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• Has anyone ever encountered a Monad Transformer in the wild?

  - by martingw

  In my area of business - back office IT for a financial institution - it is very common for a software component to carry a global configuration around, to log it's progress, to have some kind of error handling / computation short circuit... Things that can be modelled nicely by Reader-, Writer-, Maybe-monads and the like in Haskell and composed together with monad transformers. But there seem to some drawbacks: The concept behind monad transformers is quite tricky and hard to understand, monad transformers lead to very complex type signatures, and they inflict some performance penalty. So I'm wondering: Are monad transformers best practice when dealing with those common tasks mentioned above?

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• Using DTOs and BOs

  - by ryanzec

  One area of question for me about DTOs/BOs is about when to pass/return the DTOs and when to pass/return the BOs. My gut reaction tells me to always map NHibernate to the DTOs, not BOs, and always pass/return the DTOs. Then whenever I needed to perform business logic, I would convert my DTO into a BO. The way I would do this is that my BO would have a have a constructor that takes a parameter that is the type of my interface (that defines the required fields/properties) that both my DTO and BO implement as the only argument. Then I would be able to create my BO by passing it the DTO in the constructor (since both with implement the same interface, they both with have the same properties) and then be able to perform my business logic with that BO. I would then also have a way to convert a BO to a DTO. However, I have also seen where people seem to only work with BOs and only work with DTOs in the background where to the user, it looks like there are no DTOs. What benefits/downfalls are there with this architecture vs always using BO's? Should I always being passing/returning either DTOs or BOs or mix and match (seems like mixing and matching could get confusing)?

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• Design decisions

  - by Drew Gain

  I have been asked to choose between Web Forms and MVC for a minor internal company project. I do not know MVC. How much of MVC do i have to know to be able to make a decision? Note: 1. I have read up on MVC to an extent that i know the high level design choices that I will have to make, however as a developer, I do not feel comfortable unless i code in it...

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• Disable resizing tables in mozilla in design mode

  - by Anatoliy

  Is there a way to remove the attribute '_moz_resizing="true"' added by Firefox from to avoid giving user the possibility to resize table in design mode (when contentEditable=true).

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• Activator.CreateInstance(string) and Activator.CreateInstance<T>() difference

  - by Juan Manuel Formoso

  No, this is not a question about generics. I have a Factory pattern with several classes with internal constructors (I don't want them being instantiated if not through the factory). My problem is that CreateInstance fails with a "No parameterless constructor defined for this object" error unless I pass "true" on the non-public parameter. Example // Fails Activator.CreateInstance(type); // Works Activator.CreateInstance(type, true); I wanted to make the factory generic to make it a little simpler, like this: public class GenericFactory<T> where T : MyAbstractType { public static T GetInstance() { return Activator.CreateInstance<T>(); } } However, I was unable to find how to pass that "true" parameter for it to accept non-public constructors (internal). Did I miss something or it isn't possible?

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• Hide Non-Displayed ASP Elements in Design View

  - by Steven

  Is there a way to prevent non-displayed elements from appearing in the ASPX Design View editor? By "non-displayed elements", I mean the background elements (Managers, DataSources, Validators, etc) that show up as grey boxes containing the type and id. If I have several of those at the top of the page, I can't see much of the preview of my page.

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• actionscript-3: refactor interface inheritance to get rid of ambiguous reference error

  - by maxmc

  hi! imagine there are two interfaces arranged via composite pattern, one of them has a dispose method among other methods: interface IComponent extends ILeaf { ... function dispose() : void; } interface ILeaf { ... } some implementations have some more things in common (say an id) so there are two more interfaces: interface ICommonLeaf extends ILeaf { function get id() : String; } interface ICommonComponent extends ICommonLeaf, IComponent { } so far so good. but there is another interface which also has a dispose method: interface ISomething { ... function dispose() : void; } and ISomething is inherited by ICommonLeaf: interface ICommonLeaf extends ILeaf, ISomething { function get id() : String; } As soon as the dispose method is invoked on an instance which implements the ICommonComponent interface, the compiler fails with an ambiguous reference error because ISomething has a method called dispose and ILeaf also has a dispose method, both living in different interfaces (IComponent, ISomething) within the inheritace tree of ICommonComponent. I wonder how to deal with the situation if the IComponent, the ILeaf and the ISomething can't change. the composite structure must also work for for the ICommonLeaf & ICommonComponent implementations and the ICommonLeaf & ICommonComponent must conform to the ISomething type. this might be an actionscript-3 specific issue. i haven't tested how other languages (for instance java) handle stuff like this.

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• pattern for the following condition in java

  - by zahir hussain

  hi i want to know how to write pattern.. for example : the word is "AboutGoogle AdWords Drive traffic and customers to your site. Pay through Cheque, Net Banking or Credit Card. Google Toolbar Add a search box to your browser. Google SMS To find out local information simply SMS to 54664. Gmail Free email with 7.2GB storage and less spam. Try Gmail today. Our ProductsHelp Help with Google Search, Services and ProductsGoogle Web Search Features Translation, I'm Feeling Lucky, CachedGoogle Services & Tools Toolbar, Google Web APIs, ButtonsGoogle Labs Ideas, Demos, ExperimentsFor Site OwnersAdvertising AdWords, AdSenseBusiness Solutions Google Search Appliance, Google Mini, WebSearchWebmaster Central One-stop shop for comprehensive info about how Google crawls and indexes websitesSubmit your content to Google Add your site, Google SitemapsOur CompanyPress Center News, Images, ZeitgeistJobs at Google Openings, Perks, CultureCorporate Info Company overview, Philosophy, Diversity, AddressesInvestor Relations Financial info, Corporate governanceMore GoogleContact Us FAQs, Feedback, NewsletterGoogle Logos Official Logos, Holiday Logos, Fan LogosGoogle Blog Insights to Google products and cultureGoogle Store Pens, Shirts, Lava lamps©2010 Google - Privacy Policy - Terms of Service" I have to search some word... for example "google insights" so how to write the code in java... i just write small code... check my code and answer my question... that code only use for find the search word, where is that. but i need to display some words front of search word and display some words rear of search workd... similar to google search... my code is Pattern p = Pattern.compile("(?i)(.*?)"+search+""); Matcher m = p.matcher(full); String title=""; while (m.find() == true) { title=m.group(1); System.out.println(title); } the full is orignal content, search s search word... thanks and advance

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• What is the most EVIL code you have ever seen in a production enterprise environment?

  - by Registered User

  What is the most evil or dangerous code fragment you have ever seen in a production environment at a company? I've never encountered production code that I would consider to be deliberately malicious and evil, so I'm quite curious to see what others have found. The most dangerous code I have ever seen was a stored procedure two linked-servers away from our core production database server. The stored procedure accepted any NVARCHAR(8000) parameter and executed the parameter on the target production server via an double-jump sp_executeSQL command. That is to say, the sp_executeSQL command executed another sp_executeSQL command in order to jump two linked servers. Oh, and the linked server account had sysadmin rights on the target production server.

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• Command Pattern : How to pass parameters to a command ?

  - by Romain Verdier

  My question is related to the command pattern, where we have the following abstraction (C# code) : public interface ICommand { Execute(); } Let's take a simple concrete command, which aims to delete an entity from our application. A Person instance, for example. I'll have a DeletePersonCommand, which implements ICommand. This command needs the Person to delete as a parameter, in order to delete it when Execute method is called. What is the best way to manage parametrized commands ? How to pass parameters to commands, before executing them ?

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• Easymock vs Mockito: Design vs Maintainability?

  - by RAbraham

  One way of thinking about this is: if we care about the Design of the code then Easymock is the better choice as it gives feedback to you by its concept of expectations If we care about the maintainability of tests( easier to read,write and having less brittle tests which are not affected much by change), then Mockito seems a better choice. My question is: - If you have used Easymock in large scale projects, do you find that your tests are harder to maintain? - What are the limitations of Mockito( other than endo testing)

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• Designing a general database interface in PHP

  - by lamas

  I'm creating a small framework for my web projects in PHP so I don't have to do the basic work over and over again for every new website. It is not my goal to create a second CakePHP or Codeigniter and I'm also not planning to build my websites with any of the available frameworks as I prefer to use things I've created myself in general. I have no problems in designing that framework when it comes to parts like the core structure, request handling, and so on but I'm getting stuck with designing the database interface for my modules. I've already thought about using the MVC pattern but thought that it would be a bit of a overkill. So the exact problem I'm facing is how my frameworks modules (viewCustomers could be a module, for example) should interact with the database. Is it a good idea to write SQL directly in PHP (mysql_query( 'SELECT firstname, lastname(.....))? How could I abstract a query like SELECT firstname, lastname FROM customers WHERE id=X Would MySQL helper functions like $this->db->get( array('firstname', 'lastname'), array('id'=>X) ) be a good idea? I suppose not because they actually make everything more complicated by requiring arrays to be created and passed. Is the Model pattern from MVC my only real option?

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• Service Layer Patter - Could we avoid the service layer on a specific case?

  - by lidermin

  Hi, we are trying to implement an application using the Service Layer Pattern cause our application needs to connect to other multiple applications too, and googling on the web, we found this link of a demostrative graphic for the "right" way of apply the pattern: martinfowler.com - Service Layer Pattern But now we have a question: what if our system needs to implement some business logic, only for our application (like some maintenance data for the system itself) that we don't need to share with other systems. Based on this graphic: As it seems, it will be unnecesary to implement a service layer just for that; it will be more practical to avoid the service layer, and just go from User Interface to the Business Layer (for example). What should be the right way in this case to implement the Service Layer Pattern? What do you suggest us for a scenario like the one I told you? Thanks in advance.

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• Service Layer Patter - Could we avoid the service layer on a specific case?

  - by lidermin

  Hi, we are trying to implement an application using the Service Layer Pattern cause our application needs to connect to other multiple applications too, and googling on the web, we found this link of a demostrative graphic for the "right" way of apply the pattern: martinfowler.com - Service Layer Pattern But now we have a question: what if our system needs to implement some business logic, only for our application (like some maintenance data for the system itself) that we don't need to share with other systems. Based on this graphic: As it seems, it will be unnecesary to implement a service layer just for that; it will be more practical to avoid the service layer, and just go from User Interface to the Business Layer (for example). What should be the right way in this case to implement the Service Layer Pattern? What do you suggest us for a scenario like the one I told you? Thanks in advance.

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• I Clean Solution'd my Winform App and now it's broken...

  - by Refracted Paladin

  I have a Winform App that uses a 3rd Party Library of Controls, DevExpress. I also created a bunch of Controls myself, extending those controls. Everything has been working fine when all of a sudden I opened VS today and on the Design Page all my extended controls were missing. I then tried rebuilding to no avail. Then I tried Cleaning and Rebuilding and made it even worse. Now I have tons(520) of erros stating things like -- Error 179 The name 'datBirthDate' does not exist in the current context D:\Documents\Visual Studio 2008\Projects\MatrixReloaded\MatrixReloaded\Controls\Member\ucGeneral.cs 339 17 MatrixReloaded also if I try to open a form or user control in Design Mode I first get this -- could not find type, "MyType" please make sure that the assembly that contains this type is referenced and then, if I click Ignore and Continue I get this for all Forms and Contros when I try and look at them in Design Mode -- Exception of type System.OutOfMemoryException was thrown Help!?!? When I googled I came across mostly references to VS 2003...I am on 2008 sp1.

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• ASP.NET MVC: post-redirect-get pattern, with only two overloaded action methods

  - by Rafi

  Is it possible to implement post-redirect-get pattern, with two overloaded action methods(One for GET action and the other for POST action) in ASP.NET MVC. In all of the MVC post-redirect-get pattern samples, I have seen three different action methods for the post-redirect-get process, each having different names. Is this really required? For Eg:(Does the code shown below, follows Post-Redirect-Get pattern?) public class SalaryTransferController : Controller { // // GET: /SalaryTransfer/ [HttpGet] public ActionResult Index(int id) { SalaryTransferIndexViewModel vm = new SalaryTransferIndexViewModel(id) { SelectedDivision = DivisionEnum.Contracting }; //Do some processing here return View(vm); } // // POST: /SalaryTransfer/ [HttpPost] public ActionResult Index(SalaryTransferIndexViewModel vm) { bool validationsuccess = false; //validate if (validationsuccess) return RedirectToAction("Index", new {id=1234 }); else return View(vm); } } Thank you for your responses.

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• Command Pattern vs. Visitor Pattern

  - by grefly

  Is it generally acceptable to allow a Visitor to modify state of the Receiver, or should that be a Command pattern instead?

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• Consistency vs Design Guidelines

  - by Adrian Faciu

  Lets say that you get involved in the development of a large project that is already in development for a long period ( more than one year ). The projects follows some of the current design guidelines, but also has a few different, that are currently discouraged ( mostly at naming guidelines ). Supposing that you can't/aren't allowed to change the whole project: What should be more important, consistency, follow the existing ones and defy current guidelines or the usage of the guidelines, creating differences between modules of the same project ? Thanks.

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• Game AI: Pattern for implementing Sense-Think-Act components?

  - by Rosarch

  I'm developing a game. Each entity in the game is a GameObject. Each GameObject is composed of a GameObjectController, GameObjectModel, and GameObjectView. (Or inheritants thereof.) For NPCs, the GameObjectController is split into: IThinkNPC: reads current state and makes a decision about what to do IActNPC: updates state based on what needs to be done ISenseNPC: reads current state to answer world queries (eg "am I being in the shadows?") My question: Is this ok for the ISenseNPC interface? public interface ISenseNPC { // ... /// <summary> /// True if `dest` is a safe point to which to retreat. /// </summary> /// <param name="dest"></param> /// <param name="angleToThreat"></param> /// <param name="range"></param> /// <returns></returns> bool IsSafeToRetreat(Vector2 dest, float angleToThreat, float range); /// <summary> /// Finds a new location to which to retreat. /// </summary> /// <param name="angleToThreat"></param> /// <returns></returns> Vector2 newRetreatDest(float angleToThreat); /// <summary> /// Returns the closest LightSource that illuminates the NPC. /// Null if the NPC is not illuminated. /// </summary> /// <returns></returns> ILightSource ClosestIlluminatingLight(); /// <summary> /// True if the NPC is sufficiently far away from target. /// Assumes that target is the only entity it could ever run from. /// </summary> /// <returns></returns> bool IsSafeFromTarget(); } None of the methods take any parameters. Instead, the implementation is expected to maintain a reference to the relevant GameObjectController and read that. However, I'm now trying to write unit tests for this. Obviously, it's necessary to use mocking, since I can't pass arguments directly. The way I'm doing it feels really brittle - what if another implementation comes along that uses the world query utilities in a different way? Really, I'm not testing the interface, I'm testing the implementation. Poor. The reason I used this pattern in the first place was to keep IThinkNPC implementation code clean: public BehaviorState RetreatTransition(BehaviorState currentBehavior) { if (sense.IsCollidingWithTarget()) { NPCUtils.TraceTransitionIfNeeded(ToString(), BehaviorState.ATTACK.ToString(), "is colliding with target"); return BehaviorState.ATTACK; } if (sense.IsSafeFromTarget() && sense.ClosestIlluminatingLight() == null) { return BehaviorState.WANDER; } if (sense.ClosestIlluminatingLight() != null && sense.SeesTarget()) { NPCUtils.TraceTransitionIfNeeded(ToString(), BehaviorState.ATTACK.ToString(), "collides with target"); return BehaviorState.CHASE; } return currentBehavior; } Perhaps the cleanliness isn't worth it, however. So, if ISenseNPC takes all the params it needs every time, I could make it static. Is there any problem with that?

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• Generating a URL pattern when provided a set of 5 or so URLs

  - by ryan

  Provided with a set of URLs, I need to generate a pattern, For example: http://www.buy.com/prod/disney-s-star-struck/q/loc/109/213724402.html http://www.buy.com/prod/samsung-f2380-23-widescreen-1080p-lcd-monitor-150-000-1-dc-8ms-1920-x/q/loc/101/211249863.html http://www.buy.com/prod/panasonic-nnh765wf-microwave-oven-countertop-1-6-ft-1250w-panasonic/q/loc/66357/202045865.html http://www.buy.com/prod/escape-by-calvin-klein-for-women-3-4-oz-edp-spray/q/loc/66740/211210860.html http://www.buy.com/prod/v-touch-8gb-mp3-mp4-2-8-touch-screen-2mp-camera-expandable-minisd-w/q/loc/111/211402014.html Pattern is http://www.buy.com/prod/[^~]/q/loc/[^~].html

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• Asp.Net MVC best way to update cached table

  - by Eddy Mishiyev

  There are certain tables that get called often but updated rarely. One of these tables is Departments. So to save DB trips, I think it is ok to cache this table taking into consideration that the table has very small size. However, once you cached it an issue of keeping the table data fresh occurs. So what is the best way to determine that the table is dirty and therefore requires a reload and how that code should be invoked. I look for solution that will be scalable. So updating the cache right after inserting will not work. So if one machine inserted the record all other on network should get notified to reload the cache. I was thinking for calling corresponding web service from T-SQL but don't really like the idea of consuming recourses on sql server. So what are the best practices to resolve this type of problems. Thanks in advance Eddy

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• Delegates in Action -Help

  - by Amutha

  I am learning delegates.I am very curious to apply delegates to the following chain-of-responsibility pattern. Kindly help me the way to apply delegates to the following piece. Thanks in advance.Thanks for your effort. #region Chain of Responsibility Pattern namespace Chain { public class Player { public string Name { get; set; } public int Score { get; set; } } public abstract class PlayerHandler { protected PlayerHandler _Successor = null; public abstract void HandlePlayer(Player _player); public void SetupHandler(PlayerHandler _handler) { _Successor = _handler; } } public class Employee : PlayerHandler { public override void HandlePlayer(Player _player) { if (_player.Score <= 100) { MessageBox.Show(string.Format("{0} is greeted by Employee", _player.Name)); } else { _Successor.HandlePlayer(_player); } } } public class Supervisor : PlayerHandler { public override void HandlePlayer(Player _player) { if (_player.Score >100 && _player.Score<=200) { MessageBox.Show(string.Format("{0} is greeted by Supervisor", _player.Name)); } else { _Successor.HandlePlayer(_player); } } } public class Manager : PlayerHandler { public override void HandlePlayer(Player _player) { if (_player.Score > 200) { MessageBox.Show(string.Format("{0} is greeted by Manager", _player.Name)); } else { MessageBox.Show(string.Format("{0} got low score", _player.Name)); } } } } #endregion #region Main() void Main() { Chain.Player p1 = new Chain.Player(); p1.Name = "Jon"; p1.Score = 100; Chain.Player p2 = new Chain.Player(); p2.Name = "William"; p2.Score = 170; Chain.Player p3 = new Chain.Player(); p3.Name = "Robert"; p3.Score = 300; Chain.Employee emp = new Chain.Employee(); Chain.Manager mgr = new Chain.Manager(); Chain.Supervisor sup = new Chain.Supervisor(); emp.SetupHandler(sup); sup.SetupHandler(mgr); emp.HandlePlayer(p1); emp.HandlePlayer(p2); emp.HandlePlayer(p3); } #endregion

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• Generalized plugable caching pattern?

  - by BCS

  Given that it's one of the hard things in computer science, does anyone know of a way to set up a plugable caching strategy? What I'm thinking of would allow me to write a program with minimal thought as to what needs to be cached (e.i. use some sort of boiler-plate, low/no cost pattern that compiles away to nothing anywhere I might want caching) and then when things are further along and I know where I need caching I can add it in without making invasive code changes. As an idea to the kind of solution I'm looking for; I'm working with the D programing language (but halfway sane C++ would be fine) and I like template.

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• Linq to sql Repository pattern , Some doubts

  - by MindlessProgrammer

  I am using repository pattern with linq to sql, I am using a repository class per table. I want to know , am i doing at good/standard way, ContactRepository Contact GetByID() Contact GetAll() COntactTagRepository List<ContactTag> Get(long contactID) List<ContactTag> GetAll() List<ContactTagDetail> GetAllDetails() class ContactTagDetail { public Contact Contact {get;set;} public ContactTag COntactTag {get;set;} } When i need a contact i call method in contactrepository, same for contacttag but when i need contact and tags together i call GetDetais() in ContactTag repository its not returning the COntactTag entity generated by the orm insted its returning ContactTagDetail entity conatining both COntact and COntactTag generated by the orm, i know i can simple call GetAll in COntactTag repository and can access Contact.ContactTag but as its linq to sql it will there is no option to Deferred Load in query level, so whenever i need a entity with a related entity i create a projection class Another doubt is where i really need to right the method i can do it in both contact & ContactTag repostitory like In contact repository GetALlWithTags() or something but i am doing it in in COntactTag repository Whats your suggestions ?

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• StockTrader RI > Controllers, Presenters, WTF?

  - by SandRock

  I am currently learning how to make advanced usage of WPF via the Prism (Composite WPF) project. I watch many videos and examples and the demo application StockTraderRI makes me ask this question: What is the exact role of each of the following part? SomethingService: Ok, this is something to manage data SomethingView: Ok, this is what's displayed SomethingPresentationModel: Ok, this contains data and commands for the view to bind to (equivalent to a ViewModel). SomethingPresenter: I don't really understand it's usage SomethingController: Don't understand too I saw that a Presenter and a Controller are not necessary but I would like to understand why they are here. Can someone tell me their role and when to use them?

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