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• Windows Azure Emulators On Your Desktop

  - by BuckWoody

  Many people feel they have to set up a full Azure subscription online to try out and develop on Windows Azure. But you don’t have to do that right away. In fact, you can download the Windows Azure Compute Emulator – a “cloud development environment” – right on your desktop. No, it’s not for production use, and no, you won’t have other people using your system as a cloud provider, and yes, there are some differences with Production Windows Azure, but you’ll be able code, run, test, diagnose, watch, change and configure code without having any connection to the Internet at all. The best thing about this approach is that when you are ready to deploy the code you’ve been testing, a few clicks deploys it to your subscription when you make one.   So what deep-magic does it take to run such a thing right on your laptop or even a Virtual PC? Well, it’s actually not all that difficult. You simply download and install the Windows Azure SDK (you can even get a free version of Visual Studio for it to run on – you’re welcome) from here: http://msdn.microsoft.com/en-us/windowsazure/cc974146.aspx   This SDK will also install the Windows Azure Compute Emulator and the Windows Azure Storage Emulator – and then you’re all set. Right-click the icon for Visual Studio and select “Run as Administrator”:    Now open a new “Cloud” type of project:   Add your Web and Worker Roles that you want to code:   And when you’re done with your design, press F5 to start the desktop version of Azure:   Want to learn more about what’s happening underneath? Right-click the tray icon with the Azure logo, and select the two emulators to see what they are doing:          In the configuration files, you’ll see a “Use Development Storage” setting. You can call the BLOB, Table or Queue storage and it will all run on your desktop. When you’re ready to deploy everything to Windows Azure, you simply change the configuration settings and add the storage keys and so on that you need.   Want to learn more about all this?   Overview of the Windows Azure Compute Emulator: http://msdn.microsoft.com/en-us/library/gg432968.aspx Overview of the Windows Azure Storage Emulator: http://msdn.microsoft.com/en-us/library/gg432983.aspx January 2011 Training Kit: http://www.microsoft.com/downloads/en/details.aspx?FamilyID=413E88F8-5966-4A83-B309-53B7B77EDF78&displaylang=en      

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• Create a Remote Git Repository from an Existing XCode Repository

  - by codeWithoutFear

  Introduction Distributed version control systems (VCS’s), like Git, provide a rich set of features for managing source code.  Many development tools, including XCode, provide built-in support for various VCS’s.  These tools provide simple configuration with limited customization to get you up and running quickly while still providing the safety net of basic version control. I hate losing (and re-doing) work.  I have OCD when it comes to saving and versioning source code.  Save early, save often, and commit to the VCS often.  I also hate merging code.  Smaller and more frequent commits enable me to minimize merge time and effort as well. The work flow I prefer even for personal exploratory projects is: Make small local changes to the codebase to create an incrementally improved (and working) system. Commit these changes to the local repository.  Local repositories are quick to access, function even while offline, and provides the confidence to continue making bold changes to the system.  After all, I can easily recover to a recent working state. Repeat 1 & 2 until the codebase contains “significant” functionality and I have connectivity to the remote repository. Push the accumulated changes to the remote repository.  The smaller the change set, the less likely extensive merging will be required.  Smaller is better, IMHO. The remote repository typically has a greater degree of fault tolerance and active management dedicated to it.  This can be as simple as a network share that is backed up nightly or as complex as dedicated hardware with specialized server-side processing and significant administrative monitoring. XCode’s out-of-the-box Git integration enables steps 1 and 2 above.  Time Machine backups of the local repository add an additional degree of fault tolerance, but do not support collaboration or take advantage of managed infrastructure such as on-premises or cloud-based storage. Creating a Remote Repository These are the steps I use to enable the full workflow identified above.  For simplicity the “remote” repository is created on the local file system.  This location could easily be on a mounted network volume. Create a Test Project My project is called HelloGit and is located at /Users/Don/Dev/HelloGit.  Be sure to commit all outstanding changes.  XCode always leaves a single changed file for me after the project is created and the initial commit is submitted. Clone the Local Repository We want to clone the XCode-created Git repository to the location where the remote repository will reside.  In this case it will be /Users/Don/Dev/RemoteHelloGit. Open the Terminal application. Clone the local repository to the remote repository location: git clone /Users/Don/Dev/HelloGit /Users/Don/Dev/RemoteHelloGit Convert the Remote Repository to a Bare Repository The remote repository only needs to contain the Git database.  It does not need a checked out branch or local files. Go to the remote repository folder: cd /Users/Don/Dev/RemoteHelloGit Indicate the repository is “bare”: git config --bool core.bare true Remove files, leaving the .git folder: rm -R * Remove the “origin” remote: git remote rm origin Configure the Local Repository The local repository should reference the remote repository.  The remote name “origin” is used by convention to indicate the originating repository.  This is set automatically when a repository is cloned.  We will use the “origin” name here to reflect that relationship. Go to the local repository folder: cd /Users/Don/Dev/HelloGit Add the remote: git remote add origin /Users/Don/Dev/RemoteHelloGit Test Connectivity Any changes made to the local Git repository can be pushed to the remote repository subject to the merging rules Git enforces. Create a new local file: date > date.txt /li> Add the new file to the local index: git add date.txt Commit the change to the local repository: git commit -m "New file: date.txt" Push the change to the remote repository: git push origin master Now you can save, commit, and push/pull to your OCD hearts’ content! Code without fear! --Don

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• What are some good questions (and good/bad answers) to ask at an interview to gauge the competency of the company/team?

  - by Wayne M

  I'm already familiar with the Joel Test, but it's been my experience that some of the questions there have the answers "massaged" to make the company seem better than it is. I've had several jobs in the past that, for instance, claimed they had a QA process and did unit testing, and what they really meant is "The programmers test the app, and test with the debugger and via trial-and-error."; they said they used SVN but they just lumped everything into one giant repository and had no concept of branching/merging or anything more complicated than updating and committing; said they can build in one step and what they really mean is it's "one step" to copy dozens of files by hand from the programmer's PC to the live server. How do you go about properly gauging a company's environment to make sure that it's a well-evolved company and not stuck on doing things a certain way because they've done it for years and they're ignorant of change? You can almost never ask to see their source code, so you're stuck trying to figure out if the interviewer's answer is accurate or BS to make the company seem good. Besides the Joel Test what are some other good questions to get the proper feel for a company, and more importantly what are some good and bad answers that could indicate a good or bad company? I mean something like (take at face value, please, it's all I could think of at short notice): Question: How does the software team apply the SOLID principles and Inversion of Control to their code? Good Answer: We adhere to SOLID wherever possible; we use TDD so it kind of forces us to write abstract, testable code. We use Ninject for our IoC container because it's fairly easy to configure - it was that or StructureMap but I find Ninject a bit more intuitive, and who doesn't like ninjas? You're not a pirate, are you? Bad Answer: Our code is pretty secure, yeah. And what's this Inversion of Control thing? I've never heard of it before. You see what I did there. The "good" answer uses facts to back it up and has a bit of "in crowd" humor; the bad answer shows complete ignorance of the question - not necessarily a bad thing if you are interviewing for a manger/director position, but a terrible answer and a huge red flag if you're interviewing as a developer and talking to a senior developer or manager! My biggest problem at the moment is being able to take a generic response and gauge whether it's the good or bad answer; more often than not it's the bad kind and I find myself frustrated almost from day one at the new job. I suppose I could name drop if I ask about specific things (e.g. "Do you write unit tests?" and if the answer is yes, ask if they use NUnit, MbUnit or something else; if they mention data access ask if they use a clean ORM like NHibernate or something more coupled like EF or Linq) but is there another way short of being resolute to actually call the interview on things (which will almost certainly result in not getting the job, but if they are skirting the question it's probably not a job I want).

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• Barcodes and Bugs

  - by Tim Dexter

  A great mail from Mike at Browning last week. He has been through the ringer getting his BIP barcoding sorted out but he's now out of the woods. Here's the final result. By way of explanation, an excerpt from Mike's email:   This is an example of the GS1_128 carton shipping labels we are now producing with BIP in our web application for our vendors who drop ship products to our dealers. It produces 4 labels per printed page, in PDF format, on peel & stick label paper. Each label has a unique carton number, and a unique carton serial number in the SSCC-18 barcode. This example is for Cabelas (each customer has slightly different GS1-128 label format requirements – custom template for each - a pain!). I am using custom java encoders I wrote for the UPC and SSCC-18 barcodes, and a standard encoder (code128b) for the ShipTo zip barcode. Is there any way yet to get around that SUPER ANNOYING bug when opening the rtf template in MS Word, and it replaces my xsl code text in the barcode fields with gibberish??? Every time I open it I have to re-enter all the xsl code. Not only to be able to read & edit it, but also to get it to work in BIP (BIP doesn’t like the gibberish if I upload the template that has it). Mike's last point, regarding the annoying bug in the template builder, is one that I have experienced occasionally. The development team have looked at it and found it to be an issue with MSWord and not a plugin problem. That's all well and good but how can you get around it? Well, you can take advantage of the font mapping that BIP offers to get the barcodes into the PDF output. As many of you know, getting a barcode font to appear in the PDF output, you need employ the use of the xdo.cfg file in the template builder config directory.You would normally have an entry such as this:         <font family="Code 128" style="normal" weight="normal">        <truetype path="C:\windows\fonts\128R00.TTF" />       </font>to map a barcode font to get it to render in the PDF output when testing from the template builder plugin.   Mike's issue is only present when the formfield is highlighted with a barcode font. The other fields in the template are OK. What you can do to get around the issue is to bend the config entry to get around having to use the barcode font in the template at all. Changing the entry to something like:         <font family="Calibri" style="normal" weight="normal">        <truetype path="C:\windows\fonts\128R00.TTF" />       </font>   Note that we are mapping the Calibri; a humanly readable and non 'erroring' font in the template, to the code 128 barcode font. Where you used to highlight the field with the barcode in MSWord, you now use the Calibri font instead. At run time, BIP will go look for the Calibri font mapping and will drop in the Code128 font. Of course, Calibri is an example; you need to pick a font that you are not going to use any where else in the layout.

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• Workflow versioning

  - by Nitra

  I believe I have a fundamental misunderstanding when it comes to workflow engines which I would appreciate if you could help me sort out. I'm not sure if my misunderstanding is specific to the workflow engine I'm using, or if it's a general misunderstanding. I happen to use Windows Workflow Foundation (WWF). TLDR-version WWF allows you to implement business processes in long-running workflows (think months or even years). When started, the workflows can't be changed. But what business process can't change at any time? And if a business process changes, wouldn't you want your software to reflect this change for already started 'instances' of the business process? What am I missing? Background In WWF you define a workflow by combining a set of activites. There are different types of activities - some of them are for flow control, such as the IfElseActivity and the WhileActivty while others allows you to perform actual tasks, such as the CodeActivity wich allows you to run .NET code and the InvokeWebServiceActivity which allows you to call web services. The activites are combined to a workflow using a visual designer. You pretty much drag-and-drop activities from a toolbox to a designer area and connect the activites to each other. The workflow and activities have input paramters, output parameters and variables. We have a single workflow which sometimes runs in a matter of a few days, but it may run for 5-6 months. WWF takes care of persisting the workflow state (what activity are we currently executing, what are the variable values and so on). So far I think WWF makes sense. Some people will prefer to implement a software representation of a business process using a visual designer over writing all of it in code. So what's the issue then? What I don't really get is the following: WWF is designed to take care of long-running workflows. But at the same time, WWF has no built-in functionality which allows you to modify the running workflows. So if you model a business process using a workflow and run that for 6 months, you better hope that the business process does not change. Because if it do, you'll have to have multiple versions of the workflow executing at the same time. This seems like a fundamental design mistake to me, but at the same time it seems more likely that I've misunderstood something. For us, this has had some real-world effects: We release new versions every month, but some workflows may run for a year. This means that we have several versions of the workflow running in parallell, in other words several versions of the business logics. This is the same as having many differnt versions of your code running in production in the same system at the same time, which becomes a bit hard to understand for users. (depending on on whether they clicked a 'Start' button 9 or 10 months ago, the software will behave differently) Our workflow refers to different types of entities and since WWF now has persisted and serialized these we can't really refactor the entities since then existing workflows can't be resumed (deserialization will fail We've received some suggestions on how to handle this When we create a new version of the workflow, cancel all running workflows and create new ones. But in our workflows there's a lot of manual work involved and if we start from scratch a lot of people has to re-do their work. Track what has been done in the workflow and when you create a new one skip activites which have already been executed. I feel that this alternative may work for simple workflows, but it becomes hairy to automatically figure out what activities to skip if there's major refactoring done to a workflow. When we create a new version of the workflow, upgrade old versions using the new WWF 4.5 functionality for upgrading workflows. But then we would have to skip using the visual designer and write code to inject activities in the right places in the workflow. According to MSDN, this upgrade functionality is only intended for minor bug fixes and not larger changes. What am I missing?

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• Programmatically disclosing a node in af:tree and af:treeTable

  - by Frank Nimphius

  A common developer requirement when working with af:tree or af:treeTable components is to programmatically disclose (expand) a specific node in the tree. If the node to disclose is not a top level node, like a location in a LocationsView -> DepartmentsView -> EmployeesView hierarchy, you need to also disclose the node's parent node hierarchy for application users to see the fully expanded tree node structure. Working on ADF Code Corner sample #101, I wrote the following code lines that show a generic option for disclosing a tree node starting from a handle to the node to disclose. The use case in ADF Coder Corner sample #101 is a drag and drop operation from a table component to a tree to relocate employees to a new department. The tree node that receives the drop is a department node contained in a location. In theory the location could be part of a country and so on to indicate the depth the tree may have. Based on this structure, the code below provides a generic solution to parse the current node parent nodes and its child nodes. The drop event provided a rowKey for the tree node that received the drop. Like in af:table, the tree row key is not of type oracle.jbo.domain.Key but an implementation of java.util.List that contains the row keys. The JUCtrlHierBinding class in the ADF Binding layer that represents the ADF tree binding at runtime provides a method named findNodeByKeyPath that allows you to get a handle to the JUCtrlHierNodeBinding instance that represents a tree node in the binding layer. CollectionModel model = (CollectionModel) your_af_tree_reference.getValue(); JUCtrlHierBinding treeBinding = (JUCtrlHierBinding ) model.getWrappedData(); JUCtrlHierNodeBinding treeDropNode = treeBinding.findNodeByKeyPath(dropRowKey); To disclose the tree node, you need to create a RowKeySet, which you do using the RowKeySetImpl class. Because the RowKeySet replaces any existing row key set in the tree, all other nodes are automatically closed. RowKeySetImpl rksImpl = new RowKeySetImpl(); //the first key to add is the node that received the drop //operation (departments).            rksImpl.add(dropRowKey);    Similar, from the tree binding, the root node can be obtained. The root node is the end of all parent node iteration and therefore important. JUCtrlHierNodeBinding rootNode = treeBinding.getRootNodeBinding(); The following code obtains a reference to the hierarchy of parent nodes until the root node is found. JUCtrlHierNodeBinding dropNodeParent = treeDropNode.getParent(); //walk up the tree to expand all parent nodes while(dropNodeParent != null && dropNodeParent != rootNode){    //add the node's keyPath (remember its a List) to the row key set    rksImpl.add(dropNodeParent.getKeyPath());      dropNodeParent = dropNodeParent.getParent(); } Next, you disclose the drop node immediate child nodes as otherwise all you see is the department node. Its not quite exactly "dinner for one", but the procedure is very similar to the one handling the parent node keys ArrayList<JUCtrlHierNodeBinding> childList = (ArrayList<JUCtrlHierNodeBinding>) treeDropNode.getChildren();                     for(JUCtrlHierNodeBinding nb : childList){   rksImpl.add(nb.getKeyPath()); } Next, the row key set is defined as the disclosed row keys on the tree so when you refresh (PPR) the tree, the new disclosed state shows tree.setDisclosedRowKeys(rksImpl); AdfFacesContext.getCurrentInstance().addPartialTarget(tree.getParent()); The refresh in my use case is on the tree parent component (a layout container), which usually shows the best effect for refreshing the tree component. 

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• Company wants to write custom project management tool, rather then use third party product.

  - by Jason Evans

  At the company I work, we are really wanting to get into the agile methodology for developing software. One thing that I'm not excited about is the fact that management wants us to build a custom project management feature inside the company's Intranet. I think this is a total waste of time. There are many great third party tools available (e.g. Axosoft OnTime) that can do everything we need, and more. For how much development time it would cost us to build our own project management module, we could buy numerous licences for a third party product. One concern is that, whilst we are writing code for a client, and using our custom Intranet project management module, we find bugs in the module that need fixing ASAP. That means having to stop work on the client code to fix the Intranet. That just puts shivers down my spine. Another worry I have is lack of functionality. This custom module is going to be so basic, that it will just feel really crap to use. That might sound a bit snooty, but for goodness sake, many third party tools are so feature rich, that the idea of having to write our own tool makes feel very uneasy. In fact, I can't be bothered. What do you guys think? I'm going to raise this issue with my boss, since I feel it's such an important topic to talk about. EDIT: Thanks for the great responses, much appreciated. To summarize some of them: Money Naturally my boss does want to save money, by not forking out a few hundred £'s for licences. However, for us to write a custom tool, it will take x number of days, multiplied by approx £500, which is our costs. I don't see the business value in this. Management have mentioned that they want to sell the Intranet as a product in the future, but it's so custom to our needs (and downright basic), that in order to give it to another client, I can see us having to fork a version of the code and rebuild the majority of it anyway. So it's not like we're gaining anything there in reuse. Features Having our own custom module means not feature bloat - only the functionality we require will be in the product. My issue is that there are plenty of free, open-source project management tools out there with minimal features already. So even if cost is an issue, we could look into open-source. Again it all boils down to the fact that I don't see the point in writing a project management tool in this day and age. It's a bit like writing your own web browser - why?, what's the point? Although management are asking for this tool, just because they are, it does not mean I'm going to please them and do it just because they asked for it. If something does not make sense, then I will raise it as a concern. At the end of the day, it's the developers who write the code, it's the developers who make money for a business. Thus, as far I'm concerned, the devs have a very big role in deciding how a company should manage projects and what tools are used. "I am Spartan, argh!" :) Hmm, I've not been able to make this question a wiki for some reason, thus I'm going to have to pick an answer to accept. Cheers. Jas.

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• C++ property system interface for game editors (reflection system)

  - by Cristopher Ismael Sosa Abarca

  I have designed an reusable game engine for an project, and their functionality is like this: Is a completely scripted game engine instead of the usual scripting languages as Lua or Python, this uses Runtime-Compiled C++, and an modified version of Cistron (an component-based programming framework).to be compatible with Runtime-Compiled C++ and so on. Using the typical GameObject and Component classes of the Component-based design pattern, is serializable via JSON, BSON or Binary useful for selecting which objects will be loaded the next time. The main problem: We want to use our custom GameObjects and their components properties in our level editor, before used hardcoded functions to access GameObject base class virtual functions from the derived ones, if do you want to modify an property specifically from that class you need inside into the code, this situation happens too with the derived classes of Component class, in little projects there's no problem but for larger projects becomes tedious, lengthy and error-prone. I've researched a lot to find a solution without luck, i tried with the Ogitor's property system (since our engine is Ogre-based) but we find it inappropiate for the component-based design and it's limited only for the Ogre classes and can lead to performance overhead, and we tried some code we find in the Internet we tested it and worked a little but we considered the macro and lambda abuse too horrible take a look (some code omitted): IWE_IMPLEMENT_PROP_BEGIN(CBaseEntity) IWE_PROP_LEVEL_BEGIN("Editor"); IWE_PROP_INT_S("Id", "Internal id", m_nEntID, [](int n) {}, true); IWE_PROP_LEVEL_END(); IWE_PROP_LEVEL_BEGIN("Entity"); IWE_PROP_STRING_S("Mesh", "Mesh used for this entity", m_pModelName, [pInst](const std::string& sModelName) { pInst->m_stackMemUndoType.push(ENT_MEM_MESH); pInst->m_stackMemUndoStr.push(pInst->getModelName()); pInst->setModel(sModelName, false); pInst->saveState(); }, false); IWE_PROP_VECTOR3_S("Position", m_vecPosition, [pInst](float fX, float fY, float fZ) { pInst->m_stackMemUndoType.push(ENT_MEM_POSITION); pInst->m_stackMemUndoVec3.push(pInst->getPosition()); pInst->saveState(); pInst->m_vecPosition.Get()[0] = fX; pInst->m_vecPosition.Get()[1] = fY; pInst->m_vecPosition.Get()[2] = fZ; pInst->setPosition(pInst->m_vecPosition); }, false); IWE_PROP_QUATERNION_S("Orientation (Quat)", m_quatOrientation, [pInst](float fW, float fX, float fY, float fZ) { pInst->m_stackMemUndoType.push(ENT_MEM_ROTATE); pInst->m_stackMemUndoQuat.push(pInst->getOrientation()); pInst->saveState(); pInst->m_quatOrientation.Get()[0] = fW; pInst->m_quatOrientation.Get()[1] = fX; pInst->m_quatOrientation.Get()[2] = fY; pInst->m_quatOrientation.Get()[3] = fZ; pInst->setOrientation(pInst->m_quatOrientation); }, false); IWE_PROP_LEVEL_END(); IWE_IMPLEMENT_PROP_END() We are finding an simplified way to this, without leading confusing the programmers, (will be released to the public) i find ways to achieve this but they are only available for the common scripting as Lua or editors using C#. also too portable, we can write "wrappers" for different GUI toolkits as Qt or GTK, also i'm thinking to using Boost.Wave to get additional macro functionality without creating my own compiler. The properties designed to use in the editor they are removed in the game since the save file contains their data and loads it using an simple 'load' function to reduce unnecessary code bloat may will be useful if some GameObject property wants to be hidden instead. In summary, there's a way to implement an reflection(property) system for a level editor based in properties from derived classes? Also we can use C++11 and Boost (restricted only to Wave and PropertyTree)

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• How to use correctly the comments in C/++

  - by Lucio

  I'm learning to program in C and in my stage, the best form to use correctly the comments is writing good comments from the beginning. As the comments are not just for that one understands better the code but others too, I want to know the views of all of you to reach a consensus. So what I want is that the most experienced users edit the following code as you please. (If it's unnecessary, delete it; If it's wrong, correct it; If needed, add more) Thus there'll be multiple answers with different syntax and the responses with the most votes will be taken as referring when commenting. The code to copy, paste and edit to your pleasure is: (And I remark again, just import the comments, not the code) /* This programs find 1 number in 1 file. The file is binary type and has integers in series. The number is integer type and it's entered from the keyboard. When finished the program, a poster will show the results: Saying if the number is in the file or not. */ #include <stdio.h> //FUNCTION 1 //Open file 'path' and closes it. void openf(char path[]) { int num; //Read from Keyboard a Number and it save it into 'num' var printf("Ready for read number.\n\nNumber --> "); fflush(stdin); scanf("%d",&num); //Open file 'path' in READ mode FILE *fvar; fvar=fopen(path,"rb"); //IF error happens when open file, exit of function if (fvar==NULL) { printf("ERROR while open file %s in read mode.",path); exit(1); } /*Verify the result of 'funct' function IF TRUE, 'num' it's in the file*/ if (funct(path,fvar,num)) printf("The number %d it is in the file %s.",num,path); else printf("The number %d it is not in the file %s.",num,path); fclose(fvar); } /*FUNCTION 2 It is a recursive function. Reads number by number until the file is empty or the number is found. Parameters received: 'path' -> Directory file 'fvar' -> Pointer file 'num' -> Number to compare */ int funct(char path[],FILE *fvar,int num) { int compare; //FALSE condition when the pointer reaches the end if (fread(&compare,sizeof(int),1,fvar)>0) /*TRUE condition when the number readed is iqual that 'num' ELSE will go to the function itself*/ if (compare!=num) funct(path,fvar,num); else return 1; else return 0; } int main(int argc, char **argv) { char path[30]="file.bin"; //Direction of the file to process openf(path); //Function with algorithm return 0; }

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• Simple MVVM Walkthrough – Refactored

  - by Sean Feldman

  JR has put together a good introduction post into MVVM pattern. I love kick start examples that serve the purpose well. And even more than that I love examples that also can pass the real world projects check. So I took the sample code and refactored it slightly for a few aspects that a lot of developers might raise a brow. Michael has mentioned model (entity) visibility from view. I agree on that. A few other items that don’t settle are using property names as string (magical strings) and Saver class internal casting of a parameter (custom code for each Saver command). Fixing a property names usage is a straight forward exercise – leverage expressions. Something simple like this would do the initial job: class PropertyOf<T> { public static string Resolve(Expression<Func<T, object>> expression) { var member = expression.Body as MemberExpression; return member.Member.Name; } } With this, refactoring of properties names becomes an easy task, with confidence that an old property name string will not get left behind. An updated Invoice would look like this: public class Invoice : INotifyPropertyChanged { private int id; private string receiver; public event PropertyChangedEventHandler PropertyChanged; private void OnPropertyChanged(string propertyName) { if (PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } public int Id { get { return id; } set { if (id != value) { id = value; OnPropertyChanged(PropertyOf<Invoice>.Resolve(x => x.Id)); } } } public string Receiver { get { return receiver; } set { receiver = value; OnPropertyChanged(PropertyOf<Invoice>.Resolve(x => x.Receiver)); } } } For the saver, I decided to change it a little so now it becomes a “view-model agnostic” command, one that can be used for multiple commands/view-models. Updated Saver code now accepts an action at construction time and executes that action. No more black magic internal class Command : ICommand { private readonly Action executeAction; public Command(Action executeAction) { this.executeAction = executeAction; } public bool CanExecute(object parameter) { return true; } public event EventHandler CanExecuteChanged; public void Execute(object parameter) { // no more black magic executeAction(); } } Change in InvoiceViewModel is instantiation of Saver command and execution action for the specific command. public ICommand SaveCommand { get { if (saveCommand == null) saveCommand = new Command(ExecuteAction); return saveCommand; } set { saveCommand = value; } } private void ExecuteAction() { DisplayMessage = string.Format("Thanks for creating invoice: {0} {1}", Invoice.Id, Invoice.Receiver); } This way internal knowledge of InvoiceViewModel remains in InvoiceViewModel and Command (ex-Saver) is view-model agnostic. Now the sample is not only a good introduction, but also has some practicality in it. My 5 cents on the subject. Sample code MvvmSimple2.zip

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• RPi and Java Embedded GPIO: Big Data and Java Technology

  - by hinkmond

  Java Embedded and Big Data go hand-in-hand, especially as demonstrated by prototyping on a Raspberry Pi to show how well the Java Embedded platform can perform on a small embedded device which then becomes the proof-of-concept for industrial controllers, medical equipment, networking gear or any type of sensor-connected device generating large amounts of data. The key is a fast and reliable way to access that data using Java technology. In the previous blog posts you've seen the integration of a static electricity sensor and the Raspberry Pi through the GPIO port, then accessing that data through Java Embedded code. It's important to point out how this works and why it works well with Java code. First, the version of Linux (Debian Wheezy/Raspian) that is found on the RPi has a very convenient way to access the GPIO ports through the use of Linux OS managed file handles. This is key in avoiding terrible and complex coding using register manipulation in C code, or having to program in a less elegant and clumsy procedural scripting language such as python. Instead, using Java Embedded, allows a fast way to access those GPIO ports through those same Linux file handles. Java already has a very easy to program way to access file handles with a high degree of performance that matches direct access of those file handles with the Linux OS. Using the Java API java.io.FileWriter lets us open the same file handles that the Linux OS has for accessing the GPIO ports. Then, by first resetting the ports using the unexport and export file handles, we can initialize them for easy use in a Java app. // Open file handles to GPIO port unexport and export controls FileWriter unexportFile = new FileWriter("/sys/class/gpio/unexport"); FileWriter exportFile = new FileWriter("/sys/class/gpio/export"); ... // Reset the port unexportFile.write(gpioChannel); unexportFile.flush(); // Set the port for use exportFile.write(gpioChannel); exportFile.flush(); Then, another set of file handles can be used by the Java app to control the direction of the GPIO port by writing either "in" or "out" to the direction file handle. // Open file handle to input/output direction control of port FileWriter directionFile = new FileWriter("/sys/class/gpio/gpio" + gpioChannel + "/direction"); // Set port for input directionFile.write("in"); // Or, use "out" for output directionFile.flush(); And, finally, a RandomAccessFile handle can be used with a high degree of performance on par with native C code (only milliseconds to read in data and write out data) with low overhead (unlike python) to manipulate the data going in and out on the GPIO port, while the object-oriented nature of Java programming allows for an easy way to construct complex analytic software around that data access functionality to the external world. RandomAccessFile[] raf = new RandomAccessFile[GpioChannels.length]; ... // Reset file seek pointer to read latest value of GPIO port raf[channum].seek(0); raf[channum].read(inBytes); inLine = new String(inBytes); It's Big Data from sensors and industrial/medical/networking equipment meeting complex analytical software on a small constraint device (like a Linux/ARM RPi) where Java Embedded allows you to shine as an Embedded Device Software Designer. Hinkmond

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• Crime Scene Investigation: SQL Server

  - by Rodney Landrum

  “The packages are running slower in Prod than they are in Dev” My week began with this simple declaration from one of our lead BI developers, quickly followed by an emailed spreadsheet demonstrating that, over 5 executions, an extensive ETL process was running average 630 seconds faster on Dev than on Prod. The situation needed some scientific investigation to determine why the same code, the same data, the same schema would yield consistently slower results on a more powerful server. Prod had yet to be officially christened with a “Go Live” date so I had the time, and having recently been binge watching CSI: New York, I also had the inclination. An inspection of the two systems, Prod and Dev, revealed the first surprise: although Prod was indeed a “bigger” system, with double the amount of RAM of Dev, the latter actually had twice as many processor cores. On neither system did I see much sign of resources being heavily taxed, while the ETL process was running. Without any real supporting evidence, I jumped to a conclusion that my years of performance tuning should have helped me avoid, and that was that the hardware differences explained the better performance on Dev. We spent time setting up a Test system, similarly scoped to Prod except with 4 times the cores, and ported everything across. The results of our careful benchmarks left us truly bemused; the ETL process on the new server was slower than on both other systems. We burned more time tweaking server configurations, monitoring IO and network latency, several times believing we’d uncovered the smoking gun, until the results of subsequent test runs pitched us back into confusion. Finally, I decided, enough was enough. Hadn’t I learned very early in my DBA career that almost all bottlenecks were caused by code and database design, not hardware? It was time to get back to basics. With over 100 SSIS packages and hundreds of queries, each handling specific tasks such as file loads, bulk inserts, transforms, logging, and so on, the task seemed formidable. And yet, after barely an hour spent with Profiler, Extended Events, and wait statistics DMVs, I had a lead in the shape of a query that joined three tables, containing millions of rows, returned 3279 results, but performed 239K logical reads. As soon as I looked at the execution plans for the query in Dev and Test I saw the culprit, an implicit conversion warning on a join predicate field that was numeric in one table and a varchar(50) in another! I turned this information over to the BI developers who quickly resolved the data type mismatches and found and fixed “several” others as well. After the schema changes the same query with the same databases ran in under 1 second on all systems and reduced the logical reads down to fewer than 300. The analysis also revealed that on Dev, the ETL task was pulling data across a LAN, whereas Prod and Test were connected across slower WAN, in large part explaining why the same process ran slower on the latter two systems. Loading the data locally on Prod delivered a further 20% gain in performance. As we progress through our DBA careers we learn valuable lessons. Sometimes, with a project deadline looming and pressure mounting, we choose to forget them. I was close to giving into the temptation to throw more hardware at the problem. I’m pleased at least that I resisted, though I still kick myself for not looking at the code on day one. It can seem a daunting prospect to return to the fundamentals of the code so close to roll out, but with the right tools, and surprisingly little time, you can collect the evidence that reveals the true problem. It is a lesson I trust I will remember for my next 20 years as a DBA, if I’m ever again tempted to bypass the evidence.

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• NHibernate and Stored Procedures in C#

  - by Jess Nickson

  I was recently trying and failing to set up NHibernate (v1.2) in an ASP.NET project. The aim was to execute a stored procedure and return the results, but it took several iterations for me to end up with a working solution. In this post I am simply trying to put the required code in one place, in the hope that the snippets may be useful in guiding someone else through the same process. As it is kind’ve the first time I have had to play with NHibernate, there is a good chance that this solution is sub-optimal and, as such, I am open to suggestions on how it could be improved! There are four code snippets that I required: The stored procedure that I wanted to execute The C# class representation of the results of the procedure The XML mapping file that allows NHibernate to map from C# to the procedure and back again The C# code used to run the stored procedure The Stored Procedure The procedure was designed to take a UserId and, from this, go and grab some profile data for that user. Simple, right? We just need to do a join first, because the user’s site ID (the one we have access to) is not the same as the user’s forum ID. CREATE PROCEDURE [dbo].[GetForumProfileDetails] ( @userId INT ) AS BEGIN SELECT Users.UserID, forumUsers.Twitter, forumUsers.Facebook, forumUsers.GooglePlus, forumUsers.LinkedIn, forumUsers.PublicEmailAddress FROM Users INNER JOIN Forum_Users forumUsers ON forumUsers.UserSiteID = Users.UserID WHERE Users.UserID = @userId END I’d like to make a shout out to Format SQL for its help with, well, formatting the above SQL!   The C# Class This is just the class representation of the results we expect to get from the stored procedure. NHibernate requires a virtual property for each column of data, and these properties must be called the same as the column headers. You will also need to ensure that there is a public or protected parameterless constructor. public class ForumProfile : IForumProfile { public virtual int UserID { get; set; } public virtual string Twitter { get; set; } public virtual string Facebook { get; set; } public virtual string GooglePlus { get; set; } public virtual string LinkedIn { get; set; } public virtual string PublicEmailAddress { get; set; } public ForumProfile() { } }   The NHibernate Mapping File This is the XML I wrote in order to make NHibernate a) aware of the stored procedure, and b) aware of the expected results of the procedure. <?xml version="1.0" encoding="utf-8" ?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="[namespace]" assembly="[assembly]"> <sql-query name="GetForumProfileDetails"> <return-scalar column="UserID" type="Int32"/> <return-scalar column="Twitter" type="String"/> <return-scalar column="Facebook" type="String"/> <return-scalar column="GooglePlus" type="String"/> <return-scalar column="LinkedIn" type="String"/> <return-scalar column="PublicEmailAddress" type="String"/> exec GetForumProfileDetails :UserID </sql-query> </hibernate-mapping>   Calling the Stored Procedure Finally, to bring it all together, the C# code that I used in order to execute the stored procedure! public IForumProfile GetForumUserProfile(IUser user) { return NHibernateHelper .GetCurrentSession() .GetNamedQuery("GetForumProfileDetails") .SetInt32("UserID", user.UserID) .SetResultTransformer( Transformers.AliasToBean(typeof (ForumProfile))) .UniqueResult<ForumProfile>(); } There are a number of ‘Set’ methods (i.e. SetInt32) that allow you specify values for any parameters in the procedure. The AliasToBean method is then required to map the returned scalars (as specified in the XML) to the correct C# class.

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• NFJS Central Iowa Software Symposium Des Moines Trip Report

  - by reza_rahman

  As some of you may be aware, I recently joined the well-respected US based No Fluff Just Stuff (NFJS) Tour. If you work in the US and still don't know what the No Fluff Just Stuff (NFJS) Tour is, you are doing yourself a very serious disfavor. NFJS is by far the cheapest and most effective way to stay up to date through some world class speakers and talks. Following the US cultural tradition of old-fashioned roadshows, NFJS is basically a set program of speakers and topics offered at major US cities year round. The NFJS Central Iowa Software Symposium was held August 8 - 10 in Des Moines. The attendance at the event and my sessions was moderate by comparison to some of the other shows. It is one of the few events of it's kind that take place this part the country so it is extremely important. I had five talks total over two days, more or less back-to-back. The first one was my JavaScript + Java EE 7 talk titled "Using JavaScript/HTML5 Rich Clients with Java EE 7". This talk is basically about aligning EE 7 with the emerging JavaScript ecosystem (specifically AngularJS). The slide deck for the talk is here: JavaScript/HTML5 Rich Clients Using Java EE 7 from Reza Rahman The demo application code is posted on GitHub. The code should be a helpful resource if this development model is something that interests you. Do let me know if you need help with it but the instructions should be fairly self-explanatory. I am delivering this material at JavaOne 2014 as a two-hour tutorial. This should give me a little more bandwidth to dig a little deeper, especially on the JavaScript end. The second talk (on the second day) was our flagship Java EE 7/8 talk. Currently the talk is basically about Java EE 7 but I'm slowly evolving the talk to transform it into a Java EE 8 talk as we move forward. The following is the slide deck for the talk: JavaEE.Next(): Java EE 7, 8, and Beyond from Reza Rahman The next talk I delivered was my Cargo Tracker/Java EE + DDD talk. This talk basically overviews DDD and describes how DDD maps to Java EE using code examples/demos from the Cargo Tracker Java EE Blue Prints project. Applied Domain-Driven Design Blue Prints for Java EE from Reza Rahman The third was my talk titled "Using NoSQL with ~JPA, EclipseLink and Java EE". The talk covers an interesting gap that there is surprisingly little material on out there. The talk has three parts -- a birds-eye view of the NoSQL landscape, how to use NoSQL via a JPA centric facade using EclipseLink NoSQL, Hibernate OGM, DataNucleus, Kundera, Easy-Cassandra, etc and how to use NoSQL native APIs in Java EE via CDI. The slides for the talk are here: Using NoSQL with ~JPA, EclipseLink and Java EE from Reza Rahman The JPA based demo is available here, while the CDI based demo is available here. Both demos use MongoDB as the data store. Do let me know if you need help getting the demos up and running. I finishd off the event with a talk titled Building Java HTML5/WebSocket Applications with JSR 356. The talk introduces HTML 5 WebSocket, overviews JSR 356, tours the API and ends with a small WebSocket demo on GlassFish 4. The slide deck for the talk is posted below. Building Java HTML5/WebSocket Applications with JSR 356 from Reza Rahman The demo code is posted on GitHub: https://github.com/m-reza-rahman/hello-websocket. My next NFJS show is the Greater Atlanta Software Symposium on September 12 - 14. Here's my tour schedule so far, I'll keep you up-to-date as the tour goes forward: September 12 - 14, Atlanta. September 19 - 21, Boston. October 17 - 19, Seattle. I hope you'll take this opportunity to get some updates on Java EE as well as the other useful content on the tour?

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• Scenarios for Throwing Exceptions

  - by Joe Mayo

  I recently came across a situation where someone had an opinion that differed from mine of when an exception should be thrown. This particular case was an issue opened on LINQ to Twitter for an Exception on EndSession.  The premise of the issue was that the poster didn’t feel an exception should be raised, regardless of authentication status.  As first, this sounded like a valid point.  However, I went back to review my code and decided not to make any changes. Here's my rationale: 1. The exception doesn’t occur if the user is authenticated when EndAccountSession is called. 2. The exception does occur if the user is not authenticated when EndAccountSession is called. 3. The exception represents the fact that EndAccountSession is not able to fulfill its intended purpose - to end the session.  If a session never existed, then it would not be possible to perform the requested action.  Therefore, an exception is appropriate. To help illustrate how to handle this situation, I've modified the following code in Program.cs in the LinqToTwitterDemo project to illustrate the situation: static void EndSession(ITwitterAuthorizer auth) { using (var twitterCtx = new TwitterContext(auth, "https://api.twitter.com/1/", "https://search.twitter.com/")) { try { //Log twitterCtx.Log = Console.Out; var status = twitterCtx.EndAccountSession(); Console.WriteLine("Request: {0}, Error: {1}" , status.Request , status.Error); } catch (TwitterQueryException tqe) { var webEx = tqe.InnerException as WebException; if (webEx != null) { var webResp = webEx.Response as HttpWebResponse; if (webResp != null && webResp.StatusCode == HttpStatusCode.Unauthorized) Console.WriteLine("Twitter didn't recognize you as having been logged in. Therefore, your request to end session is illogical.\n"); } var status = tqe.Response; Console.WriteLine("Request: {0}, Error: {1}" , status.Request , status.Error); } } } As expected, LINQ to Twitter wraps the exception in a TwitterQueryException as the InnerException.  The TwitterQueryException serves a very useful purpose through it's Response property.  Notice in the example above that the response has Request and Error proprieties.  These properties correspond to the information that Twitter returns as part of it's response payload.  This is often useful while debugging to help you understand why Twitter was unable to perform the  requested action.  Other times, it's cryptic, but that's another story.  At least you have some way of knowing in your code how to anticipate and handle these situations, along with having extra information to debug with. To sum things up, there are two points to make: when and why an exception should be raised and when to wrap and re-throw an exception in a custom exception type. I felt it was necessary to allow the exception to be raised because the called method was unable to perform the task it was designed for.  I also felt that it is inappropriate for a general library to do anything with exceptions because that could potentially hide a problem from the caller.  A related point is that it should be the exclusive decision of the application that uses the library on what to do with an exception.  Another aspect of this situation is that I wrapped the exception in a custom exception and re-threw.  This is a tough call because I don’t want to hide any stack trace information.  However, the need to make the exception more meaningful by including vital information returned from Twitter swayed me in the direction to design an interface that was as helpful as possible to library consumers.  As shown in the code above, you can dig into the exception and pull out a lot of good information, such as the fact that the underlying HTTP response was a 401 Unauthorized.  In all, trade-offs are seldom perfect for all cases, but combining the fact that the method was unable to perform its intended function, this is a library, and the extra information can be more helpful, it seemed to be the better design. @JoeMayo

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• Reducing Deadlocks - not a DBA issue ?

  - by steveh99999

   As a DBA, I'm involved on an almost daily basis troubleshooting 'SQL Server' performance issues. Often, this troubleshooting soon veers away from a 'its a SQL Server issue' to instead become a wider application/database design/coding issue.One common perception with SQL Server is that deadlocking is an application design issue - and is fixed by recoding...  I see this reinforced by MCP-type questions/scenarios where the answer to prevent deadlocking is simply to change the order in code in which tables are accessed....Whilst this is correct, I do think this has led to a situation where many 'operational' or 'production support' DBAs, when faced with a deadlock, are happy to throw the issue over to developers without analysing the issue further....A couple of 'war stories' on deadlocks which I think are interesting :- Case One , I had an issue recently on a third-party application that I support on SQL 2008.  This particular third-party application has an unusual support agreement where the customer is allowed to change the index design on the third-party provided database.  However, we are not allowed to alter application code or modify table structure..This third-party application is also known to encounter occasional deadlocks – indeed, I have documentation from the vendor that up to 50 deadlocks per day is not unusual !So, as a DBA I have to support an application which in my opinion has too many deadlocks - but, I cannot influence the design of the tables or stored procedures for the application. This should be the classic - blame the third-party developers scenario, and hope this issue gets addressed in a future application release - ie we could wait years for this to be resolved and implemented in our production environment...But, as DBAs  can change the index layout, is there anything I could do still to reduce the deadlocks in the application ?I initially used SQL traceflag 1222 to write deadlock detection output to the SQL Errorlog – using this I was able to identify one table heavily involved in the deadlocks.When I examined the table definition, I was surprised to see it was a heap – ie no clustered index existed on the table.Using SQL profiler to see locking behaviour and plan for the query involved in the deadlock, I was able to confirm a table scan was being performed.By creating an appropriate clustered index - it was possible to produce a more efficient plan and locking behaviour.So, less locks, held for less time = less possibility of deadlocks. I'm still unhappy about the overall number of deadlocks on this system - but that's something to be discussed further with the vendor.Case Two,  a system which hadn't changed for months suddenly started seeing deadlocks on a regular basis. I love the 'nothing's changed' scenario, as it gives me the opportunity to appear wise and say 'nothings changed on this system, except the data'.. This particular deadlock occurred on a table which had been growing rapidly. By using DBCC SHOW_STATISTICS - the DBA team were able to see that the deadlocks seemed to be occurring shortly after auto-update stats had regenerated the table statistics using it's default sampling behaviour.As a quick fix, we were able to schedule a nightly UPDATE STATISTICS WITH FULLSCAN on the table involved in the deadlock - thus, greatly reducing the potential for stats to be updated via auto_update_stats, consequently reducing the potential for a bad plan to be generated based on an unrepresentative sample of the data. This reduced the possibility of a deadlock occurring.  Not a perfect solution by any means, but quick, easy to implement, and needed no application code changes. This fix gave us some 'breathing space'  to properly fix the code during the next scheduled application release.   The moral of this post - don't dismiss deadlocks as issues that can only be fixed by developers...

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• Velocity collision detection (2D)

  - by ultifinitus

  Alright, so I have made a simple game engine (see youtube) And my current implementation of collision resolution has a slight problem, involving the velocity of a platform. Basically I run through all of the objects necessary to detect collisions on and resolve those collisions as I find them. Part of that resolution is setting the player's velocity = the platform's velocity. Which works great! Unless I have a row of platforms moving at different velocities or a platform between a stack of tiles.... (current system) bool player::handle_collisions() { collisions tcol; bool did_handle = false; bool thisObjectHandle = false; for (int temp = 0; temp < collideQueue.size(); temp++) { thisObjectHandle = false; tcol = get_collision(prevPos.x,y,get_img()->get_width(),get_img()->get_height(), collideQueue[temp]->get_position().x,collideQueue[temp]->get_position().y, collideQueue[temp]->get_img()->get_width(),collideQueue[temp]->get_img()->get_height()); if (prevPos.y >= collideQueue[temp]->get_prev_pos().y + collideQueue[temp]->get_img()->get_height()) if (tcol.top > 0) { add_pos(0,tcol.top); set_vel(get_vel().x,collideQueue[temp]->get_vel().y); thisObjectHandle = did_handle = true; } if (prevPos.y + get_img()->get_height() <= collideQueue[temp]->get_prev_pos().y) if (tcol.bottom > 0) { add_pos(collideQueue[temp]->get_vel().x,-tcol.bottom); set_vel(get_vel().x/*collideQueue[temp]->get_vel().x*/,collideQueue[temp]->get_vel().y); ableToJump = true; jumpTimes = maxjumpable; thisObjectHandle = did_handle = true; } /// /// ADD CODE FROM NEXT CODE BLOCK HERE (on forum, not in code) /// } for (int temp = 0; temp < collideQueue.size(); temp++) { thisObjectHandle = false; tcol = get_collision(x,y,get_img()->get_width(),get_img()->get_height(), collideQueue[temp]->get_position().x,collideQueue[temp]->get_position().y, collideQueue[temp]->get_img()->get_width(),collideQueue[temp]->get_img()->get_height()); if (prevPos.x + get_img()->get_width() <= collideQueue[temp]->get_prev_pos().x) if (tcol.left > 0) { add_pos(-tcol.left,0); set_vel(collideQueue[temp]->get_vel().x,get_vel().y); thisObjectHandle = did_handle = true; } if (prevPos.x >= collideQueue[temp]->get_prev_pos().x + collideQueue[temp]->get_img()->get_width()) if (tcol.right > 0) { add_pos(tcol.right,0); set_vel(collideQueue[temp]->get_vel().x,get_vel().y); thisObjectHandle = did_handle = true; } } return did_handle; } (if I add the following code {where the comment to do so is}, which is glitchy, the above problem doesn't happen, though it brings others) if (!thisObjectHandle) { if (tcol.bottom > tcol.top) { add_pos(collideQueue[temp]->get_vel().x,-tcol.bottom); set_vel(get_vel().x,collideQueue[temp]->get_vel().y); } else if (tcol.top > tcol.bottom) { add_pos(0,tcol.top); set_vel(get_vel().x,collideQueue[temp]->get_vel().y); } } How would you change my system to prevent this?

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• How do I cap rendering of tiles in a 2D game with SDL?

  - by farmdve

  I have some boilerplate code working, I basically have a tile based map composed of just 3 colors, and some walls and render with SDL. The tiles are in a bmp file, but each tile inside it corresponds to an internal number of the type of tile(color, or wall). I have pretty basic collision detection and it works, I can also detetc continuous presses, which allows me to move pretty much anywhere I want. I also have a moving camera, which follows the object. The problem is that, the tile based map is bigger than the resolution, thus not all of the map can be displayed on the screen, but it's still rendered. I would like to cap it, but since this is new to me, I pretty much have no idea. Although I cannot post all the code, as even though I am a newbie and the code pretty basic, it's already quite a few lines, I can post what I tried to do void set_camera() { //Center the camera over the dot camera.x = ( player.box.x + DOT_WIDTH / 2 ) - SCREEN_WIDTH / 2; camera.y = ( player.box.y + DOT_HEIGHT / 2 ) - SCREEN_HEIGHT / 2; //Keep the camera in bounds. if(camera.x < 0 ) { camera.x = 0; } if(camera.y < 0 ) { camera.y = 0; } if(camera.x > LEVEL_WIDTH - camera.w ) { camera.x = LEVEL_WIDTH - camera.w; } if(camera.y > LEVEL_HEIGHT - camera.h ) { camera.y = LEVEL_HEIGHT - camera.h; } } set_camera() is the function which calculates the camera position based on the player's positions. I won't pretend I know much about it. Rectangle box = {0,0,0,0}; for(int t = 0; t < TOTAL_TILES; t++) { if(box.x < (camera.x - TILE_WIDTH) || box.y > (camera.y - TILE_HEIGHT)) apply_surface(box.x - camera.x, box.y - camera.y, surface, screen, &clips[tiles[t]]); box.x += TILE_WIDTH; //If we've gone too far if(box.x >= LEVEL_WIDTH) { //Move back box.x = 0; //Move to the next row box.y += TILE_HEIGHT; } } This is basically my render code. The for loop loops over 192 tiles stored in an int array, each with their own unique value describing the tile type(wall or one of three possible colored tiles). box is an SDL_Rect containing the current position of the tile, which is calculated on render. TILE_HEIGHT and TILE_WIDTH are of value 80. So the cap is determined by if(box.x < (camera.x - TILE_WIDTH) || box.y > (camera.y - TILE_HEIGHT)) However, this is just me playing with the values and see what doesn't break it. I pretty much have no idea how to calculate it. My screen resolution is 1024/768, and the tile map is of size 1280/960.

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• Why do I need two Instances in Windows Azure?

  - by BuckWoody

  Windows Azure as a Platform as a Service (PaaS) means that there are various components you can use in it to solve a problem: Compute “Roles” - Computers running an OS and optionally IIS - you can have more than one "Instance" of a given Role Storage - Blobs, Tables and Queues for Storage Other Services - Things like the Service Bus, Azure Connection Services, SQL Azure and Caching It’s important to understand that some of these services are Stateless and others maintain State. Stateless means (at least in this case) that a system might disappear from one physical location and appear elsewhere. You can think of this as a cashier at the front of a store. If you’re in line, a cashier might take his break, and another person might replace him. As long as the order proceeds, you as the customer aren’t really affected except for the few seconds it takes to change them out. The cashier function in this example is stateless. The Compute Role Instances in Windows Azure are Stateless. To upgrade hardware, because of a fault or many other reasons, a Compute Role's Instance might stop on one physical server, and another will pick it up. This is done through the controlling fabric that Windows Azure uses to manage the systems. It’s important to note that storage in Azure does maintain State. Your data will not simply disappear - it is maintained - in fact, it’s maintained three times in a single datacenter and all those copies are replicated to another for safety. Going back to our example, storage is similar to the cash register itself. Even though a cashier leaves, the record of your payment is maintained. So if a Compute Role Instance can disappear and re-appear, the things running on that first Instance would stop working. If you wrote your code in a Stateless way, then another Role Instance simply re-starts that transaction and keeps working, just like the other cashier in the example. But if you only have one Instance of a Role, then when the Role Instance is re-started, or when you need to upgrade your own code, you can face downtime, since there’s only one. That means you should deploy at least two of each Role Instance not only for scale to handle load, but so that the first “cashier” has someone to replace them when they disappear. It’s not just a good idea - to gain the Service Level Agreement (SLA) for our uptime in Azure it’s a requirement. We point this out right in the Management Portal when you deploy the application: (Click to enlarge) When you deploy a Role Instance you can also set the “Upgrade Domain”. Placing Roles on separate Upgrade Domains means that you have a continuous service whenever you upgrade (more on upgrades in another post) - the process looks like this for two Roles. This example covers the scenario for upgrade, so you have four roles total - One Web and one Worker running the "older" code, and one of each running the new code. In all those Roles you want at least two instances, and this example shows that you're covered for High Availability and upgrade paths: The take-away is this - always plan for forward-facing Roles to have at least two copies. For Worker Roles that do background processing, there are ways to architect around this number, but it does affect the SLA if you have only one.

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• DrawIndexedPrimitives overdraws data in previous buffer if called in loop

  - by Daniel Excinsky

  I doubled the question from stackoverflow here, and will delete the opposite of a question that gave me the answer. I have the Draw method in one of my renderers, that loops through the dictionary and gets precollected and preinitialized buffers. When dictionary has only one element, everything is just fine. But with more elements what I get on the screen is only the data from the last buffer (I suppose, not sure) My Draw method: public void Draw(GameTime gameTime) { if (!_areStaticEffectsSet) { // blockEffect.Parameters["TextureAtlas"].SetValue(textureAtlas); blockEffect.Parameters["HorizonColor"].SetValue(World.HORIZONCOLOR); blockEffect.Parameters["NightColor"].SetValue(World.NIGHTCOLOR); blockEffect.Parameters["MorningTint"].SetValue(World.MORNINGTINT); blockEffect.Parameters["EveningTint"].SetValue(World.EVENINGTINT); blockEffect.Parameters["SunColor"].SetValue(World.SUNCOLOR); _areStaticEffectsSet = true; } blockEffect.Parameters["World"].SetValue(Matrix.Identity); blockEffect.Parameters["View"].SetValue(_player.CameraView); blockEffect.Parameters["Projection"].SetValue(_player.CameraProjection); blockEffect.Parameters["CameraPosition"].SetValue(_player.CameraPosition); blockEffect.Parameters["timeOfDay"].SetValue(_world.TimeOfDay); var viewFrustum = new BoundingFrustum(_player.CameraView * _player.CameraProjection); _graphicsDevice.BlendState = BlendState.Opaque; _graphicsDevice.DepthStencilState = DepthStencilState.Default; foreach (KeyValuePair<int, Texture2D> textureAtlas in textureAtlases) { blockEffect.Parameters["TextureAtlas"].SetValue(textureAtlas.Value); foreach (EffectPass pass in blockEffect.CurrentTechnique.Passes) { pass.Apply(); //TODO: ?????????? ??????????????? ?? ?????? ?? ??????? ??????? VertexBuffer ? IndexBuffer foreach (Chunk chunk in _world.Chunks.Values) { if (chunk == null || chunk.IsDisposed) { continue; } if (chunk.BoundingBox.Intersects(viewFrustum) && chunk.GetBlockIndexBuffer(textureAtlas.Key) != null) { lock (chunk) { if (chunk.GetBlockIndexBuffer(textureAtlas.Key).IndexCount > 0) { VertexBuffer vertexBuffer = chunk.GetBlockVertexBuffer(textureAtlas.Key); IndexBuffer indexBuffer = chunk.GetBlockIndexBuffer(textureAtlas.Key); //if (chunk.DrawIndex == new Vector3i(0, 0, 0)) //{ //if (textureAtlas.Key == -1) //{ //var varray = new [] //{ //new VertexPositionTextureLight(new Vector3(0,68,0), new Vector2(0,1),1,new Vector3(0,0,0), new Vector3(1,1,1)), //new VertexPositionTextureLight(new Vector3(0,68,1), new Vector2(0,1),1,new Vector3(0,0,0), new Vector3(1,1,1)), //new VertexPositionTextureLight(new Vector3(1,68,0), new Vector2(0,1),1,new Vector3(0,0,0), new Vector3(1,1,1)) //}; //var iarray = new short[] {0, 1, 2}; //vertexBuffer = new VertexBuffer(_graphicsDevice, typeof(VertexPositionTextureLight), varray.Length, BufferUsage.WriteOnly); //indexBuffer = new IndexBuffer(_graphicsDevice, IndexElementSize.SixteenBits, iarray.Length, BufferUsage.WriteOnly); //vertexBuffer.SetData(varray); //indexBuffer.SetData(iarray); } } _graphicsDevice.SetVertexBuffer(vertexBuffer); _graphicsDevice.Indices = indexBuffer; _graphicsDevice.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, vertexBuffer.VertexCount, 0, indexBuffer.IndexCount / 3); } } } } } } } Noteworthy things about the code: XNA version is 4.0. I've commented the debugging code in the loop, but left it for it may bring some insight. I try not only to change vertices/indices in the loop, but textureAtlas also. Code in the shader about textureAtlas: Texture TextureAtlas; sampler TextureAtlasSampler = sampler_state { texture = <TextureAtlas>; magfilter = POINT; minfilter = POINT; mipfilter = POINT; AddressU = WRAP; AddressV = WRAP; }; struct VSInput { float4 Position : POSITION0; float2 TexCoords1 : TEXCOORD0; float SunLight : COLOR0; float3 LocalLight : COLOR1; float3 Normal : NORMAL0; }; VertexPositionTextureLight is my own realization of IVertexType. So, do anybody know about this problem, or see the wrongness in my code (that's far more likely)?

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• RemoveHandler Issues with Custom Events

  - by Jeff Certain

  This is a case of things being more complicated that I thought they should be. Since it took a while to figure this one out, I thought it was worth explaining and putting all of the pieces to the answer in one spot. Let me set the stage. Architecturally, I have the notion of generic producers and consumers. These put items onto, and remove items from, a queue. This provides a generic, thread-safe mechanism to load balance the creation and processing of work items in our application. Part of the IProducer(Of T) interface is: 1: Public Interface IProducer(Of T) 2: Event ItemProduced(ByVal sender As IProducer(Of T), ByVal item As T) 3: Event ProductionComplete(ByVal sender As IProducer(Of T)) 4: End Interface Nothing sinister there, is there? In order to simplify our developers’ lives, I wrapped the queue with some functionality to manage the produces and consumers. Since the developer can specify the number of producers and consumers that are spun up, the queue code manages adding event handlers as the producers and consumers are instantiated. Now, we’ve been having some memory leaks and, in order to eliminate the possibility that this was caused by weak references to event handles, I wanted to remove them. This is where it got dicey. My first attempt looked like this: 1: For Each producer As P In Producers 2: RemoveHandler producer.ItemProduced, AddressOf ItemProducedHandler 3: RemoveHandler producer.ProductionComplete, AddressOf ProductionCompleteHandler 4: producer.Dispose() 5: Next What you can’t see in my posted code are the warnings this caused. The 'AddressOf' expression has no effect in this context because the method argument to 'AddressOf' requires a relaxed conversion to the delegate type of the event. Assign the 'AddressOf' expression to a variable, and use the variable to add or remove the method as the handler.  Now, what on earth does that mean? Well, a quick Bing search uncovered a whole bunch of talk about delegates. The first solution I found just changed all parameters in the event handler to Object. Sorry, but no. I used generics precisely because I wanted type safety, not because I wanted to use Object. More searching. Eventually, I found this forum post, where Jeff Shan revealed a missing piece of the puzzle. The other revelation came from Lian_ZA in this post. However, these two only hinted at the solution. Trying some of what they suggested led to finally getting an invalid cast exception that revealed the existence of ItemProducedEventHandler. Hold on a minute! I didn’t create that delegate. There’s nothing even close to that name in my code… except the ItemProduced event in the interface. Could it be? Naaaaah. Hmmm…. Well, as it turns out, there is a delegate created by the compiler for each event. By explicitly creating a delegate that refers to the method in question, implicitly cast to the generated delegate type, I was able to remove the handlers: 1: For Each producer As P In Producers 2: Dim _itemProducedHandler As IProducer(Of T).ItemProducedEventHandler = AddressOf ItemProducedHandler 3: RemoveHandler producer.ItemProduced, _itemProducedHandler 4:  5: Dim _productionCompleteHandler As IProducer(Of T).ProductionCompleteEventHandler = AddressOf ProductionCompleteHandler 6: RemoveHandler producer.ProductionComplete, _productionCompleteHandler 7: producer.Dispose() 8: Next That’s “all” it took to finally be able to remove the event handlers and maintain type-safe code. Hopefully, this will save you the same challenges I had in trying to figure out how to fix this issue!

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• Make your TSQL easier to read during a presentation

  - by Jonathan Allen

  SQL Server Management Studio 2012 has some neat settings that you can use to help your presentations at a SQL event better for the attendees if you are willing to spend a few minutes making some settings changes. Historically, I have been reluctant to make changes to my SSMS settings as it is such a tedious process and it’s not 100% clear that what you think you are changing is actually what gets changed. With SSMS 2012 this has become a lot easier and a lot less risky. In any session that involves TSQL there is a trade off between the speaker having all the code on screen and the attendees being able to read any of what is on screen. You (the speaker) might be able to read this when you are working on the code but plenty of your audience wont be able to make head or tail of it. SSMS 2012 has a zoom facility that can help: but don’t go nuts … Having the font too big means you will be scrolling a lot and the code will again be rendered unreadable. There is more though but you need to take a deep breath and open the Tools menu and delve into the SSMS options. In previous versions of SSMS this is a deep, dark and scary place where changing values can be obscure and sometimes catastrophic to the UI when you get back to the code editor. First things first, we set out as a good DBA and save our current (and presumably acceptable) SSMS configuration. From the import and Export Settings you can set up a file to hold all of the settings that you currently have. The wizard will open and ask you to pick an option. This time around choose to export settings. hit next and next again and then name your settings profile in the final step of the wizard and then click Finish. Once this is done then you can change whatever you like and always get back to this configuration in a couple of clicks. So what can you change to make for a good experience? Well there are plenty of things that can be altered but don’t go too mad and change too many things without taking a look at the results for every item on the list above you can change font, size, weight, colour, background colour etc. etc. but consider what you are trying to achieve and take it slowly. I have seen presenters with their settings set to have a yellow highlight and black font rather than the default pale blue background and slightly darker font so to achieve that select Text Editor and then select “Selected Text” in the Display Items listbox. As you change things the Sample area give you an idea of what effect you are going to have. Black and yellow is the colour combination with the highest contrast – that’s why bees and wasps# are that colour. What next? how about increasing the default font for your demo scripts? This means that any script you open and any new ones that you start will take on this font. No more zooming (or forgetting to) in the middle of sessions. now don’t forget to save this profile – follow the same steps as above but give the profile a different name, something like PresentationBigFontHighContrast might be appropriate. Once you are done making changes, export the settings once more and then go into the Import Export wizard and import settings from the first profile you created. Everything will be back to normal. Now making changes to suit your environment can be done very easily and with confidence. * – and warning tape and safety signs and so forth – Health and Safety officers simply copy nature!

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• Running Powershell from within SharePoint

  - by Norgean

  Just because something is a daft idea, doesn't mean it can't be done. We sometimes need to do some housekeeping - like delete old files or list items or… yes, well, whatever you use Powershell for in a SharePoint world. Or it could be that your solution has "issues" for which you have Powershell solutions, but not the budget to transform into proper bug fixes. So you create a "how to" for the ITPro guys. Idea: What if we keep the scripts in a list, and have SharePoint execute the scripts on demand? An announcements list (because of the multiline body field). Warning! Let us be clear. This list needs to be locked down; if somebody creates a malicious script and you run it, I cannot help you. First; we need to figure out how to start Powershell scripts from C#. Hit teh interwebs and the Googlie, and you may find jpmik's post: http://www.codeproject.com/Articles/18229/How-to-run-PowerShell-scripts-from-C. (Or MS' official answer at http://msdn.microsoft.com/en-us/library/ee706563(v=vs.85).aspx) public string RunPowershell(string powershellText, SPWeb web, string param1, string param2) { // Powershell ~= RunspaceFactory - i.e. Create a powershell context var runspace = RunspaceFactory.CreateRunspace(); var resultString = new StringBuilder(); try { // load the SharePoint snapin - Note: you cannot do this in the script itself (i.e. add-pssnapin etc does not work) PSSnapInException snapInError; runspace.RunspaceConfiguration.AddPSSnapIn("Microsoft.SharePoint.PowerShell", out snapInError); runspace.Open(); // set a web variable. runspace.SessionStateProxy.SetVariable("webContext", web); // and some user defined parameters runspace.SessionStateProxy.SetVariable("param1", param1); runspace.SessionStateProxy.SetVariable("param2", param2); var pipeline = runspace.CreatePipeline(); pipeline.Commands.AddScript(powershellText); // add a "return" variable pipeline.Commands.Add("Out-String"); // execute! var results = pipeline.Invoke(); // convert the script result into a single string foreach (PSObject obj in results) { resultString.AppendLine(obj.ToString()); } } finally { // close the runspace runspace.Close(); } // consider logging the result. Or something. return resultString.ToString(); } Ok. We've written some code. Let us test it. var runner = new PowershellRunner(); runner.RunPowershellScript(@" $web = Get-SPWeb 'http://server/web' # or $webContext $web.Title = $param1 $web.Update() $web.Dispose() ", null, "New title", "not used"); Next step: Connect the code to the list, or more specifically, have the code execute on one (or several) list items. As there are more options than readers, I'll leave this as an exercise for the reader. Some alternatives: Create a ribbon button that calls RunPowershell with the body of the selected itemsAdd a layout pageSpecify list item from query string (possibly coupled with content editor webpart with html that links directly to this page with querystring)WebpartListing with an "execute" columnList with multiselect and an execute button Etc!Now that you have the code for executing powershell scripts, you can easily expand this into a timer job, which executes scripts at regular intervals. But if the previous solution was dangerous, this is even worse - the scripts will usually be run with one of the admin accounts, and can do pretty much anything...One more thing... Note that as this is running "consoleless" calls to Write-Host will fail. Two solutions; remove all output, or check if the script is run in a console-window or not.  if ($host.Name -eq "ConsoleHost") { Write-Host 'If I agreed with you we'd both be wrong' }

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• With a little effort you can &ldquo;SEMI&rdquo;-protect your C# assemblies with obfuscation.

  - by mbcrump

  This method will not protect your assemblies from a experienced hacker. Everyday we see new keygens, cracks, serials being released that contain ways around copy protection from small companies. This is a simple process that will make a lot of hackers quit because so many others use nothing. If you were a thief would you pick the house that has security signs and an alarm or one that has nothing? To so begin: Obfuscation is the concealment of meaning in communication, making it confusing and harder to interpret. Lets begin by looking at the cartoon below:     You are probably familiar with the term and probably ignored this like most programmers ignore user security. Today, I’m going to show you reflection and a way to obfuscate it. Please understand that I am aware of ways around this, but I believe some security is better than no security.  In this sample program below, the code appears exactly as it does in Visual Studio. When the program runs, you get either a true or false in a console window. Sample Program. using System; using System.Diagnostics; using System.Linq;   namespace ObfuscateMe {     class Program     {                static void Main(string[] args)         {               Console.WriteLine(IsProcessOpen("notepad")); //Returns a True or False depending if you have notepad running.             Console.ReadLine();         }             public static bool IsProcessOpen(string name)         {             return Process.GetProcesses().Any(clsProcess => clsProcess.ProcessName.Contains(name));         }     } }   Pretend, that this is a commercial application. The hacker will only have the executable and maybe a few config files, etc. After reviewing the executable, he can determine if it was produced in .NET by examing the file in ILDASM or Redgate’s Reflector. We are going to examine the file using RedGate’s Reflector. Upon launch, we simply drag/drop the exe over to the application. We have the following for the Main method:   and for the IsProcessOpen method:     Without any other knowledge as to how this works, the hacker could export the exe and get vs project build or copy this code in and our application would run. Using Reflector output. using System; using System.Diagnostics; using System.Linq;   namespace ObfuscateMe {     class Program     {                static void Main(string[] args)         {               Console.WriteLine(IsProcessOpen("notepad"));             Console.ReadLine();         }             public static bool IsProcessOpen(string name)         {             return Process.GetProcesses().Any<Process>(delegate(Process clsProcess)             {                 return clsProcess.ProcessName.Contains(name);             });         }       } } The code is not identical, but returns the same value. At this point, with a little bit of effort you could prevent the hacker from reverse engineering your code so quickly by using Eazfuscator.NET. Eazfuscator.NET is just one of many programs built for this. Visual Studio ships with a community version of Dotfoscutor. So download and load Eazfuscator.NET and drag/drop your exectuable/project into the window. It will work for a few minutes depending if you have a quad-core or not. After it finishes, open the executable in RedGate Reflector and you will get the following: Main After Obfuscation IsProcessOpen Method after obfuscation: As you can see with the jumbled characters, it is not as easy as the first example. I am aware of methods around this, but it takes more effort and unless the hacker is up for the challenge, they will just pick another program. This is also helpful if you are a consultant and make clients pay a yearly license fee. This would prevent the average software developer from jumping into your security routine after you have left. I hope this article helped someone. If you have any feedback, please leave it in the comments below.

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• Framework for Everything - Where to begin? [Longer post]

  - by SquaredSoft

  Back story of this question, feel free to skip down for the specific question Hello, I've been very interested in the idea of abstract programming the last few years. I've made about 30 attempts at creating a piece of software that is capable of almost anything you throw at it. I've undertook some attempts at this that have taken upwards of a year, while getting close, never releasing it beyond my compiler. This has been something I've always tried wrapping my head around, and something is always missing. With the title, I'm sure you're assuming, "Yes of course you noob! You can't account for everything!" To which I have to reply, "Why not?" To give you some background into what I'm talking about, this all started with doing maybe a shade of gray hat SEO software. I found myself constantly having to create similar, but slightly different sets of code. I've gone through as many iterations of way to communicate on http as the universe has particles. "How many times am I going to have to write this multi-threaded class?" is something I found myself asking a lot. Sure, I could create a class library, and just work with that, but I always felt I could optimize what I had, which often was a large undertaking and typically involved frequent use of the CRTL+A keyboard shortcut, mixed with the delete button. It dawned on me that it was time to invest in a plugin system. This would allow me to simply add snippets of code. as time went on, and I could subversion stuff out, and distribute small chunks of code, rather than something that encompasses only a specific function or design. This comes with its own complexity, of course, and by the time I had finished the software scope for this addition, it hit me that I would want to add to everything in the software, not just a new http method, or automation code for a specific website. Great, we're getting more abstract. However, the software that I have in my mind comes down to a quite a few questions regarding its execution. I have to have some parameters to what I am going to do. After writing what the perfect software would do in my mind, I came up with this as a list of requirements: Should be able to use networking A "Macro" or "Expression system" which would allow people to do something like : =First(=ParseToList(=GetUrl("http://www.google.com?q=helloworld!"), Template.Google)) Multithreaded Able to add UI elements through some type of XML -- People can make their own addons etc. Can use third party API through the plugins, such as Microsoft CRM, Exchange, etc. This would allow the software to essentially be used for everything. Really, any task you wish to automate, in a simple way. Making the UI was as also extremely hard. How do you do all of this? Its very difficult. So my question: With so many attempts at this, I'm out of ideas how to successfully complete this. I have a very specific idea in my mind, but I keep failing to execute it. I'm a self taught programmer. I've been doing it for years, and work professionally in it, but I've never encountered something that would be as complex and in-depth as a system which essentially does everything. Where would you start? What are the best practices for design? How can I avoid constantly having to go back and optimize my software. What can I do to generalize this and draw everything out to completion. These are things I struggle with. P.s., I'm using c# as my main language. I feel like in this example, I might be hitting the outer limit of the language, although, I don't know if that is the case, or if I'm just a bad programmer. Thanks for your time.

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