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• Joomla Hide Menu Item, or: Using Rich Content as part of the navigation

  - by chiccodoro

  In my Joomla based web site, I have a two layer main menu. The page layout contains two sections whereas the left one displays the content and the right one displays some other kind of content which at the same time serves as a menu. For example, if the user clicks on the "Products" - "SomeCategory" 2nd level menu item, the left section displays an image. The right section lists all products of that category. Each product is represented by an image and text. The content is scrollable. This section is implemented by means of a custom module (mod_custom) assigned to the menu. The content is rich text (HTML). Each product is entered manually by adding a picture and a text in the WYSIWYG editor, and by inserting a link for the picture and text. Now the issue: When the user clicks on a product, I want to display the corresponding product description article ("SomeProduct") to the left, accounting for the following requirements: The bread crumb now displays "Products - SomeCategory - SomeProduct" The main menu still displays the 2nd level for "Products", and "SomeCategory" is still marked as selected. (I would love if the right section which lists the product would remain in the exact same scroll state, but that's a completely different story.) If I link the product entry from the right hand side directly to the article "SomeProduct", then the article appears to the left, but the breadcrumb and menu are reset. So I wanted to create a hidden menu item "SomeProduct" beneath "SomeCategory", and to link the product entry to that menu item. This way, if I click on the product entry, the article appears to the left, the breadcrumb behaves correctly, and the menu state is preserved. However, it is not possible to configure the SomeProduct menu item as "hidden", therefore it appears in the main menu. I found some resources that suggest to create another menu, called "hidden", which does not use any modules, and to create the "SomeProduct" menu item in that menu. Unfortunately this did not work for me: If I link that menu item from the product entry, and click on that entry, then the article appears to the left, but the menu is reset, and the breadcrumb displays "SomeProduct" instead of "Products SomeCategory SomeProduct". Lucky me! I found an appropriate stackexchange site where I can pour out my heart to you guys. Sure you can help me :-)

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• Oracle JDeveloper 11gR2 Cookbook book review

  - by Chris Muir

  I recently received a free copy of Oracle JDeveloper 11gR2 Cookbook published by Packt Publishing for review. Readers of technical cookbooks would know this genre of text includes problems that developers will hit and the prescribed solutions, in this case for Oracle's Application Development Framework (ADF).  Books like this excel themselves on excellent coverage, a logical progress of solutions through out the book, and providing a readable narrative around the numerous steps and code. This book progresses well through ADF application assembly, ADF Business Components, the view layer, security, deployment and tuning.  Each recipe had a clear introduction and I especially enjoyed the "There's more" follow up sections for some recipes that leads the reader onto related ideas and issues the reader really needs to be aware of. Also worthy of comment having worked with ADF for over 5 years, there certainly was recipes and solutions I hadn't encountered before, this book gets bonus points for that. As a reviewer what negatives can I give this text? The book has cast it's net too wide by trying to cover "everything from design and construction, to deployment, testing, debugging and optimization."  ADF is such a large and sophistication technology, this book with 100 recipes barely scrapes the surface.  Don't expect all your ADF problems to be solved here. In turn there is inconsistency in the level of problems and solutions.  I felt at the beginning the book was pitching itself at advanced problems to solve (that's great for me), but then it introduces topics like building a static View Object or train.  These topics in my opinion are fairly simple and are covered by the Oracle documentation just as well, they shouldn't have been included here.  In conclusion, ADF beginners will find this book worthwhile as it will open your eyes to the wider problems and solutions required for ADF, and experts for just the fact they can point junior programmers at the book for certain problems and say "get on with it". Is there scope for more ADF tombs like this?  Yes!  I'd love to see a cookbook specializing on ADF Business Components (hint hint to budding authors).

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• Interconnect nodes in a Java distributed infrastructure for tweet processing

  - by David Moreno García

  I'm working in a new version of an old project that I used to download and process user statuses from Twitter. The main problem of that project was its infrastructure. I used multiple instances of a java application (trackers) to download from Twitter given an specific task (basically terms to search for), connected with a central node (a web application) that had to process all tweets once per day and generate a new task for each trackers once each 15 minutes. The central node also had to monitor all trackers and enable/disable them under user petition. This, as I said, was too slow because I had multiple bottlenecks, so in this new version I want to improve the infrastructure and isolate all functionalities in specific nodes. I also need a good notification system to receive notifications for any node. So, in the next diagram I show the components that I'll need in this new version: As you can see, there are more nodes. Here are some notes about them: Dashboard: Controls trackers statuses and send a single task to each of them (under user request). The trackers will use this task until replaced with a new one (if done, not each 15 minutes like before). Search engine: I need to store all the tweets. They are firstly stored in a local database for each tracker but after that I'm thinking on using something like Elasticsearch to be able to do fast searches. Tweet processor: Just and isolated component with its own database (maybe something like the search engine to have fast access to info generated by the module). In the future more could be added. Application UI: A web application with a shared database with the Dashboard (mainly to store users information and preferences). Indeed, both could be merged into a single web. The main difference with the previous version of the project is that now they will be isolated and they will only show information and send requests. I will not do any heavy task in them (like process tweets as I did before). So, having this components, my main headache is how to structure all to not have to rewrite a lot of code every time I need to access any new data. Another headache is how can I interconnect nodes. I could use sockets but that is a pain in the ass. Maybe a REST layer? And finally, if all the nodes are isolated, how could I generate notifications for each user which info is only in the database used by the Application UI? I'm programming this using Java and Spring (at least I used them in the last version) but I have no problems with changing the language if I can take advantage of a tool/library/engine to make my life easier and have a better platform. Any comment will be appreciated.

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• How to deal with malicious domain redirections?

  - by user359650

  It is possible for anybody to buy a domain name containing negative terms and point it to someone's website in order to damage their reputation. For instance someone could buy the domain child-pornography.com and point it to the address 64.34.119.12 which is the address behind stackoverflow.com and people navigating to the domain in question would end up visualizing content from StackExchange which would be detrimental to StackExchange's image. To illustrate this, I added the entry 64.34.119.12 child-pornography.com to my /etc/hosts file and tested. Here is what I obtained: I personally found this user experience terrible as someone could think that Stack Exchange are in favor of child pornography and awaiting support from the community to create a Q&A site about it. I tested with other websites and experienced other behaviors that I would categorize as follows: 1 - Useful 404 page (happens with stackoverflow.com): For me the worst way of handling this as the image of the targeted website is directly associated with the offending domain. The more useful the 404 page, the bigger the impression that the targeted website would be willing to help with child pornography. 2 - Redirection (happens with microsoft.com): For instance when accessing child-pornography.com you get redirected to www.microsoft.com. It isn't as bad as above as the offending domain name never appears alongside the targeted website's content, but still bad in my opinion as it gives the impression the targeted website bought the offending domain and redirected it to their website to get more traffic. 3 - Server error (happens with lemonde.fr): You get an error from the webserver which page doesn't contain any content that can be associated with the targeted website (e.g. default Apache 404 page, completely blank page). I believe that is good as the identify of the targeted website isn't revealed. Above are the various behaviors I experienced, but I also thought about a fourth way of dealing with this which is described below. 4 - Disclaimer page (haven't found any website implementing that technique): Display a message such as : "You ended here because someone bought and linked the child-pornography.com domain to our website. We do not own this domain and do not associate ourselves with it. This request has been logged by our servers and we will raise this issue with the competent authorities to have this domain taken down. If you want to access our website, please click here." The good thing about this method is that it can be implemented at application layer (good if you don't have control over web server which happens with some hosting solutions), allows you to protect yourself from any liability, and offer the visitor to be redirected to your own website. Which of the above options would you implement to deal with malicious domain linking (IMO only options 3 and 4 are worth considering) ?

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• Harnessing Business Events for Predictive Decision Making - part 1 / 3

  - by Sanjeev Sharma

  Businesses have long relied on data mining to elicit patterns and forecast future demand and supply trends. Improvements in computing hardware, specifically storage and compute capacity, have significantly enhanced the ability to store and analyze mountains of data in ever shrinking time-frames. Nevertheless, the reality is that data growth is outpacing storage capacity by a factor of two and computing power is still very much bounded by Moore's Law, doubling only every 18 months.Faced with this data explosion, businesses are exploring means to develop human brain-like capabilities in their decision systems (including BI and Analytics) to make sense of the data storm, in other words business events, in real-time and respond pro-actively rather than re-actively. It is more like having a little bit of the right information just a little bit before hand than having all of the right information after the fact. To appreciate this thought better let's first understand the workings of the human brain.Neuroscience research has revealed that the human brain is predictive in nature and that talent is nothing more than exceptional predictive ability. The cerebral-cortex, part of the human brain responsible for cognition, thought, language etc., comprises of five layers. The lowest layer in the hierarchy is responsible for sensory perception i.e. discrete, detail-oriented tasks whereas each of the above layers increasingly focused on assembling higher-order conceptual models. Information flows both up and down the layered memory hierarchy. This allows the conceptual mental-models to be refined over-time through experience and repetition. Secondly, and more importantly, the top-layers are able to prime the lower layers to anticipate certain events based on the existing mental-models thereby giving the brain a predictive ability. In a way the human brain develops a "memory of the future", some sort of an anticipatory thinking which let's it predict based on occurrence of events in real-time. A higher order of predictive ability stems from being able to recognize the lack of certain events. For instance, it is one thing to recognize the beats in a music track and another to detect beats that were missed, which involves a higher order predictive ability.Existing decision systems analyze historical data to identify patterns and use statistical forecasting techniques to drive planning. They are similar to the human-brain in that they employ business rules very much like mental-models to chunk and classify information. However unlike the human brain existing decision systems are unable to evolve these rules automatically (AI still best suited for highly specific tasks) and  predict the future based on real-time business events. Mistake me not,  existing decision systems remain vital to driving long-term and broader business planning. For instance, a telco will still rely on BI and Analytics software to plan promotions and optimize inventory but tap into business events enabled predictive insight to identify specifically which customers are likely to churn and engage with them pro-actively. In the next post, i will depict the technology components that enable businesses to harness real-time events and drive predictive decision making.

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• Java Embedded Releases

  - by Tori Wieldt

  Oracle today announced a new product in its Java Platform, Micro Edition (Java ME) product portfolio, Oracle Java ME Embedded 3.2, a complete client Java runtime Optimized for resource-constrained, connected, embedded systems.  Also, Oracle is releasing Oracle Java Wireless Client 3.2, Oracle Java ME Software Development Kit (SDK) 3.2. Oracle also announced Oracle Java Embedded Suite 7.0 for larger embedded devices, providing a middleware stack for embedded systems. Small is the new big! Introducing Oracle Java ME Embedded 3.2  Oracle Java ME Embedded 3.2 is designed and optimized to meet the unique requirements of small embedded, low power devices such as micro-controllers and other resource-constrained hardware without screens or user interfaces. These include: On-the-fly application downloads and updates Remote operation, often in challenging environments Ability to add new capabilities without impacting the existing functions Support for hardware with as little as 130 kB RAM and 350 kB ROM Oracle Java Wireless Client 3.2 Oracle Java Wireless Client 3.2 is built around an optimized Java ME implementation that delivers a feature-rich application environment for mass-market mobile devices. This new release: Leverages standard JSRs, Oracle optimizations/APIs and a flexible porting layer for device specific customizations, which are tuned to device/chipset requirements Supports advanced tooling functions, such as memory and network monitoring and on-device tooling Offers new support for dual SIM functionality, which is highly useful for mass-market devices supported by multiple carriers with multiple phone connections Oracle Java ME SDK 3.2 Oracle Java ME SDK 3.2 provides a complete development environment for both Oracle Java ME Embedded 3.2 and Oracle Java Wireless Client 3.2. Available for download from OTN, The latest version includes: Small embedded device support In-field and remote administration and debugging Java ME SDK plug-ins for Eclipse and the NetBeans Integrated Development Environment (IDE), enabling more application development environments for Java ME developers. A new device skin creator that developers can use to generate their custom device skins for testing their applications. Oracle Embedded Suite 7.0 The Oracle Java Embedded Suite is a new packaged solution from Oracle (including Java DB, GlassFish for Embedded Suite, Jersey Web Services Framework, and Oracle Java SE Embedded 7 platform), created to provide value added services for collecting, managing, and transmitting data to and from other embedded devices.The Oracle Java Embedded Suite is a complete device-to-data center solution subset for embedded systems.  See Java Me and Java Embedded in Action Java ME and Java Embedded technologies will be showcased for developers at JavaOne 2012 in over 60 conference sessions and BOFs, as well as in the JavaOne Exhibition Hall. For business decision makers, the new event Java Embedded @ JavaOne you learn more about Java Embedded technologies and solutions.

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• cocos2d-x simple shader usage [on hold]

  - by Narek

  I want to obtain color ramp effect from this tutorial: http://www.raywenderlich.com/10862/how-to-create-cool-effects-with-custom-shaders-in-opengl-es-2-0-and-cocos2d-2-x Here is my code in cocos2d-x 3: bool HelloWorld::init() { ////////////////////////////// // 1. super init first if ( !Layer::init() ) { return false; } Vec2 origin = Director::getInstance()->getVisibleOrigin(); sprite = Sprite::create("HelloWorld.png"); sprite->setAnchorPoint(Vec2(0, 0)); sprite->setRotation(3); sprite->setPosition(origin); addChild(sprite); std::string str = FileUtils::getInstance()->getStringFromFile("CSEColorRamp.fsh"); const GLchar * fragmentSource = str.c_str(); GLProgram* p = GLProgram::createWithByteArrays(ccPositionTextureA8Color_vert, fragmentSource); p->bindAttribLocation(GLProgram::ATTRIBUTE_NAME_POSITION, GLProgram::VERTEX_ATTRIB_POSITION); p->bindAttribLocation(GLProgram::ATTRIBUTE_NAME_TEX_COORD, GLProgram::VERTEX_ATTRIB_TEX_COORD); p->link(); p->updateUniforms(); sprite->setGLProgram(p); // 3 colorRampUniformLocation = glGetUniformLocation(sprite->getGLProgram()->getProgram(), "u_colorRampTexture"); glUniform1i(colorRampUniformLocation, 1); // 4 colorRampTexture = Director::getInstance()->getTextureCache()->addImage("colorRamp.png"); colorRampTexture->setAliasTexParameters(); // 5 sprite->getGLProgram()->use(); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, colorRampTexture->getName()); glActiveTexture(GL_TEXTURE0); return true; } And here is the fragment shader as it is in the tutorial: #ifdef GL_ES precision mediump float; #endif // 1 varying vec2 v_texCoord; uniform sampler2D u_texture; uniform sampler2D u_colorRampTexture; void main() { // 2 vec3 normalColor = texture2D(u_texture, v_texCoord).rgb; // 3 float rampedR = texture2D(u_colorRampTexture, vec2(normalColor.r, 0)).r; float rampedG = texture2D(u_colorRampTexture, vec2(normalColor.g, 0)).g; float rampedB = texture2D(u_colorRampTexture, vec2(normalColor.b, 0)).b; // 4 gl_FragColor = vec4(rampedR, rampedG, rampedB, 1); } As a result I get a black screen with 2 draw calls. What is wrong? Do I miss something?

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• Updating an Entity through a Service

  - by GeorgeK

  I'm separating my software into three main layers (maybe tiers would be a better term): Presentation ('Views') Business logic ('Services' and 'Repositories') Data access ('Entities' (e.g. ActiveRecords)) What do I have now? In Presentation, I use read-only access to Entities, returned from Repositories or Services, to display data. $banks = $banksRegistryService->getBanksRepository()->getBanksByCity( $city ); $banksViewModel = new PaginatedList( $banks ); // some way to display banks; // example, not real code I find this approach quite efficient in terms of performance and code maintanability and still safe as long as all write operations (create, update, delete) are preformed through a Service: namespace Service\BankRegistry; use Service\AbstractDatabaseService; use Service\IBankRegistryService; use Model\BankRegistry\Bank; class Service extends AbstractDatabaseService implements IBankRegistryService { /** * Registers a new Bank * * @param string $name Bank's name * @param string $bik Bank's Identification Code * @param string $correspondent_account Bank's correspondent account * * @return Bank */ public function registerBank( $name, $bik, $correspondent_account ) { $bank = new Bank(); $bank -> setName( $name ) -> setBik( $bik ) -> setCorrespondentAccount( $correspondent_account ); if( null === $this->getBanksRepository()->getDefaultBank() ) $this->setDefaultBank( $bank ); $this->getEntityManager()->persist( $bank ); return $bank; } /** * Makes the $bank system's default bank * * @param Bank $bank * @return IBankRegistryService */ public function setDefaultBank( Bank $bank ) { $default_bank = $this->getBanksRepository()->getDefaultBank(); if( null !== $default_bank ) $default_bank->setDefault( false ); $bank->setDefault( true ); return $this; } } Where am I stuck? I'm struggling about how to update certain fields in Bank Entity. Bad solution #1: Making a series of setters in Service for each setter in Bank; - seems to be quite reduntant, increases Service interface complexity and proportionally decreases it's simplicity - something to avoid if you care about code maitainability. I try to follow KISS and DRY principles. Bad solution #2: Modifying Bank directly through it's native setters; - really bad. If you'll ever need to move modification into the Service, it will be pain. Business logic should remain in Business logic layer. Plus, there are plans on logging all of the actions and maybe even involve user permissions (perhaps, through decorators) in future, so all modifications should be made only through the Service. Possible good solution: Creating an updateBank( Bank $bank, $array_of_fields_to_update) method; - makes the interface as simple as possible, but there is a problem: one should not try to manually set isDefault flag on a Bank, this operation should be performed through setDefaultBank method. It gets even worse when you have relations that you don't want to be directly modified. Of course, you can just limit the fields that can be modified by this method, but how do you tell method's user what they can and cannot modify? Exceptions?

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• Windows 8 and the future of Silverlight

  - by Laila

  After Steve Ballmer's indiscrete 'MisSpeak' about Windows 8, there has been a lot of speculation about the new operating system. We've now had a few glimpses, such as the demonstration of 'Mosh' at the D9 2011 conference, and the Youtube video, which showed a touch-centric new interface for apps built using HTML5 and JavaScript. This has caused acute anxiety to the programmers who have followed the recommended route of WPF, Silverlight and .NET, but it need not have caused quite so much panic since it was, in fact, just a thin layer to make Windows into an apparently mobile-friendly OS. More worryingly, the press-release from Microsoft was at pains to say that 'Windows 8 apps use the power of HTML5, tapping into the native capabilities of Windows using standard JavaScript and HTML', as if all thought of Silverlight, dominant in WP7, had been jettisoned. Ironically, this brave new 'happening' platform can all be done now in Windows 7 and an iPad, using Adobe Air, so it is hardly cutting-edge; in fact the tile interface had a sort of Retro-Zune Metro UI feel first seen in Media Centre, followed by Windows Phone 7, with any originality leached out of it by the corporate decision-making process. It was kinda weird seeing old Excel running alongside stodgily away amongst all the extreme paragliding videos. The ability to snap and resize concurrent apps might be a novelty on a tablet, but it is hardly so on a PC. It was at that moment that it struck me that here was a spreadsheet application that hadn't even made the leap to the .NET platform. Windows was once again trying to be all things to all men, whereas Apple had carefully separated Mac OS X development from iOS. The acrobatic feat of straddling all mobile and desktop devices with one OS is looking increasingly implausible. There is a world of difference between an operating system that facilitates business procedures and a one that drives a device for playing pop videos and your holiday photos. So where does this leave Silverlight? Pretty much where it was. Windows 8 will support it, and it will continue to be developed, but if these press-releases reflect the thinking within Microsoft, it is no longer seen as the strategic direction. However, Silverlight is still there and there will be a whole new set of developer APIs for building touch-centric apps. Jupiter, for example, is rumoured to involve an App store that provides new, Silverlight based "immersive" applications that are deployed as AppX packages. When the smoke clears, one suspects that the Javascript/HTML5 is merely an alternative development environment for Windows 8 to attract the legions of independent developers outside the .NET culture who are unlikely to ever take a shine to a more serious development environment such as WPF or Silverlight. Cheers, Laila

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• Managing Joomla via Android

  Surprisingly, it was only today that I actually looked for possible solutions to write more content for my blog. Since quite some time I'm using my Samsung Galaxy Tab 10.1 for all kind of social media activities like Google+, FB, etc. but also for my casual mail during the evening hours. And yes, I feel a little bit guilty about missing the chance to use my tablet to write some content here... OK, only a little bit. ;-) These are not the droids you are looking for But those lazy times are over! While searching the Play Store with the expression 'joomla' I got three interesting hits: - Joomla Admin Mobile! - Joooid - Joomla! Security Checklist After reading the reviews I installed the two later apps. Joomla! Security Checklist The author clearly outlines here that the app is primarily for his personal purpose to have safety checklist at hand at anytime. I guess that any reader of this article has an Android based smartphone or tablet, so that simple app should be part of your toolbox when using Joomla! for your websites. Joooid plugin & app Although I was looking for an app that could work with the default XML RPC interface of Joomla I have to admit that this combination of an enhanced Web service suits me better, mainly due to performance reason. The official website has not only the downloads for Joomla versions 1.5 - 2.5 but also very good and easy to follow step-by-step instructions to prepare your server for the Android app. It will take you less than 5 minutes to get it up and running. For safety reasons, I recommend that you should configure your Web server to have an additional authentication layer on the plugins folder. The smartphone app has the ability to run against HTTP authentication. Personally, I like the look and feel of the app. It is a little bit different compared to the web UI but still easy to use. In fact, this article is the first one written in the Joooid app. At the moment, I only miss the ability to have list tags. Quick and easy Writing full-fledged articles with images, a couple of hyperlinks and some styling here and there should be left to the desktop. At least for the moment. Let's see whether I'm going to change my mind on this during the upcoming months... I'll give it a try, and hope to publish at least once per month to write some content using Joooid. Actually, it would be great to have some feedback about other Joomla! clients in the wild.

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• .Net Application & Database Modularity/Reuse

  - by Martaver

  I'm looking for some guidance on how to architect an app with regards to modularity, separation of concerns and re-usability. I'm working on an application (ASP.Net, C#) that has distinctly generic chunks of functionality, that I'd love to be able to lift out, all layers, into re-usable components. This means the module handles the database schema, data access, API, everything so that the next time I want to use it I can just register the module and hook into it. Developing modules of re-usable functionality is a no-brainer, but what is really confusing me is what to do when it comes to handling a core re-usable database schema that serves the module's functionality. In an ideal world, I would register a module and it would ensure that the associated database schema exists in the DB. I would code on the assumption that the tables exist, calling the module's functionality through the DLL, agnostic of the database layer. Kind of like Enterprise Library's Caching/Logging Application Block, which can create a DB schema in the target DB to use as a data store. My Questions is: What do you think is the best way to achieve this, firstly, in terms design architecture, and secondly solution structure. What patterns/frameworks do you know that exist & support this kind of thing? My thoughts so far: I mostly use Entity Framework and SQL Server DB Projects. I thought about a 'black box' approach to modules of functionality. I could use use a code-first approach in EF4, and use the ObjectContext to create a database when the module is initialized. However this means that all of the entities that my module encapsulates would be disconnected from the rest of the application because they belonged to an abstracted ObjectContext. Further - Creating appropriate indexes and references between domain entities and the module's entities would be impossible to do practically. I've thought of adopting Enterprise Library and creating my own Application Blocks. I'm not sure how this would play nice with Entity Framework (if at all) though. I like the idea of building on proven patterns & practices to encapsulate established, reusable functionality. I thought of abandoning Entity Framework for the Module, and just creating a separate DB schema for the module with its own set of stored procedures & ADO.Net. Then deploying the script at run-time if interrogation shows that it doesn't exist. But once again, for application developing outside of the application, I would want to use Entity Framework and I would have to use the module separately, disconnected from the domain ObjectContext. Has anyone had experience developing these sorts of full-stack modules? What advice can you offer? Am I biting off more than I can chew?

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• Data structures for a 2D multi-layered and multi-region map?

  - by DevilWithin

  I am working on a 2D world editor and a world format subsequently. If I were to handle the game "world" being created just as a layered set of structures, either in top or side views, it would be considerably simple to do most things. But, since this editor is meant for 3rd parties, I have no clue how big worlds one will want to make and I need to keep in mind that eventually it will become simply too much to check, handling and comparing stuff that are happening completely away from the player position. I know the solution for this is to subdivide my world into sub regions and stream them on the fly, loading and unloading resources and other data. This way I know a virtually infinite game area is achievable. But, while I know theoretically what to do, I really have a few questions I'd hoped to get answered for some hints about the topic. The logic way to handle the regions is some kind of grid, would you pick evenly distributed blocks with equal sizes or would you let the user subdivide areas by taste with irregular sized rectangles? In case of even grids, would you use some kind of block/chunk neighbouring system to check when the player transposes the limit or just put all those in a simple array? Being a region a different data structure than its owner "game world", when streaming a region, would you deliver the objects to the parent structures and track them for unloading later, or retain the objects in each region for a more "hard-limit" approach? Introducing the subdivision approach to the project, and already having a multi layered scene graph structure on place, how would i make it support the new concept? Would you have the parent node have the layers as children, and replicate in each layer node, a node per region? Or the opposite, parent node owns all the regions possible, and each region has multiple layers as children? Or would you just put the region logic outside the graph completely(compatible with the first suggestion in Q.3) When I say virtually infinite worlds, I mean it of course under the contraints of the variable sizes and so on. Using float positions, a HUGE world can already be made. Do you think its sane to think beyond that? Because I think its ok to stick to this limit since it will never be reached so easily.. As for when to stream a region, I'm implementing it as a collection of watcher cameras, which the streaming system works with to know what to load/unload. The problem here is, i will be needing some kind of warps/teleports built in for my game, and there is a chance i will be teleporting a player to a unloaded region far away. How would you approach something like this? Is it sane to load any region to memory which can be teleported to by a warp within a radius from the player? Sorry for the huge question, any answers are helpful!

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• Why does my ID3DXSprite appear to be incorrectly scaled?

  - by Bjoern

  I am using D3D9 for rendering some simple things (a movie) as the backmost layer, then on top of that some text messages, and now wanted to add some buttons to that. Before adding the buttons everything seemed to have worked fine, and I was using a ID3DXSprite for the text as well (ID3DXFont), now I am loading some graphics for the buttons, but they seem to be scaled to something like 1.2 times their original size. In my test window I centered the graphic, but it being too big it just doesnt fit well, for example the client area is 640x360, the graphic is 440, so I expect 100 pixel on left and right, left side is fine [I took screenshot and "counted" the pixels in photoshop], but on the right there is only about 20 pixels) My rendering code is very simple (I am omitting error checks, et cetera, for brevity) // initially viewport was set to width/height of client area // clear device m_d3dDevice->Clear( 0, NULL, D3DCLEAR_TARGET|D3DCLEAR_STENCIL|D3DCLEAR_ZBUFFER, D3DCOLOR_ARGB(0,0,0,0), 1.0f, 0 ); // begin scene m_d3dDevice->BeginScene(); // render movie surface (just two triangles to which the movie is rendered) m_d3dDevice->SetRenderState(D3DRS_ALPHABLENDENABLE,false); m_d3dDevice->SetSamplerState( 0, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR ); // bilinear filtering m_d3dDevice->SetSamplerState( 0, D3DSAMP_MINFILTER, D3DTEXF_LINEAR ); // bilinear filtering m_d3dDevice->SetTextureStageState( 0, D3DTSS_COLORARG1, D3DTA_TEXTURE ); m_d3dDevice->SetTextureStageState( 0, D3DTSS_COLORARG2, D3DTA_DIFFUSE ); //Ignored m_d3dDevice->SetTextureStageState( 0, D3DTSS_COLOROP, D3DTOP_SELECTARG1 ); m_d3dDevice->SetTexture( 0, m_movieTexture ); m_d3dDevice->SetStreamSource(0, m_displayPlaneVertexBuffer, 0, sizeof(Vertex)); m_d3dDevice->SetFVF(Vertex::FVF_Flags); m_d3dDevice->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 2); // render sprites m_sprite->Begin(D3DXSPRITE_ALPHABLEND | D3DXSPRITE_SORT_TEXTURE | D3DXSPRITE_DO_NOT_ADDREF_TEXTURE); // text drop shadow m_font->DrawText( m_playerSprite, m_currentMessage.c_str(), m_currentMessage.size(), &m_playerFontRectDropShadow, DT_RIGHT|DT_TOP|DT_NOCLIP, m_playerFontColorDropShadow ); // text m_font->DrawText( m_playerSprite, m_currentMessage.c_str(), m_currentMessage.size(), &m_playerFontRect, DT_RIGHT|DT_TOP|DT_NOCLIP, m_playerFontColorMessage ) ); // control object m_sprite->Draw( m_texture, 0, 0, &m_vecPos, 0xFFFFFFFF ); // draws a few objects like this m_sprite->End() // end scene m_d3dDevice->EndScene(); What did I forget to do here? Except for the control objects (play button, pause button etc which are placed on a "panel" which is about 440 pixels wide) everything seems fine, the objects are positioned where I expect them, but just too big. By the way I loaded the images using D3DXCreateTextureFromFileEx (resizing wnidow, and reacting to lost device, etc, works fine too). For experimenting, I added some code to take an identity matrix and scale is down on the x/y axis to 0.75f, which then gave me the expected result for the controls (but also made the text smaller and out of position), but I don't know why I would need to scale anything. My rendering code is so simple, I just wanted to draw my 2D objects 1;1 the size they came from the file... I am really very inexperienced in D3D, so the answer might be very simple...

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• Another Custom Property Locator: a Library of Books

  - by Cindy McMullen

  Introduction The previous post gave an introduction to custom property locators and showed how create one using JDeveloper.  This post continues on the custom locator theme, with a slightly more complex locator: a library of books.  It demonstrates using the DAO pattern to delegate data access from the Locator, which is likely how many actual backing stores will integrate with the Locator.  You can imagine, rather than a library of books, the data store might be a user database of sorts.  The same sort of pattern would apply. This post uses the BookLocator example originally shown in the WebCenter documentation, but has: updated the source code to reflect the final Property APIs includes the steps for generating the namespace and property definition files via JDeveloper detailed usage of the PropertyService APIs Getting Started If you're new to JDeveloper, you might want to check out this tutorial.  There is also the "Jump-Start to using Personalization" blog post that you might find useful.  Otherwise, if you're already familiar with both, you can skip those tutorials and jump right in to using JDeveloper. Download the BookLocator.zip file (which has been updated from the original post) and unzip it to a new directory.  Start JDeveloper, navigate to the BookLocator.jws file, and open it.   It should look something like this: The Properties Namespace file contains the property definitions and property set definitions you define.  It is explained more in detail in the Namespace documentation.  Although this example doesn't show it, the property set definitions have the ability to reference multiple locators per property.   This can be done by right-clicking on the 'Locator Info' box.  Configure the contents of the Locator Map  by editing locators and mapping them to available property names in the property set definition. Compiling, deploying, and running your locator The rest of the steps in this tutorial basically follow those in the previous blog on custom locators, and won't be repeated here.   A scenario to invoke your locator is included with the sample app: see BookProperties.scenarios_diagram above.  Summary This post demonstrates a simple library of books accessed by the BookPropertyLocator via the DAO layer.  This is a useful pattern for more realistic property retrievals, such as a backing user store.  It also points out the possibility of retrieving properties from multiple locators, which would be quite handy to retrieve user attributes from multiple sources.

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• Use Expressions with LINQ to Entities

  - by EltonStoneman

  [Source: http://geekswithblogs.net/EltonStoneman] Recently I've been putting together a generic approach for paging the response from a WCF service. Paging changes the service signature, so it's not as simple as adding a behavior to an existing service in config, but the complexity of the paging is isolated in a generic base class. We're using the Entity Framework talking to SQL Server, so when we ask for a page using LINQ's .Take() method we get a nice efficient SQL query for just the rows we want, with minimal impact on SQL Server and network traffic. We use the maximum ID of the record returned as a high-water mark (rather than using .Skip() to go to the next record), so the approach caters for records being deleted between page requests. In the paged response we include a HasMorePages indicator, computed by comparing the max ID in the page of results to the max ID for the whole resultset - if the latter is bigger, then there are more pages. In some quick performance testing, the paged version of the service performed much more slowly than the unpaged version, which was unexpected. We narrowed it down to the code which gets the max ID for the full resultset - instead of building an efficient MAX() SQL query, EF was returning the whole resultset and then computing the max ID in the service layer. It's easy to reproduce - take this AdventureWorks query:             var context = new AdventureWorksEntities();             var query = from od in context.SalesOrderDetail                         where od.ModifiedDate >= modified                          && od.SalesOrderDetailID.CompareTo(id) > 0                         orderby od.SalesOrderDetailID                         select od;   We can find the maximum SalesOrderDetailID like this:             var maxIdEfficiently = query.Max(od => od.SalesOrderDetailID);   which produces our efficient MAX() SQL query. If we're doing this generically and we already have the ID function in a Func:             Func<SalesOrderDetail, int> idFunc = od => od.SalesOrderDetailID;             var maxIdInefficiently = query.Max(idFunc);   This fetches all the results from the query and then runs the Max() function in code. If you look at the difference in Reflector, the first call passes an Expression to the Max(), while the second call passes a Func. So it's an easy fix - wrap the Func in an Expression:             Expression<Func<SalesOrderDetail, int>> idExpression = od => od.SalesOrderDetailID;             var maxIdEfficientlyAgain = query.Max(idExpression);   - and we're back to running an efficient MAX() statement. Evidently the EF provider can dissect an Expression and build its equivalent in SQL, but it can't do that with Funcs.

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• Accessing SQL Server data from iOS apps

  - by RobertChipperfield

  Almost all mobile apps need access to external data to be valuable. With a huge amount of existing business data residing in Microsoft SQL Server databases, and an ever-increasing drive to make more and more available to mobile users, how do you marry the rather separate worlds of Microsoft's SQL Server and Apple's iOS devices? The classic answer: write a web service layer Look at any of the questions on this topic asked in Internet discussion forums, and you'll inevitably see the answer, "just write a web service and use that!". But what does this process gain? For a well-designed database with a solid security model, and business logic in the database, writing a custom web service on top of this just to access some of the data from a different platform seems inefficient and unnecessary. Desktop applications interact with the SQL Server directly - why should mobile apps be any different? The better answer: the iSql SDK Working along the lines of "if you do something more than once, make it shared," we set about coming up with a better solution for the general case. And so the iSql SDK was born: sitting between SQL Server and your iOS apps, it provides the simple API you're used to if you've been developing desktop apps using the Microsoft SQL Native Client. It turns out a web service remained a sensible idea: HTTP is much more suited to the Big Bad Internet than SQL Server's native TDS protocol, removing the need for complex configuration, firewall configuration, and the like. However, rather than writing a web service for every app that needs data access, we made the web service generic, serving only as a proxy between the SQL Server and a client library integrated into the iPhone or iPad app. This client library handles all the network communication, and provides a clean API. OSQL in 25 lines of code As an example of how to use the API, I put together a very simple app that allowed the user to enter one or more SQL statements, and displayed the results in a rather primitively formatted text field. The total amount of Objective-C code responsible for doing the work? About 25 lines. You can see this in action in the demo video. Beta out now - your chance to give us your suggestions! We've released the iSql SDK as a beta on the MobileFoo website: you're welcome to download a copy, have a play in your own apps, and let us know what we've missed using the Feedback button on the site. Software development should be fun and rewarding: no-one wants to spend their time writing boiler-plate code over and over again, so stop writing the same web service code, and start doing exciting things in the new world of mobile data!

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• Function like C# properties?

  - by alan2here

  I was directed here from SO as a better stack exchange site for this question. I've been thinking about the neatness and expression of C# properties over functions, although they only currently work where no parameters are used, and wondered. Is is possible, and if so why not, to have a stand alone function like C# property. For example: public class test { private byte n = 4; public test() { func = 2; byte n2 = func; func; } private byte func { get { return n; } set { n = value; } func { n++; } } } edit: Sorry for the vagueness first time round. I'm going to add some info and motivation. The 'n++' here is just a simple example, a placeholder, it's not intended to be representative of the actual code that would be used. I'm also looking at this from the point of view of looking at the property command as is, not in the context of using it for 'get_xyz' and 'set_xyz' member functions, which is certainly useful, but of instead comparing it more abstractly to functions and other programic elements. A 'get' property can be used instead of a function that takes no parameters, and syntactically they are perhaps only aesthetically, but as I see it noticeably nicer. However, properties also add the potential for an extra layer of polymorphism, one that relates to the 'func = 4;' getting, 'int n = func;' setting or 'func;' function like context in which they are used as well as the more common parameter based polymorphism. Potentially allowing for a lot of expression and contextual information reguarding how other would use your functions. As in many places uses and definitions would remain the same, it shouldn't break existing code. private byte func { get { } get bool { } set { } func { } func(bool) { } func(byte, myType) { } // etc... } So a read only function would look like this: private byte func { get { } } A normal function like this: private void func { func { } } A function with parameter polymorphism like this: private byte func { func(bool) { } func(byte, myType) { } } And a function that could return a value, or just compute, depending on the context it is used, that also has more conventional parameter polymorphism as well, like so: private byte func { get { } func(bool) { } func(byte, myType) { } }

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• Monitoring C++ applications

  - by Scott A

  We're implementing a new centralized monitoring solution (Zenoss). Incorporating servers, networking, and Java programs is straightforward with SNMP and JMX. The question, however, is what are the best practices for monitoring and managing custom C++ applications in large, heterogenous (Solaris x86, RHEL Linux, Windows) environments? Possibilities I see are: Net SNMP Advantages single, central daemon on each server well-known standard easy integration into monitoring solutions we run Net SNMP daemons on our servers already Disadvantages: complex implementation (MIBs, Net SNMP library) new technology to introduce for the C++ developers rsyslog Advantages single, central daemon on each server well-known standard unknown integration into monitoring solutions (I know they can do alerts based on text, but how well would it work for sending telemetry like memory usage, queue depths, thread capacity, etc) simple implementation Disadvantages: possible integration issues somewhat new technology for C++ developers possible porting issues if we switch monitoring vendors probably involves coming up with an ad-hoc communication protocol (or using RFC5424 structured data; I don't know if Zenoss supports that without custom Zenpack coding) Embedded JMX (embed a JVM and use JNI) Advantages consistent management interface for both Java and C++ well-known standard easy integration into monitoring solutions somewhat simple implementation (we already do this today for other purposes) Disadvantages: complexity (JNI, thunking layer between native C++ and Java, basically writing the management code twice) possible stability problems requires a JVM in each process, using considerably more memory JMX is new technology for C++ developers each process has it's own JMX port (we run a lot of processes on each machine) Local JMX daemon, processes connect to it Advantages single, central daemon on each server consistent management interface for both Java and C++ well-known standard easy integration into monitoring solutions Disadvantages: complexity (basically writing the management code twice) need to find or write such a daemon need a protocol between the JMX daemon and the C++ process JMX is new technology for C++ developers CodeMesh JunC++ion Advantages consistent management interface for both Java and C++ well-known standard easy integration into monitoring solutions single, central daemon on each server when run in shared JVM mode somewhat simple implementation (requires code generation) Disadvantages: complexity (code generation, requires a GUI and several rounds of tweaking to produce the proxied code) possible JNI stability problems requires a JVM in each process, using considerably more memory (in embedded mode) Does not support Solaris x86 (deal breaker) Even if it did support Solaris x86, there are possible compiler compatibility issues (we use an odd combination of STLPort and Forte on Solaris each process has it's own JMX port when run in embedded mode (we run a lot of processes on each machine) possibly precludes a shared JMX server for non-C++ processes (?) Is there some reasonably standardized, simple solution I'm missing? Given no other reasonable solutions, which of these solutions is typically used for custom C++ programs? My gut feel is that Net SNMP is how people do this, but I'd like other's input and experience before I make a decision.

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• Using Query Classes With NHibernate

  - by Liam McLennan

  Even when using an ORM, such as NHibernate, the developer still has to decide how to perform queries. The simplest strategy is to get access to an ISession and directly perform a query whenever you need data. The problem is that doing so spreads query logic throughout the entire application – a clear violation of the Single Responsibility Principle. A more advanced strategy is to use Eric Evan’s Repository pattern, thus isolating all query logic within the repository classes. I prefer to use Query Classes. Every query needed by the application is represented by a query class, aka a specification. To perform a query I: Instantiate a new instance of the required query class, providing any data that it needs Pass the instantiated query class to an extension method on NHibernate’s ISession type. To query my database for all people over the age of sixteen looks like this: [Test] public void QueryBySpecification() { var canDriveSpecification = new PeopleOverAgeSpecification(16); var allPeopleOfDrivingAge = session.QueryBySpecification(canDriveSpecification); } To be able to query for people over a certain age I had to create a suitable query class: public class PeopleOverAgeSpecification : Specification<Person> { private readonly int age; public PeopleOverAgeSpecification(int age) { this.age = age; } public override IQueryable<Person> Reduce(IQueryable<Person> collection) { return collection.Where(person => person.Age > age); } public override IQueryable<Person> Sort(IQueryable<Person> collection) { return collection.OrderBy(person => person.Name); } } Finally, the extension method to add QueryBySpecification to ISession: public static class SessionExtensions { public static IEnumerable<T> QueryBySpecification<T>(this ISession session, Specification<T> specification) { return specification.Fetch( specification.Sort( specification.Reduce(session.Query<T>()) ) ); } } The inspiration for this style of data access came from Ayende’s post Do You Need a Framework?. I am sick of working through multiple layers of abstraction that don’t do anything. Have you ever seen code that required a service layer to call a method on a repository, that delegated to a common repository base class that wrapped and ORMs unit of work? I can achieve the same thing with NHibernate’s ISession and a single extension method. If you’re interested you can get the full Query Classes example source from Github.

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• Ubuntu 12.04 x64 LTS VPN Server not changing IP

  - by user288778

  I used this guide http://silverlinux.blogspot.co.uk/2012/05/how-to-pptp-vpn-on-ubuntu-1204-pptpd.html and it worked fine. I'm able to connect but the problem is, that my IP being changed to "localip" not "remote ip". This is what I get from tail -f /var/log/syslog [code] June 6 00:09:19 instant5860 NetworkManager[1456]: Unmanaged Device found; state CONNECTED forced (see http://bugs.launchpad.net/bugs/191889) June 6 00:09:19 instant5860 NetworkManager[1456]: Marking connection 'Wired connection 1' invalid. June 6 00:09:19 instant5860 NetworkManager[1456]: Activation (eth1) failed. June 6 00:09:19 instant5860 NetworkManager[1456]: Activation (eth1) Stage 4 of 5 (IPv4 Configure Timeout) complete. June 6 00:09:19 instant5860 NetworkManager[1456]: (eth1): device state change: failed - disconnected (reason 'none') [120 30 0] June 6 00:09:19 instant5860 NetworkManager[1456]: (eth1): deactivating device (reason 'none') [0] June 6 00:09:19 instant5860 NetworkManager[1456]: Unmanaged Device found; state CONNECTED forced. June----- avahi-daemon[440]: Withdrawing address record for fe80......... on eth1 Jun------avahi-daemon[440]: Leaving mDNS multicast group on interface eth1. IPv6 with address fe80..... Jun------avahi-daemon[440]: Interface eth1.IPv6 no longer relevant for mDNS. Jun------avahi-daemon[440]: Joining mDNS multicast group on interface eth1.IPv6 with address fe80.... Jun------avahi-daemon[440]: New relevant interface eth1.IPv6 for mDNS Jun------avahi-daemon[440]: Registering new address record for fe80..... on eth1.*. Jun - snmpd[1172]: error on subcontainer 'ia_addr' insert (-1) dbusp382]: [syste] Activating service name='org.freedesktop.PackageKit' (using servicehelper) AptDaemon: INFO: Initializing daemon AptDaemon.PackageKit: INFO: Initializing PackageKit compat layer dbus[382]: [system] Successfu;;y activated service 'org.freedesktop.PackageKit' AptDaemon.PackageKit: INFO: Initializing PackageKit transaction AptDaemon.Worker: INFO: Simulating trans: /org/debian/apt/transaction/233beca013a0473ea34d9dea805af5df AptDaemon.Worker: INFO: Processing transaction /org/debian/apt... AptDaemon.PackageKit: INFO: Get updates() AptDaemon.Worker: INFO: Finished snmpd[1172]: error on subcontainer pptpd[23611]: CTRL: Client 82.33.... control connection started pptpd[23611]: CTRL: Starting call (launching pppd, opening GRE) pptpd[23611]: pppd 2.4.5 started by root uid 0 pptpd[23611]: Using interface ppp0 pptpd[23611]: Connect ppp0 <-- /dev/pts/1 NetworkManager[1456]: SCPlugin - Ifupdown: device added (path: /sys/devices/virtual/net/ppp0, iface: ppp0) NetworkManager[1456]:SCPlugin - Ifupdown: device added (path: /sys/devices/virtual/net/ppp0, iface: ppp0): no ifupdown configuration found. pptpd[23612]: peer from calling number 82... authorized. kernel: [2918261.416923] init: ufw pre-start process (23613) terminated with status 1 dhclient: DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 7 CTRL: Ignored a SET LING info packet with real ACCMs! local IP address:109.0.121.197 remote IP address: 109.0.84.56 dhclient: DHCPDISCOVER on eth1 to 255.255.255.255 port 67 interval 13 NetworkManager[1456]: (eth1): DHCPv4 request timed out. NetworkManager[1456]: (eth1): canceled DHCP transaction, DHCP client pid 23280 NetworkManager[1456]: Activation (eth1) Stage 4 of 5 (IPv4 Configure Timeout) scheduled... NetworkManager[1456]: Activation (eth1) Stage 4 of 5 (IPv4 Configure Timeout) started... NetworkManager[1456]: (eth1): device state change: ip-config - failed (reason 'ip-config-unavailable') [70 120 5[ NetworkManager[1456]: Unmanaged 'ia_addr' insert (-1)[/code]

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• How to get around the Circular Reference issue with JSON and Entity

  - by DanScan

  I have been experimenting with creating a website that leverages MVC with JSON for my presentation layer and Entity framework for data model/database. My Issue comes into play with serializing my Model objects into JSON. I am using the code first method to create my database. When doing the code first method a one to many relationship (parent/child) requires the child to have a reference back to the parent. (Example code my be a typo but you get the picture) class parent { public List<child> Children{get;set;} public int Id{get;set;} } class child { public int ParentId{get;set;} [ForeignKey("ParentId")] public parent MyParent{get;set;} public string name{get;set;} } When returning a "parent" object via a JsonResult a circular reference error is thrown because "child" has a property of class parent. I have tried the ScriptIgnore attribute but I lose the ability to look at the child objects. I will need to display information in a parent child view at some point. I have tried to make base classes for both parent and child that do not have a circular reference. Unfortunately when I attempt to send the baseParent and baseChild these are read by the JSON Parser as their derived classes (I am pretty sure this concept is escaping me). Base.baseParent basep = (Base.baseParent)parent; return Json(basep, JsonRequestBehavior.AllowGet); The one solution I have come up with is to create "View" Models. I create simple versions of the database models that do not include the reference to the parent class. These view models each have method to return the Database Version and a constructor that takes the database model as a parameter (viewmodel.name = databasemodel.name). This method seems forced although it works. NOTE:I am posting here because I think this is more discussion worthy. I could leverage a different design pattern to over come this issue or it could be as simple as using a different attribute on my model. In my searching I have not seen a good method to overcome this problem. My end goal would be to have a nice MVC application that heavily leverages JSON for communicating with the server and displaying data. While maintaining a consistant model across layers (or as best as I can come up with).

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• Are separate business objects needed when persistent data can be stored in a usable format?

  - by Kylotan

  I have a system where data is stored in a persistent store and read by a server application. Some of this data is only ever seen by the server, but some of it is passed through unaltered to clients. So, there is a big temptation to persist data - whether whole rows/documents or individual fields/sub-documents - in the exact form that the client can use (eg. JSON), as this removes various layers of boilerplate, whether in the form of procedural SQL, an ORM, or any proxy structure which exists just to hold the values before having to re-encode them into a client-suitable form. This form can usually be used on the server too, though business logic may have to live outside of the object, On the other hand, this approach ends up leaking implementation details everywhere. 9 times out of 10 I'm happy just to read a JSON structure out of the DB and send it to the client, but 1 in every 10 times I have to know the details of that implicit structure (and be able to refactor access to it if the stored data ever changes). And this makes me think that maybe I should be pulling this data into separate business objects, so that business logic doesn't have to change when the data schema does. (Though you could argue this just moves the problem rather than solves it.) There is a complicating factor in that our data schema is constantly changing rapidly, to the point where we dropped our previous ORM/RDBMS system in favour of MongoDB and an implicit schema which was much easier to work with. So far I've not decided whether the rapid schema changes make me wish for separate business objects (so that server-side calculations need less refactoring, since all changes are restricted to the persistence layer) or for no separate business objects (because every change to the schema requires the business objects to change to stay in sync, even if the new sub-object or field is never used on the server except to pass verbatim to a client). So my question is whether it is sensible to store objects in the form they are usually going to be used, or if it's better to copy them into intermediate business objects to insulate both sides from each other (even when that isn't strictly necessary)? And I'd like to hear from anybody else who has had experience of a similar situation, perhaps choosing to persist XML or JSON instead of having an explicit schema which has to be assembled into a client format each time.

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• Silverlight and WCF caching

  - by subodhnpushpak

  There are scenarios where Silverlight client calls WCF (or REST) service for data. Now, if the data is cached on the WCF layer, the calls can take considerable resources at the server if NOT cached. Keeping that in mind along with the fact that cache is an cross-cutting aspect, and therefore it should be as easy as possible to put Cache wherever required. The good thing about the solution is that it caches based on the inputs. The input can be basic type of any complex type. If input changes the data is fetched and then cached for further used. If same input is provided again, data id fetched from the cache. The cache logic itself is implemented as PostSharp aspect, and it is as easy as putting an attribute over service call to switch on cache. Notice how clean the code is:        [OperationContract]       [CacheOnArgs(typeof(int))] // based on actual value of cache        public string DoWork(int value)        {            return string.Format("You entered: {0} @ cached time {1}", value, System.DateTime.Now);        } The cache is implemented as POST Sharp as below 1: public override void OnInvocation(MethodInvocationEventArgs eventArgs) 2: { 3: try 4: { 5: object value = new object(); 6: object[] args = eventArgs.GetArgumentArray(); 7: if (args != null || args.Count() > 0) 8: { 9:   10: string key = string.Format("{0}_{1}", eventArgs.Method.Name, XMLUtility<object>.GetDataContractXml(args[0], null));// Compute the cache key (details omitted). 11:   12: 13: value = GetFromCache(key); 14: if (value == null) 15: { 16: eventArgs.Proceed(); 17: value = XMLUtility<object>.GetDataContractXml(eventArgs.ReturnValue, null); 18: value = eventArgs.ReturnValue; 19: AddToCache(key, value); 20: return; 21: } 22:   23:   24: Log(string.Format("Data returned from Cache {0}",value)); 25: eventArgs.ReturnValue = value; 26: } 27: } 28: catch (Exception ex) 29: { 30: //ApplicationLogger.LogException(ex.Message, Source.UtilityService); 31: } 32: } 33:   34: private object GetFromCache(string inputKey) { if (ServerConfig.CachingEnabled) { return WCFCache.Current[inputKey]; } return null; }private void AddToCache(string inputKey,object outputValue) 35: { 36: if (ServerConfig.CachingEnabled) 37: { 38: if (WCFCache.Current.CachedItemsNumber < ServerConfig.NumberOfCachedItems) 39: { 40: if (ServerConfig.SlidingExpirationTime <= 0 || ServerConfig.SlidingExpirationTime == int.MaxValue) 41: { 42: WCFCache.Current[inputKey] = outputValue; 43: } 44: else 45: { 46: WCFCache.Current.Insert(inputKey, outputValue, new TimeSpan(0, 0, ServerConfig.SlidingExpirationTime), true); 47:   48: // _bw.DoWork += bw_DoWork; 49: //string arg = string.Format("{0}|{1}", inputKey,outputValue); 50: //_bw.RunWorkerAsync(inputKey ); 51: } 52: } 53: } 54: }     The cache class can be extended to support Velocity / memcahe / Nache. the attribute can be used over REST services as well. Hope the above helps. Here is the code base for the same.   Please do provide your inputs / comments.

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• PHP - Internal APIs/Libraries - What makes sense?

  - by Mark Locker

  I've been having a discussion lately with some colleagues about the best way to approach a new project, and thought it'd be interesting to get some external thoughts thrown into the mix. Basically, we're redeveloping a fairly large site (written in PHP) and have differing opinions on how the platform should be setup. Requirements: The platform will need to support multiple internal websites, as well as external (non-PHP) projects which at the moment consist of a mobile app and a toolbar. We have no plans/need in the foreseeable future to open up an API externally (for use in products other than our own). My opinion: We should have a library of well documented native model classes which can be shared between projects. These models will represent everything in our database and can take advantage of object orientated features such as inheritance, traits, magic methods, etc. etc. As well as employing ORM. We can then add an API layer on top of these models which can basically accept requests and route them to the appropriate methods, translating the response so that it can be used platform independently. This routing for each method can be setup as and when it's required. Their opinion: We should have a single HTTP API which is used by all projects (internal PHP ones or otherwise). My thoughts: To me, there are a number of issues with using the sole HTTP API approach: It will be very expensive performance wise. One page request will result in several additional http requests (which although local, are still ones that Apache will need to handle). You'll lose all of the best features PHP has for OO development. From simple inheritance, to employing the likes of ORM which can save you writing a lot of code. For internal projects, the actual process makes me cringe. To get a users name, for example, a request would go out of our box, over the LAN, back in, then run through a script which calls a method, JSON encodes the output and feeds that back. That would then need to be JSON decoded, and be presented as an array ready to use. Working with arrays, as appose to objects, makes me sad in a modern PHP framework. Their thoughts (and my responses): Having one method of doing thing keeps things simple. - You'd only do things differently if you were using a different language anyway. It will become robust. - Seeing as the API will run off the library of models, I think my option would be just as robust. What do you think? I'd be really interested to hear the thoughts of others on this, especially as opinions on both sides are not founded on any past experience.

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• Practices for domain models in Javascript (with frameworks)

  - by AndyBursh

  This is a question I've to-and-fro'd with for a while, and searched for and found nothing on: what're the accepted practices surrounding duplicating domain models in Javascript for a web application, when using a framework like Backbone or Knockout? Given a web application of a non-trivial size with a set of domain models on the server side, should we duplicate these models in the web application (see the example at the bottom)? Or should we use the dynamic nature to load these models from the server? To my mind, the arguments for duplicating the models are in easing validation of fields, ensuring that fields that expected to be present are in fact present etc. My approach is to treat the client-side code like an almost separate application, doing trivial things itself and only relying on the server for data and complex operations (which require data the client-side doesn't have). I think treating the client-side code like this is akin to separation between entities from an ORM and the models used with the view in the UI layer: they may have the same fields and relate to the same domain concept, but they're distinct things. On the other hand, it seems to me that duplicating these models on the server side is a clear violation of DRY and likely to lead to differing results on the client- and server-side (where one piece gets updated but the other doesn't). To avoid this violation of DRY we can simply use Javascripts dynamism to get the field names and data from the server as and when they're neeed. So: are there any accepted guidelines around when (and when not) to repeat yourself in these situations? Or this a purely subjective thing, based on the project and developer(s)? Example Server-side model class M { int A DateTime B int C int D = (A*C) double SomeComplexCalculation = ServiceLayer.Call(); } Client-side model function M(){ this.A = ko.observable(); this.B = ko.observable(); this.C = ko.observable(); this.D = function() { return A() * C(); } this.SomeComplexCalculation = ko.observalbe(); return this; }l M.GetComplexValue = function(){ this.SomeComplexCalculation(Ajax.CallBackToServer()); }; I realise this question is quite similar to this one, but I think this is more about almost wholly untying the web application from the server, where that question is about doing this only in the case of complex calculation.

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