class. The idea is that you interact with the table classes, but never directly use the DAL class. If you want to support a different DB type for your app, you don't need to rewrite any queries or even any code, you simply change a setting that swaps one DAL class out for another...and that's it. To give you a better idea of how this is used, you can take a look at the DAL class, the table classes, and how they are used on this StackExchange Code Review page. To really understand what I'm trying to do, please take a look at my implementation first before suggesting a solution. Issues The strategy that I had used previously was to have all of the DAL classes share the same class name. This eliminated autoloading, so I had to manually load the appropriate DAL class in a switch statement. However, this approach presents some problems for testing and documentation purposes, so I'd like to find a different way to solve the problem of loading the correct DAL class more elegantly. Update to clarify the issue The problem basically boils down to inconsistencies in the class name (pre-PHP 5.3) or class namespace (PHP 5.3) and its location in the directory structure. At this point, all of my DAL classes have the same name, DBObject, but reside in different folders, MySQL, Oracle, etc. My table classes all extend DBObject, but which DBObject they extend varies depending on which one has been loaded. Basically, I'm trying to have my cake and eat it too. The table classes act as a stable API and extend a dynamic backend, the DAL (DBObject) classes. It works great, but I outsmarted myself and because of the inconsistencies with the class names and their locations, I can't autoload the DBObject, which makes running unit tests and generating API docs impossible for the DBObject classes because the tests and docs rely on auto-loading. Just loading the appropriate DBObject into memory using a factory method won't work because there will be times when I need to load multiple DBObjects for testing. Because the classes currently share a name, this causes a class is already defined error. I can make exceptions for the DBObjects in my test code, obviously, but I'm looking for something a little less hacky as there may future instances where something similar would need to be done. Solutions? Worst case scenario, I can continue my current strategy, but I don't like it very much, especially as I'll soon be converting my code to PHP 5.3. I suspect that I can use some sort of dynamic inheritance via either namespaces (preferred) or a dynamic class extension, but I haven't been able to find good examples of this implemented in the wild. In your answers, please suggest either an alternate pattern that would work for this use case or an example of dynamic inheritance done right. Please assume PHP 5.3 with namespaced code. Any code examples are greatly encouraged. The preferred constraints for the solution are: DAL class can be autoloaded. DAL classes don't share the same exact same namespace, but share the same class name. As an example, I would prefer to use classes named DbObject that use namespaces like Vm\Db\MySql and Vm\Db\Oracle. Table classes don't have to be rewritten with a change in DB type. The appropriate DB type is determined via a single setting only. That setting is the only thing that should need to change to interchange DB types. Ideally, the setting check should occur only once per page load, but I'm flexible on that.

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  • Multiple classes in a single .cs file - good or bad?

    - by Sergio
    Is it advisable to create multiple classes within a .cs file or should each .cs file have an individual class? For example: public class Items { public class Animal { } public class Person { } public class Object { } } Dodging the fact for a minute that this is a poor example of good architecture, is having more than a single class in a .cs file a code smell?

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  • Code maintenance: keeping a bad pattern when extending new code for being consistent or not ?

    - by Guillaume
    I have to extend an existing module of a project. I don't like the way it has been done (lots of anti-pattern involved, like copy/pasted code). I don't want to perform a complete refactor. Should I: create new methods using existing convention, even if I feel it wrong, to avoid confusion for the next maintainer and being consistent with the code base? or try to use what I feel better even if it is introducing another pattern in the code ? Precison edited after first answers: The existing code is not a mess. It is easy to follow and understand. BUT it is introducing lots of boilerplate code that can be avoided with good design (resulting code might become harder to follow then). In my current case it's a good old JDBC (spring template inboard) DAO module, but I have already encounter this dilemma and I'm seeking for other dev feedback. I don't want to refactor because I don't have time. And even with time it will be hard to justify that a whole perfectly working module needs refactoring. Refactoring cost will be heavier than its benefits. Remember: code is not messy or over-complex. I can not extract few methods there and introduce an abstract class here. It is more a flaw in the design (result of extreme 'Keep It Stupid Simple' I think) So the question can also be asked like that: You, as developer, do you prefer to maintain easy stupid boring code OR to have some helpers that will do the stupid boring code at your place ? Downside of the last possibility being that you'll have to learn some stuff and maybe you will have to maintain the easy stupid boring code too until a full refactoring is done)

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  • Does the use of mongodb enhance extending/changing database driven applications?

    - by developer10214
    When an application is created which need to store data, an SQL database is used very often. So did I in a lot of asp.net applications. The resulting applications have often an ORM like the entity framework and maybe a business layer. So when such an application needs to be extended(let's say you have to add a comment property to an object), you have to change/extend the database, then the ORM and the business layer and so on. To deploy the changes you have to update the target database and the application. I know that things like code first and fluent can make this approach easier. I tried mongodb, I only used the standard driver and I had to extend some objects and all I had to do was changing the code. So it feels that such approaches are much easier to realize when using mongodb. I don't have much experience with larger applications an mongodb. I know that a SQL database or mongodb doesn't fit for all needs and both have their pros and cons. I want to know if my feeling is right, if yes I would choose rather choose mongodb than SQL database.

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  • Why is my class worse than the hierarchy of classes in the book (beginner OOP)?

    - by aditya menon
    I am reading this book. The author is trying to model a lesson in a college. The goal is to output the Lesson Type (Lecture or Seminar), and the Charges for the lesson depending on whether it is a hourly or fixed price lesson. So the output should be: lesson charge 20. Charge type: hourly rate. lesson type seminar. lesson charge 30. Charge type: fixed rate. lesson type lecture. When the input is as follows: $lessons[] = new Lesson('hourly rate', 4, 'seminar'); $lessons[] = new Lesson('fixed rate', null, 'lecture'); I wrote this: class Lesson { private $chargeType; private $duration; private $lessonType; public function __construct($chargeType, $duration, $lessonType) { $this->chargeType = $chargeType; $this->duration = $duration; $this->lessonType = $lessonType; } public function getChargeType() { return $this->getChargeType; } public function getLessonType() { return $this->getLessonType; } public function cost() { if($this->chargeType == 'fixed rate') { return "30"; } else { return $this->duration * 5; } } } $lessons[] = new Lesson('hourly rate', 4, 'seminar'); $lessons[] = new Lesson('fixed rate', null, 'lecture'); foreach($lessons as $lesson) { print "lesson charge {$lesson->cost()}."; print " Charge type: {$lesson->getChargeType()}."; print " lesson type {$lesson->getLessonType()}."; print "<br />"; } But according to the book, I am wrong (I am pretty sure I am, too). The author gave a large hierarchy of classes as the solution instead. In a previous chapter, the author stated the following 'four signposts' as the time when I should consider changing my class structure: Code Duplication The Class Who Knew Too Much About His Context The Jack of All Trades - Classes that try to do many things Conditional Statements The only problem I can see is Conditional Statements, and that too in a vague manner - so why refactor this? What problems do you think might arise in the future that I have not foreseen?

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  • Is it evil to model JSON responses to classes when they are mostly smilar?

    - by Aybe
    Here's the problem : While implementing a C# wrapper for an online API (Discogs) I've been faced to a dilemma : quite often the responses returned have mostly similar members and while modeling these responses to classes, some questions surfaces on which way to go would be the best. Example : Querying for a 'release' or a 'master' will return an object that contains an array of 'artist', however these 'artists' do not exactly have the same members. Currently I decided to represent these 'artists' as a single 'Artist' class, against having respective 'ReleaseArtist' and 'MasterArtist' classes which soon becomes very confusing even though another problem arises : when a category (master or release) does not return these members, they will be null. Though it might sound confusing as well I find it less confusing than the former situation as I've tackled the problem by simply not showing null members when visualizing these objects. Is this the right approach to follow ? An example of these differences : public class Artist { public List<Alias> Aliases { get; set; } public string DataQuality { get; set; } public List<Image> Images { get; set; } public string Name { get; set; } public List<string> NameVariations { get; set; } public string Profile { get; set; } public string Realname { get; set; } public string ReleasesUrl { get; set; } public string ResourceUrl { get; set; } public string Uri { get; set; } public List<string> Urls { get; set; } } public class ReleaseArtist { public string Join { get; set; } public string Name { get; set; } public string Anv { get; set; } public string Tracks { get; set; } public string Role { get; set; } public string ResourceUrl { get; set; } public int Id { get; set; } }

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  • How can I use UML to model a relationship between two classes, where one has functions exposed as friend to the other?

    - by user1796528
    I have a two classes: ------------ --------------- X Y ------------ --------------- relation ------------ ------------------ --------------- A() C() B() D() E() ------------ --------------- I want to inherit just these two functions from X class, where they are defined with the friend access modifier. My class will be: --------------- Y --------------- --------------- C() A() D() --------------- Y class uses some functions of X class namely A and D. How can I model this relationship in a UML class diagram?

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  • Writing or extending existing emacs packages: is it worth or should I move to Netbeans/Eclipse?

    - by Andrea
    I'm finishing my master degree course in CS and I've almost become addicted to Emacs. I've used it to write in C, Latex, Java, JSP,XML, CommonLisp, Ada and other languages no other editor supported, like AMPL. I'd like to improve the packages I've been using the most or create new ones, but, in practice, I find that the implementation of Emacs leaves a lot to be desired. There are a lot of poorly-featured/poorly-maintained packages with either overlapping functionalities or obscure incompatibilities, and Elisp just seems to foster the situation by lacking the common features modern lisps have. In contrast Eclipse and Netbeans are actively improved and it does seem they can be effective for non-mainstream languages. I tried Hibachi for Ada in Eclipse and it worked well, there's CUPS for Lisp in Eclipse and LambdaBeans built using NetBeans components. On the other hand those plugins seem to be less active than their Emacs' counterparts, for example Hibachi was archived last year. What's your opinion on this? Which editor should I write extension for? EDIT: To answer Larry Coleman (see comment below): I like Emacs as a user because it is efficient both for me and the computer I'm using. It's fast and the textual interface (i.e. minibuffer) allows for quick interaction. It's solid and packages are usually small and easy to manage. If I need to correct or remove something I usually just have to change a row in my .emacs or an elisp file, or delete a directory. Eclipse plugins rely on a more complicated process that screwed my Eclipse configuration a couple of times, forcing me to do a clean reinstall. Emacs works as long as I use the basic packages. If I need something more complicated the situation gets pretty hairy. As a "power user" I think that the best I can hope for is to write a severely crippled version of the extensions I'd actually like to have; in other words, that it's not worth the trouble. I'd like to write extensions for the things I'd like to have automated in Emacs, for example project support with automated tag-table update on file writing. There are a few projects on this that lack integration, documentation, extensibility and so forth. The best one is probably CEDET, for which I believe the Greenspun's 10th rule can be applied. EDIT: To comment Larry Coleman's answer I'm pretty sure I can pick elisp programming but the extensions I have in mind don't exist yet despite their relative simplicity and the effort more knowledgeable people poured into related projects.This makes me wonder whether it is so because of the way emacs is developed, i.e. people tend to write their own little extensions without coordination, or its implementation, its extension language not being able to keep up with the growing complexity.

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  • Extending Expression Blend 4 &amp; Blend for Visual Studio 2012

    - by Chris Skardon
    Just getting this off the bat, I presume this will also work for Blend 5, but I can’t confirm it… Anyhews, I imagine you’re here because you want to know how to create an addin for Blend, so let’s jump right in there! First, and foremost, we’re going to need to ensure our development environment has the right setup, so the checklist: Visual Studio 2012 Blend for Visual Studio 2012 OK, let’s create a new project (class library, .NET 4.5): Hello.Extension The ‘.Extension’ bit is very very important. The addin will not work unless it is named in this way. You can put whatever you want at the front, but it has to have the extension bit. OK, so now we have a solution with one project. To this project we need to add references to the following things: Microsoft.Expression.Extensibility (from c:\program files\Microsoft Visual Studio 11.0\Blend\   -- x86 folder if you are on an x64 windows install) Microsoft.Expression.Framework (same location as above) PresentationCore PresentationFramework WindowsBase System.ComponentModel.Composition Got them? ACE. Let’s now add a project to contain our control, so, create a new WPF Application project, cunningly named something like ‘Hello.Control’… (I’m creating a WPF application here, because I’m too lazy to dig up the correct references, and this will add all the ones I need ) Once that is created, delete the App.xaml and MainWindow.xaml files, we won’t be needing them. You will also need to change the properties of the project itself, so it is only a class library. Once that is done, let’s add a new UserControl, which will be this: <UserControl x:Class="Hello.Control.HelloControl" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="300"> <Grid> <TextBlock Text="HELLO!!!"/> </Grid> </UserControl> Impressive eh? Now, let’s reference the WPF project from the Extension library. All that’s left now is to code up our extension… So, add a class to the Extension project (name wise doesn’t matter), and make it implement the IPackage interface from the Microsoft.Expression.Extensibility library: public class HelloExtension : IPackage { /**/ } We’ll implement the two methods we need to: public class HelloExtension : IPackage { public void Load(IServices services) { } public void Unload() { } } We’re only really concerned about the Load method in this case, as let’s face it, the extension we have doesn’t need to do a lot to bog off. The interesting thing about the Load method is that it receives an IServices instance. This allows us to get access to all the services that Expression provides, in this case we’re interested in one in particular, the ‘IWindowService’ So, let’s get that bad boy… private IWindowService _windowService; public void Load(IServices services) { _windowService = services.GetService<IWindowService>(); } Nailed it… But why? The WindowService allows us to register our UserControl with Blend, which in turn allows people to activate and see it, which is a big plus point. So, let’s do that… We’ll create an ‘Initialize’ method to create our new control, and add it to the WindowService: private HelloControl _helloControl; public void Initialize() { _helloControl = new HelloControl(); if (_windowService.PaletteRegistry["HelloPanel"] == null) _windowService.RegisterPalette("HelloPanel", _helloControl, "Hello Window"); } First we check that we’re not already registered, and if we’re not we register, the first argument is the identifier used by the service to, well, identify your extension. The second argument is the actual control, the third argument is the name that people will see in the ‘Windows’ menu of Blend itself (so important note here – don’t put anything embarrassing or (need I say it?) sweary…) There are only two things to do now - Call ‘Initialize()’ from our Load method, and Export the class This is easy money – add [Export(typeof(IPackage))] to the top of our class… The full code will (should) look like this: [Export(typeof (IPackage))] public class HelloExtension : IPackage { private HelloControl _helloControl; private IWindowService _windowService; public void Load(IServices services) { _windowService = services.GetService<IWindowService>(); Initialize(); } public void Unload() { } public void Initialize() { _helloControl = new HelloControl(); if (_windowService.PaletteRegistry["HelloControl"] == null) _windowService.RegisterPalette("HelloControl", _helloControl, "Hello Window"); } } If you build this and copy it to your ‘Extensions’ folder in Blend (c:\program files\microsoft visual studio 11.0\blend\) and start Blend, you should see ‘Hello Window’ listed in the Window menu: That as they say is it!

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  • Is there a recommended approach for using SQL Server as an Authorization store and extending AD properties using .Net? [closed]

    - by Jim
    We are going to be using SQL Server as an authorization store for our .Net windows services and WCF services as well as storing additional metadata about users and groups to extend the AD properties. Doing this will make this self service and not require IT to change anything for our department (for users or groups). What if any are the existing recommended stategies or technologies that do this function?

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  • Multiple classes in a single .cs file - good or bad?

    - by Sergio
    Is it advisable to create multiple classes within a .cs file or should each .cs file have an individual class? For example: public class Items { public class Animal { } public class Person { } public class Object { } } Dodging the fact for a minute that this is a poor example of good architecture, is having more than a single class in a .cs file a code smell?

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  • Is it dangerous for me to give some of my Model classes Control-like methods?

    - by Pureferret
    In my personal project I have tried to stick to MVC, but I've also been made aware that sticking to MVC too tightly can be a bad thing as it makes writing awkward and forces the flow of the program in odd ways (i.e. some simple functions can be performed by something that normally wouldn't, and avoid MVC related overheads). So I'm beginning to feel justified in this compromise: I have some 'manager programs' that 'own' data and have some way to manipulate it, as such I think they'd count as both part of the model, and part of the control, and to me this feels more natural than keepingthem separate. For instance: One of my Managers is the PlayerCharacterManager that has these methods: void buySkill(PlayerCharacter playerCharacter, Skill skill); void changeName(); void changeRole(); void restatCharacter(); void addCharacterToGame(); void createNewCharacter(); PlayerCharacter getPlayerCharacter(); List<PlayerCharacter> getPlayersCharacter(Player player); List<PlayerCharacter> getAllCharacters(); I hope the mothod names are transparent enough that they don't all need explaining. I've called it a manager because it will help manage all of the PlayerCharacter 'model' objects the code creates, and create and keep a map of these. I may also get it to store other information in the future. I plan to have another two similar classes for this sort of control, but I will orchestrate when and how this happens, and what to do with the returned data via a pure controller class. This splitting up control between informed managers and the controller, as opposed to operating just through a controller seems like it will simplify my code and make it flow more. My question is, is this a dangerous choice, in terms of making the code harder to follow/test/fix? Is this somethign established as good or bad or neutral? I oculdn't find anything similar except the idea of Actors but that's not quite why I'm trying to do. Edit: Perhaps an example is needed; I'm using the Controller to update the view and access the data, so when I click the 'Add new character to a player button' it'll call methods in the controller that then go and tell the PlayerCharacterManager class to create a new character instance, it'll call the PlayerManager class to add that new character to the player-character map, and then it'll add this information to the database, and tell the view to update any GUIs effected. That is the sort of 'control sequence' I'm hoping to create with these manager classes.

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  • Why creating a new MDX language instead of extending SQL?

    - by DReispt
    I have a long experience with SQL, but recently began working with datawarehouse and OLAP technologies: building fact and dimension tables, that then are queried using MDX (MultiDimensional eXpressions). The problem is that MDX works with a completely different logic compared to SQL, and it's a whole new learning curve even for someone with a strong SQL background. Yes, MDX allows you to do things that would be hard or almost impossible with plain SQL. But sometimes it's frustrating to be hours around an MDX to do something you know you could achieve in minutes using SQL (ok, you can tell me to RTFM ...). But why go on to the trouble of creating a new completely different language when you could build on SQL, extend it to add the features needed by OLAP applications?

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  • Want to Optimize Your Own Site? Then SEO Classes Are the Answer

    If you have decided to learn search engine optimization because you would like your website to gain higher ranking by adding targeted keywords then the best way to do this would be to attend SEO classes online. This way you won't have to pay professional SEO companies as you will be capable of setting up your own business in no time one you have completed your training.

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  • How do I prevent a font from extending off the top of a textbox?

    - by David Ellis
    I'm using a barcode font (IDAutomationMC39H) in an SSRS 2005 report I'm developing, and while it renders fine in the preview in BIDS, if I export the results to PDF, print the results, or do any of the above (including preview) in Report Manager, the barcode font is extending off the top of the textbox. The barcode itself is nearly 20px tall, even at only a 12pt size. I've tried changing the CanGrow value for the textbox, but it seems that even with that set off the barcode isn't pushing the bottom edge of the textbox downwards, it's simply extending over the top of the box. I've also tried resizing the textbox to allow it to contain the entire height of the font, but even with the VerticalAlign set to Bottom the barcode still sticks to the top of the textbox and overflows out the top. See screenshot here: http://bit.ly/9UfycP Does anyone know how to force the font to be bound by the top of the box, instead of overlapping it?

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  • Code structure for multiple applications with a common core

    - by Azrael Seraphin
    I want to create two applications that will have a lot of common functionality. Basically, one system is a more advanced version of the other system. Let's call them Simple and Advanced. The Advanced system will add to, extend, alter and sometimes replace the functionality of the Simple system. For instance, the Advanced system will add new classes, add properties and methods to existing Simple classes, change the behavior of classes, etc. Initially I was thinking that the Advanced classes simply inherited from the Simple classes but I can see the functionality diverging quite significantly as development progresses, even while maintaining a core base functionality. For instance, the Simple system might have a Project class with a Sponsor property whereas the Advanced system has a list of Project.Sponsors. It seems poor practice to inherit from a class and then hide, alter or throw away significant parts of its features. An alternative is just to run two separate code bases and copy the common code between them but that seems inefficient, archaic and fraught with peril. Surely we have moved beyond the days of "copy-and-paste inheritance". Another way to structure it would be to use partial classes and have three projects: Core which has the common functionality, Simple which extends the Core partial classes for the simple system, and Advanced which also extends the Core partial classes for the advanced system. Plus having three test projects as well for each system. This seems like a cleaner approach. What would be the best way to structure the solution/projects/code to create two versions of a similar system? Let's say I later want to create a third system called Extreme, largely based on the Advanced system. Do I then create an AdvancedCore project which both Advanced and Extreme extend using partial classes? Is there a better way to do this? If it matters, this is likely to be a C#/MVC system but I'd be happy to do this in any language/framework that is suitable.

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  • What common interface would be appropriate for these game object classes?

    - by Jefffrey
    Question A component based system's goal is to solve the problems that derives from inheritance: for example the fact that some parts of the code (that are called components) are reused by very different classes that, hypothetically, would lie in a very different branch of the inheritance tree. That's a very nice concept, but I've found out that CBS is often hard to accomplish without using ugly hacks. Implementations of this system are often far from clean. But I don't want to discuss this any further. My question is: how can I solve the same problems a CBS try to solve with a very clean interface? (possibly with examples, there are a lot of abstract talks about the "perfect" design already). Context Here's an example I was going for before realizing I was just reinventing inheritance again: class Human { public: Position position; Movement movement; Sprite sprite; // other human specific components }; class Zombie { Position position; Movement movement; Sprite sprite; // other zombie specific components }; After writing that I realized I needed an interface, otherwise I would have needed N containers for N different types of objects (or to use boost::variant to gather them all together). So I've thought of polymorphism (move what systems do in a CBS design into class specific functions): class Entity { public: virtual void on_event(Event) {} // not pure virtual on purpose virtual void on_update(World) {} virtual void on_draw(Window) {} }; class Human : public Entity { private: Position position; Movement movement; Sprite sprite; public: virtual void on_event(Event) { ... } virtual void on_update(World) { ... } virtual void on_draw(Window) { ... } }; class Zombie : public Entity { private: Position position; Movement movement; Sprite sprite; public: virtual void on_event(Event) { ... } virtual void on_update(World) { ... } virtual void on_draw(Window) { ... } }; Which was nice, except for the fact that now the outside world would not even be able to know where a Human is positioned (it does not have access to its position member). That would be useful to track the player position for collision detection or if on_update the Zombie would want to track down its nearest human to move towards him. So I added const Position& get_position() const; to both the Zombie and Human classes. And then I realized that both functionality were shared, so it should have gone to the common base class: Entity. Do you notice anything? Yes, with that methodology I would have a god Entity class full of common functionality (which is the thing I was trying to avoid in the first place). Meaning of "hacks" in the implementation I'm referring to I'm talking about the implementations that defines Entities as simple IDs to which components are dynamically attached. Their implementation can vary from C-stylish: int last_id; Position* positions[MAX_ENTITIES]; Movement* movements[MAX_ENTITIES]; Where positions[i], movements[i], component[i], ... make up the entity. Or to more C++-style: int last_id; std::map<int, Position> positions; std::map<int, Movement> movements; From which systems can detect if an entity/id can have attached components.

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  • A list of 'best practices' for extending the life between charges of a notebook battery.

    - by Tim Visher
    Hello Everyone, I'd like to compile a list of best practices for getting the most out of a single charge of a typical notebook battery (be it Li-Ion or Li-Poly). Sources would be great as well. I've heard, for instance, that the best things to do to improve battery performance (not the total lifetime of the battery, just single charge performance) are, in descending order of effectiveness: Turn your display all the way down. Turn off WiFi Turn off Bluetooth Spin down disks when they're not in use. etc… I'd like to get sources together for these and other tips for extending life-between-charge for any battery on any notebook (as these really are all about Demand Management rather than Life lime extension. Thanks!

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  • Always importing too many classes... I think!

    - by Bill
    I have a basic problem with knowing which classes to import for a given application, renderer, AS package, mxml component, etc. There seems to be hundreds of classes (both mx and flash) and I'm never sure which one(s) to import... so I just keep adding import statements until the errors go away. Is there a reference somewhere that I don't know about? Or does this just come with experience? Also... does importing a load of classes actually make the file size larger or does Flex only import the classes used nregardless of what I specify? If it only uses what is needed, why wouldn't everyone just do: import mx.*;

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  • How do game programmers design their classes to reuse in AI, network and play and pass mode?

    - by Amogh Talpallikar
    For a two player game where, your opponent could be on the network, CPU itself or near you where you would play turn by turn on the same machine. How do people design classes for re-use ? I am in a similar situation and have no experience in making such complex games. But here is what I have thought, If I am a player object , I should only be interacting with the GameManager or GameEngine Singleton , from which I will get various notifications about the game status. I dont care where and who my opponent is, this GameManager depending upon the game mode, will interact with gameNetworkManager , or AI tell me what the opponent played. I am not sure about the scenario where we play and pass [turn by turn on same machine]. Hoping for a brief but clear explanation or at least a link to a similar resource.:)

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  • Entity Framework - in model first, how do I get my EF classes to be based on the existing domain cla

    - by Greg
    Hi, If I already have domain classes, and I want to be able persist them using EF via a model first approach how do I do this? For example do I go to the EF designer (in VS2010) and create the model and generate the classes, then go to these EF classes and somehow manually modify them? But then would there be an issue if I needed to change the model and re-create database TSQL from the model for updates? What's the easiest approach?

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