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• Installing SharePoint 2010 and PowerPivot for SharePoint on Windows 7

  - by smisner

  Many people like me want (or need) to do their business intelligence development work on a laptop. As someone who frequently speaks at various events or teaches classes on all subjects related to the Microsoft business intelligence stack, I need a way to run multiple server products on my laptop with reasonable performance. Once upon a time, that requirement meant only that I had to load the current version of SQL Server and the client tools of choice. In today's post, I'll review my latest experience with trying to make the newly released Microsoft BI products work with a Windows 7 operating system. The entrance of Microsoft Office SharePoint Server 2007 into the BI stack complicated matters and I started using Virtual Server to establish a "suitable" environment. As part of the team that delivered a lot of education as part of the Yukon pre-launch activities (that would be SQL Server 2005 for the uninitiated), I was working with four - yes, four - virtual servers. That was a pretty brutal workload for a 2GB laptop, which worked if I was very, very careful. It could also be a finicky and unreliable configuration as I learned to my dismay at one TechEd session several years ago when I had to reboot a very carefully cached set of servers just minutes before my session started. Although it worked, it came back to life very, very slowly much to the displeasure of the audience. They couldn't possibly have been less pleased than me. At that moment, I resolved to get the beefiest environment I could afford and consolidate to a single virtual server. Enter the 4GB 64-bit laptop to preserve my sanity and my livelihood. Likewise, for SQL Server 2008, I managed to keep everything within a single virtual server and I could function reasonably well with this approach. Now we have SQL Server 2008 R2 plus Office SharePoint Server 2010. That means a 64-bit operating system. Period. That means no more Virtual Server. That means I must use Hyper-V or another alternative. I've heard alternatives exist, but my few dabbles in this area did not yield positive results. It might have been just me having issues rather than any failure of those technologies to adequately support the requirements. My first run at working with the new BI stack configuration was to set up a 64-bit 4GB laptop with a dual-boot to run Windows Server 2008 R2 with Hyper-V. However, I was generally not happy with running Windows Server 2008 R2 on my laptop. For one, I couldn't put it into sleep mode, which is helpful if I want to prepare for a presentation beforehand and then walk to the podium without the need to hold my laptop in its open state along the way (my strategy at the TechEd session long, long ago). Secondly, it was finicky with projectors. I had issues from time to time and while I always eventually got it to work, I didn't appreciate those nerve-wracking moments wondering whether this would be the time that it wouldn't work. Somewhere along the way, I learned that it was possible to load SharePoint 2010 in a Windows 7 which piqued my interest. I had just acquired a new laptop running Windows 7 64-bit, and thought surely running the BI stack natively on my laptop must be better than running Hyper-V. (I have not tried booting to Hyper-V VHD yet, but that's on my list of things to try so the jury of one is still out on this approach.) Recently, I had to build up a server with the RTM versions of SQL Server 2008 R2 and Sharepoint Server 2010 and decided to follow suit on my Windows 7 Ultimate 64-bit laptop. The process is slightly different, but I'm happy to report that it IS possible, although I had some fits and starts along the way. DISCLAIMER: These products are NOT intended to be run in production mode on the Windows 7 operating system. The configuration described in this post is strictly for development or learning purposes and not supported by Microsoft. If you have trouble, you will NOT get help from them. I might be able to help, but I provide no guarantees of my ability or availablity to help. I won't provide the step-by-step instructions in this post as there are other resources that provide these details, but I will provide an overview of my approach, point you to the relevant resources, describe some of the problems I encountered, and explain how I addressed those problems to achieve my desired goal. Because my goal was not simply to set up SharePoint Server 2010 on my laptop, but specifically PowerPivot for SharePoint, I started out by referring to the installation instructions at the PowerPiovt-Info site, but mainly to confirm that I was performing steps in the proper sequence. I didn't perform the steps in Part 1 because those steps are applicable only to a server operating system which I am not running on my laptop. Then, the instructions in Part 2, won't work exactly as written for the same reason. Instead, I followed the instructions on MSDN, Setting Up the Development Environment for SharePoint 2010 on Windows Vista, Windows 7, and Windows Server 2008. In general, I found the following differences in installation steps from the steps at PowerPivot-Info: You must copy the SharePoint installation media to the local drive so that you can edit the config.xml to allow installation on a Windows client. You also have to manually install the prerequisites. The instructions provides links to each item that you must manually install and provides a command-line instruction to execute which enables required Windows features. I will digress for a moment to save you some grief in the sequence of steps to perform. I discovered later that a missing step in the MSDN instructions is to install the November CTP Reporting Services add-in for SharePoint. When I went to test my SharePoint site (I believe I tested after I had a successful PowerPivot installation), I ran into the following error: Could not load file or assembly 'RSSharePointSoapProxy, Version=10.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91' or one of its dependencies. The system cannot find the file specified. I was rather surprised that Reporting Services was required. Then I found an article by Alan le Marquand, Working Together: SQL Server 2008 R2 Reporting Services Integration in SharePoint 2010,that instructed readers to install the November add-in. My first reaction was, "Really?!?" But I confirmed it in another TechNet article on hardware and software requirements for SharePoint Server 2010. It doesn't refer explicitly to the November CTP but following the link took me there. (Interestingly, I retested today and there's no longer any reference to the November CTP. Here's the link to download the latest and greatest Reporting Services Add-in for SharePoint Technologies 2010.) You don't need to download the add-in anymore if you're doing a regular server-based installation of SharePoint because it installs as part of the prerequisites automatically. When it was time to start the installation of SharePoint, I deviated from the MSDN instructions and from the PowerPivot-Info instructions: On the Choose the installation you want page of the installation wizard, I chose Server Farm. On the Server Type page, I chose Complete. At the end of the installation, I did not run the configuration wizard. Returning to the PowerPivot-Info instructions, I tried to follow the instructions in Part 3 which describe installing SQL Server 2008 R2 with the PowerPivot option. These instructions tell you to choose the New Server option on the Setup Role page where you add PowerPivot for SharePoint. However, I ran into problems with this approach and got installation errors at the end. It wasn't until much later as I was investigating an error that I encountered Dave Wickert's post that installing PowerPivot for SharePoint on Windows 7 is unsupported. Uh oh. But he did want to hear about it if anyone succeeded, so I decided to take the plunge. Perseverance paid off, and I can happily inform Dave that it does work so far. I haven't tested absolutely everything with PowerPivot for SharePoint but have successfully deployed a workbook and viewed the PowerPivot Management Dashboard. I have not yet tested the data refresh feature, but I have installed. Continue reading to see how I accomplished my objective. I unintalled SQL Server 2008 R2 and started again. I had different problems which I don't recollect now. However, I uninstalled again and approached installation from a different angle and my next attempt succeeded. The downside of this approach is that you must do all of the things yourself that are done automatically when you install PowerPivot as a new server. Here are the steps that I followed: Install SQL Server 2008 R2 to get a database engine instance installed. Run the SharePoint configuration wizard to set up the SharePoint databases. In Central Administration, create a Web application using classic mode authentication as per a TechNet article on PowerPivot Authentication and Authorization. Then I followed the steps I found at How to: Install PowerPivot for SharePoint on an Existing SharePoint Server. Especially important to note - you must launch setup by using Run as administrator. I did not have to manually deploy the PowerPivot solution as the instructions specify, but it's good to know about this step because it tells you where to look in Central Administration to confirm a successful deployment. I did spot some incorrect steps in the instructions (at the time of this writing) in How To: Configure Stored Credentials for PowerPivot Data Refresh. Specifically, in the section entitled Step 1: Create a target application and set the credentials, both steps 10 and 12 are incorrect. They tell you to provide an actual Windows user name and password on the page where you are simply defining the prompts for your application in the Secure Store Service. To add the Windows user name and password that you want to associate with the application - after you have successfully created the target application - you select the target application and then click Set credentials in the ribbon. Lastly, I followed the instructions at How to: Install Office Data Connectivity Components on a PowerPivot server. However, I have yet to test this in my current environment. I did have several stops and starts throughout this process and edited those out to spare you from reading non-essential information. I believe the explanation I have provided here accurately reflect the steps I followed to produce a working configuration. If you follow these steps and get a different result, please let me know so that together we can work through the issue and correct these instructions. I'm sure there are many other folks in the Microsoft BI community that will appreciate the ability to set up the BI stack in a Windows 7 environment for development or learning purposes. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• Tools of the Trade

  - by Ajarn Mark Caldwell

  I got pretty excited a couple of days ago when my new laptop arrived. “The new phone books are here!  The new phone books are here!  I’m a somebody!” - Steve Martin in The Jerk It is a Dell Precision M4500 with an Intel i7 Core 2.8 GHZ running 64-bit Windows 7 with a 15.6” widescreen, 8 GB RAM, 256 GB SSD.  For some of you high fliers, this may be nothing to write home about, but compared to the 32–bit Windows XP laptop with 2 GB of RAM and a regular hard disk that I’m coming from, it’s a really nice step forward.  I won’t even bore you with the details of the desktop PC I was first given when I started here 5 1/2 years ago.  Let’s just say that things have improved.  One really nice thing is that while we are definitely running a lean and mean department in terms of staffing, my boss believes in supporting that lean staff with good tools in order to stay lean instead of having to spend even more money on additional employees.  Of course, that only goes so far, and at some point you have to add more people in order to get more work done, which is why we are bringing on-board a new employee and a new contract developer next week.  But that’s a different story for a different time. But the main topic for this post is to highlight the variety of tools that I use in my job and that you might find useful, too.  This is easy to do right now because the process of building up my new laptop from scratch has forced me to assemble a list of software that had to be installed and configured.  Keep in mind as you look through this list that I play many roles in our company.  My official title is Software Engineering Manager, but in addition to managing the team, I am also an active ASP.NET and SQL developer, the Database Administrator, and 50% of the SAN Administrator team.  So, without further ado, here are the tools and some comments about why I use them: Tool Purpose Virtual Clone Drive Easily mount an ISO image as a DVD Drive.  This is particularly handy when you are downloading disk images from Microsoft for your tools. SQL Server 2008 R2 Developer Edition We are migrating all of our active systems to SQL 2008 R2.  Developer Edition has all the features of Enterprise Edition, but intended for development use. SQL Server 2005 Developer Edition (BIDS ONLY) The migration to SSRS 2008 R2 is just getting started, and in the meantime, maintenance work still has to be done on the reports on our SQL 2005 server.  For some reason, you can’t use BIDS from 2008 to write reports for a 2005 server.  There is some different format and when you open 2005 reports in 2008 BIDS, it forces you to upgrade, and they can no longer be uploaded to a 2005 server.  Hopefully Microsoft will fix this soon in some manner similar to Visual Studio now allows you to pick which version of the .NET Framework you are coding against. Visual Studio 2010 Premium All of our application development is in ASP.NET, and we might as well use the tool designed for it. I’ve used a version of Visual Studio going all the way back to VB 6.0 and Visual Interdev. Vault Professional Client Several years ago we replaced Visual Source Safe with SourceGear Vault (then Fortress, and now Vault Pro), and I love it.  It is very reliable with low overhead - perfect for a small to medium size development team.  And being a small ISV, their support is exceptional. Red-Gate Developer Bundle with the SQL Source Control update for Vault I first used, and fell in love with, SQL Prompt shortly before Red-Gate bought it, and then Red-Gate’s first release made me love it even more.  SQL Refactor (which has since been rolled into the latest version of SQL Prompt) has saved me many hours and migraine’s trying to understand somebody else’s code when their indenting was nonexistant, or worse, irrational.  SQL Compare has been awesome for troubleshooting potential schema issues between different instances of system databases.  SQL Data Compare helped us identify the cause behind a bug which appeared in PROD but could not be reproduced in a nearly (but not quite exactly) identical copy in UAT.  And the newest tool we are embracing: SQL Source Control.  I blogged about it here (and here, and here) last December.  This is really going to help us keep each developer’s copy of the database in sync with one another. Fiddler Helps you watch the whole traffic stream on web visits.  Haven’t used it a lot, but it did help me track down some odd 404 errors we were finding in our own application logs.  Has some other JavaScript troubleshooting capabilities, but some of its usefulness has been supplanted by the Developer Tools option in IE8. Funduc Search & Replace Find any string anywhere in a mound of source code really, really fast.  Does RegEx searches, if you understand that foreign language.  Has really helped with some refactoring work to pinpoint, for example, everywhere a particular stored procedure is referenced, whether in .NET code or other SQL procedures (which we have in script files).  Provides in-context preview of the search results.  Fantastic tool, and a bargain price. SciTE SciTE is a Scintilla based Text Editor and it is a fantastic, light-weight tool for quickly reviewing (or writing) program code, SQL scripts, and extract files.  It has language-specific syntax highlighting.  I used it to write several batch and CMD programs a year ago, and to examine data extract files for exchanging information with other systems.  Extremely handy are the options to View End of Line and View Whitespace.  Ever receive a file that is supposed to use CRLF as an end-of-line marker, but really only has CRs?  SciTE will quickly make that visible. Infragistics Controls We do a lot of ASP.NET development, and frequently use the WebGrid, WebTab, and date picker controls.  We will likely be implementing the Hierarchical Data Grid soon.  Infragistics has control suites for WebForms, WinForms, Silverlight, and coming soon MVC/JQuery. WinZip - WITH Command-Line add-in The classic compression program with a great command-line interface that allows me to build those CMD (and soon PowerShell) programs for automated compression jobs.  Our versioned Build packages are zip files. XML Notepad Haven’t used this a lot myself, but one of my team really likes it for examining large XML files. LINQPad Again, haven’t used this one a lot, but it was recommended to me for learning and practicing my LINQ skills which will come in handy as we implement Entity Framework. SQL Sentry Plan Explorer SQL Server Show Plan on steroids.  Great for helping you focus on the parts of a large query that are of most importance.  Also great for just compressing the graphical plan into more readable layout. Araxis Merge A great DIFF and Merge tool.  SourceGear provides a great tool called DiffMerge that we use all the time, but occasionally, I like the cross-edit capabilities of Araxis Merge.  For a while, we also produced DIFF reports in HTML that showed all the changes that occurred between two releases.  This was most important when we were putting out very small, but very important hot fixes on a very politically hot system.  The reports produced by Araxis Merge gave the Director of IS assurance that we were not accidentally introducing ripples throughout the system with our releases. Idera SQL Admin Toolset A great collection of tools including a password checker to help analyze your SQL Server for weak user passwords, a Backup Status tool to quickly scan a large list of servers and databases to identify any that are overdue for backups.  Particularly helpful for highlighting new databases that have been deployed without getting included in your backup processing.  I also like Space Analyzer to keep an eye on disk space consumed by database files. Idera SQL Job Manager This free tool provides a nice calendar view of SQL Server Job Schedules, but to a degree, you also get what you pay for.  We will be purchasing SQL Sentry Event Manager later this year as an even better job schedule reviewer/manager.  But in the meantime, this at least gives me a good view on potential resource conflicts across multiple instances of SQL Server. DBFViewer 2000 I inherited a couple of FoxPro databases that I have to keep an eye on occasionally and have not yet been able to migrate them to SQL Server. Balsamiq Mockups We are still in evaluation-mode on this tool, but I really like it as a quick UI mockup tool that does not require Visual Studio, so someone other than a programmer can do UI design.  The interface looks hand-drawn which definitely has some psychological benefits when communicating to users, too. FeedDemon I have to stay on top of my WAY TOO MANY blog subscriptions somehow.  I may read blogs on a couple of different computers, and FeedDemon’s integration with Google Reader allows me to keep them all in sync.  I don’t particularly like the Google Reader interface, or the fact that it always wanted to mark articles as read just because I scrolled past them.  FeedDemon solves this problem for me, and provides a multi-tabbed interface which is good because fairly frequently one blog will link to something else I want to read, and I can end up with a half-dozen open tabs all from one article. Synergy+ In my office, I run four monitors across two computers all with one mouse and keyboard.  Synergy is the magic software that makes this work. TweetDeck I’m not the most active Tweeter in the world, but when I want to check-in with the Twitterverse, this really helps.  I have found the #sqlhelp and #PoshHelp hash tags particularly useful, and I also have columns setup to make it easy to monitor #sqlpass, #PASSProfDev, and short term events like #sqlsat68.   Whew!  That’s a lot.  No wonder it took me a couple of days to get everything setup the way I wanted it.  Oh, that and actually getting some work accomplished at the same time.  Anyway, I know that is a huge dump of info, and most people never make it here to the end, so for those who did, let me say, CONGRATULATIONS, you made it! I hope you’ll find a new tool or two to make your work life a little easier.

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• SQL Cruise Alaska 2011

  - by Grant Fritchey

  I had the extreme good fortune to get sent on the last SQL Cruise to Alaska. I love my job. In case you don't what this is, SQL Cruise is a trip on a cruise ship during which you get to attend classes while on the boat, learning all about SQL Server and related topics as well as network with the instructors and the other Cruisers. Frankly, it's amazing. Classes ran from Monday, 5/30, to Saturday, 6/4. The networking was constant, between classes, at night on cruise ship, out on excursions in Alaskan rainforests and while snorkeling in ocean waters. Here's a run down of the experience from my point of view. Because I couldn't travel out 2 days early, I missed the BBQ that occurred the day before the cruise when many of the Cruisers received their swag bags. Some of that swag came from Red Gate. I researched what was useful on a cruise like this and purchased small flashlights and binoculars for all the Cruisers. The flashlights were because, depending on your cabin, ships can be very dark. The binoculars were so that the cruisers could watch all the beautiful landscape as it flowed by. I would have liked to have been there when the bags were opened, but I heard from several people that they appreciated the gifts. Cruisers "In" the hot tub. Pictured: Marjory Woody, Michele Grondin, Kyle Brandt, Grant Fritchey, John Halunen Sunday I went to board the ship with my wife. We had a bit of an adventure because I messed up our documents. It all worked out and we got on board to meet up at the back of the boat at one of the outdoor bars with the other Cruisers, thanks to tweets letting everyone know where to go. That was the end of electronic coordination on the trip (connectivity in Alaska was horrible for everyone except AT&T). The Cruisers were a great bunch of people and it was a real honor to meet them and get to spend time with them. After everyone settled into their cabins, our very first activity was a contest, sponsored by Red Gate. The Cruisers, in an effort to get to know each other and the ship, were required to go all over taking various photographs, some of them hilarious. The winning team of three would all win prizes. Some of the significant others helped out and I tagged along with a team that tied for first but lost the coin toss. The winning team consisted of Christina Leo (blog|twitter), Ryan Malcom (twitter), Neil Hambly (blog|twitter). They then had to do math and identify the cabin with the lowest prime number, oh, and get a picture of it and be the first to get back up to the bar where we were waiting. Christina came in first and very happily carried home an Ipad2. Ryan won a 1TB portable hard drive and Neil won a wireless mouse (picture below, note my special SQL Server Central Friday Shirt. Thanks Steve (blog|twitter)). Winners: Christina Leo, Neil Hambly, Ryan Malcolm. Just Lucky: Grant Fritchey Monday morning classes started. Buck Woody (blog|twitter) was a special guest speaker on this cruise. His theme was "Three C's on the High Seas: Career, Communication and Cloud." The first session was all on Career. I'm not going to type out all my notes from the session, but let's just say, if you get the chance to hear Buck talk about how to manage your career, I suggest you attend. I have a ton of blog posts that I'll be putting together over the next several months (yes, months) both here and over on ScaryDBA. I also have a bunch of work I'm going to be doing to get my career performance bumped up a notch or two (and let's face it, that won't be easy). Later on Monday, Tim Ford (blog|twitter) did a session on DMOs. Specifically the session was on Tim's Period Table of DMOs that he has put together, and how to use some of the more interesting DMOs in your day to day job. It was a great session, packed with good information. Next, Brent Ozar (blog|twitter) did a session on how to monitor and guide SAN configuration for the DBA that doesn't have access to the SAN. That was some seriously useful information. Tuesday morning we only had a single class. Kendra Little (blog|twitter) taught us all about "No Lock for Yes Fun".  It was all about the different transaction isolation levels and how they work. There is so often confusion in this area and Kendra does a great job in clarifying the information. Also, she tosses in her excellent drawings to liven up the presentation. Then it was excursion time in Juneau. My wife and I, along with several other Cruisers, took a hike up around the Mendenhall Glacier. It was absolutely beautiful weather and walking through the Alaskan rain forest was a treat. Our guide, Jason, was a great guy and it was a good day of hiking. Wednesday was an all day excursion in Skagway. My wife and I took the "Ghost and Good Time Girls" walking tour that ended up at a bar that used to be a brothel, the Red Onion. It was a great history of the town. We went back out and hit a few museums and exhibits. We also hiked up the side of the mountain to see the Dewey Lake and some great views of the town. Finally we hiked out to the far side of town to see the Gold Rush cemetery. Hiking done we went back to the boat and had a quiet dinner on our own. Thursday we cruised through Glacier Bay and saw at least four different glaciers including sitting next to the Marjory Glacier for  about an hour. It was amazing. Then it got better. We went into class with Buck again, this time to talk about Communication. Again, I've got pages of notes that I'm going to be referring back to for some time to come. This was an excellent opportunity to learn. Snorkelers: Nicole Bertrand, Aaron Bertrand, Grant Fritchey, Neil Hambly, Christina Leo, John Robel, Yanni Robel, Tim Ford Friday we pulled into Ketchikan. A bunch of us went snorkeling. Yes, snorkeling. Yes, in Alaska. Yes, snorkeling in the ocean in Alaska. It was fantastic. They had us put on 7mm thick wet suits (an adventure all by itself) so it was basically warm the entire time we were in the water (except for the occasional squirt of cold water down my back). Before we got in the water a bald eagle flew up and landed about 15 feet in front of us, which was just an incredible event. Then our guide pointed out about 14 other eagles in the area, hanging out in the trees. Wow! The water was pretty clear and there was a ton of things to see. That was absolutely a blast. Back on the boat I presented a session called Execution Plans: The Deep Dive (note the nautical theme). It seemed to go over well and I had several good questions come out of the session that will lead to new blog posts. After I presented, it was Aaron Bertrand's (blog|twitter) turn. He did a session on "What's New in Denali" that provided a lot of great information. He was able to incorporate new things straight out of Tech-Ed, so this was expanded beyond his usual presentation. The man really knows what he's talking about and communicates it well. Saturday we were travelling so there was time for a bunch of classes. Jeremiah Peschka (blog|twitter) did a great overview of some of the NoSQL databases and what they should be used for. The session was called "The Database is Dead" but it was really about how there are specific uses for these databases that SQL Server doesn't fill, but also that these databases can't replace SQL Server in other areas. Again, good material. Brent Ozar presented again with a session on Defensive Indexing. It was an overview of how indexes work and a deep dive into how to apply them appropriately in your databases to better support access. A good session, as you would expect. Then we pulled into Victoria, BC, in Canada and had a nice dinner with several of the Cruisers, including Denny Cherry (blog|twitter). After that it was back to Seattle on Sunday. By the way, the Science Fiction Museum in Seattle isn't a Science Fiction Museum any more. I was very disappointed to discover this. Overall, it was a great experience. I'm extremely appreciative of Red Gate for sending me and for Tim, Brent, Kendra and Jeremiah for having me. The other Cruisers were all amazing people and it was an honor & privilege to meet them and spend time with them. While this was a seriously fun time, it was also a very serious training opportunity with solid information coming from seasoned industry pros.

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• Problem with Freetype and OpenGL

  - by Morgan

  Hey, i'm having a weird issue with drawing text in openGL loaded with the Freetype 2 library. Here is a screenshot of what I'm seeing. http://img203.imageshack.us/img203/3316/freetypeweird.png Here are my code bits for loading and rendering my text. class Font { Font(const String& filename) { if (FT_New_Face(Font::ftLibrary, "arial.ttf", 0, &mFace)) { cout << "UH OH!" << endl; } FT_Set_Char_Size(mFace, 16 * 64, 16 * 64, 72, 72); } Glyph* GetGlyph(const unsigned char ch) { if(FT_Load_Char(mFace, ch, FT_LOAD_RENDER)) cout << "OUCH" << endl; FT_Glyph glyph; if(FT_Get_Glyph( mFace->glyph, &glyph )) cout << "OUCH" << endl; FT_BitmapGlyph bitmap_glyph = (FT_BitmapGlyph)glyph; Glyph* thisGlyph = new Glyph; thisGlyph->buffer = bitmap_glyph->bitmap.buffer; thisGlyph->width = bitmap_glyph->bitmap.width; thisGlyph->height = bitmap_glyph->bitmap.rows; return thisGlyph; } }; The relevant glyph information (width, height, buffer) is stored in the following struct struct Glyph { GLubyte* buffer; Uint width; Uint height; }; And finally, to render it, I have this class called RenderFont. class RenderFont { RenderFont(Font* font) { mTextureIds = new GLuint[128]; mFirstDisplayListId=glGenLists(128); glGenTextures( 128, mTextureIds ); for(unsigned char i=0;i<128;i++) { MakeDisplayList(font, i); } } void MakeDisplayList(Font* font, unsigned char ch) { Glyph* glyph = font->GetGlyph(ch); glBindTexture( GL_TEXTURE_2D, mTextureIds[ch]); glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, glyph->width, glyph->height, 0, GL_ALPHA, GL_UNSIGNED_BYTE, glyph->buffer); glNewList(mFirstDisplayListId+ch,GL_COMPILE); glBindTexture(GL_TEXTURE_2D, mTextureIds[ch]); glBegin(GL_QUADS); glTexCoord2d(0,1); glVertex2f(0,glyph->height); glTexCoord2d(0,0); glVertex2f(0,0); glTexCoord2d(1,0); glVertex2f(glyph->width,0); glTexCoord2d(1,1); glVertex2f(glyph->width,glyph->height); glEnd(); glTranslatef(16, 0, 0); glEndList(); } void Draw(const String& text, Uint size, const TransformComponent* transform, const Color32* color) { glEnable(GL_TEXTURE_2D); glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); glTranslatef(100, 250, 0.0f); glListBase(mFirstDisplayListId); glCallLists(text.length(), GL_UNSIGNED_BYTE, text.c_str()); glDisable(GL_TEXTURE_2D); glDisable(GL_BLEND); glLoadIdentity(); } private: GLuint mFirstDisplayListId; GLuint* mTextureIds; }; Can anybody see anything weird going on here that would cause the garbled text? It's strange because if I change the font size, or the DPI, then some of the letters that display correctly become garbled, and other letters that were garbled before then display correctly.

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• Spooling in SQL execution plans

  - by Rob Farley

  Sewing has never been my thing. I barely even know the terminology, and when discussing this with American friends, I even found out that half the words that Americans use are different to the words that English and Australian people use. That said – let’s talk about spools! In particular, the Spool operators that you find in some SQL execution plans. This post is for T-SQL Tuesday, hosted this month by me! I’ve chosen to write about spools because they seem to get a bad rap (even in my song I used the line “There’s spooling from a CTE, they’ve got recursion needlessly”). I figured it was worth covering some of what spools are about, and hopefully explain why they are remarkably necessary, and generally very useful. If you have a look at the Books Online page about Plan Operators, at http://msdn.microsoft.com/en-us/library/ms191158.aspx, and do a search for the word ‘spool’, you’ll notice it says there are 46 matches. 46! Yeah, that’s what I thought too... Spooling is mentioned in several operators: Eager Spool, Lazy Spool, Index Spool (sometimes called a Nonclustered Index Spool), Row Count Spool, Spool, Table Spool, and Window Spool (oh, and Cache, which is a special kind of spool for a single row, but as it isn’t used in SQL 2012, I won’t describe it any further here). Spool, Table Spool, Index Spool, Window Spool and Row Count Spool are all physical operators, whereas Eager Spool and Lazy Spool are logical operators, describing the way that the other spools work. For example, you might see a Table Spool which is either Eager or Lazy. A Window Spool can actually act as both, as I’ll mention in a moment. In sewing, cotton is put onto a spool to make it more useful. You might buy it in bulk on a cone, but if you’re going to be using a sewing machine, then you quite probably want to have it on a spool or bobbin, which allows it to be used in a more effective way. This is the picture that I want you to think about in relation to your data. I’m sure you use spools every time you use your sewing machine. I know I do. I can’t think of a time when I’ve got out my sewing machine to do some sewing and haven’t used a spool. However, I often run SQL queries that don’t use spools. You see, the data that is consumed by my query is typically in a useful state without a spool. It’s like I can just sew with my cotton despite it not being on a spool! Many of my favourite features in T-SQL do like to use spools though. This looks like a very similar query to before, but includes an OVER clause to return a column telling me the number of rows in my data set. I’ll describe what’s going on in a few paragraphs’ time. So what does a Spool operator actually do? The spool operator consumes a set of data, and stores it in a temporary structure, in the tempdb database. This structure is typically either a Table (ie, a heap), or an Index (ie, a b-tree). If no data is actually needed from it, then it could also be a Row Count spool, which only stores the number of rows that the spool operator consumes. A Window Spool is another option if the data being consumed is tightly linked to windows of data, such as when the ROWS/RANGE clause of the OVER clause is being used. You could maybe think about the type of spool being like whether the cotton is going onto a small bobbin to fit in the base of the sewing machine, or whether it’s a larger spool for the top. A Table or Index Spool is either Eager or Lazy in nature. Eager and Lazy are Logical operators, which talk more about the behaviour, rather than the physical operation. If I’m sewing, I can either be all enthusiastic and get all my cotton onto the spool before I start, or I can do it as I need it. “Lazy” might not the be the best word to describe a person – in the SQL world it describes the idea of either fetching all the rows to build up the whole spool when the operator is called (Eager), or populating the spool only as it’s needed (Lazy). Window Spools are both physical and logical. They’re eager on a per-window basis, but lazy between windows. And when is it needed? The way I see it, spools are needed for two reasons. 1 – When data is going to be needed AGAIN. 2 – When data needs to be kept away from the original source. If you’re someone that writes long stored procedures, you are probably quite aware of the second scenario. I see plenty of stored procedures being written this way – where the query writer populates a temporary table, so that they can make updates to it without risking the original table. SQL does this too. Imagine I’m updating my contact list, and some of my changes move data to later in the book. If I’m not careful, I might update the same row a second time (or even enter an infinite loop, updating it over and over). A spool can make sure that I don’t, by using a copy of the data. This problem is known as the Halloween Effect (not because it’s spooky, but because it was discovered in late October one year). As I’m sure you can imagine, the kind of spool you’d need to protect against the Halloween Effect would be eager, because if you’re only handling one row at a time, then you’re not providing the protection... An eager spool will block the flow of data, waiting until it has fetched all the data before serving it up to the operator that called it. In the query below I’m forcing the Query Optimizer to use an index which would be upset if the Name column values got changed, and we see that before any data is fetched, a spool is created to load the data into. This doesn’t stop the index being maintained, but it does mean that the index is protected from the changes that are being done. There are plenty of times, though, when you need data repeatedly. Consider the query I put above. A simple join, but then counting the number of rows that came through. The way that this has executed (be it ideal or not), is to ask that a Table Spool be populated. That’s the Table Spool operator on the top row. That spool can produce the same set of rows repeatedly. This is the behaviour that we see in the bottom half of the plan. In the bottom half of the plan, we see that the a join is being done between the rows that are being sourced from the spool – one being aggregated and one not – producing the columns that we need for the query. Table v Index When considering whether to use a Table Spool or an Index Spool, the question that the Query Optimizer needs to answer is whether there is sufficient benefit to storing the data in a b-tree. The idea of having data in indexes is great, but of course there is a cost to maintaining them. Here we’re creating a temporary structure for data, and there is a cost associated with populating each row into its correct position according to a b-tree, as opposed to simply adding it to the end of the list of rows in a heap. Using a b-tree could even result in page-splits as the b-tree is populated, so there had better be a reason to use that kind of structure. That all depends on how the data is going to be used in other parts of the plan. If you’ve ever thought that you could use a temporary index for a particular query, well this is it – and the Query Optimizer can do that if it thinks it’s worthwhile. It’s worth noting that just because a Spool is populated using an Index Spool, it can still be fetched using a Table Spool. The details about whether or not a Spool used as a source shows as a Table Spool or an Index Spool is more about whether a Seek predicate is used, rather than on the underlying structure. Recursive CTE I’ve already shown you an example of spooling when the OVER clause is used. You might see them being used whenever you have data that is needed multiple times, and CTEs are quite common here. With the definition of a set of data described in a CTE, if the query writer is leveraging this by referring to the CTE multiple times, and there’s no simplification to be leveraged, a spool could theoretically be used to avoid reapplying the CTE’s logic. Annoyingly, this doesn’t happen. Consider this query, which really looks like it’s using the same data twice. I’m creating a set of data (which is completely deterministic, by the way), and then joining it back to itself. There seems to be no reason why it shouldn’t use a spool for the set described by the CTE, but it doesn’t. On the other hand, if we don’t pull as many columns back, we might see a very different plan. You see, CTEs, like all sub-queries, are simplified out to figure out the best way of executing the whole query. My example is somewhat contrived, and although there are plenty of cases when it’s nice to give the Query Optimizer hints about how to execute queries, it usually doesn’t do a bad job, even without spooling (and you can always use a temporary table). When recursion is used, though, spooling should be expected. Consider what we’re asking for in a recursive CTE. We’re telling the system to construct a set of data using an initial query, and then use set as a source for another query, piping this back into the same set and back around. It’s very much a spool. The analogy of cotton is long gone here, as the idea of having a continual loop of cotton feeding onto a spool and off again doesn’t quite fit, but that’s what we have here. Data is being fed onto the spool, and getting pulled out a second time when the spool is used as a source. (This query is running on AdventureWorks, which has a ManagerID column in HumanResources.Employee, not AdventureWorks2012) The Index Spool operator is sucking rows into it – lazily. It has to be lazy, because at the start, there’s only one row to be had. However, as rows get populated onto the spool, the Table Spool operator on the right can return rows when asked, ending up with more rows (potentially) getting back onto the spool, ready for the next round. (The Assert operator is merely checking to see if we’ve reached the MAXRECURSION point – it vanishes if you use OPTION (MAXRECURSION 0), which you can try yourself if you like). Spools are useful. Don’t lose sight of that. Every time you use temporary tables or table variables in a stored procedure, you’re essentially doing the same – don’t get upset at the Query Optimizer for doing so, even if you think the spool looks like an expensive part of the query. I hope you’re enjoying this T-SQL Tuesday. Why not head over to my post that is hosting it this month to read about some other plan operators? At some point I’ll write a summary post – once I have you should find a comment below pointing at it. @rob_farley

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• How do I get a Java to call data from the Internet? Where to even start??

  - by cdg

  Hello oh great wizards of all things android. I really need your help. Mostly because my little brain just doesn't know were to start. I am trying to pull data from the internet to make a widget for the home screen. I have the layout built: <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/Layout" android:layout_width="fill_parent" android:layout_height="fill_parent" android:background="@drawable/widget_bg_normal" android:clipChildren="false" > <TextView android:id="@+id/text_view" android:layout_width="100px" android:layout_height="wrap_content" android:paddingTop="18px" android:layout_centerHorizontal="true" android:textSize="8px" android:text="158x154 Image downloaded from the internet goes here. Needs to be updated every evening at midnight or unless the button below is pressed. Now if I could only figure out exactly how to do this, life would be good." /> <Button android:id="@+id/new_button" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Get New" android:layout_below="@+id/scroll_image" android:layout_centerHorizontal="true" android:padding="0px" android:textSize="10px" android:height="8px" android:includeFontPadding="false" /> </RelativeLayout> Got the provider xml bulit: <?xml version="1.0" encoding="utf-8"?> <appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android" android:minWidth="150dip" android:minHeight="150dip" android:updatePeriodMillis="10000" android:initialLayout="@layout/widget" /> The Manifest works great. <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.dge.myandroid" android:versionCode="1" android:versionName="1.0"> <application android:icon="@drawable/icon" android:label="@string/app_name"> <activity android:name=".myactivty" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <!-- Widget --> <receiver android:name=".mywidget" android:label="@string/app_name" > <intent-filter> <action android:name="android.appwidget.action.APPWIDGET_UPDATE" /> </intent-filter> <meta-data android:name="android.appwidget.widgetprovider" android:resource="@xml/widgetprovider" /> </receiver> <!-- Widget End --> </application> <uses-permission android:name="android.permission.INTERNET" /> <uses-sdk android:minSdkVersion="7" /> </manifest> The data it is calling looks something like this when it is called. It basically goes to a website that uses php to random the image: <html><body bgcolor="#000000">center> <a href="http://www.website.com" target="_blank"> <img border="0" src="http://www.webiste.com//0.gif"></a> <img src="http://www.webiste.com" style="border:none;" /> </center></body></html> But here is were I am stuck. I just don't know where to start at all. The java is so far beyond my little head that I don't know what to do. package com.dge.myandroid; import android.appwidget.AppWidgetProvider; public class mywidget extends AppWidgetProvider { } The wiki example just confused me more. I just don't know where to begin. Please help.

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• The Java Specialist: An Interview with Java Champion Heinz Kabutz

  - by Janice J. Heiss

  Dr. Heinz Kabutz is well known for his Java Specialists’ Newsletter, initiated in November 2000, where he displays his acute grasp of the intricacies of the Java platform for an estimated 70,000 readers; for his work as a consultant; and for his workshops and trainings at his home on the Island of Crete where he has lived since 2006 -- where he is known to curl up on the beach with his laptop to hack away, in between dips in the Mediterranean. Kabutz was born of German parents and raised in Cape Town, South Africa, where he developed a love of programming in junior high school through his explorations on a ZX Spectrum computer. He received a B.S. from the University of Cape Town, and at 25, a Ph.D., both in computer science. He will be leading a two-hour hands-on lab session, HOL6500 – “Finding and Solving Java Deadlocks,” at this year’s JavaOne that will explore what causes deadlocks and how to solve them. Q: Tell us about your JavaOne plans.A: I am arriving on Sunday evening and have just one hands-on-lab to do on Monday morning. This is the first time that a non-Oracle team is doing a HOL at JavaOne under Oracle's stewardship and we are all a bit nervous about how it will turn out. Oracle has been immensely helpful in getting us set up. I have a great team helping me: Kirk Pepperdine, Dario Laverde, Benjamin Evans and Martijn Verburg from jClarity, Nathan Reynolds from Oracle, Henri Tremblay of OCTO Technology and Jeff Genender of Savoir Technologies. Monday will be hard work, but after that, I will hopefully get to network with fellow Java experts, attend interesting sessions and just enjoy San Francisco. Oh, and my kids have already given me a shopping list of things to get, like a GoPro Hero 2 dive housing for shooting those nice videos of Crete. (That's me at the beginning diving down.) Q: What sessions are you attending that we should know about?A: Sometimes the most unusual sessions are the best. I avoid the "big names". They often are spread too thin with all their sessions, which makes it difficult for them to deliver what I would consider deep content. I also avoid entertainers who might be good at presenting but who do not say that much.In 2010, I attended a session by Vladimir Yaroslavskiy where he talked about sorting. Although he struggled to speak English, what he had to say was spectacular. There was hardly anybody in the room, having not heard of Vladimir before. To me that was the highlight of 2010. Funnily enough, he was supposed to speak with Joshua Bloch, but if you remember, Google cancelled. If Bloch has been there, the room would have been packed to capacity.Q: Give us an update on the Java Specialists’ Newsletter.A: The Java Specialists' Newsletter continues being read by an elite audience around the world. The apostrophe in the name is significant.  It is a newsletter for Java specialists. When I started it twelve years ago, I was trying to find non-obvious things in Java to write about. Things that would be interesting to an advanced audience.As an April Fool's joke, I told my readers in Issue 44 that subscribing would remain free, but that they would have to pay US$5 to US$7 depending on their geographical location. I received quite a few angry emails from that one. I would have not earned that much from unsubscriptions. Most readers stay for a very long time.After Oracle bought Sun, the Java community held its breath for about two years whilst Oracle was figuring out what to do with Java. For a while, we were quite concerned that there was not much progress shown by Oracle. My newsletter still continued, but it was quite difficult finding new things to write about. We have probably about 70,000 readers, which is quite a small number for a Java publication. However, our readers are the top in the Java industry. So I don't mind having "only" 70000 readers, as long as they are the top 0.7%.Java concurrency is a very important topic that programmers think they should know about, but often neglect to fully understand. I continued writing about that and made some interesting discoveries. For example, in Issue 165, I showed how we can get thread starvation with the ReadWriteLock. This was a bug in Java 5, which was corrected in Java 6, but perhaps a bit too much. Whereas we could get starvation of writers in Java 5, in Java 6 we could now get starvation of readers. All of these interesting findings make their way into my courseware to help companies avoid these pitfalls.Another interesting discovery was how polymorphism works in the Server HotSpot compiler in Issue 157 and Issue 158. HotSpot can inline methods from interfaces that have only one implementation class in the JVM. When a new subclass is instantiated and called for the first time, the JVM will undo the previous optimization and re-optimize differently.Here is a little memory puzzle for your readers: public class JavaMemoryPuzzle {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzle jmp = new JavaMemoryPuzzle();    jmp.f();  }}When you run this you will always get an OutOfMemoryError, even though the local variable data is no longer visible outside of the code block.So here comes the puzzle, that I'd like you to ponder a bit. If you very politely ask the VM to release memory, then you don't get an OutOfMemoryError: public class JavaMemoryPuzzlePolite {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    for(int i=0; i<10; i++) {      System.out.println("Please be so kind and release memory");    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzlePolite jmp = new JavaMemoryPuzzlePolite();    jmp.f();    System.out.println("No OutOfMemoryError");  }}Why does this work? When I published this in my newsletter, I received over 400 emails from excited readers around the world, most of whom sent me the wrong explanation. After the 300th wrong answer, my replies became unfortunately a bit curt. Have a look at Issue 174 for a detailed explanation, but before you do, put on your thinking caps and try to figure it out yourself. Q: What do you think Java developers should know that they currently do not know?A: They should definitely get to know more about concurrency. It is a tough subject that most programmers try to avoid. Unfortunately we do come in contact with it. And when we do, we need to know how to protect ourselves and how to solve tricky system errors.Knowing your IDE is also useful. Most IDEs have a ton of shortcuts, which can make you a lot more productive in moving code around. Another thing that is useful is being able to read GC logs. Kirk Pepperdine has a great talk at JavaOne that I can recommend if you want to learn more. It's this: CON5405 – “Are Your Garbage Collection Logs Speaking to You?” Q: What are you looking forward to in Java 8?A: I'm quite excited about lambdas, though I must confess that I have not studied them in detail yet. Maurice Naftalin's Lambda FAQ is quite a good start to document what you can do with them. I'm looking forward to finding all the interesting bugs that we will now get due to lambdas obscuring what is really going on underneath, just like we had with generics.I am quite impressed with what the team at Oracle did with OpenJDK's performance. A lot of the benchmarks now run faster.Hopefully Java 8 will come with JSR 310, the Date and Time API. It still boggles my mind that such an important API has been left out in the cold for so long.What I am not looking forward to is losing perm space. Even though some systems run out of perm space, at least the problem is contained and they usually manage to work around it. In most cases, this is due to a memory leak in that region of memory. Once they bundle perm space with the old generation, I predict that memory leaks in perm space will be harder to find. More contracts for us, but also more pain for our customers. Originally published on blogs.oracle.com/javaone.

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• The Java Specialist: An Interview with Java Champion Heinz Kabutz

  - by Janice J. Heiss

  Dr. Heinz Kabutz is well known for his Java Specialists’ Newsletter, initiated in November 2000, where he displays his acute grasp of the intricacies of the Java platform for an estimated 70,000 readers; for his work as a consultant; and for his workshops and trainings at his home on the Island of Crete where he has lived since 2006 -- where he is known to curl up on the beach with his laptop to hack away, in between dips in the Mediterranean. Kabutz was born of German parents and raised in Cape Town, South Africa, where he developed a love of programming in junior high school through his explorations on a ZX Spectrum computer. He received a B.S. from the University of Cape Town, and at 25, a Ph.D., both in computer science. He will be leading a two-hour hands-on lab session, HOL6500 – “Finding and Solving Java Deadlocks,” at this year’s JavaOne that will explore what causes deadlocks and how to solve them. Q: Tell us about your JavaOne plans.A: I am arriving on Sunday evening and have just one hands-on-lab to do on Monday morning. This is the first time that a non-Oracle team is doing a HOL at JavaOne under Oracle's stewardship and we are all a bit nervous about how it will turn out. Oracle has been immensely helpful in getting us set up. I have a great team helping me: Kirk Pepperdine, Dario Laverde, Benjamin Evans and Martijn Verburg from jClarity, Nathan Reynolds from Oracle, Henri Tremblay of OCTO Technology and Jeff Genender of Savoir Technologies. Monday will be hard work, but after that, I will hopefully get to network with fellow Java experts, attend interesting sessions and just enjoy San Francisco. Oh, and my kids have already given me a shopping list of things to get, like a GoPro Hero 2 dive housing for shooting those nice videos of Crete. (That's me at the beginning diving down.) Q: What sessions are you attending that we should know about?A: Sometimes the most unusual sessions are the best. I avoid the "big names". They often are spread too thin with all their sessions, which makes it difficult for them to deliver what I would consider deep content. I also avoid entertainers who might be good at presenting but who do not say that much.In 2010, I attended a session by Vladimir Yaroslavskiy where he talked about sorting. Although he struggled to speak English, what he had to say was spectacular. There was hardly anybody in the room, having not heard of Vladimir before. To me that was the highlight of 2010. Funnily enough, he was supposed to speak with Joshua Bloch, but if you remember, Google cancelled. If Bloch has been there, the room would have been packed to capacity.Q: Give us an update on the Java Specialists’ Newsletter.A: The Java Specialists' Newsletter continues being read by an elite audience around the world. The apostrophe in the name is significant.  It is a newsletter for Java specialists. When I started it twelve years ago, I was trying to find non-obvious things in Java to write about. Things that would be interesting to an advanced audience.As an April Fool's joke, I told my readers in Issue 44 that subscribing would remain free, but that they would have to pay US$5 to US$7 depending on their geographical location. I received quite a few angry emails from that one. I would have not earned that much from unsubscriptions. Most readers stay for a very long time.After Oracle bought Sun, the Java community held its breath for about two years whilst Oracle was figuring out what to do with Java. For a while, we were quite concerned that there was not much progress shown by Oracle. My newsletter still continued, but it was quite difficult finding new things to write about. We have probably about 70,000 readers, which is quite a small number for a Java publication. However, our readers are the top in the Java industry. So I don't mind having "only" 70000 readers, as long as they are the top 0.7%.Java concurrency is a very important topic that programmers think they should know about, but often neglect to fully understand. I continued writing about that and made some interesting discoveries. For example, in Issue 165, I showed how we can get thread starvation with the ReadWriteLock. This was a bug in Java 5, which was corrected in Java 6, but perhaps a bit too much. Whereas we could get starvation of writers in Java 5, in Java 6 we could now get starvation of readers. All of these interesting findings make their way into my courseware to help companies avoid these pitfalls.Another interesting discovery was how polymorphism works in the Server HotSpot compiler in Issue 157 and Issue 158. HotSpot can inline methods from interfaces that have only one implementation class in the JVM. When a new subclass is instantiated and called for the first time, the JVM will undo the previous optimization and re-optimize differently.Here is a little memory puzzle for your readers: public class JavaMemoryPuzzle {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzle jmp = new JavaMemoryPuzzle();    jmp.f();  }}When you run this you will always get an OutOfMemoryError, even though the local variable data is no longer visible outside of the code block.So here comes the puzzle, that I'd like you to ponder a bit. If you very politely ask the VM to release memory, then you don't get an OutOfMemoryError: public class JavaMemoryPuzzlePolite {  private final int dataSize =      (int) (Runtime.getRuntime().maxMemory() * 0.6);  public void f() {    {      byte[] data = new byte[dataSize];    }    for(int i=0; i<10; i++) {      System.out.println("Please be so kind and release memory");    }    byte[] data2 = new byte[dataSize];  }  public static void main(String[] args) {    JavaMemoryPuzzlePolite jmp = new JavaMemoryPuzzlePolite();    jmp.f();    System.out.println("No OutOfMemoryError");  }}Why does this work? When I published this in my newsletter, I received over 400 emails from excited readers around the world, most of whom sent me the wrong explanation. After the 300th wrong answer, my replies became unfortunately a bit curt. Have a look at Issue 174 for a detailed explanation, but before you do, put on your thinking caps and try to figure it out yourself. Q: What do you think Java developers should know that they currently do not know?A: They should definitely get to know more about concurrency. It is a tough subject that most programmers try to avoid. Unfortunately we do come in contact with it. And when we do, we need to know how to protect ourselves and how to solve tricky system errors.Knowing your IDE is also useful. Most IDEs have a ton of shortcuts, which can make you a lot more productive in moving code around. Another thing that is useful is being able to read GC logs. Kirk Pepperdine has a great talk at JavaOne that I can recommend if you want to learn more. It's this: CON5405 – “Are Your Garbage Collection Logs Speaking to You?” Q: What are you looking forward to in Java 8?A: I'm quite excited about lambdas, though I must confess that I have not studied them in detail yet. Maurice Naftalin's Lambda FAQ is quite a good start to document what you can do with them. I'm looking forward to finding all the interesting bugs that we will now get due to lambdas obscuring what is really going on underneath, just like we had with generics.I am quite impressed with what the team at Oracle did with OpenJDK's performance. A lot of the benchmarks now run faster.Hopefully Java 8 will come with JSR 310, the Date and Time API. It still boggles my mind that such an important API has been left out in the cold for so long.What I am not looking forward to is losing perm space. Even though some systems run out of perm space, at least the problem is contained and they usually manage to work around it. In most cases, this is due to a memory leak in that region of memory. Once they bundle perm space with the old generation, I predict that memory leaks in perm space will be harder to find. More contracts for us, but also more pain for our customers.

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• Ubuntu 12.04 does not see windows already install on my computer (dual installation)

  - by jacinta

  I was trying to install the ubuntu 12.4 along side windows 7 on my new HP Pavilion 64k desktop with windows 7 computer but Ubuntu said that ( This computer has no detected operating system) and some one said (I suggest you chkdsk your Windows partition. I also suggest you resize the NTFS in WIndows then install Ubuntu to the free space.) Therefore I did (To shrink a simple or spanned volume using the Windows interface In Disk Management, right-click the simple or spanned volume you want to shrink. Click Shrink Volume…. Follow the instructions on your screen.) Then When I try to install ubuntu 12.4 after doing this, I received the same error. I was going to undo what I did but I see that I lose 1g when I do that so now what do I do? it says I can do a new simple volume and maybe then the space will no longer be unallocated. Please help me. I think I have a bad cd (ubuntu 12.4) cause from my research I see that I am not suppose to get a screen saying that (The computer has no detected operating system) I think this is a bad cd and I hope I did not mess up my computer. Please help. .................................................................................... O k I think I am following what you said about how to edit my question irrational john. I did chkdsk as you and actionparsnip (andrew-woodhead666) told me to AND ALSO did a lot of other things before I found out how to chkdsk. No problems. Thank you. Then I put back the space (extended) I took from system. I still was only able to put back 15 and not 16 so it is up to 99mb not back to 100mb. Then I shrank HP (C) as you told me, to 10 13,240 mb which is (12.93gb Unallocated). I did not change it into NTSF by doing the (New Simple Volume Action) I just left it. Then I tried to install UBUNTU 12.04 live CD amd64 and it gave me the results it was sometimes giving me before which is result (THAT Ubuntu) does not tell me weather I have or have not an already installed windows7. It just goes to a window that would have showed me information on what I have and on the bottom (DEVICE FOR BOOT LOADER INSTALLATION /dev/sda ) and the option to go BACK, QUIT, or INSTALL. (I think it is the INSTALLATION TYPE window). Therefore I do what I have been doing and I QUIT. What do I do now? Sorry that it seems like I cannot do anything on my own. On the Youtube video how to install ubuntu dual-boot alongside windows UBUNTU is installed so easy. The installation option page gives 3 options including dual instillation and the disk even lets you use a slider to slide to the size of the partition size you want. Yet my UBUNTU live cd is a mess and I checked it as one of you guys told me and got back information that it is good. Oh well this guy says you should press a control key to tell which device you are using to install ubuntu before the screen comes up. I guess cause it is old. This page also shows you easy stuff that do not show up on my cd. how to dual-boot UBUNTU and windows 7 P.S.. I saw this on the windows 7 website windows.microsoft.com/en-US/windows7/Formatting-disks-and-drives-frequently-asked-questions CREATE A BOOT PARTITION I HAD TO LEAVE OUT THE HTTP STUFF CAUSE I AM ONLY ALLOWED 2 ON A PAGE IT SAID To create a boot partition Warning Warning If you are installing different versions of Windows, you must install the earliest version first. If you don't do this, your computer may become inoperable. Open Computer Management by clicking the Start button Picture of the Start button, clicking Control Panel, clicking System and Security, clicking Administrative Tools, and then double-clicking Computer Management.? Administrator permission required If you're prompted for an administrator password or confirmation, type the password or provide confirmation. In the left pane, under Storage, click Disk Management. Right-click an unallocated region on your hard disk, and then click New Simple Volume. In the New Simple Volume Wizard, click Next. Type the size of the volume you want to create in megabytes (MB) or accept the maximum default size, and then click Next. Accept the default drive letter or choose a different drive letter to identify the volume, and then click Next. In the Format Partition dialog box, do one of the following: If you don't want to format the volume right now, click Do not format this volume, and then click Next. To format the volume with the default settings, click Next. For more information about formatting, see Formatting disks and drives: frequently asked questions. Review your choices, and then click Finish. AND THIS ON ANOTHER PAGE. Formatting disks and drives: frequently asked questions Hard disks, the primary storage devices on your computer, need to be formatted before you can use them. When you format a disk, you configure it with a file system so that Windows can store information on the disk. Hard disks in new computers running Windows are already formatted. If you buy an additional hard disk to expand the storage of your computer, you might need to format it. Storage devices such as USB flash drives and flash memory cards usually come preformatted by the manufacturer, so you probably won't need to format them. CDs and DVDs, on the other hand, use different formats from hard disks and removable storage devices. For information about formatting CDs and DVDs, see Which CD or DVD format should I use? Warning Warning Formatting erases any existing files on a hard disk. If you format a hard disk that has files on it, the files will be deleted. WHAT I DID WAS I GOT TO COMPUTER MANAGEMENT SECTION THEN I CLICKED ON DRIVE HP(C) (it put stripes on to show it is selected) Then I click on ACTION selected ALL TASKS AND THEN selected SHRINK VOLUME and then chose how much space from what it was giving me that I wanted. (12.93gb) AND THAT WAS ALL I DID. THEN I TRIED TO INSTALL UBUNTU i NEVER GOT THE 3RD SCREEN THAT IS IN THE VIDEO I INCLUDED (THE YOUTUBE WITH THE ENGLISH GUY) INSTALLATION TYPE I ALSO DID NOT GET THE 4TH SCREEN THAT ALLOWS YOU TO SELECT PARTITION SIZE what i got next was the 2nd INSTILLATION TYPE window shown on the (LINUX BS DOS.COM) PAGE THAT I INCLUDED and it showed no information about any drives (no drives /partition or stuff was shown) only the Boot Loader statement and the dev/sda bar and that's why i did not press install but chose to QUIT. SORRY I JUST NOW SAW YOUR ANSWER IRRATIONAL JOHN. I SHRANK HP(C) BY 12.93GB MY UNALLOCATED SPACE IS NOW 12.93GB HP(C) = 907.17gb NTSF...YOU ARE CORRECT WITH EVERYTHING YOU SAID This is what i read on (http://)windows.microsoft.com/en-US/windows7/Create-a-boot-partition I am only allowed 2 links Create a boot partition You must be logged on as an administrator to perform these steps. A boot partition is a partition that contains the files for the Windows operating system. If you want to install a second operating system on your computer (called a dual-boot or multiboot configuration), you need to create another partition on the hard disk, and then install the additional operating system on the new partition. Your hard disk would then have one system partition and two boot partitions. (A system partition is the partition that contains the hardware-related files. These tell the computer where to look to start Windows.) To create a partition on a basic disk, there must be unallocated disk space on your hard disk. With Disk Management, you can create a maximum of three primary partitions on a hard disk. You can create extended partitions, which include logical drives within them, if you need more partitions on the disk. Picture of disk space in Computer ManagementUnallocated disk space If there is no unallocated space, you will either need to create space by shrinking or deleting an existing partition or by using a third-party partitioning tool to repartition your hard disk. For more information, see Can I repartition my hard disk? To create a boot partition Warning Warning If you are installing different versions of Windows, you must install the earliest version first. If you don't do this, your computer may become inoperable. Open Computer Management by clicking the Start button Picture of the Start button, clicking Control Panel, clicking System and Security, clicking Administrative Tools, and then double-clicking Computer Management.? Administrator permission required If you're prompted for an administrator password or confirmation, type the password or provide confirmation. In the left pane, under Storage, click Disk Management. Right-click an unallocated region on your hard disk, and then click New Simple Volume. In the New Simple Volume Wizard, click Next. Type the size of the volume you want to create in megabytes (MB) or accept the maximum default size, and then click Next. Accept the default drive letter or choose a different drive letter to identify the volume, and then click Next. In the Format Partition dialog box, do one of the following: If you don't want to format the volume right now, click Do not format this volume, and then click Next. To format the volume with the default settings, click Next. For more information about formatting, see Formatting disks and drives: frequently asked questions. Review your choices, and then click Finish. I did what you told me @irrational john and this is the screen shot. I ENTERED ubuntu@ubuntu:~$ sudo os-prober computer did not respond so I entered ubuntu@ubuntu:~$ sudo apt-get -y remove dmraid computer responded with Reading package lists... Done Building dependency tree Reading state information... Done The following packages will be REMOVED: dmraid 0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded. After this operation, 141 kB disk space will be freed. (Reading database ... 147515 files and directories currently installed.) Removing dmraid ... update-initramfs is disabled since running on read-only media Processing triggers for man-db ... I entered ubuntu@ubuntu:~$ sudo os-prober Computer Responded with /dev/sda1:Windows 7 (loader):Windows:chain /dev/sda3:Windows Recovery Environment (loader):Windows1:chain ubuntu@ubuntu:~$ ............... @obsessiveFOSS I don't know what is a Grub menu and I do not know what is the Ubuntu boot option The answer you gave to me was correct. This one {This apparently removes the dmraid metadata. After doing that, you can use the desktop icon Install Ubuntu 12.04 LTS to start the Ubuntu installer. This time the Installation Type window should contain the option to Install Ubuntu alongside Windows 7.} This is what I decided to do. I did not see the rest of your help 'till now. Never the less. I think the best thing for me to do now is to get a cheap used laptop and either do a dual installation or just install Ubuntu on to it. This way if I have any issues that I cannot solve like the one I had here, at least I will still have a usable computer to work on and to use to get answers with because I am not an expert like the people on this forum. Thanks a lot I will try to keep learning and do research enough to some day help someone else.

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• sending a $_SESSION array to my class and attempting to get the value fro it in a for loop .php

  - by eoin

  i have a class which in which iam using a method to get information from a session array via a for loop the 2 for loops in each method are used 1.to count total amount of items , and 2. to add up the total price but neither seem to be returning anything. im using the total amount to check it against the mc_gross posted value from an IPN and if the values are equal i plan to commit the sale to a database as it has been verified. for the method where im looking to get the total price im getting 0.00 returned to me. i think ive got the syntax wrong here somehow here is my class for purchase the two methods iam having trouble with are the gettotalcost() and gettotalitems() shown below is my class. <?php class purchase { private $itemnames; // from session array private $amountofitems; // from session array private $itemcost; //session array private $saleid; //posted transaction id value to be used in sale and sale item tables private $orderdate; //get current date time to be entered as datetime in sale table private $lastname; //posted from ipn private $firstname; //posted from ipn private $emailadd; //uses sessionarray value public function __construct($saleid,$firstname,$lastname) { $this->itemnames = $_SESSION['itemnames']; $this->amountofitems =$_SESSION['quantity']; $this->itemcost =$_SESSION['price']; $this->saleid = $saleid; $this->firstname = $firstname; $this->lastname = $lastname; $this->emailadd = $SESSION['username']; mail($myemail, "session vardump ", echo var_dump($_SESSION), "From: [email protected]" ); mail($myemail, "session vardump ",count($_SESSION['itemnames']) , "From: [email protected]" ); } public function commit() { $databaseinst = database::getinstance(); $databaseinst->connect(); $numrows = $databaseinst->querydb($query); //to be completed } public function gettotalitems() { $numitems; $i; for($i=0; $i < count($this->amountofitems);$i++) { $numitems += (int) $this->amountofitems[$i]; } return $numitems; } public function gettotalcost() { $totalcost; $i; for($i=0; $i < count($this->amountofitems);$i++) { $numitems = (int) $this->amountofitems[$i]; $costofitem =doubleval($this->itemcost [$i]); $totalcost += $numitems * $costofitem; } return $totalcost; } } ?> and here is where i create an instance of the class and attempt to use it. include("purchase.php"); $purchase = new purchase($_POST['txn_id'],$_POST['first_name'],$_POST['last_name']); $fullamount = $purchase->gettotalcost(); $fullAmount = number_format($fullAmount, 2); $grossAmount = $_POST['mc_gross']; if ($fullAmount != $grossAmount) { $message = "Possible Price Jack attempt! the amount the customer payed is : " . $grossAmount . " which is not equal to the full amount. the price of the products combined is " . $fullAmount. " the transaction number for which is " . $_POST['txn_id'] . "\n\n\n$req"; mail("XXXXXXXXXXXX", "Price Jack attempt ", $message, "From: [email protected]" ); exit(); // exit } thanks for the help in advance! ive also added these lines to my constructor. the mail returns that there is nothing in the vardump uh oh! mail($myemailaddress, "session vardump ", var_dump($_SESSION), "From: [email protected]" ); also added session_start(); at the top of the constructor and it dont work! help

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• Agile Testing Days 2012 – Day 2 – Learn through disagreement

  - by Chris George

  I think I was in the right place! During Day 1 I kept on reading tweets about Lean Coffee that has happened earlier that morning. It intrigued me and I figured in for a penny in for a pound, and set my alarm for 6:45am. Following the award night the night before, it was _really_ hard getting up when it went off, but I did and after a very early breakfast, set off for the 10 min walk to the Dorint. With Lean Coffee due to start at 07:30, I arrived at the hotel and made my way to one of the hotel bars. I soon realised I was in the right place as although the bar was empty, there was a table with post-it’s and pens! This MUST be the place! The premise of Lean Coffee is to have several small timeboxed discussions. Everyone writes down what they would like to discuss on post-its that are then briefly explained and submitted to the pile. Once everyone is done, the group dot-votes on the topics. The topics are then sorted by the dot vote counts and the discussions begin. Each discussion had 8 mins to start with, which meant it prevented the discussions getting off topic too much. After the time elapsed, the group had a vote whether to extend the discussion by a further 4 mins or move on. Several discussion were had around training, soft skills etc. The conversations were really interesting and there were quite a few good ideas. Overall it was a very enjoyable experience, certainly worth the early start! Make Melly Happy Following Lean Coffee was real coffee, and much needed that was! The first keynote of the day was “Let’s help Melly (Changing Work into Life)”by Jurgen Appelo. Draw lines to track happiness This was a very interesting presentation, and set the day nicely. The theme to the keynote was projects are about the people, more-so than the actual tasks. So he started by showing a photo of an employee ‘Melly’ who looked happy enough. He then stated that she looked happy but actually hated her job. In fact 50% of Americans hate their jobs. He went on to say that the world over 50% of people hate Americans their jobs. Jurgen talked about many ways to reduce the feedback cycle, not only of the project, but of the people management. Ideas such as Happiness doors, happiness tracking (drawing lines on a wall indicating your happiness for that day), kudo boxes (to compliment a colleague for good work). All of these (and more) ideas stimulate conversation amongst the team, lead to early detection of issues and investigation of solutions. I’ve massively simplified Jurgen’s keynote and have certainly not done it justice, so I will post a link to the video once it’s available. Following more coffee, the next talk was “How releasing faster changes testing” by Alexander Schwartz. This is a topic very close to our hearts at the moment, so I was eager to find out any juicy morsels that could help us achieve more frequent releases, and Alex did not disappoint. He started off by confirming something that I have been a firm believer in for a number of years now; adding more people can do more harm than good when trying to release. This is for a number of reasons, but just adding new people to a team at such a critical time can be more of a drain on resources than they add. The alternative is to have the whole team have shared responsibility for faster delivery. So the whole team is responsible for quality and testing. Obviously you will have the test engineers on the project who have the specialist skills, but there is no reason that the entire team cannot do exploratory testing on the product. This links nicely with the Developer Exploratory testing presented by Sigge on Day 1, and certainly something that my team are really striving towards. Focus on cycle time, so what can be done to reduce the time between dev cycles, release cycles. What’s stops a release, what delays a release? all good solid questions that can be answered. Alex suggested that perhaps the product doesn’t need to be fully tested. Doing less testing will reduce the cycle time therefore get the release out faster. He suggested a risk-based approach to planning what testing needs to happen. Reducing testing could have an impact on revenue if it causes harm to customers, so test the ‘right stuff’! Determine a set of tests that are ‘face saving’ or ‘smoke’ tests. These tests cover the core functionality of the product and aim to prevent major embarrassment if these areas were to fail! Amongst many other very good points, Alex suggested that a good approach would be to release after every new feature is added. So do a bit of work -> release, do some more work -> release. By releasing small increments of work, the impact on the customer of bugs being introduced is reduced. Red Pill, Blue Pill The second keynote of the day was “Adaptation and improvisation – but your weakness is not your technique” by Markus Gartner and proved to be another very good presentation. It started off quoting lines from the Matrix which relate to adapting, improvising, realisation and mastery. It has alot of nerds in the room smiling! Markus went on to explain how through deliberate practice ( and a lot of it!) you can achieve mastery, but then you never stop learning. Through methods such as code retreats, testing dojos, workshops you can continually improve and learn. The code retreat idea was one that interested me. It involved pairing to write an automated test for, say, 45 mins, they deleting all the code, finding a different partner and writing the same test again! This is another keynote where the video will speak louder than anything I can write here! Markus did elaborate on something that Lisa and Janet had touched on yesterday whilst busting the myth that “Testers Must Code”. Whilst it is true that to be a tester, you don’t need to code, it is becoming more common that there is this crossover happening where more testers are coding and more programmers are testing. Markus made a special distinction between programmers and developers as testers develop tests code so this helped to make that clear. “Extending Continuous Integration and TDD with Continuous Testing” by Jason Ayers was my next talk after lunch. We already do CI and a bit of TDD on my project team so I was interested to see what this continuous testing thing was all about and whether it would actually work for us. At the start of the presentation I was of the opinion that it just would not work for us because our tests are too slow, and that would be the case for many people. Jason started off by setting the scene and saying that those doing TDD spend between 10-15% of their time waiting for tests to run. This can be reduced by testing less often, reducing the test time but this then increases the risk of introduced bugs not being spotted quickly. Therefore, in comes Continuous Testing (CT). CT systems run your unit tests whenever you save some code and runs them in the background so you can continue working. This is a really nice idea, but to do this, your tests must be fast, independent and reliable. The latter two should be the case anyway, and the first is ideal, but hard! Jason makes several suggestions to make tests fast. Firstly keep the scope of the test small, secondly spin off any expensive tests into a suite which is run, perhaps, overnight or outside of the CT system at any rate. So this started to change my mind, perhaps we could re-engineer our tests, and continuously run the quick ones to give an element of coverage. This talk was very interesting and I’ve already tried a couple of the tools mentioned on our product (Mighty Moose and NCrunch). Sadly due to the way our solution is built, it currently doesn’t work, but we will look at whether we can make this work because this has the potential to be a mini-game-changer for us. Using the wrong data Gojko’s Hierarchy of Quality The final keynote of the day was “Reinventing software quality” by Gojko Adzic. He opened the talk with the statement “We’ve got quality wrong because we are using the wrong data”! Gojko then went on to explain that we should judge a bug by whether the customer cares about it, not by whether we think it’s important. Why spend time fixing issues that the customer just wouldn’t care about and releasing months later because of this? Surely it’s better to release now and get customer feedback? This was another reference to the idea of how it’s better to build the right thing wrong than the wrong thing right. Get feedback early to make sure you’re making the right thing. Gojko then showed something which was very analogous to Maslow’s heirachy of needs. Successful – does it contribute to the business? Useful – does it do what the user wants Usable – does it do what it’s supposed to without breaking Performant/Secure – is it secure/is the performance acceptable Deployable Functionally ok – can it be deployed without breaking? He then explained that User Stories should focus on change. In other words they should focus on the users needs, not the users process. Describe what the change will be, how that change will happen then measure it! Networking and Beer Following the day’s closing keynote, there were drinks and nibble for the ‘Networking’ evening. This was a great opportunity to talk to people. I find approaching strangers very uncomfortable but once again, when in Rome! Pete Walen and I had a long conversation about only fixing issues that the customer cares about versus fixing issues that make you proud of your software! Without saying much, and asking the right questions, Pete made me re-evaluate my thoughts on the matter. Clever, very clever!  Oh and he ‘bought’ me a beer! My Takeaway Triple from Day 2: release small and release often to minimize issues creeping in and get faster feedback from ‘the real world’ Focus on issues that the customers care about, not what we think is important It’s okay to disagree with someone, even if they are well respected agile testing gurus, that’s how discussion and learning happens!  

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• initializing structs using user-input information

  - by johnny boy

  I am trying to make a program that works with poker (texas holdem) starting hands; each hand has a value from 1 to 169, and i want to be able to input each card and whether they are suited or not, and have those values correspond to a series of structs. Here is the code so far, i cant seem to get it to work (im a beginning programmer). oh and im using visual studio 2005 by the way #include "stdafx.h" #include <iostream> int main() { using namespace std; struct FirstCard { struct SecondCard { int s; //suited int n; //non-suited }; SecondCard s14; SecondCard s13; SecondCard s12; SecondCard s11; SecondCard s10; SecondCard s9; SecondCard s8; SecondCard s7; SecondCard s6; SecondCard s5; SecondCard s4; SecondCard s3; SecondCard s2; }; FirstCard s14; //ace FirstCard s13; //king FirstCard s12; //queen FirstCard s11; //jack FirstCard s10; FirstCard s9; FirstCard s8; FirstCard s7; FirstCard s6; FirstCard s5; FirstCard s4; FirstCard s3; FirstCard s2; s14.s14.n = 169; // these are the values that each combination s13.s13.n = 168; // will evaluate to, would eventually have s12.s12.n = 167; // hand combinations all the way down to 1 s11.s11.n = 166; s14.s13.s = 165; s14.s13.s = 164; s10.s10.n = 163; //10, 10, nonsuited s14.s13.n = 162; s14.s11.s = 161; s13.s12.s = 160;// king, queen, suited s9.s9.n = 159; s14.s10.s = 158; s14.s12.n = 157; s13.s11.s = 156; s8.s8.n = 155; s12.s11.s = 154; s13.s10.s = 153; s14.s9.s = 152; s14.s11.n = 151; cout << "enter first card: " << endl; cin >> somthing?//no idea what to put here, but this would somehow //read out the user input (a number from 2 to 14) //and assign it to the corresponding struct cout << firstcard.secondcard.suited_or_not << endl; //this would change depending //on what the user inputs system("Pause"); }

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• How do you stop scripters from slamming your website hundreds of times a second?

  - by davebug

  [update] I've accepted an answer, as lc deserves the bounty due to the well thought-out answer, but sadly, I believe we're stuck with our original worst case scenario: CAPTCHA everyone on purchase attempts of the crap. Short explanation: caching / web farms make it impossible for us to actually track hits, and any workaround (sending a non-cached web-beacon, writing to a unified table, etc.) slows the site down worse than the bots would. There is likely some pricey bit of hardware from Cisco or the like that can help at a high level, but it's hard to justify the cost if CAPTCHAing everyone is an alternative. I'll attempt to do a more full explanation in here later, as well as cleaning this up for future searchers (though others are welcome to try, as it's community wiki). I've added bounty to this question and attempted to explain why the current answers don't fit our needs. First, though, thanks to all of you who have thought about this, it's amazing to have this collective intelligence to help work through seemingly impossible problems. I'll be a little more clear than I was before: This is about the bag o' crap sales on woot.com. I'm the president of Woot Workshop, the subsidiary of Woot that does the design, writes the product descriptions, podcasts, blog posts, and moderates the forums. I work in the css/html world and am only barely familiar with the rest of the developer world. I work closely with the developers and have talked through all of the answers here (and many other ideas we've had). Usability of the site is a massive part of my job, and making the site exciting and fun is most of the rest of it. That's where the three goals below derive. CAPTCHA harms usability, and bots steal the fun and excitement out of our crap sales. To set up the scenario a little more, bots are slamming our front page tens of times a second screenscraping (and/or scanning our rss) for the Random Crap sale. The moment they see that, it triggers a second stage of the program that logs in, clicks I want One, fills out the form, and buys the crap. In current (2/6/2009) order of votes: lc: On stackoverflow and other sites that use this method, they're almost always dealing with authenticated (logged in) users, because the task being attempted requires that. On Woot, anonymous (non-logged) users can view our home page. In other words, the slamming bots can be non-authenticated (and essentially non-trackable except by IP address). So we're back to scanning for IPs, which a) is fairly useless in this age of cloud networking and spambot zombies and b) catches too many innocents given the number of businesses that come from one IP address (not to mention the issues with non-static IP ISPs and potential performance hits to trying to track this). Oh, and having people call us would be the worst possible scenario. Can we have them call you? BradC Ned Batchelder's methods look pretty cool, but they're pretty firmly designed to defeat bots built for a network of sites. Our problem is bots are built specifically to defeat our site. Some of these methods could likely work for a short time until the scripters evolved their bots to ignore the honeypot, screenscrape for nearby label names instead of form ids, and use a javascript-capable browser control. lc again "Unless, of course, the hype is part of you

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• overloaded stream insetion operator with a vector

  - by julz666

  hi, i'm trying to write an overloaded stream insertion operator for a class who's only member is a vector. i dont really know what i'm doing. (lets make that clear) it's a vector of "Points" which is a struct containing two doubles. i figure what i want is to insert user input (a bunch of doubles) into a stream that i then send to a modifier method? i keep working off other stream insertion examples such as... std::ostream& operator<< (std::ostream& o, Fred const& fred) { return o << fred.i_; } but when i try a similar..... istream & operator >> (istream &inStream, Polygon &vertStr) { inStream >> ws; inStream >> vertStr.vertices; return inStream; } i get an error "no match for operator etc etc. if i leave off the .vertices it compiles but i figure it's not right? (vertices is the name of my vector ) and even if it is right, i dont actually know what syntax to use in my driver to use it? also not %100 on what my modifier method needs to look like. here's my Polygon class //header #ifndef POLYGON_H #define POLYGON_H #include "Segment.h" #include <vector> class Polygon { friend std::istream & operator >> (std::istream &inStream, Polygon &vertStr); public: //Constructor Polygon(const Point &theVerts); //Default Constructor Polygon(); //Copy Constructor Polygon(const Polygon &polyCopy); //Accessor/Modifier methods inline std::vector<Point> getVector() const {return vertices;} //Return number of Vector elements inline int sizeOfVect() const {return (int) vertices.capacity();} //add Point elements to vector inline void setVertices(const Point &theVerts){vertices.push_back (theVerts);} private: std::vector<Point> vertices; }; #endif //Body using namespace std; #include "Polygon.h" // Constructor Polygon::Polygon(const Point &theVerts) { vertices.push_back (theVerts); } //Copy Constructor Polygon::Polygon(const Polygon &polyCopy) { vertices = polyCopy.vertices; } //Default Constructor Polygon::Polygon(){} istream & operator >> (istream &inStream, Polygon &vertStr) { inStream >> ws; inStream >> vertStr; return inStream; } any help greatly appreciated, sorry to be so vague, a lecturer has just kind of given us a brief example of stream insertion then left us on our own thanks. oh i realise there are probably many other problems that need fixing

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• opengl 3d texture issue

  - by user1478217

  Hi i'm trying to use a 3d texture in opengl to implement volume rendering. Each voxel has an rgba colour value and is currently rendered as a screen facing quad.(for testing purposes). I just can't seem to get the sampler to give me a colour value in the shader. The quads always end up black. When I change the shader to generate a colour (based on xyz coords) then it works fine. I'm loading the texture with the following code: glGenTextures(1, &tex3D); glBindTexture(GL_TEXTURE_3D, tex3D); unsigned int colours[8]; colours[0] = Colour::AsBytes<unsigned int>(Colour::Blue); colours[1] = Colour::AsBytes<unsigned int>(Colour::Red); colours[2] = Colour::AsBytes<unsigned int>(Colour::Green); colours[3] = Colour::AsBytes<unsigned int>(Colour::Magenta); colours[4] = Colour::AsBytes<unsigned int>(Colour::Cyan); colours[5] = Colour::AsBytes<unsigned int>(Colour::Yellow); colours[6] = Colour::AsBytes<unsigned int>(Colour::White); colours[7] = Colour::AsBytes<unsigned int>(Colour::Black); glTexImage3D(GL_TEXTURE_3D, 0, GL_RGBA, 2, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, colours); The colours array contains the correct data, i.e. the first four bytes have values 0, 0, 255, 255 for blue. Before rendering I bind the texture to the 2nd texture unit like so: glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_3D, tex3D); And render with the following code: shaders["DVR"]->Use(); shaders["DVR"]->Uniforms["volTex"].SetValue(1); shaders["DVR"]->Uniforms["World"].SetValue(Mat4(vl_one)); shaders["DVR"]->Uniforms["viewProj"].SetValue(cam->GetViewTransform() * cam->GetProjectionMatrix()); QuadDrawer::DrawQuads(8); I have used these classes for setting shader params before and they work fine. The quaddrawer draws eight instanced quads. The vertex shader code looks like this: #version 330 layout(location = 0) in vec2 position; layout(location = 1) in vec2 texCoord; uniform sampler3D volTex; ivec3 size = ivec3(2, 2, 2); uniform mat4 World; uniform mat4 viewProj; smooth out vec4 colour; void main() { vec3 texCoord3D; int num = gl_InstanceID; texCoord3D.x = num % size.x; texCoord3D.y = (num / size.x) % size.y; texCoord3D.z = (num / (size.x * size.y)); texCoord3D /= size; texCoord3D *= 2.0; texCoord3D -= 1.0; colour = texture(volTex, texCoord3D); //colour = vec4(texCoord3D, 1.0); gl_Position = viewProj * World * vec4(texCoord3D, 1.0) + (vec4(position.x, position.y, 0.0, 0.0) * 0.05); } uncommenting the line where I set the colour value equal to the texcoord works fine, and makes the quads coloured. The fragment shader is simply: #version 330 smooth in vec4 colour; out vec4 outColour; void main() { outColour = colour; } So my question is, what am I doing wrong, why is the sampler not getting any colour values from the 3d texture? [EDIT] Figured it out but can't self answer (new user): As soon as I posted this I figured it out, I'll put the answer up to help anyone else (it's not specifically a 3d texture issue, and i've also fallen afoul of it before, D'oh!). I didn't generate mipmaps for the texture, and the default magnification/minification filters weren't set to either GL_LINEAR, or GL_NEAREST. Boom! no textures. Same thing happens with 2d textures.

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• ublas::bounded_vector<> being resized?

  - by n2liquid

  Now, seriously... I'll refrain from using bad words here because we're talking about the Boost fellows. It MUST be my mistake to see things this way, but I can't understand why, so I'll ask it here; maybe someone can enlighten me in this matter. Here it goes: uBLAS has this nice class template called bounded_vector<> that's used to create fixed-size vectors (or so I thought). From the Effective uBLAS wiki (http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl?Effective_UBLAS): The default uBLAS vector and matrix types are of variable size. Many linear algebra problems involve vectors with fixed size. 2 and 3 elements are common in geometry! Fixed size storage (akin to C arrays) can be implemented efficiently as it does not involve the overheads (heap management) associated with dynamic storage. uBLAS implements fixed sizes by changing the underling storage of a vector/matrix to a "bounded_array" from the default "unbounded_array". Alright, this bounded_vector<> thing is used to free you from specifying the underlying storage of the vector to a bounded_array<> of the specified size. Here I ask you: doesn't it look like this bounded vector thing has fixed size to you? Well, it doesn't have. At first I felt betrayed by the wiki, but then I reconsidered the meaning of "bounded" and I think I can let it pass. But in case you, like me (I'm still uncertain), is still wondering if this makes sense, what I found out is that the bounded_vector<> actually can be resized, it may only not be greater than the size specified as template parameter. So, first off, do you think they've had a good reason not to make a real fixed<< size vector or matrix type? Do you think it's okay to "sell" this bounded -- as opposed to fixed-size -- vector to the users of my library as a "fixed-size" vector replacement, even named "Vector3" or "Vector2", like the Effective uBLAS wiki did? Do you think I should somehow implement a vector with fixed size for this purpose? If so, how? (Sorry, but I'm really new to uBLAS; just tried it today) I am developing a 3D game. Should uBLAS be used for the calculations involved in this ("hey, geometry!", per Effective uBLAS wiki)? What replacement would you suggest, if not? -- edit And just in case, yes, I've read this warning: It should be noted that this only changes the storage uBLAS uses for the vector3. uBLAS will still use all the same algorithm (which assume a variable size) to manipulate the vector3. In practice this seems to have no negative impact on speed. The above runs just as quickly as a hand crafted vector3 which does not use uBLAS. The only negative impact is that the vector3 always store a "size" member which in this case is redundant [or isn't it? I mean......]. I see it uses the same algorithm, assuming a variable size, but if an operation were to actually change its size, shouldn't it be stopped (assertion)? ublas::bounded_vector<float,3> v3; ublas::bounded_vector<float,2> v2; v3 = v2; std::cout << v3.size() << '\n'; // prints 2 Oh, come on, isn't this just plain betrayal?

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• Of transactions and Mongo

  - by Nuri Halperin

  Originally posted on: http://geekswithblogs.net/nuri/archive/2014/05/20/of-transactions-and-mongo-again.aspxWhat's the first thing you hear about NoSQL databases? That they lose your data? That there's no transactions? No joins? No hope for "real" applications? Well, you *should* be wondering whether a certain of database is the right one for your job. But if you do so, you should be wondering that about "traditional" databases as well! In the spirit of exploration let's take a look at a common challenge: You are a bank. You have customers with accounts. Customer A wants to pay B. You want to allow that only if A can cover the amount being transferred. Let's looks at the problem without any context of any database engine in mind. What would you do? How would you ensure that the amount transfer is done "properly"? Would you prevent a "transaction" from taking place unless A can cover the amount? There are several options: Prevent any change to A's account while the transfer is taking place. That boils down to locking. Apply the change, and allow A's balance to go below zero. Charge person A some interest on the negative balance. Not friendly, but certainly a choice. Don't do either. Options 1 and 2 are difficult to attain in the NoSQL world. Mongo won't save you headaches here either. Option 3 looks a bit harsh. But here's where this can go: ledger. See, and account doesn't need to be represented by a single row in a table of all accounts with only the current balance on it. More often than not, accounting systems use ledgers. And entries in ledgers - as it turns out – don't actually get updated. Once a ledger entry is written, it is not removed or altered. A transaction is represented by an entry in the ledger stating and amount withdrawn from A's account and an entry in the ledger stating an addition of said amount to B's account. For sake of space-saving, that entry in the ledger can happen using one entry. Think {Timestamp, FromAccountId, ToAccountId, Amount}. The implication of the original question – "how do you enforce non-negative balance rule" then boils down to: Insert entry in ledger Run validation of recent entries Insert reverse entry to roll back transaction if validation failed. What is validation? Sum up the transactions that A's account has (all deposits and debits), and ensure the balance is positive. For sake of efficiency, one can roll up transactions and "close the book" on transactions with a pseudo entry stating balance as of midnight or something. This lets you avoid doing math on the fly on too many transactions. You simply run from the latest "approved balance" marker to date. But that's an optimization, and premature optimizations are the root of (some? most?) evil.. Back to some nagging questions though: "But mongo is only eventually consistent!" Well, yes, kind of. It's not actually true that Mongo has not transactions. It would be more descriptive to say that Mongo's transaction scope is a single document in a single collection. A write to a Mongo document happens completely or not at all. So although it is true that you can't update more than one documents "at the same time" under a "transaction" umbrella as an atomic update, it is NOT true that there' is no isolation. So a competition between two concurrent updates is completely coherent and the writes will be serialized. They will not scribble on the same document at the same time. In our case - in choosing a ledger approach - we're not even trying to "update" a document, we're simply adding a document to a collection. So there goes the "no transaction" issue. Now let's turn our attention to consistency. What you should know about mongo is that at any given moment, only on member of a replica set is writable. This means that the writable instance in a set of replicated instances always has "the truth". There could be a replication lag such that a reader going to one of the replicas still sees "old" state of a collection or document. But in our ledger case, things fall nicely into place: Run your validation against the writable instance. It is guaranteed to have a ledger either with (after) or without (before) the ledger entry got written. No funky states. Again, the ledger writing *adds* a document, so there's no inconsistent document state to be had either way. Next, we might worry about data loss. Here, mongo offers several write-concerns. Write-concern in Mongo is a mode that marshals how uptight you want the db engine to be about actually persisting a document write to disk before it reports to the application that it is "done". The most volatile, is to say you don't care. In that case, mongo would just accept your write command and say back "thanks" with no guarantee of persistence. If the server loses power at the wrong moment, it may have said "ok" but actually no written the data to disk. That's kind of bad. Don't do that with data you care about. It may be good for votes on a pole regarding how cute a furry animal is, but not so good for business. There are several other write-concerns varying from flushing the write to the disk of the writable instance, flushing to disk on several members of the replica set, a majority of the replica set or all of the members of a replica set. The former choice is the quickest, as no network coordination is required besides the main writable instance. The others impose extra network and time cost. Depending on your tolerance for latency and read-lag, you will face a choice of what works for you. It's really important to understand that no data loss occurs once a document is flushed to an instance. The record is on disk at that point. From that point on, backup strategies and disaster recovery are your worry, not loss of power to the writable machine. This scenario is not different from a relational database at that point. Where does this leave us? Oh, yes. Eventual consistency. By now, we ensured that the "source of truth" instance has the correct data, persisted and coherent. But because of lag, the app may have gone to the writable instance, performed the update and then gone to a replica and looked at the ledger there before the transaction replicated. Here are 2 options to deal with this. Similar to write concerns, mongo support read preferences. An app may choose to read only from the writable instance. This is not an awesome choice to make for every ready, because it just burdens the one instance, and doesn't make use of the other read-only servers. But this choice can be made on a query by query basis. So for the app that our person A is using, we can have person A issue the transfer command to B, and then if that same app is going to immediately as "are we there yet?" we'll query that same writable instance. But B and anyone else in the world can just chill and read from the read-only instance. They have no basis to expect that the ledger has just been written to. So as far as they know, the transaction hasn't happened until they see it appear later. We can further relax the demand by creating application UI that reacts to a write command with "thank you, we will post it shortly" instead of "thank you, we just did everything and here's the new balance". This is a very powerful thing. UI design for highly scalable systems can't insist that the all databases be locked just to paint an "all done" on screen. People understand. They were trained by many online businesses already that your placing of an order does not mean that your product is already outside your door waiting (yes, I know, large retailers are working on it... but were' not there yet). The second thing we can do, is add some artificial delay to a transaction's visibility on the ledger. The way that works is simply adding some logic such that the query against the ledger never nets a transaction for customers newer than say 15 minutes and who's validation flag is not set. This buys us time 2 ways: Replication can catch up to all instances by then, and validation rules can run and determine if this transaction should be "negated" with a compensating transaction. In case we do need to "roll back" the transaction, the backend system can place the timestamp of the compensating transaction at the exact same time or 1ms after the original one. Effectively, once A or B visits their ledger, both transactions would be visible and the overall balance "as of now" would reflect no change.  The 2 transactions (attempted/ reverted) would be visible , since we do actually account for the attempt. Hold on a second. There's a hole in the story: what if several transfers from A to some accounts are registered, and 2 independent validators attempt to compute the balance concurrently? Is there a chance that both would conclude non-sufficient-funds even though rolling back transaction 100 would free up enough for transaction 117 (some random later transaction)? Yes. there is that chance. But the integrity of the business rule is not compromised, since the prime rule is don't dispense money you don't have. To minimize or eliminate this scenario, we can also assign a single validation process per origin account. This may seem non-scalable, but it can easily be done as a "sharded" distribution. Say we have 11 validation threads (or processing nodes etc.). We divide the account number space such that each validator is exclusively responsible for a certain range of account numbers. Sounds cunningly similar to Mongo's sharding strategy, doesn't it? Each validator then works in isolation. More capacity needed? Chop the account space into more chunks. So where  are we now with the nagging questions? "No joins": Huh? What are those for? "No transactions": You mean no cross-collection and no cross-document transactions? Granted - but don't always need them either. "No hope for real applications": well... There are more issues and edge cases to slog through, I'm sure. But hopefully this gives you some ideas of how to solve common problems without distributed locking and relational databases. But then again, you can choose relational databases if they suit your problem.

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• C++: casting to void* and back

  - by MInner

  * ---Edit - now the whole sourse* When I debug it on the end, "get" and "value" have different values! Probably, I convert to void* and back to User the wrong way? #include <db_cxx.h> #include <stdio.h> struct User{ User(){} int name; int town; User(int a){}; inline int get_index(int a){ return town; } //for another stuff }; int main(){ try { DbEnv* env = new DbEnv(NULL); env->open("./", DB_CREATE | DB_INIT_MPOOL | DB_THREAD | DB_INIT_LOCK | DB_INIT_TXN | DB_RECOVER | DB_INIT_LOG, 0); Db* datab = new Db(env, 0); datab->open(NULL, "db.dbf", NULL, DB_BTREE, DB_CREATE | DB_AUTO_COMMIT, 0); Dbt key, value, get; char a[10] = "bbaaccd"; User u; u.name = 1; u.town = 34; key.set_data(a); key.set_size(strlen(a) + 1 ); value.set_data((void*)&u); value.set_size(sizeof(u)); get.set_flags(DB_DBT_MALLOC); DbTxn* txn; env->txn_begin(NULL, &txn, 0); datab->put(txn, &key, &value, 0); datab->get(txn, &key, &get, 0); txn->commit(0); User g; g = *((User*)&get); printf("%d", g.town); getchar(); return 0; }catch (DbException &e){ printf("%s", e.what()); getchar(); } solution create a kind of "serializator" what would convert all POD's into void* and then will unite these pieces PS Or I'd rewrite User into POD type and everything will be all right, I hope. Add It's strange, but... I cast a defenetly non-pod object to void* and back (it has std::string inside) and it's all right (without sending it to the db and back). How could it be? And after I cast and send 'trough' db defenetly pod object (no extra methods, all members are pod, it's a simple struct {int a; int b; ...}) I get back dirted one. What's wrong with my approach? Add about week after first 'add' Damn... I've compiled it ones, just for have a look at which kind of dirt it returnes, and oh! it's okay!... I can't ! ... AAh!.. Lord... A reasonable question (in 99.999 percent of situations right answer is 'my', but... here...) - whos is this fault? My or VSs?

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• can't get texture to work

  - by user583713

  It been a while since I use android opengl but for what ever reason I get a white squre box and not the texture I what on the screen. Oh I do not think this would matter but just in case I put a linerlayout view first then the surfaceview on but anyway Here my code: public class GameEngine { private float vertices[]; private float textureUV[]; private int[] textureId = new int[1]; private FloatBuffer vertextBuffer; private FloatBuffer textureBuffer; private short indices[] = {0,1,2,2,1,3}; private ShortBuffer indexBuffer; private float x, y, z; private float rot, rotX, rotY, rotZ; public GameEngine() { } public void setEngine(float x, float y, float vertices[]){ this.x = x; this.y = y; this.vertices = vertices; ByteBuffer vbb = ByteBuffer.allocateDirect(this.vertices.length * 4); vbb.order(ByteOrder.nativeOrder()); vertextBuffer = vbb.asFloatBuffer(); vertextBuffer.put(this.vertices); vertextBuffer.position(0); vertextBuffer.clear(); ByteBuffer ibb = ByteBuffer.allocateDirect(indices.length * 2); ibb.order(ByteOrder.nativeOrder()); indexBuffer = ibb.asShortBuffer(); indexBuffer.put(indices); indexBuffer.position(0); indexBuffer.clear(); } public void draw(GL10 gl){ gl.glLoadIdentity(); gl.glTranslatef(x, y, z); gl.glRotatef(rot, rotX, rotY, rotZ); gl.glBindTexture(GL10.GL_TEXTURE_2D, textureId[0]); gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY); gl.glVertexPointer(2, GL10.GL_FLOAT, 0, vertextBuffer); gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer); gl.glDrawElements(GL10.GL_TRIANGLES, indices.length, GL10.GL_UNSIGNED_SHORT, indexBuffer); gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY); } public void LoadTexture(float textureUV[], GL10 gl, InputStream is) throws IOException{ this.textureUV = textureUV; ByteBuffer tbb = ByteBuffer.allocateDirect(this.textureUV.length * 4); tbb.order(ByteOrder.nativeOrder()); textureBuffer = tbb.asFloatBuffer(); textureBuffer.put(this.textureUV); textureBuffer.position(0); textureBuffer.clear(); Bitmap bitmap = null; try{ bitmap = BitmapFactory.decodeStream(is); }finally{ try{ is.close(); is = null; gl.glGenTextures(1, textureId,0); gl.glBindTexture(GL10.GL_TEXTURE_2D, textureId[0]); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR); //Different possible texture parameters, e.g. GL10.GL_CLAMP_TO_EDGE gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S, GL10.GL_REPEAT); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T, GL10.GL_REPEAT); //Use the Android GLUtils to specify a two-dimensional texture image from our bitmap GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0); gl.glBlendFunc(GL10.GL_SRC_ALPHA, GL10.GL_ONE_MINUS_SRC_ALPHA); //Clean up gl.glBindTexture(GL10.GL_TEXTURE_2D, textureId[0]); bitmap.recycle(); }catch(IOException e){ } } } public void setVector(float x, float y, float z){ this.x = x; this.y = y; this.z = z; } public void setRot(float rot, float x, float y, float z){ this.rot = rot; this.rotX = x; this.rotY = y; this.rotZ = z; } public float getZ(){ return z; } }

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• reloading page while an ajax request in progress gives empty response and status as zero

  - by Jayapal Chandran

  Hi, Browser is firefox 3.0.10 I am requesting a page using ajax. The response is in progress may be in readyState less than 4. In this mean time i am trying to reload the page. What happens is the request ends giving an empty response. I used alert to find what string has been given as response text. I assume that by this time the ready state 4 is reached. why it is empty string. when i alert the xmlhttpobject.status it displayed 0. when i alert the xmlhttpobject.statusText an exception occurs stating that NOT AVAILABLE. when i read in the document http://www.devx.com/webdev/Article/33024/0/page/2 it said for 3 and 4 status and statusText are available but when i tested only status is available but not satausText Here is a sample code. consider that i have requested a page and my callback function is as follows function cb(rt) { if(rt.readyState==4) { alert(rt.status); alert(rt.statusText); // which throws an exception } } and my server side script is as follows sleep(30); //flushing little drop down code besides these i noticed the following... assume again i am requesting the above script using ajax. now there will be an idle time till 30 seconds is over before that 30 seconds i press refresh. i got xmlhttpobject.status as 0 but still the browser did not reload the page untill that 30 seconds. WHY? so what is happening when i refresh a page before an ajax request is complete is the status value is set to zero and the ready state is set to 4 but the page still waits for the response from the server to end... what is happening... THE REASON FOR ME TO FACE SOME THING LIKE THIS IS AS FOLLOWS. when ever i do an ajax request ... if the process succeeded like inserting some thing or deleting something i popup a div stating that updated successfully and i will reload the page. but if there is any error then i do not reload the page instead i just alert that unable to process this request. what happens if the user reloads the page before any of this request is complete is i get an empty response which in my calculation is there is a server error. so i was debugging the ajax response to filter out that the connection has been interrupted because the user had pressed reload. so in this time i don't want to display unable to process this request when the user reloads the page before the request has been complete. oh... a long story. IT IS A LONG DESCRIPTION SO THAT I CAN MAKE EXPERTS UNDERSTAND MY DOUBT. so what i want form the above. any type of answer would clear my mind. or i would like to say all type of answers. EDIT: 19 dec. If i did not get any correct answer then i would delete this question and will rewrite with examples. else i will accept after experimenting.

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• Suggestions on how to map from Domain (ORM) objects to Data Transfer Objects (DTO)

  - by FryHard

  The current system that I am working on makes use of Castle Activerecord to provide ORM (Object Relational Mapping) between the Domain objects and the database. This is all well and good and at most times actually works well! The problem comes about with Castle Activerecords support for asynchronous execution, well, more specifically the SessionScope that manages the session that objects belong to. Long story short, bad stuff happens! We are therefore looking for a way to easily convert (think automagically) from the Domain objects (who know that a DB exists and care) to the DTO object (who know nothing about the DB and care not for sessions, mapping attributes or all thing ORM). Does anyone have suggestions on doing this. For the start I am looking for a basic One to One mapping of object. Domain object Person will be mapped to say PersonDTO. I do not want to do this manually since it is a waste. Obviously reflection comes to mind, but I am hoping with some of the better IT knowledge floating around this site that "cooler" will be suggested. Oh, I am working in C#, the ORM objects as said before a mapped with Castle ActiveRecord. Example code: By @ajmastrean's request I have linked to an example that I have (badly) mocked together. The example has a capture form, capture form controller, domain objects, activerecord repository and an async helper. It is slightly big (3MB) because I included the ActiveRecored dll's needed to get it running. You will need to create a database called ActiveRecordAsync on your local machine or just change the .config file. Basic details of example: The Capture Form The capture form has a reference to the contoller private CompanyCaptureController MyController { get; set; } On initialise of the form it calls MyController.Load() private void InitForm () { MyController = new CompanyCaptureController(this); MyController.Load(); } This will return back to a method called LoadComplete() public void LoadCompleted (Company loadCompany) { _context.Post(delegate { CurrentItem = loadCompany; bindingSource.DataSource = CurrentItem; bindingSource.ResetCurrentItem(); //TOTO: This line will thow the exception since the session scope used to fetch loadCompany is now gone. grdEmployees.DataSource = loadCompany.Employees; }, null); } } this is where the "bad stuff" occurs, since we are using the child list of Company that is set as Lazy load. The Controller The controller has a Load method that was called from the form, it then calls the Asyc helper to asynchronously call the LoadCompany method and then return to the Capture form's LoadComplete method. public void Load () { new AsyncListLoad<Company>().BeginLoad(LoadCompany, Form.LoadCompleted); } The LoadCompany() method simply makes use of the Repository to find a know company. public Company LoadCompany() { return ActiveRecordRepository<Company>.Find(Setup.company.Identifier); } The rest of the example is rather generic, it has two domain classes which inherit from a base class, a setup file to instert some data and the repository to provide the ActiveRecordMediator abilities.

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• web application with secured sections, sessions and related trouble

  - by spirytus

  I would like to create web application with admin/checkout sections being secured. Assuming I have SSL set up for subdomain.mydomain.com I would like to make sure that all that top-secret stuff ;) like checkout pages and admin section is transferred securely. Would it be ok to structure my application as below? subdomain.mydomain.com adminSectionFolder adminPage1.php adminPage2.php checkoutPagesFolder checkoutPage1.php checkoutPage2.php checkoutPage3.php homepage.php loginPage.php someOtherPage.php someNonSecureFolder nonSecurePage1.php nonSecurePage2.php nonSecurePage3.php imagesFolder image1.jpg image2.jpg image3.jpg Users would access my web application via http as there is no need for SSL for homepage and similar. Checkout/admin pages would have to be accessed via https though (that I would ensure via .htaccess redirects). I would also like to have login form on every page of the site, including non-secure pages. Now my questions are: if I have form on non-secure page e.g http://subdomain.mydomain.com/homepage.php and that form sends data to http://subdomain.mydomain.com/loginPage.php, is data being send encrypted as if it were sent from https://subdomain.mydomain.com/homepage.php? I do realize users will not see padlock, but browser still should encrypt it, is it right? If on secure page loginPage.php (or any other accessed via https for that instance) I created session, session ID would be assigned, and in case of my web app. something like username of the logged in user. Would I be able to access these session variable from http://subdomain.mydomain.com/homepage.php to for example display greeting message? If session ID is stored in cookies then it would be trouble I assume, but could someone clarify how it should be done? It seems important to have username and password send over SSL. Related to above question I think.. would it actually make any sense to have login secured via SSL so usenrame/password would be transferred securely, and then session ID being transferred with no SSL? I mean wouldnt it be the same really if someone caught username and password being transferred, or caught session ID? Please let me know if I make sense here cause it feels like I'm missing something important. EDIT: I came up with idea but again please let me know if that would work. Having above, so assuming that sharing session between http and https is as secure as login in user via plain http (not https), I guess on all non secure pages, like homepage etc. I could check if user is already logged in, and if so from php redirect to https version of same page. So user fills in login form from homepage.php, over ssl details are send to backend so probably https://.../homepage.php. Trying to access http://.../someOtherPage.php script would always check if session is created and if so redirect user to https version of this page so https://.../someOtherPage.php. Would that work? 4.To avoid browser popping message "this page contains non secure items..." my links to css, images and all assets, e.g. in case of http://subdomain.mydomain.com/checkoutPage1.php should be absolute so "/images/image1.jpg" or relative so "../images/image1.jpg"? I guess one of those would have to work :) wow that's long post, thanks for your patience if you got that far and any answers :) oh yeh and I use php/apache on shared hosting

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• how convert this c# cod to php

  - by user3694473

  I'm trying to convert this class from C# to php and i wante to convert this c# class to php ... how i can do it Thanks in advance hi I'm trying to convert this class from C# to php and i wante to convert this c# class to php ... how i can do it Thanks in advance public class CreateCode { public string SazBon(string MM) { string RET = ""; string[] ME = new string[25]; for (int i = 1; i < MM.Length; i += 2) { ME[i] = MM[i - 1].ToString(); } for (int j = 0; j < MM.Length; j += 2) { ME[j] = MM[j + 1].ToString(); } ME[20] = "1"; ME[21] = "OH"; ME[22] = "23"; ME[23] = "fXC"; ME[24] = "5"; ME[5] = ME[14]; ME[13] = ME[23]; ME[2] = ME[22]; ME[18] = ME[21]; ME[23] = ME[11]; ME[19] = ME[0]; foreach (string item in ME) { RET += item; } string BACK = Encrypt(RET, RET, 256); BACK = encryptString(BACK); return BACK; } string encryptString(string strToEncrypt) // md5 { UTF8Encoding ue = new UTF8Encoding(); byte[] bytes = ue.GetBytes(strToEncrypt); MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider(); byte[] hashBytes = md5.ComputeHash(bytes); // Bytes to string return System.Text.RegularExpressions.Regex.Replace (BitConverter.ToString(hashBytes), "-", "").ToLower(); } private byte[] Encrypt(byte[] clearData, byte[] Key, byte[] IV) { MemoryStream ms = new MemoryStream(); Rijndael alg = Rijndael.Create(); alg.Key = Key; alg.IV = IV; CryptoStream cs = new CryptoStream(ms, alg.CreateEncryptor(), CryptoStreamMode.Write); cs.Write(clearData, 0, clearData.Length); cs.Close(); byte[] encryptedData = ms.ToArray(); return encryptedData; } byte[] A; private string Encrypt(string Data, string Password, int Bits) { byte[] clearBytes = System.Text.Encoding.Unicode.GetBytes(Data); PasswordDeriveBytes pdb = new PasswordDeriveBytes(Password, new byte[] { 0x00, 0x01, 0x02, 0x1C, 0x1D, 0x1E, 0x03, 0x04, 0x05, 0x0F, 0x20, 0x21, 0xAD, 0xAF, 0xA4 }); if (Bits == 128) { byte[] encryptedData = Encrypt(clearBytes, pdb.GetBytes(16), pdb.GetBytes(16)); return Convert.ToBase64String(encryptedData); } else if (Bits == 192) { byte[] encryptedData = Encrypt(clearBytes, pdb.GetBytes(24), pdb.GetBytes(16)); return Convert.ToBase64String(encryptedData); } else if (Bits == 256) { byte[] encryptedData = Encrypt(clearBytes, pdb.GetBytes(32), pdb.GetBytes(16)); return Convert.ToBase64String(encryptedData); } else { return string.Concat(Bits); } } // AES }

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• Stumbling Through: Visual Studio 2010 (Part IV)

  So finally we get to the fun part the fruits of all of our middle-tier/back end labors of generating classes to interface with an XML data source that the previous posts were about can now be presented quickly and easily to an end user.  I think.  Well see.  Well be using a WPF window to display all of our various MFL information that weve collected in the two XML files, and well provide a means of adding, updating and deleting each of these entities using as little code as possible.  Additionally, I would like to dig into the performance of this solution as well as the flexibility of it if were were to modify the underlying XML schema.  So first things first, lets create a WPF project and include our xml data in a data folder within.  On the main window, well drag out the following controls: A combo box to contain all of the teams A list box to show the players of the selected team, along with add/delete player buttons A text box tied to the selected players name, with a save button to save any changes made to the player name A combo box of all the available positions, tied to the currently selected players position A data grid tied to the statistics of the currently selected player, with add/delete statistic buttons This monstrosity of a form and its associated project will look like this (dont forget to reference the DataFoundation project from the Presentation project): To get to the visual data binding, as we learned in a previous post, you have to first make sure the project containing your bindable classes is compiled.  Do so, and then open the Data Sources pane to add a reference to the Teams and Positions classes in the DataFoundation project: Why only Team and Position?  Well, we will get to Players from Teams, and Statistics from Players so no need to make an interface for them as well see in a second.  As for Positions, well need a way to bind the dropdown to ALL positions they dont appear underneath any of the other classes so we need to reference it directly.  After adding these guys, expand every node in your Data Sources pane and see how the Team node allows you to drill into Players and then Statistics.  This is why there was no need to bring in a reference to those classes for the UI we are designing: Now for the seriously hard work of binding all of our controls to the correct data sources.  Drag the following items from the Data Sources pane to the specified control on the window design canvas: Team.Name > Teams combo box Team.Players.Name > Players list box Team.Players.Name > Player name text box Team.Players.Statistics > Statistics data grid Position.Name > Positions combo box That is it!  Really?  Well, no, not really there is one caveat here in that the Positions combo box is not bound the selected players position.  To do so, we will apply a binding to the position combo boxs SelectedValue to point to the current players PositionId value: That should do the trick now, all we need to worry about is loading the actual data.  Sadly, it appears as if we will need to drop to code in order to invoke our IO methods to load all teams and positions.  At least Visual Studio kindly created the stubs for us to do so, ultimately the code should look like this: Note the weirdness with the InitializeDataFiles call that is my current means of telling an IO where to load the data for each of the entities.  I havent thought of a more intuitive way than that yet, but do note that all data is loaded from Teams.xml besides for positions, which is loaded from Lookups.xml.   I think that may be all we need to do to at least load all of the data, lets run it and see: Yay!  All of our glorious data is being displayed!  Er, wait, whats up with the position dropdown?  Why is it red?  Lets select the RB and see if everything updates: Crap, the position didnt update to reflect the selected player, but everything else did.  Where did we go wrong in binding the position to the selected player?  Thinking about it a bit and comparing it to how traditional data binding works, I realize that we never set the value member (or some similar property) to tell the control to join the Id of the source (positions) to the position Id of the player.  I dont see a similar property to that on the combo box control, but I do see a property named SelectedValuePath that might be it, so I set it to Id and run the app again: Hey, all right!  No red box around the positions combo box.  Unfortunately, selecting the RB does not update the dropdown to point to Runningback.  Hmmm.  Now what could it be?  Maybe the problem is that we are loading teams before we are loading positions, so when it binds position Id, all of the positions arent loaded yet.  I went to the code behind and switched things so position loads first and no dice.  Same result when I run.  Why?  WHY?  Ok, ok, calm down, take a deep breath.  Get something with caffeine or sugar (preferably both) and think rationally. Ok, gigantic chocolate chip cookie and a mountain dew chaser have never let me down in the past, so dont fail me now!  Ah ha!  of course!  I didnt even have to finish the mountain dew and I think Ive got it:  Data Context.  By default, when setting on the selected value binding for the dropdown, the data context was list_team.  I dont even know what the heck list_team is, we want it to be bound to our team players view source resource instead, like this: Running it now and selecting the various players: Done and done.  Everything read and bound, thank you caffeine and sugar!  Oh, and thank you Visual Studio 2010.  Lets wire up some of those buttons now There has got to be a better way to do this, but it works for now.  What the add player button does is add a new player object to the currently selected team.  Unfortunately, I couldnt get the new object to automatically show up in the players list (something about not using an observable collection gotta look into this) so I just save the change immediately and reload the screen.  Terrible, but it works: Lets go after something easier:  The save button.  By default, as we type in new text for the players name, it is showing up in the list box as updated.  Cool!  Why couldnt my add new player logic do that?  Anyway, the save button should be as simple as invoking MFL.IO.Save for the selected player, like this: MFL.IO.Save((MFL.Player)lbTeamPlayers.SelectedItem, true); Surprisingly, that worked on the first try.  Lets see if we get as lucky with the Delete player button: MFL.IO.Delete((MFL.Player)lbTeamPlayers.SelectedItem); Refresh(); Note the use of the Refresh method again I cant seem to figure out why updates to the underlying data source are immediately reflected, but adds and deletes are not.  That is a problem for another day, and again my hunch is that I should be binding to something more complex than IEnumerable (like observable collection). Now that an example of the basic CRUD methods are wired up, I want to quickly investigate the performance of this beast.  Im going to make a special button to add 30 teams, each with 50 players and 10 seasons worth of stats.  If my math is right, that will end up with 15000 rows of data, a pretty hefty amount for an XML file.  The save of all this new data took a little over a minute, but that is acceptable because we wouldnt typically be saving batches of 15k records, and the resulting XML file size is a little over a megabyte.  Not huge, but big enough to see some read performance numbers or so I thought.  It reads this file and renders the first team in under a second.  That is unbelievable, but we are lazy loading and the file really wasnt that big.  I will increase it to 50 teams with 100 players and 20 seasons each - 100,000 rows.  It took a year and a half to save all of that data, and resulted in an 8 megabyte file.  Seriously, if you are loading XML files this large, get a freaking database!  Despite this, it STILL takes under a second to load and render the first team, which is interesting mostly because I thought that it was loading that entire 8 MB XML file behind the scenes.  I have to say that I am quite impressed with the performance of the LINQ to XML approach, particularly since I took no efforts to optimize any of this code and was fairly new to the concept from the start.  There might be some merit to this little project after all Look out SQL Server and Oracle, use XML files instead!  Next up, I am going to completely pull the rug out from under the UI and change a number of entities in our model.  How well will the code be regenerated?  How much effort will be required to tie things back together in the UI?Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Defend PHP; convince me it isn't horrible

  - by Jason L

  I made a tongue-in-cheek comment in another question thread calling PHP a terrible language and it got down-voted like crazy. Apparently there are lots of people here who love PHP. So I'm genuinely curious. What am I missing? What makes PHP a good language? Here are my reasons for disliking it: PHP has inconsistent naming of built-in and library functions. Predictable naming patterns are important in any design. PHP has inconsistent parameter ordering of built-in functions, eg array_map vs. array_filter which is annoying in the simple cases and raises all sorts of unexpected behaviour or worse. The PHP developers constantly deprecate built-in functions and lower-level functionality. A good example is when they deprecated pass-by-reference for functions. This created a nightmare for anyone doing, say, function callbacks. A lack of consideration in redesign. The above deprecation eliminated the ability to, in many cases, provide default keyword values for functions. They fixed this in PHP 5, but they deprecated the pass-by-reference in PHP 4! Poor execution of name spaces (formerly no name spaces at all). Now that name spaces exist, what do we use as the dereference character? Backslash! The character used universally for escaping, even in PHP! Overly-broad implicit type conversion leads to bugs. I have no problem with implicit conversions of, say, float to integer or back again. But PHP (last I checked) will happily attempt to magically convert an array to an integer. Poor recursion performance. Recursion is a fundamentally important tool for writing in any language; it can make complex algorithms far simpler. Poor support is inexcusable. Functions are case insensitive. I have no idea what they were thinking on this one. A programming language is a way to specify behavior to both a computer and a reader of the code without ambiguity. Case insensitivity introduces much ambiguity. PHP encourages (practically requires) a coupling of processing with presentation. Yes, you can write PHP that doesn't do so, but it's actually easier to write code in the incorrect (from a sound design perspective) manner. PHP performance is abysmal without caching. Does anyone sell a commercial caching product for PHP? Oh, look, the designers of PHP do. Worst of all, PHP convinces people that designing web applications is easy. And it does indeed make much of the effort involved much easier. But the fact is, designing a web application that is both secure and efficient is a very difficult task. By convincing so many to take up programming, PHP has taught an entire subgroup of programmers bad habits and bad design. It's given them access to capabilities that they lack the understanding to use safely. This has led to PHP's reputation as being insecure. (However, I will readily admit that PHP is no more or less secure than any other web programming language.) What is it that I'm missing about PHP? I'm seeing an organically-grown, poorly-managed mess of a language that's spawning poor programmers. So convince me otherwise!

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