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  • Design Decision - Scaling out web based application's architecture

    - by Vadi
    This question is about design decision. I am currently working on a web project that will have 40K users to start with and in couple of month expected to grow 50M users (not concurrent users though). I would like to have a architecture that can be scaled out easily without much effort. In order to explain, I would like to use a trivial scenario. Lets say, User entities and services such as CreateUser, AuthenticateUser etc., are a simple method calls for the Page Controllers. But once the traffic increases, for example, authenticating user (or such services related to user entities) has to be moved out to a different internal server to spread the load. But at the same time using RPC calls over the network when the user count is 40K would become overkill. My proposal was to use IPC initially and when we need to scale out we can interally switch to TCP based RPC calls so that it can easily scale out. For example, I am referring to System.IO.Pipes.NamedPipeStreamServer to start with and move on to a TcpListener later on. If we have proper design that can encapsulate above said approach, it would easy for us to scale out services into multiple network servers but at the same time avoid network calls when the user count is small. Is this is a best approach? Any suggestions would be great .. Note: The database scaling is definetly the second phase optimization so we have already made architectural design in place to easily partition data when traffic increases. The primary bottleneck would be application servers over the time period.

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  • System.Design cannot be referenced in Class Library?

    - by Alex Yeung
    Hi all, I have a very strange problem that I cannot fix and don't know what's going on... I am using VS 2010 Premium and .NET 4.0. Here are my steps to simulate the problem. Step 1. Create a new VB class library project named "MyClassLib" Step 2. Create a new class named "MyTestingClass". Public Class MyTestingClass Inherits System.ComponentModel.Design.CollectionEditor Public Sub New() MyBase.New(GetType(List(Of String))) End Sub End Class Step 3. Add two .net reference. "System.Design" and "System.Drawing". Step 4. Create a new VB console application named "MyClassExe" Step 5. Add "MyClassLib" reference to "MyClassExe". Step 6. Open Module1.vb in "MyClassExe" project Step 7. In the Main method, type Dim a = New MyClassLib.MyTestingClass() Step 8. Try to compile "MyClassLib". It doesn't have problem. Step 9. Try to compile "MyClassExe". It cannot compile because the WHOLE MyClassLib cannot be found!!! I have no idea what's going on? Moreover, the same case happens in C#. Does anyone know what's the problem with "System.Design"? Thank!!!

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  • Why isn't JML implemented as Annotations in Java?

    - by devoured elysium
    Contrary to Code Contracts in C#, in JML Code Contracts are just text that's used in the form of comments in the header of a method. Wouldn't it be better to have them exposed as Annotations, then? That way even when compiling the information would persist on the .class's metadata, contrary to comments, that get erased. Am I missing something? Thanks

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  • Repeating fields in similar database tables

    - by user1738833
    I have been tasked with working on a database that I have never seen before and I'm looking at the DB structure. Some of the central and most heavily queried and joined tables look like virtual duplicates of each other. Here's a massively simplified representation of the situation, with business-sensitive information changed, listing hypothetical table names and fields: TopLevelGroup: PK_TLGroupId, DisplaysXOnBill, DisplaysYOnBill, IsInvoicedForJ, IsInvoicedForK SubGroup: PK_SubGroupId, FK_ParentTopLevelGroupId, DisplaysXOnBill, DisplaysYOnBill, IsInvoicedForJ, IsInvoicedForK SubSubGroup: PK_SubSUbGroupId, FK_ParentSubGroupId, DisplaysXOnBill, DisplaysYOnBill, IsInvoicedForJ, IsInvoicedForK I haven't listed the types of the fields as I don't think it's particularly important to the situation. In addition, it's worth saying that rather than four repeated fields as in the example above, I'm looking at 86 repeated fields. For the most part, those fields genuinely do represent "facts" about the primary table entity, so it's not automatically wrong for that reason. In addition, the "groups" represented here have a property inheritance relationship. If DisplaysXOnBill is NULL in the SubSubGroup, it takes the value of DisplaysXOnBillfrom it's parent, the SubGroup, and so-on up to the TopLevelGroup. Further, the requirements will never require that the model extends beyond three levels, so there is no need for flexibility in that area. Is there a design smell from several tables which describe very similar entities having almost identical fields? If so, what might be a better design of the example above? I'm using the phrase "design smell" to indicate a possible problem. Of course, in any given situation, a particular design might well be the best solution. I'm looking for a more general answer - wondering what might be wrong with this design and what might be the better design were that the case. Possibly related, but not primary questions: Is this database schema in a reasonably normal form (e.g. to 3NF), insofar as can be told from the information I've provided. I can't see a problem with the requirements of 2NF and 3NF, except in their inheriting the requirements of 1NF. Is 1NF satisfied though? Are repeating groups allowed in different tables? Is there a best-practice method for implementing the inheritance relationship in a database as I require? The method above feels clunky to me because any query on the SubSubGroup necessarily needs to join onto the SubGroup and the TopLevelGroup tables to collect inherited facts, which can make even trivial joins requiring facts from the SubSubGroup table rather long-winded. There are, of course, political considerations to making a relatively large change like this. For the purpose of this question, I'm happy to ignore that fact in the interests of keeping the answers ring-fenced to the technical problem.

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  • Code Contracts Vs. Object Initializers (.net 4.0)

    - by Mystagogue
    At face value, it would seem that object initializers present a problem for .net 4.0 "code contracts", where normally the invariant should be established by the time the object constructor is finished. Presumably, however, object-initializers require properties to be set after construction is complete. My question is if the invariants of "code contracts" are able to handle object initializers, "as if" the properties were set before the constructor completes? That would be very nice indeed!!

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  • interface as a method parameter in Java

    - by PeterYu
    Hi all, I had an interview days ago and was thrown a question like this. Q: Reverse a linked list. Following code is given: public class ReverseList { interface NodeList { int getItem(); NodeList nextNode(); } void reverse(NodeList node) { } public static void main(String[] args) { } } I was confused because I did not know an interface object could be used as a method parameter. The interviewer explained a little bit but I am still not sure about this. Could somebody enlighten me?

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  • How would you rewrite/refactor this ?

    - by frostings
    Old application that is used by 50-60.000 paying customers. Company is several hundred people big. Application has a lot of business critical code (30% of all code) written in classic asp. Application has a lot more .net code. Application has a COM+ bridge for enabling asp to "talk" to .net Organization lacks some/a lot knowledge on what is causing the 10-20% server-reset per day (might be due to COM+ ?) There is no red line through the application; no architecture, no real patterns etc. The application has been like this for at least 5 years. The asp code base is increasing, slowly but certainly. I have read refactoring stories and I have knowledge on why you some of the times should not re-write a system. I would love for the old asp code to vanish as well as the COM+ component. But the pain is that no one really knows what is going on inside the asp classic code and the attitude inside all the teams are "this is just how it is". Down the line, this causes a lot of other issues like recruiting, dev effeciency, business needs that cannot be met, scale etc. With these little facts, does that justify a re-write of the asp code and the removal of the COM+ component ? How would you go about it ?

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  • How to handle business rules with a REST API?

    - by Ciprio
    I have a REST API to manage a booking system I'm searching how to manage this situation : A customer can book a time slot : A TimeSlot resource is created and linked to a Person resource. In order to create the link between a time lot and a person, the REST client send a POST request on the TimeSlot resource But if too many people booked the same slot (let's say the limit is 5 links), it must be impossible to create more associations. How can I handle this business restriction ? Can I return a 404 status code with a JSON response detailing the error with a status code ? Is it a RESTFul approach ? EDIT : Like suggested below I used status 409 Conflict in addition to a JSON response detailing the error

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  • Is a text file with names/pixel locations something a graphic artist can/should produce? [on hold]

    - by edA-qa mort-ora-y
    I have an artist working on 2D graphics for a game UI. He has no problem producing a screenshot showing all the bits, but we're having some trouble exporting this all into an easy-to-use format. For example, take the game HUD, which is a bunch of elements laid out around the screen. He exports the individual graphics for each one, but how should he communicate the positioning of each of them? My desire is to have a yaml file (or some other simple markup file) that contains the name of each asset and pixel position of that element. For example: fire_icon: pos: 20, 30 fire_bar: pos: 30, 80 Is producing such files a common task of a graphic artist? Is is reasonable to request them to produce such files as part of their graphic work?

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  • Creating site with wix.com or weebly.com [on hold]

    - by Edgar
    I decided to create web page and for that purpose I find out that I can use wix.com portal. My knowledge of HTML,CSS is on basic level. So I want to ask what are pros and cons of creating webPages using WIX to compare with making your on your own (writing code by yourself). One of the questions is: can I put custom advertisements to the my page. Also would appreciate of suggestions what portal is better for wix.com or weebly.com or for good website I should choose codding by myself? Finally, would be nice to get any suggestions in this field.

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  • How to remove CRUD operations from Entity Class

    - by GlutVonSmark
    Trying to get my head around removing dataStore access from my entity classes. Lets say I have an AccountsGroup entity class. I put the all DBAccess into AccountsGroupRepository class. Now should I have a DeleteFromDB method in the AccountsGroup class, that will call the repository? Public Sub DeleteFromDB dim repository as new AccountsGroupRepository(me) repository.DelteFromDB End Sub Or should I just always use repositry whenever I need to delete an entity, and not have the CRUD methods in the entity class? What happens when there is some business logic validation that needs to be done before the delete can proceed. For example if AccountsGroup still has some Accounts in it the delete method should throw an exception. Where do I put that?

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  • Using a service registry that doesn’t suck part II: Dear registry, do you have to be a message broker?

    - by gsusx
    Continuing our series of posts about service registry patterns that suck, we decided to address one of the most common techniques that Service Oriented (SOA) governance tools use to enforce policies. Scenario Service registries and repositories serve typically as a mechanism for storing service policies that model behaviors such as security, trust, reliable messaging, SLAs, etc. This makes perfect sense given that SOA governance registries were conceived as a mechanism to store and manage the policies...(read more)

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  • What is a "wrapper" program?

    - by user6950
    Where I work, employees use a third-party desktop program for their clients. This program saves data to a flat file. My colleague wants to write a Java program that uploads that flat file to a remote server, opens the desktop program when the flat file is downloaded from a Web site, and checks if the desktop program is running or not by looking at the Windows processes. He keeps calling this helper/utility program a "wrapper." But it doesn't wrap anything! I tried to clear it up with him, but he said, "Well, I call it a wrapper." He now has everyone in the company calling it a "wrapper." What would you call it? I say that it's a helper program or utility program.

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  • Web 2.0 Extension for ASP.NET

    - by Visual WebGui
    ASP.NET is now much extended to support line of business and data centric applications, providing Web 2.0 rich user interfaces within a native web environment. New capabilities allowed by the Visual WebGui extension turn Visual Studio into a rapid development tool for the web, leveraging the wide set of ASP.NET web infrastructures runtime and extending its paradigms to support highly interactive applications. Taking advantage of the ASP.NET infrastructures Using the native ASP.NET ISAPI filter: aspnet_isapi...(read more)

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  • Multi-tenancy - single database vs multiple database

    - by RichardW1001
    We have a number of clients, whose systems share some functionality, but also have quite a degree of diversity. The number of clients is growing - always a healthy thing! - and the diversity between their businesses is also increasing. At present there is a single ASP.Net (Web Forms) Web Site (as opposed to web project), which has sub-folders for each tenant, with that tenant's non-standard pages. There is a separate model project, which deals with database access and business logic. Which is preferable - and most importantly, why - between having (a) 1 database per client, with only the features associated with that client; or (b) a single database shared by all clients, where only a subset of tables are used by any one client. The main concerns within the business are over: maintenance of multiple assets - backups, version control and the like promoting re-use as much as possible How would you ensure these concerns are addressed, which solution is preferable, and why? (I have been also compiling responses to similar questions)

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  • Adobe Photoshop Vs Lightroom Vs Aperture

    - by Aditi
    Adobe Photoshop is the standard choice for photographers, graphic artists and Web designers. Adobe Photoshop Lightroom  & Apple’s Aperture are also in the same league but the usage is vastly different. Although Photoshop is most popular & widely used by photographers, but in many ways it’s less relevant to photographers than ever before. As Lightroom & Aperture is aimed squarely at photographers for photo-processing. With this write up we are going to help you choose what is right for you and why. Adobe Photoshop Adobe Photoshop is the most liked tool for the detailed photo editing & designing work. Photoshop provides great features for rollover and Image slicing. Adobe Photoshop includes comprehensive optimization features for producing the highest quality Web graphics with the smallest possible file sizes. You can also create startling animations with it. Designers & Editors know how important precise masking is, PhotoShop lets you do that with various detailing tools. Art history brush, contact sheets, and history palette are some of the smart features, which add to its viability. Download Whether you’re producing printed pages or moving images, you can work more efficiently and produce better results because of its smooth integration across other adobe applications. Buy supporting layer effects, it allows you to quickly add drop shadows, inner and outer glows, bevels, and embossing to layers. It also provides Seamless Web Graphics Workflow. Photoshop is hands-down the BEST for editing. Photoshop Cons: • Slower, less precise editing features in Bridge • Processing lots of images requires actions and can be slower than exporting images from Lightroom • Much slower with editing and processing a large number of images Aperture Apple Aperture is aimed at the professional photographer who shoots predominantly raw files. It helps them to manage their workflow and perform their initial Raw conversion in a better way. Aperture provides adjustment tools such as Histogram to modify color and white balance, but most of the editing of photos is left for Photoshop. It gives users the option of seeing their photographs laid out like slides or negatives on a light table. It boasts of – stars, color-coding and easy techniques for filtering and picking images. Aperture has moved forward few steps than Photoshop, but most of the editing work has been left for Photoshop as it features seamless Photoshop integration. Aperture Pros: Aperture is a step up from the iPhoto software that comes with every Mac, and fairly easy to learn. Adjustments are made in a logical order from top to bottom of the menu. You can store the images in a library or any folder you choose. Aperture also works really well with direct Canon files. It is just $79 if you buy it through Apple’s App Store Moving forward, it will run on the iPad, and possibly the iPhone – Adobe products like Lightroom and Photoshop may never offer these options It is much nicer and simpler user interface. Lightroom Lightroom does a smashing job of basic fixing and editing. It is more advanced tool for photographers. They can use it to have a startling photography effect. Light room has many advanced features, which makes it one of the best tools for photographers and far ahead of the other two. They are Nondestructive editing. Nothing is actually changed in an image until the photo is exported. Better controls over organizing your photos. Lightroom helps to gather a group of photos to use in a slideshow. Lightroom has larger Compare and Survey views of images. Quickly customizable interface. Simple keystrokes allow you to perform different All Lightroom controls are kept available in panels right next to the photos. Always-available History palette, it doesn’t go when you close lightroom. You gain more colors to work with compared to Photoshop and with more precise control. Local control, or adjusting small parts of a photo without affecting anything else, has long been an important part of photography. In Lightroom 2, you can darken, lighten, and affect color and change sharpness and other aspects of specific areas in the photo simply by brushing your cursor across the areas. Photoshop has far more power in its Cloning and Healing Brush tools than Lightroom, but Lightroom offers simple cloning and healing that’s nondestructive. Lightroom supports the RAW formats of more cameras than Aperture. Lightroom provides the option of storing images outside the application in the file system. It costs less than photoshop. Download Why PhotoShop is advanced than Lightroom? There are countless image processing plug-ins on the market for doing specialized processing in Photoshop. For example, if your image needs sophisticated noise reduction, you can use the Noiseware plug-in with Photoshop to do a much better job or noise removal than Lightroom can do. Lightroom’s advantages over Aperture 3 Will always have better integration with Photoshop. Lightroom is backed by bigger and more active user community (So abundant availability for tutorials, etc.) Better noise reduction tool. Especially for photographers the Lens-distortion correction tool  is perfect Lightroom Cons: • Have to Import images to work on them • Slows down with over 10,000 images in the catalog • For processing just one or two images this is a slower workflow Photoshop Pros: • ACR has the same RAW processing controls as Lightroom • ACR Histogram is specialized to the chosen color space (Lightroom is locked into ProPhoto RGB color space with an sRGB tone curve) • Don’t have to Import images to open in Bridge or ACR • Ability to customize processing of RAW images with Photoshop Actions Pricing and Availability Get LightRoomGet PhotoShop Latest version Of Photoshop can be purchased from Adobe store and Adobe authorized reseller and it costs US$999. Latest version of Aperture can be bought for US$199 from Apple Online store or Mac App Store. You can buy latest version of LightRoom from Adobe Store or Adobe Authorized reseller for US$299. Related posts:Adobe Photoshop CS5 vs Photoshop CS5 extended Web based Alternatives to Photoshop 10 Free Alternatives for Adobe Photoshop Software

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  • Physics in my game confused after restructuring the Game loop

    - by Julian Assange
    Hello! I'm on my way with making a game in Java. Now I have some trouble with an interpolation based game loop in my calculations. Before I used that system the calculation of a falling object was like this: Delta based system private static final float SPEED_OF_GRAVITY = 500.0f; @Override public void update(float timeDeltaSeconds, Object parentObject) { parentObject.y = parentObject.y + (parentObject.yVelocity * timeDeltaSeconds); parentObject.yVelocity -= SPEED_OF_GRAVITY * timeDeltaSeconds; ...... What you see here is that I used that delta value from previous frame to the current frame to calculate the physics. Now I switched and implement a interpolation based system and I actually left the current system where I used delta to calculate my physics. However, with the interpolation system the delta time is removed - but now are my calculations screwed up and I've tried the whole day to solve this: Interpolation based system private static final float SPEED_OF_GRAVITY = 500.0f; @Override public void update(Object parentObject) { parentObject.y = parentObject.y + (parentObject.yVelocity); parentObject.yVelocity -= SPEED_OF_GRAVITY; ...... I'm totally clueless - how should this be solved? The rendering part is solved with a simple prediction method. With the delta system I could see my object be smoothly rendered to the screen, but with this interpolation/prediction method the object just appear sticky for one second and then it's gone. The core of this game loop is actually from here deWiTTERS Game Loop, where I trying to implement the last solution he describes. Shortly - my physics are in a mess and this need to be solved. Any ideas? Thanks in advance!

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  • S#arp Architecture 1.5 released

    - by AlecWhittington
    The past two weeks have been wonderful for me, spending 12 days on Oahu, Hawaii. Then followed up with the S#arp Architecture 1.5 release. It has been a short 4 months since taking over as the project lead and this is my first major milestone. With this release, we advance S# even more forward with the ASP.NET MVC 2 enhancements. What's is S#? Pronounced "Sharp Architecture," this is a solid architectural foundation for rapidly building maintainable web applications leveraging the ASP.NET MVC framework...(read more)

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