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  • Knowing state of game in real time

    - by evthim
    I'm trying to code a tic tac toe game in java and I need help figuring out how to efficiently and without freezing the program check if someone won the game. I'm only in the design stages now, I haven't started programming anything but I'm wondering how would I know at all times the state of the game and exactly when someone wins? Response to MarkR: (note: had to place comment here, it was too long for comment section) It's not a homework problem, I'm trying to get more practice programming GUI's which I've only done once as a freshman in my second introductory programming course. I understand I'll have a 2D array. I plan to have a 2D integer array where x would equal 1 and o would equal 0. However, won't it take too much time if I check after every move if someone won the game? Is there a way or a data structure or algorithm I can use so that the program will know the state (when I say state I mean not just knowing every position on the board, the int array will take care of that, I mean knowing that user 1 will win if he places x on this block) of the game at all times and thus can know automatically when someone won?

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  • Is there a typical career path to learn game development "on the job"?

    - by mac
    The extended version of the question is: what is the typical career paths that a developer without specific experience in game development should take if he/she wishes to work in the game development industry? In other words, what are the positions such a programmer might aspire to get hired for, in the game industry? I am asking because it seems to me that - even without direct experience with 3D modelling, physics engines, shaders, etc... - for as much complex as these topics might be - they are still "just" top layers one can learn "on the job" if he/she has already good programming skills and experience in software design (for example during peer-programming sessions). I have no knowledge whatsoever of the game industry, so maybe I am being naïve here, but for all the other programming jobs I previously took, I learnt most of the specificities while working on concrete projects... so I wonder if there is a chance to do the same with game development. Thanks for your time and advice! :) PS: I don't know if this is important or not for answering the question, but scripting languages are the languages I am more proficient in. /mac

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  • How do I use an API?

    - by GRardB
    Background I have no idea how to use an API. I know that all APIs are different, but I've been doing research and I don't fully understand the documentation that comes along with them. There's a programming competition at my university in a month and a half that I want to compete in (revolved around APIs) but nobody on my team has ever used one. We're computer science majors, so we have experience programming, but we've just never been exposed to an API. I tried looking at Twitter's documentation, but I'm lost. Would anyone be able to give me some tips on how to get started? Maybe a very easy API with examples, or explaining essential things about common elements of different APIs? I don't need a full-blown tutorial on Stack Overflow; I just need to be pointed in the right direction. Update The programming languages that I'm most fluent in are C (simple text editor usually) and Java (Eclipse). In an attempt to be more specific with my question: I understand that APIs (and yes, external libraries are what I was referring to) are simply sets of functions. Question I guess what I'm trying to ask is how I would go about accessing those functions. Do I need to download specific files and include them in my programs, or do they need to be accessed remotely, etc.?

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  • How do I use an API?

    - by GRardB
    Background I have no idea how to use an API. I know that all APIs are different, but I've been doing research and I don't fully understand the documentation that comes along with them. There's a programming competition at my university in a month and a half that I want to compete in (revolved around APIs) but nobody on my team has ever used one. We're computer science majors, so we have experience programming, but we've just never been exposed to an API. I tried looking at Twitter's documentation, but I'm lost. Would anyone be able to give me some tips on how to get started? Maybe a very easy API with examples, or explaining essential things about common elements of different APIs? I don't need a full-blown tutorial on Stack Overflow; I just need to be pointed in the right direction. Update The programming languages that I'm most fluent in are C (simple text editor usually) and Java (Eclipse). In an attempt to be more specific with my question: I understand that APIs (and yes, external libraries are what I was referring to) are simply sets of functions. Question I guess what I'm trying to ask is how I would go about accessing those functions. Do I need to download specific files and include them in my programs, or do they need to be accessed remotely, etc.?

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  • How to tackle an experienced C# Programmer?

    - by nandu.com
    I am a noob in c# and asp.net developing. I have spent 6 months in design and another 6 in sql and asp.net programming. I just know the basics of asp.net and C#. I was programming as per the instruction of my tech leads and all good things changed in a day. :( All my tech leads (2+ experienced) left the company complaining about salary. And instead of those, company has recruited a 5+ experienced programmer cum tech lead (who is very strict), he is expecting me to code anything he says. Previous seniors of me, would say 'use ajax for this, use query for this instead of coding' and so on. I will do it exactly. I am not experienced enough to perform it myself. Now I am in a dilemma. I want to stay in the company and learn some more, but this new tech lead is expecting me to learn everything myself (he is telling me to learn jquery, javascript menus, session and chart in .Net, and so on and do things myself without asking him anything...I mean anything) :(((( PLease suggest to me some good tips to handle him. I think all programmers world wide would have faced a similar problem atleast once in the big programming life. So please..help .. 911

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  • How should an undergraduate programmer organize his time learning the maximum possible?

    - by nischayn22
    I started programming lately(pre-final year of a CS degree) and now feel like there's a sea of uncovered treasure for me out there. So, I decided to cover as much as is possible before I look out for a job after graduation. So, I started to read books (The C++ Programming Language, Introduction to Algorithms, Cracking the Coding Interview, Programming Pearls,etc ) participate in StackExchange sites, solving problems (InterviewStreet and ProjectEuler), coding for open source, chatting to fellow programmers/mentors and try to learn more and more. Good,then what's the problem?? The problem is I am trying to do many things, but I am doubtful that I am still utilizing my time properly. I am reading many books and sometimes I just leave a book halfway (jumping from one book to another), sometimes I spend way too much time on chatting and also in getting lost somewhere in the huge internet world, and lastly the wasteful burden of attending classes (I don't think my teachers know good enough or I prefer learning on my own) May be some of you had similar situation. How did you organize your time? Or what do you think is the best way to organize it for an undergraduate? Also what mistakes am I making that you can warn me of

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  • sharing life experience

    - by gcc
    I am a student of computer engineering. I have never done any programming before, and as you can understand, I don't know how to study it or how to make my own programs. My English is weak [edited for clarity - ed], and so if you don't like the choices I list, please feel free to provide others. How should I study? How should I learn programming languages? Study completely from a book. Don't study from a book, just try writing code. A mix of the two; study from a book, then try writing code. Study half the book, then write the code by hand on paper. Listed to the teacher, then try to solve general problems (those not from any specific chapter). I have send that question to stackoverflow before when I am at first year. Now, I want to construct webpage to guide fresh students by giving advise of yours and mines.Maybe, you wonder Why I want to construct webpage , I just want help the other student. I am giving a link to that question < http://stackoverflow.com/questions/3389465/how-should-i-study-programming-languagess If you have other advice, feel free. EDIT: This web cite, I think , is constructed to share member's life experience and also I know these experiences is valuable . So I have no right to want your opinion, But I want your opinion / experience even if you think it is not so helpful to other

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  • Moving From IT to Embedded software Developing

    - by Ameer Adel
    i worked for two years at a channel station, managing various Types of tasks, varying from printers installation, software solution, down to managing and maintaining server automation, to be honest, i always been enthusiastic about programming, i studied at some affordable college and finished my IT path successfully, my graduation project was in C# ADO.NET couple of years ago. Obviously it was so much of a beginner spaghetti code than a well furnished code. I also had the chance; after leaving the IT career, to study about some ASP.NET MVC and web apps development. I have rookie level of coding skills due to the poor level of education i endured, and sufficient resources. Currently i m working as a trainee in a newly opened embedded software development company, that is being said, i am, as i sound, have a little idea about the algorithms included, as i was reading for the past couple of days, embedded system development requires more strict coding skills, including memory management, CPU optimization according to its architect, and couple of other tricks regarding the display, and power management if mobile.. etc. My question is, What type of Algorithms am i supposed to use in such cases, as i mentioned before, i am really enthusiastic about learning programming skills and algorithms related to embedded systems and programming languages, including C/C++, Java, C#, and some EC++ if still operational.

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  • What are some good ways for an intermediate programmer to build skills?

    - by Jordan
    Preface: I work mostly in Python, and Web Dev languages (HTML, CSS, Javascript and Jquery, PHP) I'm proficient at coding but I want to get better. In larger more advanced projects my programming skills break down. The more code there is the more trouble I have fitting all the pieces together. I understand syntax well, and I can catch and correct errors fairly easier. But the more advanced it gets the more I struggle. I believe I have a good understand of the basic and nuts and bolts of programming and I understand what's going on, but when it comes to larger projects, especially ones with heavy math involved my confidence flags and I start making mistakes. It's not that I can't do it, I'm just not used to doing it. Does anyone have any advice for someone who knows programming, but wants to get better? The only tutorials I can really find are beginner basic type stuff. Basically what I'm saying is I want to be confident when I'm tackling advanced projects, but I can't because I have little experience dealing with difficult situations.

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  • How much a programmer should read in order to keep himself updated? [closed]

    - by anything
    There are lots of technical books available. Below are few links which lists some good books If you could only have one programming related book on your bookshelf what would it be and why? What non-programming books should a programmer read to help develop programming/thinking skills? Best books on the theory and practice of software architecture? http://stackoverflow.com/questions/1711/what-is-the-single-most-influential-book-every-programmer-should-read ... and the list can go on and on and on. It will be really difficult to read all of the above mentioned books. I am not sure if its even possible for anyone to do that. Even if you filter it based on one's area of interest or work, list is still very large. .. and the technology keeps on changing (even more books :-( ) So, my question is how much a programmer should read lets say per year? How much hours one should put in such activities to keep oneself up to date? How do we find out the time required? PS: Average programmer reads less than one book per year (Code complete). What about the good programmers?

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  • What is involved with writing a lobby server?

    - by Kira
    So I'm writing a Chess matchmaking system based on a Lobby view with gaming rooms, general chat etc. So far I have a working prototype but I have big doubts regarding some things I did with the server. Writing a gaming lobby server is a new programming experience to me and so I don't have a clear nor precise programming model for it. I also couldn't find a paper that describes how it should work. I ordered "Java Network Programming 3rd edition" from Amazon and still waiting for shipment, hopefully I'll find some useful examples/information in this book. Meanwhile, I'd like to gather your opinions and see how you would handle some things so I can learn how to write a server correctly. Here are a few questions off the top of my head: (may be more will come) First, let's define what a server does. It's primary functionality is to hold TCP connections with clients, listen to the events they generate and dispatch them to the other players. But is there more to it than that? Should I use one thread per client? If so, 300 clients = 300 threads. Isn't that too much? What hardware is needed to support that? And how much bandwidth does a lobby consume then approx? What kind of data structure should be used to hold the clients' sockets? How do you protect it from concurrent modification (eg. a player enters or exists the lobby) when iterating through it to dispatch an event without hurting throughput? Is ConcurrentHashMap the correct answer here, or are there some techniques I should know? When a user enters the lobby, what mechanism would you use to transfer the state of the lobby to him? And while this is happening, where do the other events bubble up? Screenshot : http://imageshack.us/photo/my-images/695/sansrewyh.png/

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  • Book / software to learn ERP?

    - by user22311
    For a while I've been wanting to learn ERP. What I would like to do is set up a system, and then practice running a business doing things like generating invoices, raising purchase orders, producing monthly accounts, keeping track of fixed assets etc. Then look at enhancing the system further by adding custom code. I know there are a variety of open source ERP systems around, but really I would prefer a widely used commercial system as having familiarity with such a system would be more marketable. So are there any such systems that have a free developer version available? I've looked around, but I've had trouble finding such a system. Also I would like to find a good book or more likely books to read on ERP. Ideally I would be able to get an indepth explanation ERP from a business perspective, ie the accounting operations it supports, how to do all the regular accounting tasks, configuration, business operations best practices, accounting controls and so on. In addition I would like an IT perspective, ie setting up the system, developing forms and reports. Unfortunately the few books I've looked at have been really superficial and totally inadequate. They either fall into the beginning programmer camp, where they use the programming tools but concentrate on programming 101 topics like loops, flow control etc. Or they cover setting up the system with lots of screen shots, but little substance as to why things should be done a certain way. I have a programming background but no real experience in implementing ERP systems. Also I have a reasonable accounting knowledge, and have used ERP systems in various jobs, but only to a very limited degree. So are there any ERP experts who can point me in the right direction? Thanks.

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  • Problem with understanding how to start

    - by Coolface
    Okay, this might be a little off-topic but i try anyway. Sorry to bother. So i'm working as sysadmin for at least 5 years now and i quite enjoy IT field in general. Somehow i was never interested in programming much but always want to learn something at least easy and for personal usage. As sysadmin i need scripting skills so learn shell scripting without much problems, i also try to learn pascal, delphi, basic over time and must recent was python. Well, my problem is when i try to learn programming i just can't apply what i learn from the books to the real word. What i mean is i understand there are data structures, algorithms, variables, lib's, if-then logic, etc. but i just can't understand how to apply this things when i want to do real things. Like i want to get a something simple as parse web page, i draw a quick algorithm like get a web page, find a word on it and write a to file, on the paper everything look simple but when i get to the coding i just stuck pretty much from the start. I try read code of the real programs that just totally confusing especially big parts with many classes so i'm just quickly lost a trail what this code do. I think i just lack some fundamentals to see a big picture but don't really know what this might be? Or maybe i just don't have a passion to programming at all... My best bet was a shell scripting so i have really no problems to write complex scripts but this just not enough. Recently i was read around 5 or 6 python books because everyone say it's so easy even kid can code something but still no much luck, python is good and easy but i can't make something harder then a prodecurial style code like in bash for easy things but when i want harder things i'm still stuck. In college i was also not a math and tech guy and like to study non-tech stuff mostly like economy, psychology maybe that my problem? Anyway any advice would be greatly appriciated.

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  • How do I tell my parents that landing a job is what actually counts?

    - by shovonr
    On one side, I just want to get a degree with a 3.0 GPA. On the other side, my parents want more than just a 3. Now here's the thing. I program with a passion. I spend day and night programming. And I ace all my programming courses. However, I do terrible on all my elective courses -- such as writing, history, and all that stuff -- which only leaves me with a 3.1 to 3.2 GPA. And my parents want more. They think that university is like high school, where you need super-stellar grades to get to the next level. But they don't realize that good enough grades will land me a job. And they don't realize that a programmer needs to practice to become good at programming, and that having good skills is what will land a job in a nice software development company. Thankfully, though, they don't threaten to beat me with a baseball bat or anything like that. They just occasionally give me the little "tsk-tsk". But even that little "tsk-tsk" makes me feel guilty for opening up an IDE. And on top of that, I procrastinate because of that feeling of guilt. So now, I want to come clean with them. I want to know what's a good way to do that. [Edit] OK, so now, I realized, I should aim for higher grades, as some have suggested below.

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  • Objective C and C++ for Game Development

    - by Holland
    I'm trying to figure out which language I should begin learning. I've only been programming for about 6 months, with languages like PHP, Java, and C#. I want to learn how to dev games, and while I know in most cases the answer to this would be through C++ (at least, I would think), though I'm still curious about what Objective C can offer in the sense of long term benefit. It seems like there's a chance that Objective-C may actually become more popular than C++ in a few years, and for all I know, it may become the de facto standard development language for games. Still, despite all of this, I really don't know anything, and this is all speculation. Both languages seem very interesting, and obviously can pull a lot of out of themselves. What do you think? Note: despite what some might say, I really don't want to end up using prebuilt engines, and would rather just learn how to make my own. I'm well aware that it takes a lot more time, but I'm quite ok with that.

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  • Visual Basic 2010 Language Enhancements

    Earlier this month Microsoft released Visual Studio 2010, the .NET Framework 4.0 (which includes ASP.NET 4.0), and new versions of their core programming languages: C# 4.0 and Visual Basic 10 (also referred to as Visual Basic 2010). Previously, the C# and Visual Basic programming languages were managed by two separate teams within Microsoft, which helps explain why features found in one language was not necessarily found in the other. For example, C# 3.0 introduced <a href="http://weblogs.asp.net/scottgu/archive/2007/03/08/new-c-orcas-language-features-automatic-properties-object-initializers-and-collection-initializers.aspx"><i>collection initializers</i></a>, which enable developers to define the contents of a collection when declaring it; however,

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  • What’s New for Oracle Commerce? Executive QA with John Andrews, VP Product Management, Oracle Commerce

    - by Katrina Gosek
    Oracle Commerce was for the fifth time positioned as a leader by Gartner in the Magic Quadrant for E-Commerce. This inspired me to sit down with Oracle Commerce VP of Product Management, John Andrews to get his perspective on what continues to make Oracle a leader in the industry and what’s new for Oracle Commerce in 2013. Q: Why do you believe Oracle Commerce continues to be a leader in the industry? John: Oracle has a great acquisition strategy – it brings best-of-breed technologies into the product fold and then continues to grow and innovate them. This is particularly true with products unified into the Oracle Commerce brand. Oracle acquired ATG in late 2010 – and then Endeca in late 2011. This means that under the hood of Oracle Commerce you have market-leading technologies for cross-channel commerce and customer experience, both designed and developed in direct response to the unique challenges online businesses face. And we continue to innovate on capabilities core to what our customers need to be successful – contextual and personalized experience delivery, merchant-inspired tools, and architecture for performance and scalability. Q: It’s not a slow moving industry. What are you doing to keep the pace of innovation at Oracle Commerce? John: Oracle owes our customers the most innovative commerce capabilities. By unifying the core components of ATG and Endeca we are delivering on this promise. Oracle Commerce is continuing to innovate and redefine how commerce is done and in a way that drive business results and keeps customers coming back for experiences tailored just for them. Our January and May 2013 releases not only marked the seventh significant releases for the solution since the acquisitions of ATG and Endeca, we also continue to demonstrate rapid and significant progress on the unification of commerce and customer experience capabilities of the two commerce technologies. Q: Can you tell us what was notable about these latest releases under the Oracle Commerce umbrella? John: Specifically, our latest product innovations give businesses selling online the ability to get to market faster with more personalized commerce experiences in the following ways: Mobile: the latest Commerce Reference Application in this release offers a wider range of examples for online businesses to leverage for iOS development and specifically new iPad reference capabilities. This release marks the first release of the iOS Universal application that serves both the iPhone and iPad devices from a single download or binary. Business users can now drive page content management and layout of search results and category pages, as well as create additional storefront elements such as categories, facets / dimensions, and breadcrumbs through Experience Manager tools. Cross-Channel Commerce: key commerce platform capabilities have been added to support cross-channel commerce, including an expanded inventory model to maintain inventory for stores, pickup in stores and Web-based returns. Online businesses with in-store operations can now offer advanced shipping options on the web and make returns and exchange logic easily available on the web. Multi-Site Capabilities: significant enhancements to the Commerce Platform multi-site architecture that allows business users to quickly launch and manage multiple sites on the same cluster and share data, carts, and other components. First introduced in 2010, with this latest release business users can now partition or share customer profiles, control users’ site-based access, and manage personalization assets using site groups. Internationalization: continued language support and enhancements for business user tools as well and search and navigation. Guided Search now supports 35 total languages with 11 new languages (including Danish, Arabic, Norwegian, Serbian Cyrillic) added in this release. Commerce Platform tools now include localized support for 17 locales with 4 new languages (Danish, Portuguese (European), Finnish, and Thai). No development or customization is required in order for business users to use the applications in any of these supported languages. Business Tool Experience: valuable new Commerce Merchandising features include a new workflow for making emergency changes quickly and increased visibility into promotions rules and qualifications in preview mode. Oracle Commerce business tools continue to become more and more feature rich to provide intuitive, easy- to-use (yet powerful) capabilities to allow business users to manage content and the shopping experience. Commerce & Experience Unification: demonstrable unification of commerce and customer experience capabilities include – productized cartridges that provide supported integration between the Commerce Platform and Experience Management tools, cross-channel returns, Oracle Service Cloud integration, and integrated iPad application. The mission guiding our product development is to deliver differentiated, personalized user experiences across any device in a contextual manner – and to give the business the best tools to tune and optimize those user experiences to meet their business objectives. We also need to do this in a way that makes it operationally efficient for the business, keeping the overall total cost of ownership low – yet also allows the business to expand, whether it be to new business models, geographies or brands. To learn more about the latest Oracle Commerce releases and mission, visit the links below: • Hear more from John about the Oracle Commerce mission • Hear from Oracle Commerce customers • Documentation on the new releases • Listen to the Oracle ATG Commerce 10.2 Webcast • Listen to the Oracle Endeca Commerce 3.1.2 Webcast

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  • Le C++ expressif n° 1 : introduction, un article d'Eric Niebler traduit par Timothée Bernard

    Dissimulé dans C++ se cache un autre langage - d'innombrables autres langages, en fait - tous sont meilleurs que le C++ pour résoudre certains types de problèmes. Ces domain-specific languages (abrégé DSL) sont par exemple des langages pour l'algèbre linéaire ou des langages de requêtes, ils ne peuvent faire qu'une seule chose, mais ils le font bien. On peut créer et utiliser ces langages directement dans le C++, en utilisant la puissance et la flexibilité du C++ pour remplacer les parties communes du langage par les parties spécifiques au domaine que nous utilisons. Dans cette série d'article, Eric Niebler regarde de près les domain-specific languages, dans quels domaines ils sont utiles et comment on peut facilement les implémenter en C++ avec l'aide de

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  • Introducing a new Umbraco datatype for Multi-lingual websites.

    - by Vizioz Limited
    Over the last 6 months we have been building various multi-lingual sites for different clients and for some of the clients they have 1 to 1 relationships between some or all of their pages.Within Umbraco, you can copy a page ( or whole tree of pages ) and keep a relationship between each of the pages and their new copy, this allows content editors to subscribe to change notifications that Umbraco can create if one of the linked pages is changed.Unfortunately one thing that is missing in Umbraco is any way to see which pages are related to each other and to have a quick and easy way to jump between the related pages.We created a datatype that solves these problems and thought we would release it as an open source project ( which we are still maintaining )Currently you can:1) See current relationships2) Add relationships3) Limit the number of relationships that can be added ( by the data type )4) See the Country flag ( assuming a culture has been set on each of your top level site nodes for each country site )5) Link between the documents6) Change or delete the linksAn example where multiple languages are allowed:An example where only 2 languages exist (1 relationship):You can download the datatype from the Umbraco project page:Vizioz Relationships for UmbracoPlease do let us know what you think :)

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  • JIT compiler for C, C++, and the likes

    - by Ebrahim
    Is there any just-in-time compiler out there for compiled languages, such as C and C++? (The first names that come to mind are Clang and LLVM! But I don't think they currently support it.) Explanation: I think the software could benefit from runtime profiling feedback and aggressively optimized recompilation of hotspots at runtime, even for compiled-to-machine languages like C and C++. Profile-guided optimization does a similar job, but with the difference a JIT would be more flexible in different environments. In PGO you run your binary prior to releasing it. After you released it, it would use no environment/input feedbacks collected at runtime. So if the input pattern is changed, it is probe to performance penalty. But JIT works well even in that conditions. However I think it is controversial wether the JIT compiling performance benefit outweights its own overhead. Edit: Grammar

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  • Xampp : http://localhost/xampp/splash.php :english : nothing happens

    - by Oussama Abdallah
    After I start Xampp on my Ubuntu 12.04 I go to the localhost and I come to the site, where all languages are listed .... when I click any of these languages nothing happens. Follow steps are already done: I started Xampp with: sudo /opt/lamp/lamp start after doing so, I get in the console, that everything is running: Starting XAMPP for Linux ... XAMPP: Starting Apache...ok. XAMPP: Starting MySQL... ok. XAMPP: Starting ProFTPD...ok. Can you please help me solve this problem?

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  • How do you guys handle translation for software localization?

    - by JohnFx
    Most of the software I have written over my career has been built for English speaking customers, but recently I've been working on a project where localization of the UI for a wider range of languages is desired. I am just curious how other programming shops obtain the translations. Do they use the notoriously flawed online translation engines? I know there are for-hire translators out there, but am I going to have to track down and contract like a dozen of them to do a thorough job of localizing my interface? Are there services that specialize in doing this for a wide range of languages? Perhaps using something like Amazon's Mechanical Turk would be an option, but I have no idea how diverse the available workforce is on that site. I'd imagine not very.

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  • Are there advantages for using recursion over iteration - other than sometimes readability and elegance?

    - by Prog
    I am about to make two assumptions. Please correct me if they're wrong: There isn't a recursive algorithm without an iterative equivalent. Iteration is always cheaper performance-wise than recursion (at least in general purpose languages such as Java, C++, Python etc.). If it's true that recursion is always more costly than iteration, and that it can always be replaced with an iterative algorithm (in languages that allow it) - than I think that the two remaining reasons to use recursion are: elegance and readability. Some algorithms are expressed more elegantly with recursion. E.g. scanning a binary tree. However apart from that, are there any reasons to use recursion over iteration? Does recursion have advantages over iteration other than sometimes elegance and readability?

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  • Using TPL and PLINQ to raise performance of feed aggregator

    - by DigiMortal
    In this posting I will show you how to use Task Parallel Library (TPL) and PLINQ features to boost performance of simple RSS-feed aggregator. I will use here only very basic .NET classes that almost every developer starts from when learning parallel programming. Of course, we will also measure how every optimization affects performance of feed aggregator. Feed aggregator Our feed aggregator works as follows: Load list of blogs Download RSS-feed Parse feed XML Add new posts to database Our feed aggregator is run by task scheduler after every 15 minutes by example. We will start our journey with serial implementation of feed aggregator. Second step is to use task parallelism and parallelize feeds downloading and parsing. And our last step is to use data parallelism to parallelize database operations. We will use Stopwatch class to measure how much time it takes for aggregator to download and insert all posts from all registered blogs. After every run we empty posts table in database. Serial aggregation Before doing parallel stuff let’s take a look at serial implementation of feed aggregator. All tasks happen one after other. internal class FeedClient {     private readonly INewsService _newsService;     private const int FeedItemContentMaxLength = 255;       public FeedClient()     {          ObjectFactory.Initialize(container =>          {              container.PullConfigurationFromAppConfig = true;          });           _newsService = ObjectFactory.GetInstance<INewsService>();     }       public void Execute()     {         var blogs = _newsService.ListPublishedBlogs();           for (var index = 0; index <blogs.Count; index++)         {              ImportFeed(blogs[index]);         }     }       private void ImportFeed(BlogDto blog)     {         if(blog == null)             return;         if (string.IsNullOrEmpty(blog.RssUrl))             return;           var uri = new Uri(blog.RssUrl);         SyndicationContentFormat feedFormat;           feedFormat = SyndicationDiscoveryUtility.SyndicationContentFormatGet(uri);           if (feedFormat == SyndicationContentFormat.Rss)             ImportRssFeed(blog);         if (feedFormat == SyndicationContentFormat.Atom)             ImportAtomFeed(blog);                 }       private void ImportRssFeed(BlogDto blog)     {         var uri = new Uri(blog.RssUrl);         var feed = RssFeed.Create(uri);           foreach (var item in feed.Channel.Items)         {             SaveRssFeedItem(item, blog.Id, blog.CreatedById);         }     }       private void ImportAtomFeed(BlogDto blog)     {         var uri = new Uri(blog.RssUrl);         var feed = AtomFeed.Create(uri);           foreach (var item in feed.Entries)         {             SaveAtomFeedEntry(item, blog.Id, blog.CreatedById);         }     } } Serial implementation of feed aggregator downloads and inserts all posts with 25.46 seconds. Task parallelism Task parallelism means that separate tasks are run in parallel. You can find out more about task parallelism from MSDN page Task Parallelism (Task Parallel Library) and Wikipedia page Task parallelism. Although finding parts of code that can run safely in parallel without synchronization issues is not easy task we are lucky this time. Feeds import and parsing is perfect candidate for parallel tasks. We can safely parallelize feeds import because importing tasks doesn’t share any resources and therefore they don’t also need any synchronization. After getting the list of blogs we iterate through the collection and start new TPL task for each blog feed aggregation. internal class FeedClient {     private readonly INewsService _newsService;     private const int FeedItemContentMaxLength = 255;       public FeedClient()     {          ObjectFactory.Initialize(container =>          {              container.PullConfigurationFromAppConfig = true;          });           _newsService = ObjectFactory.GetInstance<INewsService>();     }       public void Execute()     {         var blogs = _newsService.ListPublishedBlogs();                var tasks = new Task[blogs.Count];           for (var index = 0; index <blogs.Count; index++)         {             tasks[index] = new Task(ImportFeed, blogs[index]);             tasks[index].Start();         }           Task.WaitAll(tasks);     }       private void ImportFeed(object blogObject)     {         if(blogObject == null)             return;         var blog = (BlogDto)blogObject;         if (string.IsNullOrEmpty(blog.RssUrl))             return;           var uri = new Uri(blog.RssUrl);         SyndicationContentFormat feedFormat;           feedFormat = SyndicationDiscoveryUtility.SyndicationContentFormatGet(uri);           if (feedFormat == SyndicationContentFormat.Rss)             ImportRssFeed(blog);         if (feedFormat == SyndicationContentFormat.Atom)             ImportAtomFeed(blog);                }       private void ImportRssFeed(BlogDto blog)     {          var uri = new Uri(blog.RssUrl);          var feed = RssFeed.Create(uri);           foreach (var item in feed.Channel.Items)          {              SaveRssFeedItem(item, blog.Id, blog.CreatedById);          }     }     private void ImportAtomFeed(BlogDto blog)     {         var uri = new Uri(blog.RssUrl);         var feed = AtomFeed.Create(uri);           foreach (var item in feed.Entries)         {             SaveAtomFeedEntry(item, blog.Id, blog.CreatedById);         }     } } You should notice first signs of the power of TPL. We made only minor changes to our code to parallelize blog feeds aggregating. On my machine this modification gives some performance boost – time is now 17.57 seconds. Data parallelism There is one more way how to parallelize activities. Previous section introduced task or operation based parallelism, this section introduces data based parallelism. By MSDN page Data Parallelism (Task Parallel Library) data parallelism refers to scenario in which the same operation is performed concurrently on elements in a source collection or array. In our code we have independent collections we can process in parallel – imported feed entries. As checking for feed entry existence and inserting it if it is missing from database doesn’t affect other entries the imported feed entries collection is ideal candidate for parallelization. internal class FeedClient {     private readonly INewsService _newsService;     private const int FeedItemContentMaxLength = 255;       public FeedClient()     {          ObjectFactory.Initialize(container =>          {              container.PullConfigurationFromAppConfig = true;          });           _newsService = ObjectFactory.GetInstance<INewsService>();     }       public void Execute()     {         var blogs = _newsService.ListPublishedBlogs();                var tasks = new Task[blogs.Count];           for (var index = 0; index <blogs.Count; index++)         {             tasks[index] = new Task(ImportFeed, blogs[index]);             tasks[index].Start();         }           Task.WaitAll(tasks);     }       private void ImportFeed(object blogObject)     {         if(blogObject == null)             return;         var blog = (BlogDto)blogObject;         if (string.IsNullOrEmpty(blog.RssUrl))             return;           var uri = new Uri(blog.RssUrl);         SyndicationContentFormat feedFormat;           feedFormat = SyndicationDiscoveryUtility.SyndicationContentFormatGet(uri);           if (feedFormat == SyndicationContentFormat.Rss)             ImportRssFeed(blog);         if (feedFormat == SyndicationContentFormat.Atom)             ImportAtomFeed(blog);                }       private void ImportRssFeed(BlogDto blog)     {         var uri = new Uri(blog.RssUrl);         var feed = RssFeed.Create(uri);           feed.Channel.Items.AsParallel().ForAll(a =>         {             SaveRssFeedItem(a, blog.Id, blog.CreatedById);         });      }        private void ImportAtomFeed(BlogDto blog)      {         var uri = new Uri(blog.RssUrl);         var feed = AtomFeed.Create(uri);           feed.Entries.AsParallel().ForAll(a =>         {              SaveAtomFeedEntry(a, blog.Id, blog.CreatedById);         });      } } We did small change again and as the result we parallelized checking and saving of feed items. This change was data centric as we applied same operation to all elements in collection. On my machine I got better performance again. Time is now 11.22 seconds. Results Let’s visualize our measurement results (numbers are given in seconds). As we can see then with task parallelism feed aggregation takes about 25% less time than in original case. When adding data parallelism to task parallelism our aggregation takes about 2.3 times less time than in original case. More about TPL and PLINQ Adding parallelism to your application can be very challenging task. You have to carefully find out parts of your code where you can safely go to parallel processing and even then you have to measure the effects of parallel processing to find out if parallel code performs better. If you are not careful then troubles you will face later are worse than ones you have seen before (imagine error that occurs by average only once per 10000 code runs). Parallel programming is something that is hard to ignore. Effective programs are able to use multiple cores of processors. Using TPL you can also set degree of parallelism so your application doesn’t use all computing cores and leaves one or more of them free for host system and other processes. And there are many more things in TPL that make it easier for you to start and go on with parallel programming. In next major version all .NET languages will have built-in support for parallel programming. There will be also new language constructs that support parallel programming. Currently you can download Visual Studio Async to get some idea about what is coming. Conclusion Parallel programming is very challenging but good tools offered by Visual Studio and .NET Framework make it way easier for us. In this posting we started with feed aggregator that imports feed items on serial mode. With two steps we parallelized feed importing and entries inserting gaining 2.3 times raise in performance. Although this number is specific to my test environment it shows clearly that parallel programming may raise the performance of your application significantly.

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