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• The inevitable Hello World post!

  - by brendonpage

  Greetings to anyone reading this! This is my first of hopefully many posts. I would like to use this post to introduce myself and to let you know what to expect from this blog in future. Okay so a bit about myself. In case you missed the name of this blog, my name is Brendon Page! I am a Software Developer from South Africa and work for a small company who’s main focus is producing software for the kitchen cupboard industry, although from time to time we do produce custom solutions for other industries. I work in a small team of 3, including myself, and am fortunate enough to work from home! I have been involved in IT since 1996, which is when I got my first PC, and started working as a junior programmer in 2003. Outside of work I enjoy playing squash, PC Games and of course LANing with my friends. If I get any free time between all of that I will usually dedicate some of it to a personal project, these are mainly prototypes for an idea I have had or for something that could be useful at work. I was in 2 minds on whether to include a photo of myself. The reason for this was because while I was looking for a suitable photo to use, it dawned on me how much time I dedicate to pulling funny faces in photos! I also realized how little I shave, which I blame completely on working form home. So after much debate here I am, funny face, beard and all!   Now that you know a bit about me lets move onto what expect from this blog. I work predominantly with Microsoft technologies so most if not all of my posts will be related to something Microsoft. Since most of my job entails Software Development you can expect a lot of posts which will deal with the .NET Framework. I am currently working on a large Silverlight project, so my first few posts will be targeted at in that direction. I will be striving to make the content of my posts as useful as possible from both an explanation and code perspective, I aim to include a working solution for every post, which I will put up on my skydrive for download. Here is what I have planned for my next few posts: Where did my session variables go?  Here I will take you through the lessons I learnt the hard way about the ASP.NET session. I am not going to go into to much depth in this post, as there is already a lot of information available on it. I mainly want to cover it in an effort to keep the scope creep of my posts to a minimum, some the solutions I upload will use it and I would like to have a post that I can reference to explain why I am doing something a certain way. Uploading files through SIlverlight Again there is a lot of existing information on this topic, so I wont be going into to much depth, but I will be using the solution from this as a base for my next post. Generating and Displaying DeepZoom images dynamically in Silverlight Well the title pretty much speaks for it’s self on this one. As I mentioned I will be building off the solution that I create in my ‘Uploading files through Silverlight’ post. Securing DeepZoom images using a custom implementation of the MultiScaleTileSource In this post I will look at the privacy issue surrounding the default usage of DeepZoom images in Silverlight and how to overcome it. This makes the use of DeepZoom in privacy conscious applications more viable. Thanks to anyone who actually read this post! I look forward to producing more which will hopefully be helpful to you.

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• Ti Launchpad

  - by raysmithequip

  Just thought I would get a couple of notes up here for reference to anyone that is interested...it is now Feb 2011 and I have not been posting here enough to remember this blog. Back in Nov 2010 I ordered the Ti launchpad msp430, it is a little target board kit replete with a mini USB cable, two very inexpensive programmable mcu's and a couple of pin headers with a couple of led's on board, a spi connector some on board jumpers and two programmable micro switches....all for less than $5.00...INCLUDING SHIPPING!!....not bad when the ardruino's are running around 20.00 for the target board, atmega328 and cable off of eBay...I wont even mention the microchip pic right now.  Naw, for $5.00 the Ti launchpad kit is about the cheapest fun around...if-uns your a geek that is... Well, the launchpad was backordered for almost two months, came like Xmas eve in fact...I had almost forgotten it!! And really, it was way late and not my idea of an Xmas present for myself.  That would of been the web expressions 4 I bought a few weeks back.  With all the holidays, I did not even look at it till last week, in fact I passed the wrapped board around at my local ham club meeting during points of personal privilege....some oh's and ahhs but mostly duhs...I actually ordered it to avoid downloading the huge code compressor studio 4 (CCS) that was supposed to be included on the cd.  No cd.  I had already downloaded IAR  another programming IDE for these little micro bugs. In my spare time I toyed with IAR and the launchpad board but after about two days of playing delete the driver with windows I decided to just download CCS 4, the code limited version, and give that a shot......CCS 4, is a good rewrite from the earlier versions, it is based on Eclipse as an IDE and includes the drivers for the msp430 target board I received in the kit.  Once installed I quickly configured the debugger for the target chip which was already plugged into the dip socket at the factory, msp430G2131 from he drop down list and clicked ok...I was in!! The CCS4 is full of bells and whistles compared to the IAR, which I would of preferred for the simplicity.  But the code compressor studio really does have it all!!..the code limited version is free, and of all things will give you java script editor box.  The whole layout in debugger mode reminds me of any modern programmer IDE...I mean sure give me Tex anytime but you simply must admire all the boxes and options included in the GUI.  It was a simple matter to check the assembly code in the flash and ram memory that came preloaded for the launchpad kit.  Assembly.  I am right now looking for my old assembly textbooks...sure I remember how to use mov and add etc but a couple of the commands are a little more than vague anymore.  Still, these little mcu's are about 50 cents each and might just work in a couple of projects I have lined up for the near future.  I may document the code here.  Luckily, I plan to write the code in c++ for the main project but if it has to be assembly, no prob.  For reference, the program that came already on the 2131 in the kit was a temperature indicator that alternately flashed red and green leds and changed the intensity of either depending on whether the temp was rising or falling...neat.  Neat enough that it might be worthwhile banging out a little GUI in windows 7 to test the new user device system calls, maybe put a temp gauge widget up on the desktop...just to keep from getting bored.  If you see some assembly code on this blog, you know I was doing something with one of the many mcu's out there.....thats all for now, more to follow...a bit later, of course.

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• Google Fetch issue

  - by Karen

  When I do a Google fetch on any of my webpages the results are all the same (below). I'm not a programmer but I'm pretty sure this is not correct. Out of all the fetches I have done only one was different and the content length was 6x below and showed meta tags etc. Maybe this explains other issues I've been having with the site: a drop in indexed pages. Meta tag analyzer says I have no title tag, meta tags or description even though I do it on all pages. I had an SEO team working on the site and they were stumped by why pages were not getting indexed. So they figure it was some type of code error. Are they right? HTTP/1.1 200 OK Cache-Control: private Content-Type: text/html; charset=utf-8 Content-Encoding: gzip Vary: Accept-Encoding Server: Microsoft-IIS/7.5 X-AspNet-Version: 4.0.30319 X-Powered-By: ASP.NET Date: Thu, 11 Oct 2012 11:45:41 GMT Content-Length: 1054 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title></title> <script type="text/javascript"> function getCookie(cookieName) { if (document.cookie.length > 0) { cookieStart = document.cookie.indexOf(cookieName + "="); if (cookieStart != -1) { cookieStart = cookieStart + cookieName.length + 1; cookieEnd = document.cookie.indexOf(";", cookieStart); if (cookieEnd == -1) cookieEnd = document.cookie.length; return unescape(document.cookie.substring(cookieStart, cookieEnd)); } } return ""; } function setTimezone() { var rightNow = new Date(); var jan1 = new Date(rightNow.getFullYear(), 0, 1, 0, 0, 0, 0); // jan 1st var june1 = new Date(rightNow.getFullYear(), 6, 1, 0, 0, 0, 0); // june 1st var temp = jan1.toGMTString(); var jan2 = new Date(temp.substring(0, temp.lastIndexOf(" ") - 1)); temp = june1.toGMTString(); var june2 = new Date(temp.substring(0, temp.lastIndexOf(" ") - 1)); var std_time_offset = (jan1 - jan2) / (1000 * 60 * 60); var daylight_time_offset = (june1 - june2) / (1000 * 60 * 60); var dst; if (std_time_offset == daylight_time_offset) { dst = "0"; // daylight savings time is NOT observed } else { // positive is southern, negative is northern hemisphere var hemisphere = std_time_offset - daylight_time_offset; if (hemisphere >= 0) std_time_offset = daylight_time_offset; dst = "1"; // daylight savings time is observed } var exdate = new Date(); var expiredays = 1; exdate.setDate(exdate.getDate() + expiredays); document.cookie = "TimeZoneOffset=" + std_time_offset + ";"; document.cookie = "Dst=" + dst + ";expires=" + exdate.toUTCString(); } function checkCookie() { var timeOffset = getCookie("TimeZoneOffset"); var dst = getCookie("Dst"); if (!timeOffset || !dst) { setTimezone(); window.location.reload(); } } </script> </head> <body onload="checkCookie()"> </body> </html>

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• Efficiently separating Read/Compute/Write steps for concurrent processing of entities in Entity/Component systems

  - by TravisG

  Setup I have an entity-component architecture where Entities can have a set of attributes (which are pure data with no behavior) and there exist systems that run the entity logic which act on that data. Essentially, in somewhat pseudo-code: Entity { id; map<id_type, Attribute> attributes; } System { update(); vector<Entity> entities; } A system that just moves along all entities at a constant rate might be MovementSystem extends System { update() { for each entity in entities position = entity.attributes["position"]; position += vec3(1,1,1); } } Essentially, I'm trying to parallelise update() as efficiently as possible. This can be done by running entire systems in parallel, or by giving each update() of one system a couple of components so different threads can execute the update of the same system, but for a different subset of entities registered with that system. Problem In reality, these systems sometimes require that entities interact(/read/write data from/to) each other, sometimes within the same system (e.g. an AI system that reads state from other entities surrounding the current processed entity), but sometimes between different systems that depend on each other (i.e. a movement system that requires data from a system that processes user input). Now, when trying to parallelize the update phases of entity/component systems, the phases in which data (components/attributes) from Entities are read and used to compute something, and the phase where the modified data is written back to entities need to be separated in order to avoid data races. Otherwise the only way (not taking into account just "critical section"ing everything) to avoid them is to serialize parts of the update process that depend on other parts. This seems ugly. To me it would seem more elegant to be able to (ideally) have all processing running in parallel, where a system may read data from all entities as it wishes, but doesn't write modifications to that data back until some later point. The fact that this is even possible is based on the assumption that modification write-backs are usually very small in complexity, and don't require much performance, whereas computations are very expensive (relatively). So the overhead added by a delayed-write phase might be evened out by more efficient updating of entities (by having threads work more % of the time instead of waiting). A concrete example of this might be a system that updates physics. The system needs to both read and write a lot of data to and from entities. Optimally, there would be a system in place where all available threads update a subset of all entities registered with the physics system. In the case of the physics system this isn't trivially possible because of race conditions. So without a workaround, we would have to find other systems to run in parallel (which don't modify the same data as the physics system), other wise the remaining threads are waiting and wasting time. However, that has disadvantages Practically, the L3 cache is pretty much always better utilized when updating a large system with multiple threads, as opposed to multiple systems at once, which all act on different sets of data. Finding and assembling other systems to run in parallel can be extremely time consuming to design well enough to optimize performance. Sometimes, it might even not be possible at all because a system just depends on data that is touched by all other systems. Solution? In my thinking, a possible solution would be a system where reading/updating and writing of data is separated, so that in one expensive phase, systems only read data and compute what they need to compute, and then in a separate, performance-wise cheap, write phase, attributes of entities that needed to be modified are finally written back to the entities. The Question How might such a system be implemented to achieve optimal performance, as well as making programmer life easier? What are the implementation details of such a system and what might have to be changed in the existing EC-architecture to accommodate this solution?

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• Where should you put constants and why?

  - by Tim Meyer

  In our mostly large applications, we usually have a only few locations for constants: One class for GUI and internal contstants (Tab Page titles, Group Box titles, calculation factors, enumerations) One class for database tables and columns (this part is generated code) plus readable names for them (manually assigned) One class for application messages (logging, message boxes etc) The constants are usually separated into different structs in those classes. In our C++ applications, the constants are only defined in the .h file and the values are assigned in the .cpp file. One of the advantages is that all strings etc are in one central place and everybody knows where to find them when something must be changed. This is especially something project managers seem to like as people come and go and this way everybody can change such trivial things without having to dig into the application's structure. Also, you can easily change the title of similar Group Boxes / Tab Pages etc at once. Another aspect is that you can just print that class and give it to a non-programmer who can check if the captions are intuitive, and if messages to the user are too detailed or too confusing etc. However, I see certain disadvantages: Every single class is tightly coupled to the constants classes Adding/Removing/Renaming/Moving a constant requires recompilation of at least 90% of the application (Note: Changing the value doesn't, at least for C++). In one of our C++ projects with 1500 classes, this means around 7 minutes of compilation time (using precompiled headers; without them it's around 50 minutes) plus around 10 minutes of linking against certain static libraries. Building a speed optimized release through the Visual Studio Compiler takes up to 3 hours. I don't know if the huge amount of class relations is the source but it might as well be. You get driven into temporarily hard-coding strings straight into code because you want to test something very quickly and don't want to wait 15 minutes just for that test (and probably every subsequent one). Everybody knows what happens to the "I will fix that later"-thoughts. Reusing a class in another project isn't always that easy (mainly due to other tight couplings, but the constants handling doesn't make it easier.) Where would you store constants like that? Also what arguments would you bring in order to convince your project manager that there are better concepts which also comply with the advantages listed above? Feel free to give a C++-specific or independent answer. PS: I know this question is kind of subjective but I honestly don't know of any better place than this site for this kind of question. Update on this project I have news on the compile time thing: Following Caleb's and gbjbaanb's posts, I split my constants file into several other files when I had time. I also eventually split my project into several libraries which was now possible much easier. Compiling this in release mode showed that the auto-generated file which contains the database definitions (table, column names and more - more than 8000 symbols) and builds up certain hashes caused the huge compile times in release mode. Deactivating MSVC's optimizer for the library which contains the DB constants now allowed us to reduce the total compile time of your Project (several applications) in release mode from up to 8 hours to less than one hour! We have yet to find out why MSVC has such a hard time optimizing these files, but for now this change relieves a lot of pressure as we no longer have to rely on nightly builds only. That fact - and other benefits, such as less tight coupling, better reuseability etc - also showed that spending time splitting up the "constants" wasn't such a bad idea after all ;-)

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• Move on and look elsewhere, or confront the boss?

  - by Meister

  Background: I have my Associates in Applied Science (Comp/Info Tech) with a strong focus in programming, and I'm taking University classes to get my Bachelors. I was recently hired at a local company to be a Software Engineer I on a team of about 8, and I've been told they're looking to hire more. This is my first job, and I was offered what I feel to be an extremely generous starting salary ($30/hr essentially + benefits and yearly bonus). What got me hired was my passion for programming and a strong set of personal projects. Problem: I had no prior experience when I interviewed, so I didn't know exactly what to ask them about the company when I was hired. I've spotted a number of warning signs and annoyances since then, such as: Four developers when I started, with everyone talking about "Ben" or "Ryan" leaving. One engineer hired thirty days before me, one hired two weeks after me. Most of the department has been hiring a large number of people since I started. Extremely limited internet access. I understand the idea from an IT point of view, but not only is Facebook blocked, but so it Youtube, Twitter, and Pandora. I've also figured out that they block all access to non-DNS websites (http://xxx.xxx.xxx.xxx/) and strangely enough Miranda-IM. Low cubicles. Which is fine because I like my immediate coworkers, but they put the developers with the customer service, customer training, and QA department in a huge open room. Noise, noise, noise, and people stop to chitchat all day long. Headphones only go so far. Several emails have been sent out by my boss since I started telling us programmers to not talk about non-work-related-things like Video Games at our cubicles, despite us only spending maybe five minutes every few hours doing so. Further digging tells me that this is because someone keeps complaining that the programmers are "slacking off". People are looking over my shoulder all day. I was in the Freenode webchat to get help with a programming issue, and within minutes I had an email from my boss (to all the developers) telling us that we should NOT be connected to any outside chat servers at work. Version control system from 2005 that we must access with IE and keep the Java 1.4 JRE installed to be able to use. I accidentally updated to Java 6 one day and spent the next two days fighting with my PC to undo this "problem". No source control, no comments on anything, no standards, no code review, no unit testing, no common sense. I literally found a problem in how they handle string resource translations that stems from the simple fact that they don't trim excess white spaces, leading to developers doing: getResource("Date: ") instead of: getResource("Date") + ": ", and I was told to just add the excess white spaces back to the database instead of dealing with the issue directly. Some of these things I'd like to try to understand, but I like having IRC open to talk in a few different rooms during the day and keep in touch with friends/family over IM. They don't break my concentration (not NEARLY as much as the lady from QA stopping by to talk about her son), but because people are looking over my shoulder all day as they walk by they complain when they see something that's not "programmer-looking work". I've been told by my boss and QA that I do good, fast work. I should be judged on my work output and quality, not what I have up on my screen for the five seconds you're walking by So, my question is, even though I'm just barely at my 90 days: How do you decide to move on from a job and looking elsewhere, or when you should start working with your boss to resolve these issues? Is it even possible to get the boss to work with me in many of these things? This is the only place I heard back from even though I sent out several resume's a day for several months, and this place does pay well for putting up with their many flaws, but I'm just starting to get so miserable working here already. Should I just put up with it?

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• Any tips on getting hired as a software project manager straight out of college?

  - by MHarrison

  I graduated with a BS in compsci last September, and I've been trying (unsuccessfully) to find a job as a project manager ever since. I fell in love with software engineering (the formal practice behind it all, not just coding) in school, and I've dedicated the last 3-4 years of my life to learning everything I can about project management and gaining experience. I've managed several projects (with teams around 12 people) while in school, and I worked with my university's software engineering research lab. My résumé is also decent - I worked as a programmer before I went to school (I'm 27 now), and I did Google Summer of Code for 3 summers. I also have general "people management" experience via working as the photo editor for my university's newspaper for 2 years. My first problem with the job hunt is not getting enough interviews. I use careers.stackoverflow.com, which is awesome because I usually get contacted by non-HR people who know what they're talking about, but there's just not enough companies using it for me to get interviews on a regular basis. I've also tried sites like monster.com, and in a fit of desperation, I sent out no less than 60 applications to project management positions. I've gotten 3 automated rejection letters and that's it. At least careers.stackoverflow gets me a phone interview with 8/10 places I apply to. But the main (and extremely frustrating) problem is the matter of experience. I've successfully managed projects from start to finish (in my software engineering classes we had real customers come in with a real software need and we built it for them), but I've never had to deal with budgets and money (I know this is why HR people immediately turn me away). Most of these positions require 5+ years PM experience, and I've seen absurd things like 12+ years required. Interviews are also maddening. I've had so many places who absolutely loved me and I made it to the final round of interviews, and I left thinking things went extremely well and they'd consider me. However, when I check in with them a week later, they tell me "We really liked you and your qualifications are excellent, but we're hoping to find someone with more experience." The bad interviews I can understand - like the PM position that would have had me managing developers both locally and overseas - I had 3 interviews with them and the ENTIRE interview process was them asking me CS brainteasers and having me waste time on things like writing quicksort on paper or writing binary search trees. Even when I tried steering the discussion towards more relevant PM stuff, they gave me some vague generic replies and went back to the "We want to be Google/MS" crap. But when I have a GOOD interview, they say my "qualifications are excellent" but they want "more experience"...that makes me want to tear my hair out. What else can I DO? While I'm aiming for technically-involved PM positions (not just crunching budget numbers), I really don't want a straight development job because I like creating software from the very high-level vs. spending a lot of time debugging memory leaks. In fact, I can't even GET development positions that I'm qualified for because I make the mistake of telling them that my future career goals are as PM (which usually results in them saying something like "Well we already have PMs and this position isn't really set up to get you there." - which I take to mean "No, that's my job, stay away.") My apologies on the long rant, but I'm seriously hellbent on getting hired as a PM since it's both my career goal and the passion that keeps me awake at night. Any suggestions on what the heck else I can do? I'm currently writing a blog where I talk about my philosophies about software engineering, and I'm writing up specs for an iOS app which I will design, code, and show employers, but this takes an awful lot of time that I don't have.

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• Refactoring existing PHP Project. I need some advices

  - by b0x

  i have a small SAS ERP that was written some years ago using PHP. At that time, it didn't used any framework, but the code isn't a mess as i will explain more detailed in the following lines. Nowadays, the project grow and I’m now working with 3 more programmers. Often, they ask to me why we don’t migrate to a framework such Laravel. Although I'd love trying Laravel, I’m a small business and i don't have time/money to stop and spend a whole year building everything from scratch. I need to live and pay the bills. So, I've read a lot about this matter, and I decided that doing a refactoring is the best way to do it. Also, I'm not so sure that a framework will make things easy. Business goals are: Make the code easier to new hired programmers I must separate the "view", because: I want to release different versions of this product (using the same code), but under different brands and websites at the minimum cost (just changing view) Release different versions to fit mobile/tablet. Make different types of this product, seeling packages as if it were plugins. Develop custom packages for some costumers (like plugins/addon's that they can buy to put on the main application). Code goals: Introduce best pratices, standards for everyone Try to build my own MVC structure Improve validation of data/forms (today they are mixed in both ajax and classes) Create automated testing rotines, to quality assurance. My actual structure project: class\ extra\ hd\ logs\ public_html\ public_html\includes\ public_html\css|js|images\ class\ There are three types of classes. They are all “autoloaded” with something similar with PSR-0, but I don’t use namespaces. 1. class.Something.php Connects to Database using specific methods. I.e: Costumer-list(); It uses “class.Db.php”, that it’s an abstraction of mysqli on every method. 2. class.SomethingProc.php Do things that “join” things that come from “class.Something.php”. Like IF/ELSE, math operations. 3. class.SomethingHTML.php The classes with “HTML” suffix implements only static methods and HTML code only. A real life example: All the programmers need to use $cSomething ($c to class) and $arrSomething (to array). Costumer.php (view) <?php $cCosumter = new Costumer(); $arrCostumer = $cCostumer->list(); echo CostumerHTML::table($arrCostumer); ?> Extra\ Store 3rdparty projects/classes from others, such MPDF, PHPMailer, etc. Hd\ Store user’s fies outsite wwwroot dir. Logs\ Store phplogs and the system itself logs (We have a static Log::error() method, that we put in every method of every class) Public_html\ Stores the files that people use. Public_html\includes\ Store the main “config.php” file and all files that do “ajax things” ajax.Costumer.php, for example. Help is needed ;) So, as you can see we have some standards, and also for database things. But i want to write a manual of our rules. Something that i can give to any new programmer at my companie and he can go on. This is not totally a mess, but It could be better seeing the new practices. What could I do to separate this as MVC, to have multiple VIEW’s. Could you gimme some tips considering my goals? Keep im mind the different products/custom things for specific costumers without breaking the main application. URL for tutorials, books, etc. It would be nice. Thanks!

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• Notes - Part II - Play with JavaFX

  - by Silviu Turuga

  Open the project from last lesson Double click on NotesUI.fmxl, this will open the JavaFX Scene Builder On the left side you have a area called Hierarchy, from there press Del or Shift+Backspace on Mac to delete the Button and the Label. You'll receive a warning, that some components have been assigned an fx:id, click Delete as we don't need them anymore. Resize the AnchorPane to have enough room for our design, eg. 820x550px From the top left pick the Container called Accordion and drag over the AnchorPane design Chose then from Controls a List View and drag inside the Accordion. You'll notice that by default the Accordion has 2 TitledPane, and you can switch between them by clicking on their name. I'll let you the pleasure to do the rest in order to get the following result  Here is the list of objects used Save it and then return to NetBeans Run the application and it should be run without any issue. If you click on buttons they all are functional, but nothing happens as we didn't link them with any action. We'll see this in the next episode. Now, let's play a little bit with the application and try to resize it… Have you notice the behavior? If the form is too small, some objects aren't visible, if it is too large there is too much space . That's for sure something that your users won't like and you as a programmer have to care about this. From NetBeans double click NotesUI.fmxl so to return back to JavaFX Scene Builder Select the TextField from bottom left of Notes, the one where I put the text Category and then from the right part of JavaFX Scene Builder you'll notice a panel called Inspector. Chose Layout and then click on the dotted lines from left and bottom of the square, like you see in the below image This will make the textfield to have always the same distance from left and bottom no matter the size of the form. Save and run the application. Note that whenever the form is changing the Height, the Category TextField has the same distance from the bottom. Select Accordion and do the same steps but also check the top dotted line, because we want the Accordion to have the same height as the main form has. I'll let you the pleasure to do the same for the rest of components. It's very important to design an application that can be resize by user and in the same time, all the buttons are on place. Last step is to make sure our application is not getting smaller then a certain size, as this will hide parts of our layout. So select the AnchorPane and from Inspector go to Layout and note down the Width and Height. Go back to NetBeans and open the file Main.java and add the following code just after stage.setScene(scene); (around line 26) stage.setMinWidth(820); stage.setMinHeight(550); Use your own width and height. This will prevent user to reduce the width or height of your application to a value that will hide parts of your layout. So now you should have done most of the design part and next time we'll see how can we enter some data into our newly created application… Note: in case you miss something, here are the source files of the project till this point. 

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• Advice on refactoring PHP Project

  - by b0x

  I have a small SAS ERP that was written some years ago using PHP. At that time, it didn't use any framework, but the code isn't a mess. Nowadays, the project grows and I’m now working with 3 more programmers. Often, they ask to me why we don’t migrate to a framework such as Laravel. Although I'd love trying Laravel, I’m a small business and I don't have time nor money to stop and spend a whole year building everything from scratch. I need to live and pay the bills. So, I've read a lot about this matter, and I decided that doing a refactoring is the best way to do it. Also, I'm not so sure that a framework will make things easy. Business goals are: Make the code easier to new hired programmers Separate the "view", in order to: release different versions of this product (using the same code), but under different brands and websites at the minimum cost (just changing view) release different versions to fit mobile/tablet. Make different types of this product, selling packages as if they were plugins. Develop custom packages for some costumers (like plugins/addon's that they can buy to put on the main application). Code goals: Introduce best pratices, standards for everyone Try to build my own MVC structure Improve validation of data/forms (today they are mixed in both ajax and classes) Create automated testing routines for quality assurance. My current structure project: class\ extra\ hd\ logs\ public_html\ public_html\includes\ public_html\css|js|images\ class\ There are three types of classes. They are all “autoloaded” with something similar with PSR-0, but I don’t use namespaces. 1. class.Something.php Connects to Database using specific methods. I.e: Costumer-list(); It uses “class.Db.php”, that it’s an abstraction of mysql on every method. 2. class.SomethingProc.php Do things that “join” things that come from “class.Something.php”. Like IF/ELSE, math operations. 3. class.SomethingHTML.php The classes with “HTML” suffix implements only static methods and HTML code only. A real life example: All the programmers need to use $cSomething ($c to class) and $arrSomething (to array). Costumer.php (view) <?php $cCosumter = new Costumer(); $arrCostumer = $cCostumer->list(); echo CostumerHTML::table($arrCostumer); ?> Extra\ Store 3rdparty projects/classes from others, such MPDF, PHPMailer, etc. Hd\ Store user’s files outsite wwwroot dir. Logs\ Store phplogs and the system itself logs (We have a static Log::error() method, that we put in every method of every class) Public_html\ Stores the files that people use. Public_html\includes\ Store the main “config.php” file and all files that do “ajax things” ajax.Costumer.php, for example. Help is needed ;) So, as you can see we have some standards, and also for database things. But I want to write a manual of our rules. Something that I can give to any new programmer at my company and he can go on. This is not totally a mess, but it could be better seeing the new practices. What could I do to separate this as MVC, to have multiple views. Could you give me some tips considering my goals? Keep im mind the different products/custom things for specific costumers without breaking the main application. URL for tutorials, books, etc, would be nice.

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• Investigating Strategies For Functional Decomposition

  - by Liam McLennan

  Introducing Functional Decomposition Before I begin I must apologise. I think I am using the term ‘functional decomposition’ loosely, and probably incorrectly. For the purpose of this article I use functional decomposition to mean the recursive splitting of a large problem into increasingly smaller ones, so that the one large problem may be solved by solving a set of smaller problems. The justification for functional decomposition is that the decomposed problem is more easily solved. As software developers we recognise that the smaller pieces are more easily tested, since they do less and are more cohesive. Functional decomposition is important to all scientific pursuits. Once we understand natural selection we can start to look for humanities ancestral species, once we understand the big bang we can trace our expanding universe back to its origin. Isaac Newton acknowledged the compositional nature of his scientific achievements: If I have seen further than others, it is by standing upon the shoulders of giants   The Two Strategies For Functional Decomposition of Computer Programs Private Methods When I was working on my undergraduate degree I was taught to functionally decompose problems by using private methods. Consider the problem of painting a house. The obvious solution is to solve the problem as a single unit: public void PaintAHouse() { // all the things required to paint a house ... } We decompose the problem by breaking it into parts: public void PaintAHouse() { PaintUndercoat(); PaintTopcoat(); } private void PaintUndercoat() { // everything required to paint the undercoat } private void PaintTopcoat() { // everything required to paint the topcoat } The problem can be recursively decomposed until a sufficiently granular level of detail is reached: public void PaintAHouse() { PaintUndercoat(); PaintTopcoat(); } private void PaintUndercoat() { prepareSurface(); fetchUndercoat(); paintUndercoat(); } private void PaintTopcoat() { fetchPaint(); paintTopcoat(); } According to Wikipedia, at least one computer programmer has referred to this process as “the art of subroutining”. The practical issues that I have encountered when using private methods for decomposition are: To preserve the top level API all of the steps must be private. This means that they can’t easily be tested. The private methods often have little cohesion except that they form part of the same solution. Decomposing to Classes The alternative is to decompose large problems into multiple classes, effectively using a class instead of each private method. The API delegates to related classes, so the API is not polluted by the sub-steps of the problem, and the steps can be easily tested because they are each in their own highly cohesive class. Additionally, I think that this technique facilitates better adherence to the Single Responsibility Principle, since each class can be decomposed until it has precisely one responsibility. Revisiting my previous example using class composition: public class HousePainter { private undercoatPainter = new UndercoatPainter(); private topcoatPainter = new TopcoatPainter(); public void PaintAHouse() { undercoatPainter.Paint(); topcoatPainter.Paint(); } } Summary When decomposing a problem there is more than one way to represent the sub-problems. Using private methods keeps the logic in one place and prevents a proliferation of classes (thereby following the four rules of simple design) but the class decomposition is more easily testable and more compatible with the Single Responsibility Principle.

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• Move over DFS and Robocopy, here is SyncToy!

  - by andywe

  Ever since Windows 2000, I have always had the need to replicate data to multiple endpoints with the same content. Until DFS was introduced, the method of thinking was to either manually copy the data location by location, or to batch script it with xcopy and schedule a task. Even though this worked (and still does today), it was cumbersome, and intensive on the network, especially when dealing with larger amounts of data. Then along came robocopy, as an internal tool written by an enterprising programmer at Microsoft. We used it quite a bit, especially when we could not use DFS in the early days. It was received so well, it made it into the public realm. At least now we could have the ability to determine what files had changed and only replicate those. Well, over time there has been evolution of this ideal. DFS is obviously the Windows enterprise class service to do this, along with BrancheCache..however you don’t always need or want the power of DFS, especially when it comes to small datacenter installations, or remote offices. I have specific data sets that are on closed or restricted networks, that either have a security need for this, or are in remote countries where bandwidth is a premium. FOr this, I use the latest evolution for one off replication names Synctoy. Synctoy is from Microsoft, seemingly released in 2009, that wraps a nice GUI around setting up a paired set of folders (remember the mobile briefcase from Windows 98?), and allowing you the choice of synchronization methods. 1 way, or 2 way. Simply create a paired set of folders on the source and destination, choose your options for content, exclude any file types you don’t want to replicate, and click run. Scheduling is even easier. MS has included a wrapper for doing just this so all you enter in your task schedule in the SynToyCMD.exe, a –R as an argument, and the time schedule. No more complicated command lines or scripts.   I find this especially useful when I use MS backup to back up a system volume, but only want subsets of backup information of a data share and ONLY when that dataset has changed. Not relying on full backups and incremental. An example of this is my application installation master share. I back this up with SyncToy because I do not need multiple backup copies..one copy elsewhere suffices to back it up. At home, very useful for your pictures, videos, music, ect..the backup is online and ready to access, not waiting for you to restore a backup file, and no need to institute a domain simply to have DFS.'   Do note there is a risk..if you accidently delete a file and do not catch this before the next sync, then depending on your SyncToy settings, you can indeed lose that file as the destination updates..so due diligence applies. I make it a rule to sync manly one way…I use my master share for making changes, and allow the schedule to follow suit. Any real important file I lock down as read only through file permissions so it cannot be deleted unless I intervene.   Check out the tool and have some fun! http://www.microsoft.com/en-us/download/details.aspx?DisplayLang=en&id=15155

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• Questions to ask to ensure someone understands programming? (and iOS)

  - by Stephen J

  So, I've been tutoring my friend for 2 years. Most people learn programming on their own in 3-6 months, (sans algorithms). It's confusing 'cause he'll run anywhere I tell him to, understands how to read C and C++ honestly better than the average college student, and he'll modify and repeat anything I do... but for the love of god he doesn't move on to new things and he still has test anxiety. I've recently realized he's copied and toyed with existing, but not once gained an understanding of why. I was under the impression he was learning fast because he could write it, but when you say "Make a function that takes an NSString" and he says "How?" and I say "The same way you make ANY function that takes any parameter, NSString is just a type like int" and all I hear is "No, it's an NSString, it's a special thing." and we get into an arguing match 'cause I'm like "It's just a class like any other class, you've used them for months now" and blah... I've subconsciously avoided comprehension questions because of this. Anyway, if you have him copy a program and say "Just initialize it" "Where?" "I don't care, didLoad or initWithCoder or Awake from nib, anywhere it gets initialized" and "No, it has to be exactly where you had it!" "No it doesn't!" I'm sick of this, but he won't give up. So I'm done avoiding these yelling matches and becoming a sadist from now on. I would like some help in finding questions to ask him that force him to understand what he's doing. I'd like some help and any resources I can find. CQuestions looked like a good site, but now I need some iPhone stuff. For example: *What do properties do? How are they changed? How do you change the name of the getter? *Why are Booleans inefficent? What advantage does int have over a boolean and how does the bit-shift operator help? *What does Copy do to a string? *What's the difference between a view controller and a uiview? *Write a program from memory that displays blah on screen, and flashes each view one by one. From beginner up to intermediate, hobbyist with some algebra at most. I'm just looking for resources to work with. I left in backstory so you know to "twist" the questions so he doesn't know he's supposed to init a variable here or there, but has to figure it out, and learn why it goes "here" or that "anywhere is fine as long as it's". Sample programs, anything. I'm relatively open about this because, being a programmer, I seriously doubt he's the only one who has this issue. I'd like to know how others have overcome similar. What made things "click"? for you? Did you have a hard time finding answers on Google, and how did you learn a better way to find what you were looking for? (He's so exact, he'll search for how to write a checkers program with color X and Y inside a uiview, as his search string, instead of breaking it up into components, I need help with that too, and believe it is related). This type of problem has to remind one of us of someone they know. So, Exercises to force them to think? Ways we overcame this thing in the past? I greatly appreciate any help.

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• Cream of the Crop

  - by KemButller

  JD Edwards has been working hard to ensure that you shouldn't have to work so hard! Yet there are still JD Edwards customers that may not be up to speed on all the new and or improved tools and utilities we have delivered, all designed to make your life easier. So today, I want to share what I consider to be the cream of the crop….those items that every customer should know about and leverage to make ERP life just a little bit (or A LOT) easier! These are my top picks, the cream of a very good crop! Explore and enjoy, and gain some of your time back to do with as you please. · www.runjde.com It’s where to go when you need to know! The Resource Kits available on www.runjde.com provide comprehensive Resource Kits (guides) by user type. The guides provide brief descriptions of the wide array of resources that are available to JD Edwards’s eco system and links to each of those resources. · My Oracle Support (MOS) Information Centers This link will take you to an index that is designed to provide you with simple and quick navigation to the available EnterpriseOne Information Centers. This index provides links to: · EnterpriseOne Application specific Information Centers · EnterpriseOne Tools and Technology Information Centers · EnterpriseOne Performance Information Center · EnterpriseOne 9.1 and 9.0 Information Centers Information Centers give Oracle the ability to aggregate content for a given focus area and present this content in categories for easy browsing by our customers. Information Centers offer a variety of focused dynamic content organized around one or more of the following tasks. · Overview · Use · Troubleshooting · Patching and Maintenance · Install and Configure · Upgrade · Optimize Performance · Security · Certify JD Edwards Newsletters Be in the know by reading the Global Customer Support Product Newsletters. They are PACKED with news and information covering a wide range of topics and news. It is a must read if you want to know what’s happening in the JD Edwards universe! Read the latest EntepriseOne newsletter Read the latest World newsletter Learn How to receive notification when a new newsletter edition is published Oracle Learning Library – (OLL) Oracle Learn Library is the place to go for easy access to JD Edwards Application and Tools training. For a comprehensive view of the training available for a specific product/functional area, explore the Knowledge Paths For Net Change (new feature) training, explore the TOI sessions (TOI stands for Transfer Of Information). Tip: Be sure to experiment with the search filters! · www.upgradejde.com The site designed to help customers and partners with the process of upgrading JD Edwards. The site is a wealth of information, tools and resources designed to assist in the evaluation, planning and execution steps required when upgrading. Of note is the wildly successful upgrade strategy known as “The Art of the Possible” wherein JD Edwards and many of our partners hold free workshops to teach customers how to conduct upgrades in 100 days or less. Equally important is the fact that on www.upgradejde.com, customers can gain visibility into planned enhancements using the Product and Technology Feature Catalogs. The catalogs are great for creating customer specific reports about the net change between older releases and current or planned releases. Examples of other key resources on www.upgradejde.com are the product data base changes between releases, extensibility guides, (formerly known as programmer’s guides), whitepapers, ROI calculators and much more!

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• The long road to bug-free software

  - by Tony Davis

  The past decade has seen a burgeoning interest in functional programming languages such as Haskell or, in the Microsoft world, F#. Though still on the periphery of mainstream programming, functional programming concepts are gradually seeping into the imperative C# language (for example, Lambda expressions have their root in functional programming). One of the more interesting concepts from functional programming languages is the use of formal methods, the lofty ideal behind which is bug-free software. The idea is that we write a specification that describes exactly how our function (say) should behave. We then prove that our function conforms to it, and in doing so have proved beyond any doubt that it is free from bugs. All programmers already use one form of specification, specifically their programming language's type system. If a value has a specific type then, in a type-safe language, the compiler guarantees that value cannot be an instance of a different type. Many extensions to existing type systems, such as generics in Java and .NET, extend the range of programs that can be type-checked. Unfortunately, type systems can only prevent some bugs. To take a classic problem of retrieving an index value from an array, since the type system doesn't specify the length of the array, the compiler has no way of knowing that a request for the "value of index 4" from an array of only two elements is "unsafe". We restore safety via exception handling, but the ideal type system will prevent us from doing anything that is unsafe in the first place and this is where we start to borrow ideas from a language such as Haskell, with its concept of "dependent types". If the type of an array includes its length, we can ensure that any index accesses into the array are valid. The problem is that we now need to carry around the length of arrays and the values of indices throughout our code so that it can be type-checked. In general, writing the specification to prove a positive property, even for a problem very amenable to specification, such as a simple sorting algorithm, turns out to be very hard and the specification will be different for every program. Extend this to writing a specification for, say, Microsoft Word and we can see that the specification would end up being no simpler, and therefore no less buggy, than the implementation. Fortunately, it is easier to write a specification that proves that a program doesn't have certain, specific and undesirable properties, such as infinite loops or accesses to the wrong bit of memory. If we can write the specifications to prove that a program is immune to such problems, we could reuse them in many places. The problem is the lack of specification "provers" that can do this without a lot of manual intervention (i.e. hints from the programmer). All this might feel a very long way off, but computing power and our understanding of the theory of "provers" advances quickly, and Microsoft is doing some of it already. Via their Terminator research project they have started to prove that their device drivers will always terminate, and in so doing have suddenly eliminated a vast range of possible bugs. This is a huge step forward from saying, "we've tested it lots and it seems fine". What do you think? What might be good targets for specification and verification? SQL could be one: the cost of a bug in SQL Server is quite high given how many important systems rely on it, so there's a good incentive to eliminate bugs, even at high initial cost. [Many thanks to Mike Williamson for guidance and useful conversations during the writing of this piece] Cheers, Tony.

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• Representing Mauritius in the 2013 Bench Games

  Only by chance I came across an interesting option for professionals and enthusiasts in IT, and quite honestly I can't even remember where I caught attention of Brainbench and their 2013 Bench Games event. But having access to 600+ free exams in a friendly international intellectual competition doesn't happen to be available every day. So, it was actually a no-brainer to sign up and browse through the various categories. Most interestingly, Brainbench is not only IT-related. They offer a vast variety of fields in their Test Center, like Languages and Communication, Office Skills, Management, Aptitude, etc., and it can be a little bit messy about how things are organised. Anyway, while browsing through their test offers I added a couple of exams to 'My Plan' which I would give a shot afterwards. Self-assessments Actually, I took the tests based on two major aspects: 'Fun Factor' and 'How good would I be in general'... Usually, you have to pay for any kind of exams and given this unique chance by Brainbench to simply train this kind of tests was already worth the time. Frankly speaking, the tests are very close to the ones you would be asked to do at Prometric or Pearson Vue, ie. Microsoft exams, etc. Go through a set of multiple choice questions in a given time frame. Most of the tests I did during the Bench Games were based on 40 questions, each with a maximum of 3 minutes to answer. Ergo, one test in maximum 2 hours - that sounds feasible, doesn't it? The Measure of Achievement While the 2013 Bench Games are considered a worldwide friendly competition of knowledge I was really eager to get other Mauritians attracted. Using various social media networks and community activities it all looked quite well at the beginning. Mauritius was listed on rank #19 of Most Certified Citizens and rank #10 of Most Master Level Certified Nation - not bad, not bad... Until... the next update of the Bench Games Leaderboard. The downwards trend seemed to be unstoppable and I couldn't understand why my results didn't show up on the Individual Leader Board. First of all, I passed exams that were not even listed and second, I had better results on some exams listed. After some further information from the organiser it turned out that my test transcript wasn't available to the public. Only then results are considered and counted in the competition. During that time, I actually managed to hold 3 test results on the Individuals... Other participants were merciless, eh, more successful than me, produced better test results than I did. But still I managed to stay on the final score board: An 'exotic' combination of exam, test result, country and person itself Representing Mauritius and the Visual FoxPro community in that fun event. And although I mainly develop in Visual FoxPro 9.0 SP2 and C# using .NET Framework from 2.0 to 4.5 since a couple of years I still managed to pass on Master Level. Hm, actually my Microsoft Certified Programmer (MCP) exams are dated back in June 2004 - more than 9 years ago... Look who got lucky... As described above I did a couple of exams as time allowed and without any preparations, but still I received the following mail notification: "Thank you for recently participating in our Bench Games event.  We wanted to inform you that you obtained a top score on our test(s) during this event, and as a result, will receive a free annual Brainbench subscription.  Your annual subscription will give you access to all our tests just like Bench Games, but for an entire year plus additional benefits!" -- Leader Board Notification from Brainbench Even fun activities get rewarded sometimes. Thanks to @Brainbench_com for the free annual subscription based on my passed 2013 Bench Games Master Level exam. It would be interesting to know about the total figures, especially to see how many citizens of Mauritius took part in this year's Bench Games. Anyway, I'm looking forward to be able to participate in other challenges like this in the future.

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• What Counts For a DBA – Depth

  - by Louis Davidson

  SQL Server offers very simple interfaces to many of its features. Most people could open up SSMS, connect to a server, write a simple query and see the results. Even several of the core DBA tasks are deceptively straightforward. It doesn’t take a rocket scientist to perform a basic database backup or run a trace (even using the newfangled Extended Events!). However, appearances can be deceptive, and often times it is really important that a DBA understands not just the basics of how to perform a task, but why we do a task, and how that task works. As an analogy, consider a child walking into a darkened room. Most would know that they need to turn on the light, and how to do it, so they flick the switch. But what happens if light fails to shine forth. Most would immediately tell you that you need to consider changing the light bulb. So you hop in the car and take them to the local home store and instruct them to buy a replacement. Confronted with a 40 foot display of light bulbs, how will they decide which of the hundreds of types of bulbs, of different types, fittings, shapes, colors, power and efficiency ratings, is the right choice? Obviously the main lesson the child is going to learn this day is how to use their cell phone as a flashlight so they don’t have to ask for help the next time. Likewise, when the metaphorical toddlers who use your database server have issues, they will instinctively know something is wrong, and may even have some idea what caused it, but will have no depth of knowledge to figure out the right solution. That is where the DBA comes in and attempts to save the day. However, when one looks beneath the shiny UI, SQL Server has its own “40 foot display of light bulbs”, in the form of the tremendous number of tools and the often-bewildering amount of information they can present to the DBA, to help us find issues. Unfortunately, resorting to guesswork, to trying different “bulbs” over and over, hoping to stumble on the answer. This is where the right depth of knowledge goes a long way. If we need to write a SELECT statement, then knowing the syntax and where to find the data is not enough. Knowledge of indexes and query plans is essential. Without it, we might hit on a query that “works”, but we are basically still a user, not a programmer, because we have no real control over our platform. Is that level of knowledge deep enough? Probably not, since knowledge of the underlying metadata and structures would be very useful in helping us make sense of any query plan. Understanding the structure of an index makes the “key lookup” operator not sound like what you do when someone tapes your car key to the ceiling. So is even this level of understanding deep enough? Do we need to understand the memory architecture used to process the query? It might be a comforting level of knowledge, and will doubtless come in handy at some point, but is not strictly necessary in most cases. Beyond that lies (more or less) full knowledge of SQL language and the intricacies of every step the SQL Server engine takes to process our query. My personal theory is that, as a professional, our knowledge of a given task should extend, at a minimum, one level deeper than is strictly necessary to perform the task. Anything deeper can be left to the ridiculously smart, or obsessive, or both. As an example. tasked with storing an integer value between 0 and 99999999, it’s essential that I know that choosing an Integer over Decimal(8,0) will likely offer performance benefits. It is then useful that I also understand the value of adding a CHECK constraint, to make sure the values are valid to the desired range; and comforting that I know a little about the underlying processors, registers and computer math. Anything further, I leave to the likes of Joe Chang, whose recent blog post on the topic offers depth by the bucketful!  

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• Modernizr Rocks HTML5

  - by Laila

  HTML5 is a moving target.  At the moment, we don't know what will be in future versions.  In most circumstances, this really matters to the developer. When you're using Adobe Air, you can be reasonably sure what works, what is there, and what isn't, since you have a version of the browser built-in. With Metro, you can assume that you're going to be using at least IE 10.   If, however,  you are using HTML5 in a web application, then you are going to rely heavily on Feature Detection.  Feature-Detection is a collection of techniques that tell you, via JavaScript, whether the current browser has this feature natively implemented or not Feature Detection isn't just there for the esoteric stuff such as  Geo-location,  progress bars,  <canvas> support,  the new <input> types, Audio, Video, web workers or storage, but is required even for semantic markup, since old browsers make a pigs ear out of rendering this.  Feature detection can't rely just on reading the browser version and inferring from that what works. Instead, you must use JavaScript to check that an HTML5 feature is there before using it.  The problem with relying on the user-agent is that it takes a lot of historical data  to work out what version does what, and, anyway, the user-agent can be, and sometimes is, spoofed. The open-source library Modernizr  is just about the most essential  JavaScript library for anyone using HTML5, because it provides APIs to test for most of the CSS3 and HTML5 features before you use them, and is intelligent enough to alter semantic markup into 'legacy' 'markup  using shims  on page-load  for old browsers. It also allows you to check what video Codecs are installed for playing video. It also provides media queries  and conditional resource-loading (formerly YepNope.js.).  Generally, Modernizr gives you the choice of what you do about browsers that don't support the feature that you want. Often, the best choice is graceful degradation, but the resource-loading feature allows you to dynamically load JavaScript Shims to replace the standard API for missing or defective HTML5 functionality, called 'PolyFills'.  As the Modernizr site says 'Yes, not only can you use HTML5 today, but you can use it in the past, too!' The evolutionary progress of HTML5  requires a more defensive style of JavaScript programming where the programmer adopts a mindset of fearing the worst ( IE 6)  rather than assuming the best, whilst exploiting as many of the new HTML features as possible for the requirements of the site or HTML application.  Why would anyone want the distraction of developing their own techniques to do this when  Modernizr exists to do this for you? Laila

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• The long road to bug-free software

  - by Tony Davis

  The past decade has seen a burgeoning interest in functional programming languages such as Haskell or, in the Microsoft world, F#. Though still on the periphery of mainstream programming, functional programming concepts are gradually seeping into the imperative C# language (for example, Lambda expressions have their root in functional programming). One of the more interesting concepts from functional programming languages is the use of formal methods, the lofty ideal behind which is bug-free software. The idea is that we write a specification that describes exactly how our function (say) should behave. We then prove that our function conforms to it, and in doing so have proved beyond any doubt that it is free from bugs. All programmers already use one form of specification, specifically their programming language's type system. If a value has a specific type then, in a type-safe language, the compiler guarantees that value cannot be an instance of a different type. Many extensions to existing type systems, such as generics in Java and .NET, extend the range of programs that can be type-checked. Unfortunately, type systems can only prevent some bugs. To take a classic problem of retrieving an index value from an array, since the type system doesn't specify the length of the array, the compiler has no way of knowing that a request for the "value of index 4" from an array of only two elements is "unsafe". We restore safety via exception handling, but the ideal type system will prevent us from doing anything that is unsafe in the first place and this is where we start to borrow ideas from a language such as Haskell, with its concept of "dependent types". If the type of an array includes its length, we can ensure that any index accesses into the array are valid. The problem is that we now need to carry around the length of arrays and the values of indices throughout our code so that it can be type-checked. In general, writing the specification to prove a positive property, even for a problem very amenable to specification, such as a simple sorting algorithm, turns out to be very hard and the specification will be different for every program. Extend this to writing a specification for, say, Microsoft Word and we can see that the specification would end up being no simpler, and therefore no less buggy, than the implementation. Fortunately, it is easier to write a specification that proves that a program doesn't have certain, specific and undesirable properties, such as infinite loops or accesses to the wrong bit of memory. If we can write the specifications to prove that a program is immune to such problems, we could reuse them in many places. The problem is the lack of specification "provers" that can do this without a lot of manual intervention (i.e. hints from the programmer). All this might feel a very long way off, but computing power and our understanding of the theory of "provers" advances quickly, and Microsoft is doing some of it already. Via their Terminator research project they have started to prove that their device drivers will always terminate, and in so doing have suddenly eliminated a vast range of possible bugs. This is a huge step forward from saying, "we've tested it lots and it seems fine". What do you think? What might be good targets for specification and verification? SQL could be one: the cost of a bug in SQL Server is quite high given how many important systems rely on it, so there's a good incentive to eliminate bugs, even at high initial cost. [Many thanks to Mike Williamson for guidance and useful conversations during the writing of this piece] Cheers, Tony.

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• Why do I get "Invalid Column Name" errors in EF4?

  - by camainc

  I am trying to learn Entity Framework 4.0. Disclaimer 1: I am brand new to Entity Framework. I have successfully used LinqToSQL. Disclaimer 2: I am really a VB.Net programmer, so the problem could be in the C# code. Given this code snippet: public int Login(string UserName, string Password) { return _dbContext.Memberships .Where(membership => membership.UserName.ToLower() == UserName.ToLower() && membership.Password == Password) .SingleOrDefault().PrimaryKey; } Why do you suppose I get "Invalid column name" errors? {"Invalid column name 'UserName'.\r\nInvalid column name 'Password'.\r\nInvalid column name 'UserName'.\r\nInvalid column name 'Password'."} Those column names are spelled and cased correctly. I also checked the generated code for the entity in question, and those columns are properties in the entity. The intellisense and code completion also puts the column names into the expression just as they are here. I am stumped by this. Any help would be much appreciated. https://docs.google.com/leaf?id=0B-xLbzoqGvXvNjBmZmNjNDAtY2RhNC00NDA2LWIxNzMtYjhjNTYxMDIyZmZl&hl=en

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• faster implementation of sum ( for Codility test )

  - by Oscar Reyes

  How can the following simple implementation of sum be faster? private long sum( int [] a, int begin, int end ) { if( a == null ) { return 0; } long r = 0; for( int i = begin ; i < end ; i++ ) { r+= a[i]; } return r; } EDIT Background is in order. Reading latest entry on coding horror, I came to this site: http://codility.com which has this interesting programming test. Anyway, I got 60 out of 100 in my submission, and basically ( I think ) is because this implementation of sum, because those parts where I failed are the performance parts. I'm getting TIME_OUT_ERROR's So, I was wondering if an optimization in the algorithm is possible. So, no built in functions or assembly would be allowed. This my be done in C, C++, C#, Java or pretty much in any other. EDIT As usual, mmyers was right. I did profile the code and I saw most of the time was spent on that function, but I didn't understand why. So what I did was to throw away my implementation and start with a new one. This time I've got an optimal solution [ according to San Jacinto O(n) -see comments to MSN below - ] This time I've got 81% on Codility which I think is good enough. The problem is that I didn't take the 30 mins. but around 2 hrs. but I guess that leaves me still as a good programmer, for I could work on the problem until I found an optimal solution: Here's my result. I never understood what is those "combinations of..." nor how to test "extreme_first"

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• python unhashable type - posting xml data

  - by eterry28

  First, I'm not a python programmer. I'm an old C dog that's learned new Java and PHP tricks, but python looks like a pretty cool language. I'm getting an error that I can't quite follow. The error follows the code below. import httplib, urllib url = "pdb-services-beta.nipr.com" xml = '<?xml version="1.0"?><!DOCTYPE SCB_Request SYSTEM "http://www.nipr.com/html/SCB_XML_Request.dtd"><SCB_Request Request_Type="Create_Report"><SCB_Login_Data CustomerID="someuser" Passwd="somepass" /><SCB_Create_Report_Request Title=""><Producer_List><NIPR_Num_List_XML><NIPR_Num NIPR_Num="8980608" /><NIPR_Num NIPR_Num="7597855" /><NIPR_Num NIPR_Num="10166016" /></NIPR_Num_List_XML></Producer_List></SCB_Create_Report_Request></SCB_Request>' params = {} params['xmldata'] = xml headers = {} headers['Content-type'] = 'text/xml' headers['Accept'] = '*/*' headers['Content-Length'] = "%d" % len(xml) connection = httplib.HTTPSConnection(url) connection.set_debuglevel(1) connection.request("POST", "/pdb-xml-reports/scb_xmlclient.cgi", params, headers) response = connection.getresponse() print response.status, response.reason data = response.read() print data connection.close Here's the error: Traceback (most recent call last): File "C:\Python27\tutorial.py", line 14, in connection.request("POST", "/pdb-xml-reports/scb_xmlclient.cgi", params, headers) File "C:\Python27\lib\httplib.py", line 958, in request self._send_request(method, url, body, headers) File "C:\Python27\lib\httplib.py", line 992, in _send_request self.endheaders(body) File "C:\Python27\lib\httplib.py", line 954, in endheaders self._send_output(message_body) File "C:\Python27\lib\httplib.py", line 818, in _send_output self.send(message_body) File "C:\Python27\lib\httplib.py", line 790, in send self.sock.sendall(data) File "C:\Python27\lib\ssl.py", line 229, in sendall v = self.send(data[count:]) TypeError: unhashable type My log file says that the xmldata parameter is empty. Any ideas?

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• Negative ItemCount in SharePoint Document Library

  - by ccomet

  What can be done about negative numbers in library item counts? ItemCount is a read-only property, what are you supposed to do when it is drastically incorrect? Earlier last week, I was doing some testing involving the copying and moving of files and folders from one document library to another. I was transfering the items from our actual document library to a sandbox "Test" library that I used to run all sorts of object model and workflow testing in before migrating to the public lists and libraries. I noticed that with files, things worked correctly, but when I copied a folder that had a file inside it (using SPFolder.CopyTo()), the item count for the test library did not actually update. Since this testing was mostly playing around, I paid it little heed. Today I was back in the test library to test a different workflow (regarding PDF conversion). While I was there, I decided to delete the folder I left last week since I didn't need it anymore. And that's when I saw the item count for the list drop to -1 in the All Site Content View. When I deleted the new PDF I had just uploaded, it then dropped to -2! I even checked with the object model... getting an instance of the library I checked the ItemCount property... lo and behold it was also -2. Is there any process which runs in the background, kinda like the one that cleans up workflow history, which will correct this kind of issue? Or is a programmer expected to keep watch for this kind of situation and come up with calculations to compensate the "count penalty", as it were?

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• Why were namespaces removed from ECMAScript consideration?

  - by Bob

  Namespaces were once a consideration for ECMAScript (the old ECMAScript 4) but were taken out. As Brendan Eich says in this message: One of the use-cases for namespaces in ES4 was early binding (use namespace intrinsic), both for performance and for programmer comprehension -- no chance of runtime name binding disagreeing with any earlier binding. But early binding in any dynamic code loading scenario like the web requires a prioritization or reservation mechanism to avoid early versus late binding conflicts. Plus, as some JS implementors have noted with concern, multiple open namespaces impose runtime cost unless an implementation works significantly harder. For these reasons, namespaces and early binding (like packages before them, this past April) must go. But I'm not sure I understand all of that. What exactly is a prioritization or reservation mechanism and why would either of those be needed? Also, must early binding and namespaces go hand-in-hand? For some reason I can't wrap my head around the issues involved. Can anyone attempt a more fleshed out explanation? Also, why would namespaces impose runtime costs? In my mind I can't help but see little difference in concept between a namespace and a function using closures. For instance, Yahoo and Google both have YAHOO and google objects that "act like" namespaces in that they contain all of their public and private variables, functions, and objects within a single access point. So why, then, would a namespace be so significantly different in implementation? Maybe I just have a misconception as to what a namespace is exactly.

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• Algorithm design, "randomising" timetable schedule in Python although open to other languages.

  - by S1syphus

  Before I start I should add I am a musician and not a native programmer, this was undertook to make my life easier. Here is the situation, at work I'm given a new csv file each which contains a list of sound files, their length, and the minimum total amount of time they must be played. I create a playlist of exactly 60 minutes, from this excel file. Each sample played the by the minimum number of instances, but spread out from each other; so there will never be a period where for where one sound is played twice in a row or in close proximity to itself. Secondly, if the minimum instances of each song has been used, and there is still time with in the 60 min, it needs to fill the remaining time using sounds till 60 minutes is reached, while adhering to above. The smallest duration possible is 15 seconds, and then multiples of 15 seconds. Here is what I came up with in python and the problems I'm having with it, and as one user said its buggy due to the random library used in it. So I'm guessing a total rethink is on the table, here is where I need your help. Whats is the best way to solve the issue, I have had a brief look at things like knapsack and bin packing algorithms, while both are relevant neither are appropriate and maybe a bit beyond me.

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