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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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  • 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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  • 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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  • 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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  • 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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  • 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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  • Implementing traffic conditions in TORCS

    - by user1837811
    I am working on a project about "Effects of Traffic conditions and Track Complexity on Car Driving Behavior". Is it possible to implement traffic in TORCS, or should I use another car simulator? By the word "traffic" I mean there are cars running on both tracks in both directions and I can detect the distances, direction and speed of these cars. Depending on this information I can decide whether I should slow down, speed up and calculate the correct timing to overtake.

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  • How one could use a live editor

    - by Sathvik
    I was thinking about a live editing environment where code / a source file is synchronized so that, changes made by one user would be carried across to all others editing the file. Something like Google Wave, but for code. Could this kind of an environment be better for the code, as changes are shared instantly? (with revision-control, of course) Has anyone tried (or has had a need for) using a shared environment for code?

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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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  • Triggering Data Changes in N-Tier

    - by Ryan Kinal
    I've been studying n-tier architectures as of late, particularly in VB.NET with Entity Framework and/or LINQ to SQL. I understand the basic concepts, but have been wondering about best practices in regard to triggering CRUD-type operations from user input/action. So, the arcitecture looks something like the following: [presentation layer] - [business layer] - [data layer] - (database) Getting information from the database into the presentation layer is simple and abstracted. It's just a matter of instantiating a new object from the business layer, which in turn uses the data layer to get at the correct information. However, saving (updating and inserting), and deleting seem to require particular APIs on the relevant business objects. I have to assume this is standard practice, unless a business object will save itself on various operations (which seems inefficient), or on disposal (which seems like it just wouldn't work, or may be unwieldy and unreliable). Should my "savable" business objects all implement a particular "ISavable" or "IDatabaseObject" interface? Is this a recognized (anti-)pattern? Are there other, better patterns I should be using that I'm just unaware of? The TLDR question, I suppose, is How does the presentation layer trigger database changes?

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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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  • 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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  • User input and Automated input seperation

    - by tpaksu
    I have a mysql db and I have an automation script which modifies the data inside once a day. And, these columns may have changed by an user manually. What is the best approach to make the system only update the automated data, not the manually edited ones? I mean yes, flagging the cell which is manually edited is one way to do it, but I want to know if there's another way to accomplish this? Just curiosity.

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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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  • How to handle sorting of complex objects?

    - by AedonEtLIRA
    How would one sort a list of objects that have more than one sortable element? Suppose you have a simple object Car and car is a defined as such: class Car { public String make; public String model; public int year; public String color; // ... No methods, just a structure / container } I designed a simple framework that would allow for multiple SortOptions to be provided to a Sorter that would then sort the list. interface ISorter<T> { List<T> sort(List<T> items); void addSortOption(ISortOption<T> option); ISortOption<T>[] getSortOptions(); void setSortOption(ISortOption<T> option); } interface ISortOption<T> { String getLabel(); int compare(T t1, T t2); } Example use class SimpleStringSorter extends MergeSorter<String> { { addSorter(new AlphaSorter()); } private static final class AlphaSorter implements ISortOption<String> { // ... implementation of alpha compare and get label } } The issue with this solution is that it is not easily expandable. If car was to ever receive a new field, say, currentOwner. I would need to add the field, then track down the sorter class file, implement a new sort option class then recompile the application for redistribution. Is there an easier more expandable/practical way to sort data like this?

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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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  • What is best way to manage all images in a big project, inline images, background images, css sprite images?

    - by metal-gear-solid
    How do you manage all images in a big project, inline images, background images, css sprite images? Do you follow any naming convention? Do you create sub-folders to manage images? In a big project how to make it easy to find for new people in the development team if any images which they want to use (because it's in new PSD they received from designer) is already available in images folder of project and how they can find it easily.

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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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  • What is MVC, really?

    - by NickC
    As a serious programmer, how do you answer the question What is MVC? In my mind, MVC is sort of a nebulous topic — and because of that, if your audience is a learner, then you're free to describe it in general terms that are unlikely to be controversial. However, if you are speaking to a knowledgeable audience, especially an interviewer, I have a hard time thinking of a direction to take that doesn't risk a reaction of "well that's not right!...". We all have different real-world experience, and I haven't truly met the same MVC implementation pattern twice. Specifically, there seem to be disagreements regarding strictness, component definition, separation of parts (what piece fits where), etc. So, how should I explain MVC in a way that is correct, concise, and uncontroversial?

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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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  • C#.NET: How to update multiple .NET pages when a particular event occurs in one .Net page? In another words how to use Observer pattern(Publish and subscribe to events)

    Problem: Suppose you have a scenario in which you have to update multiple pages when an event occurs in main page. For example imagine you have a main page where you are dispalying a tab control. This tab control has 3 tab pages where you are loading 3 different user controls. On click of an update button in main page imagine if you have do something in all the 3 tab panels. In other words an event in main page has to be handled in many other pages. An event in main page which contains the tab control has to be handled in all the tab panels(user controls) Answer: Use Observer pattern Define a base page for the page that contains the tab control. Main page which contains the tab: Baseline_Baseline Basepage for the above main page: BaselineBasePage User control that has to be udpated for an event in main page: Baseline_PriorNonDeloitte Source Code: public class BaselineBasePage : System.Web.UI.Page { IList lstControls = new List(); public void Add(IObserver userControl) { lstControls.Add(userControl); } public void Remove(IObserver userControl) { lstControls.Remove(userControl); } public void RemoveAllUserControls() { lstControls.Clear(); } public void Update(SaveEventArgs e) { foreach (IObserver LobjControl in lstControls) { LobjControl.Save(e); } } } public interface IObserver { void Update(SaveEventArgs e); } public partial class Baseline_Baseline : BaselineBasePage { . . . this.Add(_ucPI); this.Add(_ucPI1); protected void abActionBar_saveClicked(object sender, EventArgs e) { SaveEventArgs se = new SaveEventArgs(); se.TabType = (BaselineTabType)tcBaseline.ActiveTabIndex; this.Update(se); } } Public class Baseline_PriorNonDeloitte : System.Web.UI.UserControl,IObserver { public void Update(SaveEventArgs e) { } } More info at: http://www.dofactory.com/Patterns/PatternObserver.aspx span.fullpost {display:none;}

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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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  • 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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  • 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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  • Would it be possible to build a client portal on Squarespace6?

    - by aBathologist
    I'm helping a family member set up a site which will need to include a secure client portal, providing access to documents and a simple database. I have been encouraging them to go with a more established, open source CSM like drupal or joomla, whose capability in this area is evident. However, they have a strong preference for Squarespace. Does any one know if it would be possible to accomplish this with the new developer platform for squarespace 6? I've spent well over an hour searching google, the squarespace site and stackexchange, but can't seem to find any clear answer to this question. I'm grateful for any insight you all can provide.

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