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• Should I use a config file or database for storing business rules?

  - by foiseworth

  I have recently been reading The Pragmatic Programmer which states that: Details mess up our pristine code—especially if they change frequently. Every time we have to go in and change the code to accommodate some change in business logic, or in the law, or in management's personal tastes of the day, we run the risk of breaking the system—of introducing a new bug. Hunt, Andrew; Thomas, David (1999-10-20). The Pragmatic Programmer: From Journeyman to Master (Kindle Locations 2651-2653). Pearson Education (USA). Kindle Edition. I am currently programming a web app that has some models that have properties that can only be from a set of values, e.g. (not actual example as the web app data confidential): light-type = sphere / cube / cylinder The light type can only be the above three values but according to TPP I should always code as if they could change and place their values in a config file. As there are several incidents of this throughout the app, my question is: Should I store possibly values like these in: a config file: 'light-types' = array(sphere, cube, cylinder), 'other-type' = value, 'etc = etc-value a single table in a database with one line for each config item a database with a table for each config item (e.g. table: light_types; columns: id, name) some other way? Many thanks for any assistance / expertise offered.

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• Patterns for a tree of persistent data with multiple storage options?

  - by Robin Winslow

  I have a real-world problem which I'll try to abstract into an illustrative example. So imagine I have data objects in a tree, where parent objects can access children, and children can access parents: // Interfaces interface IParent<TChild> { List<TChild> Children; } interface IChild<TParent> { TParent Parent; } // Classes class Top : IParent<Middle> {} class Middle : IParent<Bottom>, IChild<Top> {} class Bottom : IChild<Middle> {} // Usage var top = new Top(); var middles = top.Children; // List<Middle> foreach (var middle in middles) { var bottoms = middle.Children; // List<Bottom> foreach (var bottom in bottoms) { var middle = bottom.Parent; // Access the parent var top = middle.Parent; // Access the grandparent } } All three data objects have properties that are persisted in two data stores (e.g. a database and a web service), and they need to reflect and synchronise with the stores. Some objects only request from the web service, some only write to it. Data Mapper My favourite pattern for data access is Data Mapper, because it completely separates the data objects themselves from the communication with the data store: class TopMapper { public Top FetchById(int id) { var top = new Top(DataStore.TopDataById(id)); top.Children = MiddleMapper.FetchForTop(Top); return Top; } } class MiddleMapper { public Middle FetchById(int id) { var middle = new Middle(DataStore.MiddleDataById(id)); middle.Parent = TopMapper.FetchForMiddle(middle); middle.Children = BottomMapper.FetchForMiddle(bottom); return middle; } } This way I can have one mapper per data store, and build the object from the mapper I want, and then save it back using the mapper I want. There is a circular reference here, but I guess that's not a problem because most languages can just store memory references to the objects, so there won't actually be infinite data. The problem with this is that every time I want to construct a new Top, Middle or Bottom, it needs to build the entire object tree within that object's Parent or Children property, with all the data store requests and memory usage that that entails. And in real life my tree is much bigger than the one represented here, so that's a problem. Requests in the object In this the objects request their Parents and Children themselves: class Middle { private List<Bottom> _children = null; // cache public List<Bottom> Children { get { _children = _children ?? BottomMapper.FetchForMiddle(this); return _children; } set { BottomMapper.UpdateForMiddle(this, value); _children = value; } } } I think this is an example of the repository pattern. Is that correct? This solution seems neat - the data only gets requested from the data store when you need it, and thereafter it's stored in the object if you want to request it again, avoiding a further request. However, I have two different data sources. There's a database, but there's also a web service, and I need to be able to create an object from the web service and save it back to the database and then request it again from the database and update the web service. This also makes me uneasy because the data objects themselves are no longer ignorant of the data source. We've introduced a new dependency, not to mention a circular dependency, making it harder to test. And the objects now mask their communication with the database. Other solutions Are there any other solutions which could take care of the multiple stores problem but also mean that I don't need to build / request all the data every time?

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• Box2dWeb positioning relative to HTML5 Canvas

  - by Joe

  I'm new with HTML5 canvas and Box2DWeb and I'm trying to make an Asteroids game. So far I think I'm doing okay, but one thing I'm struggling to comprehend is how positioning works in relation to the canvas. I understand that Box2DWeb is only made to deal with physical simulation, but I don't know how to deal with positioning on the canvas. The canvas is 100% viewport and thus can vary size. I want to fill the screen with some asteroids, but if I hardcore certain values such as bodyDef.position.x = Math.random() * 50; the asteroid may appear off canvas for someone with a smaller screen? Can anybody help me understand how I can deal with relative positioning on the canvas?

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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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• Is it relevant to warn about truncating real constants to 32 bits?

  - by zneak

  I'm toying around with LLVM and looking at what it would take to make yet another strongly-typed language, and now that I'm around the syntax, I've noticed that it seems to be a pet peeve of strongly typed language to warn people that their constants won't fit inside a float: // both in Java and C# float foo = 3.2; // error: implicitly truncating a double into a float // or something along these lines Why doesn't this work in Java and C#? I know it's easy to add the f after the 3.2, but is it really doing anything useful? Must I really be that aware that I'm using single-precision reals instead of double-precision reals? Maybe I'm just missing something (which, basically, is why I'm asking). Note that float foo = [const] is not the same thing as float foo = [double variable], where requiring the cast seems normal to me.

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• Database structure for various items

  - by XGouchet

  I'm building a sqlite database for an android app which will hold a list of items, each of which have different characteristics. Some of the characteristics are available for all objects, some are only relevant for a subset of objects. For example, all my items have a name, a description, an image. Some items will also have an expiration date, others wont. Some will have a size, some wont. Etc... How should I build my Database, as I don't know how many characteristics may be added in the future, and knowing I should be able to filter the list by any characteristic ?

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• Cliché monsters to populate a steampunk fantasy setting dwarven dungeon?

  - by Alexander Gladysh

  I'm looking for a list of cliché monsters for a steampunk computer game (assume one kind or another of casual rogue-like RPG), to populate lower levels of ancient dwarven-built dungeons. Dwarves are a technology/science race in the setting I am aiming for. The world is a low-magic one. I'm stuck after listing various mechanical golems, gigantic spiders (every dungeon must have some of them!), and maybe a mechanical barlog as a megaboss. What would player expect? What are the key cultural references for such setting? I know a couple of games with suitable steampunk dwarves, but none are detailed enough in the underworld monsters area. Please point me in the right direction. (If you have a single funny monster suggestion, please mention it in comments, not in answer. ;-) )

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• How do I deal with the problems of a fast side-scroller?

  - by Ska

  I'm making a side scrolling airplane game and when I begin going very fast I begin to experience some problems as a player: Elements are not distinguishable, like power-ups from bullets, etc I start to feel dizzy and uncomfortable There isn't enough time to see what's coming How can I sort this out? Do I use less details in all the grahpics? Tiny Wings has the same horizontal movement speed as in my game but it doesn't suffer from these problems. Are there any other really fast side-scrollers I could take as a reference?

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• Splitting Logic, Data, Layout and "Hacks"

  - by fjdumont

  Sure, we all heard of programming patterns such as MVVM, MVC and such. But that isn't really what I'm looking into as Layout, Data and Logic is already pretty much split up (XML-Layout markup, Database, insert your language of choice here). The platform I am developing for is hard to maintain over the updated versions and older OSes. The project significantly grew up over the last few months and dealing with different platform versions really is a pain. For example simply disabling an user interface control for all existing versions took me around 40 lines of code in the logic layer, wrangling around with invocation, delegation, singletons that provide UI handling and so on. Is there a clean way to keep track of those "hacks" by maybe excluding it into separate classes or even packages? Should I overwrite existing framework code in order to handle my requirements correctly? If so, does that concept have a name?

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• Do I need to be a genius to succeed in this field? [on hold]

  - by user46104

  I could not draw in high school only stick figures I have adhd but I thought some people with adhd/autism in this field are making inventions Do I have to be like michael angelo who could remember his dreams and drawed perfectly or is that someone else.Do I need to be able to read very fast like 30 books a year? sorry I never had a career counsellor who really supported me to dream big and to find me other people who can test if I am qualified for such dreams

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• Writing a dynamic achievement system without hardcoding rules into the application

  - by imaginative

  I really enjoyed the solution provided here for groundwork on writing an achievement framework. The problem I have is I have game designers that would like to be able to insert achievements into a CMS at runtime. In a way, it sounds insane and complex to do this, but is it really? I think the concept of having to do a hard push of the application for every new achievement is cumbersome. I would love to be able to give our designers the capability to put together new achievements by entering them into a database. It shouldn't matter what tool I'm using, but for those interested, my backend is being written in JRuby (Ruby on top of the JVM). What are some possible ways of going about abstracting the logic in the aforementioned link even further so that rules can be interpreted at runtime?

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• Gathering IP address and workstation information; does it belong in a state class?

  - by p.campbell

  I'm writing an enterprisey utility that collects exception information and writes to the Windows Event Log, sends an email, etc. This utility class will be used by all applications in the corporation: web, BizTalk, Windows Services, etc. Currently this class: holds state given to it via public properties calls out to .NET Framework methods to gather information about runtime details. Included are call to various properties and methods from System.Environment, Reflection details, etc. This implementation has the benefit of allowing all those callers not to have to make these same calls themselves. This means less code for the caller to forget, screw up, etc. Should this state class (please what's the phrase I'm looking for [like DTO]?) know how to resolve/determine runtime details (like the IP address and machine name that it's running on)? It seems to me on second thought that it's meant to be a class that should hold state, and not know how to call out to the .NET Framework to find information. var myEx = new AppProblem{MachineName="Riker"}; //Will get "Riker 10.0.0.1" from property MachineLongDesc Console.WriteLine("full machine details: " + myEx.MachineLongDesc); public class AppProblem { public string MachineName{get;set;} public string MachineLongDesc{ get{ if(string.IsNullOrEmpty(this.MachineName) { this.MachineName = Environment.MachineName; } return this.MachineName + " " + GetCurrentIP(); } } private string GetCurrentIP() { return System.Net.Dns.GetHostEntry(this.MachineName) .AddressList.First().ToString(); } } This code was written by hand from memory, and presented for simplicity, trying to illustrate the concept.

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• New Project Starting. Got Gas?

  - by merrillaldrich

  “Storage is just like gasoline,” said a fellow DBA at the office the other day. This DBA, Mike is his name, is one of the smartest people I know, so I pressed him, in my subtle and erudite way, to elaborate. “Um, whut?” I said. “Yeah. Now that everything is shared – VMs or consolidated SQL Servers and shared storage – if you want to do a big project, like, say, drive to Vegas, you better fill the car with gas. Drive back and forth to work every day? Gas. Same for storage.” This was a light-bulb-above-my-head...(read more)

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• Styling specific columns and rows

  - by hattenn

  I'm trying to style some specific parts of a 5x4 table that I create. It should be like this: Every even numbered row and every odd numbered row should get a different color. Text in the second, third, and fourth columns should be centered. I have this table: <table> <caption>Some caption</caption> <colgroup> <col> <col class="value"> <col class="value"> <col class="value"> </colgroup> <thead> <tr> <th id="year">Year</th> <th>1999</th> <th>2000</th> <th>2001</th> </tr> </thead> <tbody> <tr class="oddLine"> <td>Berlin</td> <td>3,3</td> <td>1,9</td> <td>2,3</td> </tr> <tr class="evenLine"> <td>Hamburg</td> <td>1,5</td> <td>1,3</td> <td>2,0</td> </tr> <tr class="oddLine"> <td>München</td> <td>0,6</td> <td>1,1</td> <td>1,0</td> </tr> <tr class="evenLine"> <td>Frankfurt</td> <td>1,3</td> <td>1,6</td> <td>1,9</td> </tr> </tbody> <tfoot> <tr class="oddLine"> <td>Total</td> <td>6,7</td> <td>5,9</td> <td>7,2</td> </tr> </tfoot> </table> And I have this CSS file: table, th, td { border: 1px solid black; border-collapse: collapse; padding: 0px 5px; } #year { text-align: left; } .oddLine { background-color: #DDDDDD; } .evenLine { background-color: #BBBBBB; } .value { text-align: center; } And this doesn't work. The text in the columns are not centered. What is the problem here? And is there a way to solve it (other than changing the class of all the cells that I want centered)? P.S.: I think there's some interference with .evenLine and .oddLine classes. Because when I put "background: black" in the class "value", it changes the background color of the columns in the first row. The thing is, if I delete those two classes, text-align still doesn't work, but background attribute works perfectly. Argh...

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• Handling deleted users - separate or same table?

  - by Alan Beats

  The scenario is that I've got an expanding set of users, and as time goes by, users will cancel their accounts which we currently mark as 'deleted' (with a flag) in the same table. If users with the same email address (that's how users log in) wish to create a new account, they can signup again, but a NEW account is created. (We have unique ids for every account, so email addresses can be duplicated amongst live and deleted ones). What I've noticed is that all across our system, in the normal course of things we constantly query the users table checking the user is not deleted, whereas what I'm thinking is that we dont need to do that at all...! [Clarification1: by 'constantly querying', I meant that we have queries which are like: '... FROM users WHERE isdeleted="0" AND ...'. For example, we may need to fetch all users registered for all meetings on a particular date, so in THAT query, we also have FROM users WHERE isdeleted="0" - does this make my point clearer?] (1) continue keeping deleted users in the 'main' users table (2) keep deleted users in a separate table (mostly required for historical book-keeping) What are the pros and cons of either approach?

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• Good university for computer science with plans for Game Dev.

  - by DukeYore

  I am starting my Computer science degree at a local community college in Programming using C++. However, i will be transferring to a 4-year university. Does anyone have any insight on university programs? I know Cal State Fullerton has a degree with a minor in Game Dev. however, is that as important as getting a degree from a really great school? if i could shoot for something like Cal Poly would that be better? Or even Stanford or SF state being so close to so many gaming companies up there in the bay area? thank you in advance for any guidance.

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• What books/references are recommended on the subject of planning and developing efficient web sites [closed]

  - by Shakil

  Once I visited a site containing videos; a well-known web developer creating a site from scratch via planning(paper, software), management, designing then development. I bookmarked the site but unable to find it now. My question is : How to do web-development effectively? What books or videos are recommended ???(I tried google but unable to find useful books or videos). I want to learn how people does it. Can you share resources(books, videos, links) about this... Thanks in advance.. Note: I created a job site for my university project. It gave me huge pain. Thats why I want to learn efficient way. I know html, css, javascript, jquery, php[learning(mvc and framework not yet completed)], phpmyadmin.

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• Is there a pattern or logical structure I can follow for Event Log Numbers?

  - by makerofthings7

  What are some ideas or structure I can use when assigning EventID to events that will be saved to the Event Log? Some options I've considered Sequential (0... int.Max) Multiple of 10, where the "0" is replaced with how noisy the debugLevel is set. xxx0 may represent exceptions, critical information, start, stop etc. ...? What numbering approach gives you the most insight when a user describes the event in an email or phone? What is the most useful to support staff?

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• Why do most programming languages only support returning a single value from a function?

  - by M4N

  Is there a reason or an explanation why functions in most(?) programming languages are designed to support any number of input parameters but only one return value? In most languages, it is possible to "work around" that limitation, e.g. by using out-parameters, returning pointers or by defining/returning structs/classes. But it seems strange, that programming languages were not designed to support multiple return values in a more "natural" way.

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• Why is facebook cache buggy?

  - by IAdapter

  I just started using facebook and I see that many times when I add something to my profile and visit it later its not there. I bet the reason is that the page is cached and not updated very often. Is this on purpose or is it a bug? P.S. For example I added the music I like and later I see that I did not add it, but next day when I visit again its there. I saw it in two web-browsers, so its a facebook bug. Does it has something to do with scalability?

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• doing a full permutation search and replace on a string

  - by user73307

  I'm writing an app that does something like a custom number (licence) place generator tool where if I ask for the plate "robin" it will suggest I try: r0bin rob1n r0b1n Are there any published algorithms which can do this? It has to be able to handle replacing single letters with multiples, e.g. m with rn and vise-versa and not fall over if it replaces an i with an l then comes to check the l and replaces it back to an i. The list of what gets swapped with what is going to be user input but I'm not expecting a huge list, possibly 10 pairs at most. I'll be implementing this in Ruby or Python but I should be able to convert code from any other language.

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• DirectX 10 Instancing Problem (objects cannot be seen)

  - by Riffraff

  Right now I'm trying to implement an area that is filled with vegetation. I have tried mesh version and right now I'm trying to implement instancing version but I cannot manage to make it work. I can't see any object. I search for any problem of buffers with FAILED() and D3D10_CREATE_DEVICE_DEBUG but they didn't help me either. Right now I don't even know which part of my code to share to explain my problem.

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• Can the Abstract Factory pattern be considered as a case of polymorphism?

  - by rogcg

  I was looking for a pattern/solution that allows me call a method as a runtime exception in a group of different methods without using Reflection. I've recently become aware of the Abstract Factory Pattern. To me, it looks so much like polymorphism, and I thought it could be a case of polymorphism but without the super class WidgetFactory, as you can see in the example of the link above. Am I correct in this assumption?

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• Should an object know its own ID?

  - by xenoterracide

  obj.id seems fairly common and also seems to fall within the range of something an object could know about itself. I find myself asking why should my object know its own id? It doesn't seem to have a reason to have it? One of the main reason for it existing is retrieve it, and so my repositories need to know it, and thus use it for database interaction. I also once encountered a problem where I wanted to serialize an object to JSON for a RESTful API where the id did not seem to fit in the payload, but only the URI and including it in the object made that more difficult. Should an object know it's own id? why or why not?

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• Creating an online community - use templates or self-develop?

  - by ican ican

  PHPMotion, Joomla or develop my own? I'm thinking of developing a common interest online community. It will be have UGC, stats, etc.. functionality, and perhaps an online store. Though cost is an issue at this time, I want to be professional and effective. Should I use existing free platform templates, like PHP, Joomla, or should I develop my own? What are the advantages/disadvantages of either option? As a rough estimate, how much will it cost me to develop and manage my own? And how long will it take. In general what should I be careful about on this journey?

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