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  • C++ Singleton design pattern

    - by Artem Barger
    Recently I've bumped into a realization/implementation of the Singleton design pattern for C++. It has looked like this (I have adopted it from the real life example): // a lot of methods are omitted here class Singleton { public: static Singleton* getInstance( ); ~Singleton( ); private: Singleton( ); static Singleton* instance; }; From this declaration I can deduce that the instance field is initiated on the heap. That means there is a memory allocation. What is completely unclear for me is when exactly the memory is going to be deallocated? Or is there a bug and memory leak? It seems like there is a problem in the implementation. My main question is, how do I implement it in the right way?

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  • Using TweenMax to fade in div with background pattern and z-index not working

    - by shibbydoo
    I'm trying to do this really simple fade using TweenMax for this div I have. Here's the css for the div .aboutBg { background:url(../images/pattern.jpg); top:0; right:0; left:0; bottom:0, position:fixed; border:10px solid red; z-index:10; } TweenMax.to('.aboutPage', 0.5, {autoAlpha:1}); What's happening is the border would fade in nicely but the patterned bg is not, it just pops up at the end of the tween. If I remove the z-index everything works, but I have to have set the z-index so it's on top of my other content. Also I'm not tweening the z-index, it's set before the tween, so I'm not sure why it's not fading correctly. Anyone has any idea? Thanks.

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  • find a specific string pattern in an array jquery

    - by Bwyss
    Apologies if this is a duplicate, but I can't seem to find the solution. I am trying to find a specific string pattern in an array. I want to find all values in data that contain 'underscore r underscore'. I then want to create a new array that contains only those keys and values. var data = ["something", "bar_r_something"]; var resultArray = new Array(); for (var i = 0; i < data.length; i++) { var bar = /_r_/; if ($.inArray(bar, data[i].length) > 0) { console.log("found _r_"); resultArray.push(data[i]); } }; I just can't seem to get that $.inArray to work, it seems to always kick out -1.

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  • singleton pattern in java- lazy Intialization

    - by flash
    public static MySingleton getInstance() { if (_instance==null) { synchronized (MySingleton.class) { _instance = new MySingleton(); } } return _instance; } 1.is there a flaw with the above implementation of the getInstance method? 2.What is the difference between the two implementations.? public static synchronized MySingleton getInstance() { if (_instance==null) { _instance = new MySingleton(); } return _instance; } I have seen a lot of answers on the singleton pattern in stackoverflow but the question I have posted is to know mainly difference of 'synchronize' at method and block level in this particular case.

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  • Doubt about a particular pattern of Javascript class definition

    - by fenderplayer
    Recently i saw the following code that creates a class in javascript: var Model.Foo = function(){ // private stuff var a, b; // public properties this.attr1 = ''; this.attr2 = ''; if(Model.Foo._init === 'undefined'){ Model.Foo.prototype = { func1 : function(){ //...}, func2 : function(){ //... }, //other prototype functions } } Model.Foo._init = true; } // Instantiate and use the class as follows: var foo = new Model.Foo(); foo.func1(); I guess the _init variable is used to make sure we don't define the prototypes again. Also, i feel the code is more readable since i am placing everything in a function block (so in oop-speak, all attributes and methods are in one place). Do you see any issues with the code above? Any pitfalls of using this pattern if i need to create lots of classes in a big project?

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  • [Bash] Save part of matching pattern to variable

    - by Ben
    I want to extract a substring matching a pattern and save it to a file. An example string: Apr 12 19:24:17 PC_NMG kernel: sd 11:0:0:0: [sdf] Attached SCSI removable disk I want to extract the part between the brackets, in this case []. I tried to do something like grep -e '[$subtext]' to save the text in the brackets to a variable. Of course it doesn't work, but I am looking for a way similar to this. It would be very elegant to include a variable in a regex like this. What can I do best? Thanks!

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  • What Design Pattern To Replace 'CurrentStep' Variable

    - by Rob P.
    Tried to search but didn't know how to phrase it. I've got some code that is essentially... Private CurMajorStep as Integer = 0 Private CurMinorStep as Integer = 0 Public Sub PerformNextStep() Select Case iMajorStep Case 0 ThingOne() Case 1 ThingTwo() Case 2 ThingThree() Case 3 ThingFour() Case 4 AnythingElse() Case 5 Finish() End Select End Sub And then, in some of those, the CurMinorStep keeps track of the current state of that particular 'step'. I hope that all makes sense. The code is messy and I know it's going to be problematic to maintain. Can someone point me to a clean OO pattern to handle this?

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  • Is this a right way to use NHibernate?

    - by Venemo
    I spent the rest of the evening reading StackOverflow questions and also some blog entries and links about the subject. All of them turned out to be very helpful, but I still feel that they don't really answer my question. So, I'm developing a simple web application. I'd like to create a reusable data access layer which I can later reuse in other solutions. 99% of these will be web applications. This seems to be a good excuse for me to learn NHibernate and some of the patterns around it. My goals are the following: I don't want the business logic layer to know ANYTHING about the inner workings of the database, nor NHibernate itself. I want the business logic layer to have the least possible number of assumptions about the data access layer. I want the data access layer as simplistic and easy-to-use as possible. This is going to be a simple project, so I don't want to overcomplicate anything. I want the data access layer to be as non-intrusive as possible. Will all this in mind, I decided to use the popular repository pattern. I read about this subject on this site and on various dev blogs, and I heard some stuff about the unit of work pattern. I also looked around and checked out various implementations. (Including FubuMVC contrib, and SharpArchitecture, and stuff on some blogs.) I found out that most of these operate with the same principle: They create a "unit of work" which is instantiated when a repository is instantiated, they start a transaction, do stuff, and commit, and then start all over again. So, only one ISession per Repository and that's it. Then the client code needs to instantiate a repository, do stuff with it, and then dispose. This usage pattern doesn't meet my need of being as simplistic as possible, so I began thinking about something else. I found out that NHibernate already has something which makes custom "unit of work" implementations unnecessary, and that is the CurrentSessionContext class. If I configure the session context correctly, and do the clean up when necessary, I'm good to go. So, I came up with this: I have a static class called NHibernateHelper. Firstly, it has a static property called CurrentSessionFactory, which upon first call, instantiates a session factory and stores it in a static field. (One ISessionFactory per one AppDomain is good enough.) Then, more importantly, it has a CurrentSession static property, which checks if there is an ISession bound to the current session context, and if not, creates one, and binds it, and it returns with the ISession bound to the current session context. Because it will be used mostly with WebSessionContext (so, one ISession per HttpRequest, although for the unit tests, I configured ThreadStaticSessionContext), it should work seamlessly. And after creating and binding an ISession, it hooks an event handler to the HttpContext.Current.ApplicationInstance.EndRequest event, which takes care of cleaning up the ISession after the request ends. (Of course, it only does this if it is really running in a web environment.) So, with all this set up, the NHibernateHelper will always be able to return a valid ISession, so there is no need to instantiate a Repository instance for the "unit of work" to operate properly. Instead, the Repository is a static class which operates with the ISession from the NHibernateHelper.CurrentSession property, and exposes some functionality through that. I'm curious, what do you think about this? Is it a valid way of thinking, or am I completely off track here?

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  • Entity Framework RC1 DbContext query issue

    - by Steve
    I'm trying to implement the repository pattern using entity framework code first rc 1. The problem I am running into is with creating the DbContext. I have an ioc container resolving the IRepository and it has a contextprovider which just news up a new DbContext with a connection string in a windsor.config file. With linq2sql this part was no problem but EF seems to be choking. I'll describe the problem below with an example. I've pulled out the code to simplify things a bit so that is why you don't see any repository pattern stuff here. just sorta what is happening without all the extra code and classes. using (var context = new PlssContext()) { var x = context.Set<User>(); var y = x.Where(u => u.UserName == LogOnModel.UserName).FirstOrDefault(); } using (var context2 = new DbContext(@"Data Source=.\SQLEXPRESS;Initial Catalog=PLSS.Models.PlssContext;Integrated Security=True;MultipleActiveResultSets=True")) { var x = context2.Set<User>(); var y = x.Where(u => u.UserName == LogOnModel.UserName).FirstOrDefault(); } PlssContext is where I am creating my DbContext class. The repository pattern doesn't know anything about PlssContext. The best I thought I could do was create a DbContext with the connection string to the sqlexpress database and query the data that way. The connection string in the var context2 was grabbed from the context after newing up the PlssContext object. So they are pointing at the same sqlexpress database. The first query works. The second query fails miserably with this error: The model backing the 'DbContext' context has changed since the database was created. Either manually delete/update the database, or call Database.SetInitializer with an IDatabaseInitializer instance. For example, the DropCreateDatabaseIfModelChanges strategy will automatically delete and recreate the database, and optionally seed it with new data. on this line var y = x.Where(u => u.UserName == LogOnModel.UserName).FirstOrDefault(); Here is my DbContext namespace PLSS.Models { public class PlssContext : DbContext { public DbSet<User> Users { get; set; } public DbSet<Corner> Corners { get; set; } public DbSet<Lookup_County> Lookup_County { get; set; } public DbSet<Lookup_Accuracy> Lookup_Accuracy { get; set; } public DbSet<Lookup_MonumentStatus> Lookup_MonumentStatus { get; set; } public DbSet<Lookup_CoordinateSystem> Lookup_CoordinateSystem { get; set; } public class Initializer : DropCreateDatabaseAlways<PlssContext> { protected override void Seed(PlssContext context) { I've tried all of the Initializer strategies with the same errors. I don't think the database is changing. If I remove the modelBuilder.Conventions.Remove<IncludeMetadataConvention>(); Then the error returns is The entity type User is not part of the model for the current context. Which sort of makes sense. But how do you bring this all together?

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  • Web.xml: Are url-pattern tags relative to each other?

    - by sixtyfootersdude
    <servlet-mapping> <servlet-name>myName</servlet-name> <url-pattern>/aName</url-pattern> </servlet-mapping> <security-constraint> <web-resource-collection> ... <url-pattern> /* </url-pattern> </web-resource-collection> ... </security-constraint> This is an excerpt from web.xml (using it to configure a jboss/tomcat webservice). Just wondering if the url-pattern in web-resource-collection is relative to the url-pattern in servlet-mapping.

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  • Web.xml: Are url-pattern tags relitive to each other?

    - by sixtyfootersdude
    <servlet-mapping> <servlet-name>myName</servlet-name> <url-pattern>/aName</url-pattern> </servlet-mapping> <security-constraint> <web-resource-collection> ... <url-pattern> /* </url-pattern> </web-resource-collection> ... </security-constraint> This is an excerpt from web.xml (using it to configure a jboss/tomcat webservice). Just wondering if the url-pattern in web-resource-collection is relative to the url-pattern in servlet-mapping.

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  • Microsoft Press Deal of the Day - 13/April/2012 - Building Enterprise Applications with Windows® Presentation Foundation and the MVVM Pattern

    - by TATWORTH
    Today's deal of the day from Microsoft Press at http://shop.oreilly.com/product/0790145309686.do is Building Enterprise Applications with Windows® Presentation Foundation and the MVVM Pattern"Simplify and improve business application development by applying the MVVM pattern to Windows Presentation Foundation (WPF) and Microsoft® Silverlight® 4. With this hands-on guide, you'll use MVVM with data binding, commands, and behaviors to create user interfaces loosely coupled to business logic. MVVM is ideal for .NET developers working with WPF and Silverlight—whether or not you have experience building enterprise applications."

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  • Tests unitaires d'un DomainService WCF RIA : pattern Repository, un tutoriel de Kyle McClellan, traduit par Deepin Prayag

    Citation: Étant donné que WCF RIA Services emploie un « pipeline pattern » pour invoquer vos opérations DomainService, il n'est pas toujours évident de savoir comment les tester. Dans cette série d'articles nous allons voir un petit DomainService et comment le tester. Entre autres nous allons voir comment implémenter une IDomainServiceFactory personnalisée, comment implémenter le pattern Repository, et comment utiliser la DomainServiceTestHos...

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  • Are there any drawbacks to the Major.Minor.YMDD.Build version strategy?

    - by Chu
    I'm trying to come up with a good version strategy to fit our specific needs. We've proposed settling on this and I wanted to ask the question to see if anyone's experience would suggest avoiding this or altering it in any way. Here's our proposal: Versions are released in this format: MAJOR.MINOR.YMDD.BN. Here it is broken out: MAJOR & MINOR are typical; we'll increase MINOR when we feel code and new feature sets warrants it; once every few months most likely. MAJOR will increase ~yearly. YMDD: Y will be the last digit of the current year, so "1" for 2011, "2" for 2012, etc. A non-padded month will be used to keep the number smaller (9 instead of 09 for example). DD of course is the day, padded with a zero for days under 10. BN: BN is the build number and increases by one anytime we make a change to a branch of the code represented by the build, for example: If were to make a build today, our release would be version 5.0.1707.1. I release to QA today and 3 days from now QA finds that a change broke the save functionality on a page. Instead of me changing our current development code, I'd go back to the code that I used to create version 5.0.1707.1, make the fix there, then increase the BN portion of the version and would then re-release 5.0.1707.2 back to QA. In short, anytime a change is made to a branched version that isn't the active dev branch, we'd use the original version number and increase only the BN portion (even if the change happened 3 days, 3 weeks or 3 months from the initial release of that version). Anytime we make a new release from our Active dev branch, we'd come up with a new version based on the M/D of the release using the outlined strategy. We do this once every 2-3 weeks. Are there holes or pitfalls with this? If so, what are they? Thanks EDIT To clarify one point that I didn't get out very well - Oct/Nov/Dec will be two digits, it's only the year that won't be. So 9 for Sept, 10 for Oct, 11 for Nov, etc.

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  • As the current draft stands, what is the most significant change the "National Strategy for Trusted Identities in Cyberspace" will provoke?

    - by mfg
    A current draft of the "National Strategy for Trusted Identities in Cyberspace" has been posted by the Department of Homeland Security. This question is not asking about privacy or constitutionality, but about how this act will impact developers' business models and development strategies. When the post was made I was reminded of Jeff's November blog post regarding an internet driver's license. Whether that is a perfect model or not, both approaches are attempting to handle a shared problem (of both developers and end users): How do we establish an online identity? The question I ask here is, with respect to the various burdens that would be imposed on developers and users, what are some of the major, foreseeable implementation issues that will arise from the current U.S. Government's proposed solution? For a quick primer on the setup, jump to page 12 for infrastructure components, here are two stand-outs: An Identity Provider (IDP) is responsible for the processes associated with enrolling a subject, and establishing and maintaining the digital identity associated with an individual or NPE. These processes include identity vetting and proofing, as well as revocation, suspension, and recovery of the digital identity. The IDP is responsible for issuing a credential, the information object or device used during a transaction to provide evidence of the subject’s identity; it may also provide linkage to authority, roles, rights, privileges, and other attributes. The credential can be stored on an identity medium, which is a device or object (physical or virtual) used for storing one or more credentials, claims, or attributes related to a subject. Identity media are widely available in many formats, such as smart cards, security chips embedded in PCs, cell phones, software based certificates, and USB devices. Selection of the appropriate credential is implementation specific and dependent on the risk tolerance of the participating entities. Here are the first considered actionable components of the draft: Action 1: Designate a Federal Agency to Lead the Public/Private Sector Efforts Associated with Achieving the Goals of the Strategy Action 2: Develop a Shared, Comprehensive Public/Private Sector Implementation Plan Action 3:Accelerate the Expansion of Federal Services, Pilots, and Policies that Align with the Identity Ecosystem Action 4:Work Among the Public/Private Sectors to Implement Enhanced Privacy Protections Action 5:Coordinate the Development and Refinement of Risk Models and Interoperability Standards Action 6: Address the Liability Concerns of Service Providers and Individuals Action 7: Perform Outreach and Awareness Across all Stakeholders Action 8: Continue Collaborating in International Efforts Action 9: Identify Other Means to Drive Adoption of the Identity Ecosystem across the Nation

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  • Get a Live Update from Oracle HCM Strategy in Atlanta, Charlotte, or Arlington next week!

    - by jay.richey
    Join Oracle for an exclusive breakfast or lunch briefing where you will have the opportunity to hear about Oracle's current blockbuster releases for HCM: PeopleSoft 9.1 and E-Business Suite 12.1. Humair Ghauri, Senior Director, HCM Product Strategy, will share how Oracle's latest HCM offerings - Fusion HCM and Fusion Talent Management On Demand - can work alongside your Oracle PeopleSoft HR foundation to show immediate business value. February 15 - Atlanta, GA - click to Register February 16 - Charlotte, NC - click to Register February 17 - Arlington, VA - click to Register

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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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  • Want to make RTS strategy game, good starting point...?

    - by NOLANDI
    everybody! I find this community because I did research about game developing topics. So I decide to register on this community and ask for your opinion. I am not begineer in computer stuffs, and I know logic of programming language. I have little knowlegde of C, C++, Started to learn C#...but I was always oriented about other areas of IT. Amateur for game making but not in IT general! I am interested to make RTS strategy video game, isometric camera view (like PC GAME COMMANDOS for example)...so I started to read many books about DirectX, XNA, OpenGL, C#, AI programming...so I want to know where is good starting point for making this game genre. I want to use C# for this project, not C++, since I always had trouble with it, because it is too complicated. I see good oportunity for learning C#, since it has more object-oriented concept, with much less code and easy readible code for writing. Beside of that I know that C++ is the more powerful language until today. So I want to use DirectX and C# for my project. But it will required more time for sure, to learn it. I have trouble with finding books for c# & DirectX (I found just one), but in every next book, it is programming in c++! I read many web sites and they mentioned Slim DX, and in generaly, other articles which I read tells that it is possible to make good game with combination c# and directX, but...I don't have enough information about all this stuffs, so I became confused! It is really hard to have wish to learn c++ from scratch, since I started c# and I like it really...I don't try OpenGL, but I am already familiar with DirectX (some beginning stuffs), and I think that it is good and interesting. So, I decide to choose between maybe Unity3d and XNA first. XNA...hm, it sound that it is not bad solution, but I heard that it is already overcome technology, and I think that it is better to wait with XNA, until I try to make something with DirectX and C#, at first. But I dont know it is possible to make strategy game in XNA?! Maybe I am wrong. I also, find Unity 3D game engine and I find that I could programming there in C#, but many all examples are written in Javascript (Digital tutors videos)...But I generaly have wish to learn it too, because it allows to export games to mobile phones, there a lot of documentations, it is free, etc... I want to find best way to learn C# and DirectX, and make this game, but I dont know if it's possible to combine?! But maybe is good to first try Unity and XNA, because I am beginner?! Thank you all! I am willing to hear your expirience.

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  • MVC - Cocoa interface - Cocoa Design pattern book

    - by Idan
    So I started reading this book: http://www.amazon.com/Cocoa-Design-Patterns-Erik-Buck/dp/0321535022 On chapter 2 it explains about the MVC design pattern and gives and example which I need some clarification to. The simple example shows a view with the following fields: hourlyRate, WorkHours, Standarthours , salary. The example is devided into 3 parts : View - contains some text fiels and a table (the table contains a list of employees' data). Controller - comprised of NSArrayController class (contains an array of MyEmployee) Model - MyEmployee class which describes an employee. MyEmployee class has one method which return the salary according to the calculation logic, and attributes in accordance with the view UI controls. MyEmployee inherits from NSManagedObject. Few things i'm not sure of : 1. Inside the MyEmplpyee class implemenation file, the calculation method gets the class attributes using sentence like " [[self valueForKey:@"hourlyRate"] floatValue];" Howevern, inside the header there is no data member named hourlyRate or any of the view fields. I'm not quite sure how does it work, and how it gets the value from the right view field. (does it have to be the same name as the field name in the view). maybe the conncetion is made somehow using the Interface builder and was not shown in the book ? and more important: 2. how does it seperate the view from the model ? let's say ,as the book implies might happen, I decide one day to remove one of the fields in the view. as far as I understand, that means changing the way the salary method works in MyEmplpyee (cause we have one field less) , and removing one attribute from the same calss. So how is that separate the View from the Model if changing one reflect on the other ? I guess I get something wrong... Any comments ? Thanks

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  • Business Logic Layer Pattern on Rails? MVCL

    - by Fabiano PS
    That is a broad question, and I appreciate no short/dumb asnwers like: "Oh that is the model job, this quest is retarded (period)" PROBLEM Where I work at people created a system over 2 years for managing the manufacture process over demand in the most simplified still broad as possible, involving selling, buying, assemble, The system is coded over Ruby On Rails. The app has been changed lots of times and the result is a mess on callbacks (some are called several times), 200+ models, and fat controllers: Total bad. The QUESTION is, if there is a gem, or pattern designed to handle Rails large app logic? The logic whould be able to fully talk to models (whose only concern would be data format handling and validation) What I EXPECT is to reduce complexity from various controllers, and hard to track callbacks into files with the responsibility to handle a business operation logic. In some cases there is the need to wait for a response, in others, only validation of the input is enough and a bg process would take place. ie: -- Sell some products (need to wait the operation to finish) 1. Set a View able to get the products input 2. Controller gets the product list inputed by employee and call the logic Logic::ExecuteWithResponse('sell', 'products', :prods => @product_list_with_qtt, :when => @date, :employee => current_user() ) This Logic would handle buying order, assemble order, machine schedule, warehouse reservation, and others. Have in mind that a callback on SalesOrder is not enough, since it depends on where it is called (no field for that), depends on the class of the user, among other stuff not visible for the model, or in some cases it would take long for the model to process.

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  • Java exception handling in non sequential tasks (pattern/good practice)

    - by Hernán Eche
    There are some task that should't be done in parallel, (for example opening a file, reading, writing, and closing, there is an order on that...) But... Some task are more like a shoping list, I mean they could have a desirable order but it's not a must..example in communication or loading independient drivers etc.. For that kind of tasks, I would like to know a java best practice or pattern for manage exceptions.. The java simple way is: getUFO { try { loadSoundDriver(); loadUsbDriver(); loadAlienDetectorDriver(); loadKeyboardDriver(); } catch (loadSoundDriverFailed) { doSomethingA; } catch (loadUsbDriverFailed) { doSomethingB; } catch (loadAlienDetectorDriverFailed) { doSomethingC; } catch (loadKeyboardDriverFailed) { doSomethingD; } } But what about having an exception in one of the actions but wanting to try with the next ones?? I've thought this approach, but don't seem to be a good use for exceptions I don't know if it works, doesn't matter, it's really awful!! getUFO { Exception ex=null; try { try{ loadSoundDriver(); }catch (Exception e) { ex=e; } try{ loadUsbDriver(); }catch (Exception e) { ex=e; } try{ loadAlienDetectorDriver(); }catch (Exception e) { ex=e; } try{ loadKeyboardDriver() }catch (Exception e) { ex=e; } close the file; if(ex!=null) { throw ex; } } catch (loadSoundDriverFailed) { doSomethingA; } catch (loadUsbDriverFailed) { doSomethingB; } catch (loadAlienDetectorDriverFailed) { doSomethingC; } catch (loadKeyboardDriverFailed) { doSomethingD; } } seems not complicated to find a better practice for doing that.. I still didn't thanks for any advice

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  • Pattern for sharing data between views (MVP or MVVM)

    - by Dovix
    What is a good pattern for sharing data between related views?. I have an application where 1 form contains many small views, each views behaves independently from each other more or less (they communicate/interact via an event bus). Every so often I need to pass the same objects to the child views. Sometimes I need this same object to be passed to a child view and then the child passes it onto another child itself contains. What is a good approach to sharing this data between all the views contained within the parent form (view) ? I have looked into CAB and their approach and every "view" has a "root work item" this work item has dictionary that contains a shared "state" between the views that are contained. Is this the best approach? just a shared dictionary all the views under a root view can access? My current approach right now is to have a function on the view that allows one to set the object for that view. Something like view.SetCustomer(Customer c); then if the view contains a child view it knows to set it on the child view ala: this.childview1.SetCustomer(c); The application is written in C# 3.5, for winforms using MVP with structure map as a IoC/DI provider.

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  • Seeking help with a MT design pattern

    - by SamG
    I have a queue of 1000 work items and a n-proc machine (assume n = 4).The main thread spawns n (=4) worker threads at a time ( 25 outer iterations) and waits for all threads to complete before processing the next n (=4) items until the entire queue is processed for(i= 0 to queue.Length / numprocs) for(j= 0 to numprocs) { CreateThread(WorkerThread,WorkItem) } WaitForMultipleObjects(threadHandle[]) The work done by each (worker) thread is not homogeneous.Therefore in 1 batch (of n) if thread 1 spends 1000 s doing work and rest of the 3 threads only 1 s , above design is inefficient,becaue after 1 sec other 3 processors are idling. Besides there is no pooling - 1000 distinct threads are being created How do I use the NT thread pool (I am not familiar enough- hence the long winded question) and QueueUserWorkitem to achieve the above. The following constraints should hold The main thread requires that all worker items are processed before it can proceed.So I would think that a waitall like construct above is required I want to create as many threads as processors (ie not 1000 threads at a time) Also I dont want to create 1000 distinct events, pass to the worker thread, and wait on all events using the QueueUserWorkitem API or otherwise Exisitng code is in C++.Prefer C++ because I dont know c# I suspect that the above is a very common pattern and was looking for input from you folks.

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  • IRequest / IResponse Pattern

    - by traderde
    I am trying to create an Interface-based Request/Response pattern for Web API requests to allow for asynchronous consumer/producer processing, but not sure how I would know what the underlying IResponse class is. public void Run() { List<IRequest> requests = new List<IRequest>(); List<IResponse> responses = new List<IResponse(); requests.Add(AmazonWebRequest); //should be object, trying to keep it simple requests.Add(EBayWebRequest); //should be object, trying to keep it simple foreach (IRequest req in requests) { responses.Add(req.GetResponse()); } foreach (IResponse resp in response) { typeof resp???? } } interface IRequest { IResponse GetResponse(); } interface IResponse { } public class AmazonWebServiceRequest : IRequest { public AmazonWebServiceRequest() { //get data; } public IResponse GetResponse() { AmazonWebServiceRequest request = new AmazonWebServiceRequest(); return (IResponse)request; } } public class AmazonWebServiceResponse : IResponse { XmlDocument _xml; public AmazonWebServiceResponse(XmlDocument xml) { _xml = xml; _parseXml(); } private void _parseXml() { //parse Xml into object; } } public class EBayWebRequest : IRequest { public EBayWebRequest () { //get data; } public IResponse GetResponse() { EBayWebRequest request = new EBayWebRequest(); return (IResponse)request; } } public class EBayWebResponse : IResponse { XmlDocument _xml; public EBayWebResponse(XmlDocument xml) { _xml = xml; _parseXml(); } private void _parseXml() { //parse Xml into object; } }

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