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• Why do bind1st and bind2nd require constant function objects?

  - by rlbond

  So, I was writing a C++ program which would allow me to take control of the entire world. I was all done writing the final translation unit, but I got an error: error C3848: expression having type 'const `anonymous-namespace'::ElementAccumulator<T,BinaryFunction>' would lose some const-volatile qualifiers in order to call 'void `anonymous-namespace'::ElementAccumulator<T,BinaryFunction>::operator ()(const point::Point &,const int &)' with [ T=SideCounter, BinaryFunction=std::plus<int> ] c:\program files (x86)\microsoft visual studio 9.0\vc\include\functional(324) : while compiling class template member function 'void std::binder2nd<_Fn2>::operator ()(point::Point &) const' with [ _Fn2=`anonymous-namespace'::ElementAccumulator<SideCounter,std::plus<int>> ] c:\users\****\documents\visual studio 2008\projects\TAKE_OVER_THE_WORLD\grid_divider.cpp(361) : see reference to class template instantiation 'std::binder2nd<_Fn2>' being compiled with [ _Fn2=`anonymous-namespace'::ElementAccumulator<SideCounter,std::plus<int>> ] I looked in the specifications of binder2nd and there it was: it took a const AdaptibleBinaryFunction. So, not a big deal, I thought. I just used boost::bind instead, right? Wrong! Now my take-over-the-world program takes too long to compile (bind is used inside a template which is instantiated quite a lot)! At this rate, my nemesis is going to take over the world first! I can't let that happen -- he uses Java! So can someone tell me why this design decision was made? It seems like an odd decision. I guess I'll have to make some of the elements of my class mutable for now...

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• 'Bank Switching' Sprites on old NES applications

  - by Jeffrey Kern

  I'm currently writing in C# what could basically be called my own interpretation of the NES hardware for an old-school looking game that I'm developing. I've fired up FCE and have been observing how the NES displayed and rendered graphics. In a nutshell, the NES could hold two bitmaps worth of graphical information, each with the dimensions of 128x128. These are called the PPU tables. One was for BG tiles and the other was for sprites. The data had to be in this memory for it to be drawn on-screen. Now, if a game had more graphical data then these two banks, it could write portions of this new information to these banks -overwriting what was there - at the end of each frame, and use it from the next frame onward. So, in old games how did the programmers 'bank switch'? I mean, within the level design, how did they know which graphic set to load? I've noticed that Mega Man 2 bankswitches when the screen programatically scrolls from one portion of the stage to the next. But how did they store this information in the level - what sprites to copy over into the PPU tables, and where to write them at? Another example would be hitting pause in MM2. BG tiles get over-written during pause, and then get restored when the player unpauses. How did they remember which tiles they replaced and how to restore them? If I was lazy, I could just make one huge static bitmap and just grab values that way. But I'm forcing myself to limit these values to create a more authentic experience. I've read the amazing guide on how M.C. Kids was made, and I'm trying to be barebones about how I program this game. It still just boggles my mind how these programmers accomplisehd what they did with what they had. EDIT: The only solution I can think of would be to hold separate tables that state what tiles should be in the PPU at what time, but I think that would be a huge memory resource that the NES wouldn't be able to handle.

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• Content Management Systems for Adaptive Content [closed]

  - by andrewap

  Content management systems (CMS) allow us to easily maintain blogs, news sites, general websites, and so on. Many of them are designed to manage pages of content, and provide tools to organize and customize how that content is displayed on the web. However, as explained by Mark Boulton in his Adaptive Content Management article, and by Karen McGrane in her talk on Adapting Ourselves to Adaptive Content, we are increasingly delivering content not just to the web, but also to other platforms and channels. We need tools to manage pieces of content with meaningful metadata attached. Create once, publish everywhere. The main idea is to store content cleanly, without intertwining it with presentation markup specific to the web. Because pieces of content is compartmentalized semantically, it can easily adapt to fit in different platforms and channels. Hence, it's called adaptive content. Let's look at a quick example to compare: Say I manage news articles and events. To create a news article, I would tell the CMS the type of content I'm creating, and be asked to fill in a form with individual fields tailored to news articles (e.g. headline, subtitle, full text, short snippet, and images). — i.e. pieces of content With a traditional web publishing tool, I would probably have had to create a new page under News, and then type in and format the news article in a blank WYSIWYG text editor. — i.e. pages of content As you can see, the first design allows me to individually specify content in its smallest semantic unit. When I want to display or consume it, the system can easily provide the pieces I need. So here's my question: Is there a CMS that is designed specifically with adaptive content in mind, and that is decoupled with the presentation layer? Note: This is not a discussion about the best CMS, or which CMS I should use. I am asking whether a very specific type of tool — CMS designed for adaptive content — exists for developers to use.

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• How does static code run with multiple threads?

  - by Krisc

  I was reading http://stackoverflow.com/questions/1511798/threading-from-within-a-class-with-static-and-non-static-methods and I am in a similar situation. I have a static method that pulls data from a resource and creates some runtime objects based on the data. static class Worker{ public static MyObject DoWork(string filename){ MyObject mo = new MyObject(); // ... does some work return mo; } } The method takes awhile (in this case it is reading 5-10mb files) and returns an object. I want to take this method and use it in a multiple thread situation so I can read multiple files at once. Design issues / guidelines aside, how would multiple threads access this code? Let's say I have something like this... class ThreadedWorker { public void Run() { Thread t = new Thread(OnRun); t.Start(); } void OnRun() { MyObject mo = Worker.DoWork("somefilename"); mo.WriteToConsole(); } } Does the static method run for each thread, allowing for parallel execution?

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• The Implications of Modern Day Software Development Abstractions

  - by Andreas Grech

  I am currently doing a dissertation about the implications or dangers that today's software development practices or teachings may have on the long term effects of programming. Just to make it clear: I am not attacking the use abstractions in programming. Every programmer knows that abstractions are the bases for modularity. What I want to investigate with this dissertation are the positive and negative effects abstractions can have in software development. As regards the positive, I am sure that I can find many sources that can confirm this. But what about the negative effects of abstractions? Do you have any stories to share that talk about when certain abstractions failed on you? The main concern is that many programmers today are programming against abstractions without having the faintest idea of what the abstraction is doing under-the-covers. This may very well lead to bugs and bad design. So, in you're opinion, how important is it that programmers actually know what is going below the abstractions? Taking a simple example from Joel's Back to Basics, C's strcat: void strcat( char* dest, char* src ) { while (*dest) dest++; while (*dest++ = *src++); } The above function hosts the issue that if you are doing string concatenation, the function is always starting from the beginning of the dest pointer to find the null terminator character, whereas if you write the function as follows, you will return a pointer to where the concatenated string is, which in turn allows you to pass this new pointer to the concatenation function as the *dest parameter: char* mystrcat( char* dest, char* src ) { while (*dest) dest++; while (*dest++ = *src++); return --dest; } Now this is obviously a very simple as regards abstractions, but it is the same concept I shall be investigating. Finally, what do you think about the issue that schools are preferring to teach Java instead of C and Lisp ? Can you please give your opinions and your says as regards this subject? Thank you for your time and I appreciate every comment.

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• iPad width in viewport settings overflowing past device width

  - by user1327771

  I am at my wit's end here, and I beseech the fine folks here at stackoverflow for help. I am working on a design for a blog for a friend of mine, and I'm working in HTML5. I am trying to get the width of the page to span the width of an iPad. So, in my document head, I have the following: <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0"> Now, if you go to the index page, on an iPad, it looks just fine. The width of the page spans the width of the iPad in portrait mode, as I expect it to: http://www.alanreuterart.com/femmegamers/index.html It also looks fine on any individual blog posts as well. However, on the "about" and "join" pages, the width does not do this. It's actually overflowing past the length of the iPad to the right. View the following page on an iPad to see what I mean: http://www.alanreuterart.com/femmegamers/about.html I've tried everything. I cannot, for the life of me, figure out how to get it those two pages to correctly span the device width of the iPad. One important note, though: before anyone tells me to set my viewport width to 960, I cannot do that because the pages have media queries in them to convert to a mobile layout for the iPhone and other mobile phones. (I am not making a special unique layout for the iPad.) Can ANYONE help out here? Thanks in advance! —Me.

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• BackgroundWorker and foreach loop

  - by tomfox66

  I have to process a loop with backgroundworkers. Before I start a new loop iteration I need to wait until the provious backgroundworker has finished. A while loop inside my foreach loop with isbusy flag doesn's seem like a good idea to me. How should I design this loop so it waits for the bg-worker to end before iterating the loop public void AutoConnect() { string[] HardwareList = new string[] { "d1", "d4", "ds1_2", "ds4_2" }; foreach (string HW in HardwareList) { if (backgroundWorker1.IsBusy != true) { backgroundWorker1.RunWorkerAsync(HW); // Wait here until backgroundWorker1 finished } } } private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e) { BackgroundWorker worker = sender as BackgroundWorker; string FileName = e.Argument as string; try { if ((worker.CancellationPending == true)) { e.Cancel = true; } else { // Time consuming operation ParseFile(Filename); } } catch { } } private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e) { label1.Text = e.ProgressPercentage.ToString() + " lines"; } private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) { if(e.Cancelled == true) { //this.tbProgress.Text = "Canceled!"; } else if(!(e.Error == null)) { //this.tbProgress.Text = ("Error: " + e.Error.Message); } else { label1.text = "Done!"; } }

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• using dummy row with NOT NULL to solve DEFAULT NULL

  - by Tony38

  I know having DEFAULT NULLS is not a good practice but I have many optional lookup values which are FK in the system so to solve this issue here is what i am doing: I use NOT NULL for every FK / lookup colunms. I have the first row in every lookup table which is PK id = 1 as a dummy row with just "none" in all the columns. This way I can use NOT NULL in my schema and if needed reference to the none row values PK =1 for FKs which do not have any lookup value. Is this a good design or any other work arounds? EDIT: I have: Neighborhood table Postal table. Every neighborhood has a city, so the FK can be NOT NULL. But not every postal code belongs to a neighborhood. Some do, some don't depending on the country. So if i use NOT NULL for the FK between postal and neighborhood then I will be screwed as there has to be some value entered. So what i am doing in essence is: have a row in every table to be a dummy row just to link the FKs. This way row one in neighborhood table will be: n_id = 1 name =none etc... In postal table I can have: postal_code = 3456A3 FK (city) = Moscow FK (neighborhood_id)=1 as a NOT NULL. If I don't have a dummy row in the neighborhood lookup table then I have to declare FK (neighborhood_id) as a Default null column and store blanks in the table. This is an example but there is a huge number of values which will have blanks then in many tables.

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• Image appearing in the wrong place.

  - by Luke

  I have a list that I want to precede on each line with a small image. The CSS: .left div.arrow{background-image: url(../images/design/box.png); float:left; height:15px; width:15px; margin-right:2px;} .left a.list:link, a:visited, a:active {color:black; font-size:0.8em; text-decoration:none; display:block; float:left;} The HTML: <div class="panel">My quick links</div> <div class="arrow"></div> <a href="/messages.php?p=new" class="list">Send a new message</a> <br /> <div class="arrow"></div> <a href="/settings.php#password" class="list">Change my password</a> <br /> <div class="arrow"></div> <a href="/settings.php#picture" class="list">Upload a new site image</a> <br /> As you can see, each image should go before the writing. On the first line, the text "Send a new message" has the preceeding image. However, each line afterwards has the image at the end. So "Send a new message" has an image at the start and finish. It is like the images are staying at the end of the previous line. Any ideas?

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• Add dynamic charts using ASP.NET CHART CONTROL, c#

  - by dhareni

  I wanted to add dynamic charts in the webpage. It goes like this... I get the start and end date from user and draw separate charts for each date bewteen the start and end date. I get the data from sql database and bind it with the chart like this: SqlConnection UsageLogConn = new SqlConnection(ConfigurationManager.ConnectionStrings["UsageConn"].ConnectionString); UsageLogConn.Open();//open connection string sql = "SELECT v.interval,dateadd(mi,(v.interval-1)*2,'" + startdate + " 00:00:00') as 'intervaltime',COUNT(Datediff(minute,'" + startdate + " 00:00:00',d.DateTime)/2) AS Total FROM usage_internet_intervals v left outer join (select * from Usage_Internet where " + name + " LIKE ('%" + value + "%') and DateTime BETWEEN '" + startdate + " 00:00:00' AND '" + enddate + " 23:59:59') d on v.interval = Datediff(minute,'" + startdate + " 00:00:00',d.DateTime)/2 GROUP BY v.interval,Datediff(minute,'" + startdate + " 00:00:00',d.DateTime)/2 ORDER BY Interval"; SqlCommand cmd = new SqlCommand(sql, UsageLogConn); SqlDataAdapter mySQLadapter = new SqlDataAdapter(cmd); Chart1.DataSource = cmd; // set series members names for the X and Y values Chart1.Series["Series 1"].XValueMember = "intervaltime"; Chart1.Series["Series 1"].YValueMembers = "Total"; UsageLogConn.Close(); // data bind to the selected data source Chart1.DataBind(); cmd.Dispose(); The above code adds only one chart for one date and I have added 'chart1' to design view and its not created dynamic. But I wanted to add more charts dynamic at runtime to the webpage. Can anyone help me with this? I am using VS 2008, ASP.NET 3.5 and the charting lib is: using System.Web.UI.DataVisualization.Charting;

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• Does QThread::sleep() require the event loop to be running?

  - by suszterpatt

  I have a simple client-server program written in Qt, where processes communicate using MPI. The basic design I'm trying to implement is the following: The first process (the "server") launches a GUI (derived from QMainWindow), which listens for messages from the clients (using repeat fire QTimers and asynchronous MPI receive calls), updates the GUI depending on what messages it receives, and sends a reply to every message. Every other process (the "clients") runs in an infinite loop, and all they are intended to do is send a message to the server process, receive the reply, go to sleep for a while, then wake up and repeat. Every process instantiates a single object derived from QThread, and calls its start() method. The run() method of these classes all look like this: from foo.cpp: void Foo::run() { while (true) { // Send message to the first process // Wait for a reply // Do uninteresting stuff with the reply sleep(3); // also tried QThread::sleep(3) } } In the client's code, there is no call to exec() anywhere, so no event loop should start. The problem is that the clients never wake up from sleeping (if I surround the sleep() call with two writes to a log file, only the first one is executed, control never reaches the second). Is this because I didn't start the event loop? And if so, what is the simplest way to achieve the desired functionality?

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• Good PHP / MYSQL hashing solution for large number of text values

  - by Dave

  Short descriptio: Need hashing algorithm solution in php for large number of text values. Long description. PRODUCT_OWNER_TABLE serial_number (auto_inc), product_name, owner_id OWNER_TABLE owner_id (auto_inc), owener_name I need to maintain a database of 200000 unique products and their owners (AND all subsequent changes to ownership). Each product has one owner, but an owner may have MANY different products. Owner names are "Adam Smith", "John Reeves", etc, just text values (quite likely to be unicode as well). I want to optimize the database design, so what i was thinking was, every week when i run this script, it fetchs the owner of a proudct, then checks against a table i suppose similar to PRODUCT_OWNER_TABLE, fetching the owner_id. It then looks up owner_id in OWNER_TABLE. If it matches, then its the same, so it moves on. The problem is when its different... To optimize the database, i think i should be checking against the other "owner_name" entries in OWNER_TABLE to see if that value exists there. If it does, then i should use that owner_id. If it doesnt, then i should add another entry. Note that there is nothing special about the "name". as long as i maintain the correct linkagaes AND make the OWNER_TABLE "read-only, append-new" type table - I should be able create a historical archive of ownership. I need to do this check for 200000 entries, with i dont know how many unique owner names (~50000?). I think i need a hashing solution - the OWNER_TABLE wont be sorted, so search algos wont be optimal. programming language is PHP. database is MYSQL.

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• Unity IoC and MVC modelbinding

  - by danielovich

  Is it ok to have a static field in my controller for my modelbinder to call ? Eg. public class AuctionItemsController : Controller { private IRepository<IAuctionItem> GenericAuctionItemRepository; private IAuctionItemRepository AuctionItemRepository; public AuctionItemsController(IRepository<IAuctionItem> genericAuctionItemRepository, IAuctionItemRepository auctionItemRepository) { GenericAuctionItemRepository = genericAuctionItemRepository; AuctionItemRepository = auctionItemRepository; StaticGenericAuctionItemRepository = genericAuctionItemRepository; } internal static IRepository<IAuctionItem> StaticGenericAuctionItemRepository; here is the modelbinder public class AuctionItemModelBinder : DefaultModelBinder { public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) { if (AuctionItemsController.StaticGenericAuctionItemRepository != null) { AuctionLogger.LogException(new Exception("controller is null")); } NameValueCollection form = controllerContext.HttpContext.Request.Form; var item = AuctionItemsController.StaticGenericAuctionItemRepository.GetSingle(Convert.ToInt32(controllerContext.RouteData.Values["id"])); item.Description = form["title"]; item.Price = int.Parse(form["price"]); item.Title = form["title"]; item.CreatedDate = DateTime.Now; item.AuctionId = 1; //TODO: Stop hardcoding this item.UserId = 1; return item; }} i am using Unity as IoC and I find it weird to register my modelbinder in the IoC container. Any other good design considerations I shold do ?

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• vertical align of some inline-block divs with different content

  - by Jan Möller

  i want to center some inline-block divs. I want to create a responsive design, so if the screen size is too small, the horizontal elements should be under each other. How can i center them vertical, so they are side by side without a difference in height? (See fiddle). Moveover those elements should be verticaly centered, if the screen size is too small. http://jsfiddle.net/5dpRs/52/ CSS .repeat { display:inline-block; border-style:solid; border-width:2px; height:50px; width:50px; } #content { border-style:solid; border-width:2px; text-align:center; } HTML <div id="content"> <div class="repeat"> <p>hello</p> </div> <div class="repeat"> </div> </div> Thank you :)

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• Website Live Chat Script - Interface With Windows Live Messenger?

  - by Sootah

  Hello again fellow StackOverflow users! What I am looking for currently is your opinions on the what the best live chat script would be for my website. I'd be using this on both my local computer repair (which I've not really set up yet) company's site, as well as my other technical support site that is geared more towards showing people how to fix whatever problem they have themselves. It'll be a little bit before I launch it on either site, as I need to find a good design for my local computer repair company's site, as well as redesign TweaksForGeeks.com's layout so that it's more magazine like. (If you have any suggestions on good Wordpress templates for these, that'd also be swell. :) ) Features I'd like for the live chat script to have: (if possible) Real-time posting of messages (or as close to real time as possible) Integration into my Windows Live Messenger account - By this I mean it'd be handy if instead of me having to man a separate open browser window and constantly check it for new messages, it'd be much more convenient if it would instead just allow me to receive and respond to messages via my Windows Live account the same way I'd chat with any other person on my contact list. Sound notification of new messages when the chat isn't the focused window - In the event that using Windows Messenger isn't possible then I'd need it to notify me upon receipt of a new message. Recording of chat transcripts - This is a MUST HAVE Easy customization - I'll likely want to modify how it looks and whatnot, in addition to the fact that I'm going to set it up so that the chat transcripts can be posted to my site easily in order to be useful to my other visitors later on. With all that in mind, what is available out there? I've not really researched this at all yet; aside from doing a cursory search just before I decided to ask my StackOverflow brothers. As always, thank you! -Sootah

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• MySQL Normalization stored procedure performance

  - by srkiNZ84

  Hi, I've written a stored procedure in MySQL to take values currently in a table and to "Normalize" them. This means that for each value passed to the stored procedure, it checks whether the value is already in the table. If it is, then it stores the id of that row in a variable. If the value is not in the table, it stores the newly inserted value's id. The stored procedure then takes the id's and inserts them into a table which is equivalent to the original de-normailized table, but this table is fully normalized and consists of mainly foreign keys. My problem with this design is that the stored procedure takes approximately 10ms or so to return, which is too long when you're trying to work through some 10million records. My suspicion is that the performance is to do with the way in which I'm doing the inserts. i.e. INSERT INTO TableA (first_value) VALUES (argument_from_sp) ON DUPLICATE KEY UPDATE id=LAST_INSERT_ID(id); SET @TableAId = LAST_INSERT_ID(); The "ON DUPLICATE KEY UPDATE" is a bit of a hack, due to the fact that on a duplicate key I don't want to update anything but rather just return the id value of the row. If you miss this step though, the LAST_INSERT_ID() function returns the wrong value when you're trying to run the "SET ..." statement. Does anyone know of a better way to do this in MySQL? Thank you

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• How can I make this SQL query more efficient? PHP.

  - by Alan Grant

  Hi all, I have a system whereby a user can view categories that they've subscribed to individually, and also those that are available in the region they belong in by default. So, the tables are as follows: Categories UsersCategories RegionsCategories I'm querying the db for all the categories within their region, and also all the individual categories that they've subscribed to. My query is as follows: Select * FROM (categories c) LEFT JOIN users_categories uc on uc.category_id = c.id LEFT JOIN regions_categories rc on rc.category_id = c.id WHERE (rc.region_id = ? OR uc.user_id = ?) At least I believe that's the query, I'm creating it using Cake's ORM layer, so the exact one is: $conditions = array( array( "OR" => array ( 'RegionsCategories.region_id' => $region_id, 'UsersCategories.user_id' => $user_id ) )); $this->find('all', $conditions); This turns out to be incredibly slow (sometimes around 20 seconds or so. Each table has around 5,000 rows). Is my design at fault here? How can I retrieve both the users' individual categories and those within their region all in one query without it taking ages? Thanks!

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• How are you using C++0x today? [closed]

  - by Roger Pate

  This is a question in two parts, the first is the most important and concerns now: Are you following the design and evolution of C++0x? What blogs, newsgroups, committee papers, and other resources do you follow? Even where you're not using any new features, how have they affected your current choices? What new features are you using now, either in production or otherwise? The second part is a follow-up, concerning the new standard once it is final: Do you expect to use it immediately? What are you doing to prepare for C++0x, other than as listed for the previous questions? Obviously, compiler support must be there, but there's still co-workers, ancillary tools, and other factors to consider. What will most affect your adoption? Edit: The original really was too argumentative; however, I'm still interested in the underlying question, so I've tried to clean it up and hopefully make it acceptable. This seems a much better avenue than duplicating—even though some answers responded to the argumentative tone, they still apply to the extent that they addressed the questions, and all answers are community property to be cleaned up as appropriate, too.

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• What Do You Need To Write Your Own Blog Engine?

  - by deworde

  I've been messing around with basic websites for a few years, using companies like www.Fasthosts.co.uk to do my web hosting. But I'd like to expand my skills from C++ and Java app programming into Web-based programming, and I think the best way to do that is with a project. I've chosen to go with a blog engine because it's a relative comprehensive yet non-complex project. I'm aware that you can just go to Blogger and bam! One blog. I've done that, so that I can at least have some content, and work out what I want to do with this blog. At the moment, I'm thinking I'll use it to chart my progress creating the blogging engine. But I have some questions. Do you need to be running your own server? Or is it more sensible in the short-term to use a hosting company? What types of language are worth considering? What's important to focus on from a design perspective? What unexpected problems might I encounter?

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• Two questions on ensuring EndInvoke() gets called on a list of IAsyncResult objects

  - by RobV

  So this question is regarding the .Net IAsyncResult design pattern and the necessity of calling EndInvoke as covered in this question Background I have some code where I'm firing off potentially many asynchronous calls to a particular function and then waiting for all these calls to finish before using EndInvoke() to get back all the results. Question 1 I don't know whether any of the calls has encountered an exception until I call EndInvoke() and in the event that an exception occurs in one of the calls the entire method should fail and the exception gets wrapped into an API specific exception and thrown upwards. So my first question is what's the best way then to ensure that the remainder of the async calls get properly terminated? Is a finally block which calls EndInvoke() on the remainder of the unterminated calls (and ignores any further exceptions) the best way to do this? Question 2 Secondly when I first fire off all my asyc calls I then call WaitHandle.WaitAll() on the array of WaitHandle instances that I've got from my IAsyncResult instances. The method which is firing all these async calls has a timeout to adhere to so I provide this to the WaitAll() method. Then I test whether all the calls have completed, if not then the timeout must have been reached so the method should also fail and throw another API specific exception. So my second question is what should I do in this case? I need to call EndInvoke() to terminate all these async calls before I throw the error but at the same time I don't want the code to get stuck since EndInvoke() is blocking. In theory at least if the WaitAll() call times out then all the async calls should themselves have timed out and thrown exceptions (thus completing the call) since they are also governed by a timeout but this timeout is potentially different from the main timeout

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• C++ return a "NULL" object if search result not found

  - by aduric

  I'm pretty new to C++ so I tend to design with a lot of Java-isms while I'm learning. Anyway, in Java, if I had class with a 'search' method that would return an object T from a Collection< T that matched a specific parameter, I would return that object and if the object was not found in the collection, I would return a NULL. Then in my calling function I would just check if(T != NULL) { ... } In C++, I'm finding out that I can't return a NULL if the object doesn't exist. I just want to return an 'indicator' of type T that notifies the calling function that no object has been found. I don't want to throw an exception because it's not really an exceptional circumstance. class Node { .... Attr& getAttribute(const string& attribute_name) const { //search collection //if found at i return attributes[i]; //if not found return NULL; } private: vector<Attr> attributes; }

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• SQL Query to duplicate records based on If statement

  - by user328371

  Hi, I'm trying to write an SQL query that will duplicate records depending on a field in another table. I am running mySQL 5. (I know duplicating records shows that the database structure is bad, but I did not design the database and am not in a position to redo it all - it's a shopp ecommerce database running on wordpress.) Each product with a particular attribute needs a link to the same few images, so the product will need a row per image in a table - the database doesn't actually contain the image, just its filename. (the images are of clipart for a customer to select from) Based on these records... SELECT * FROM `wp_shopp_spec` WHERE name='Can Be Personalised' and content='Yes' I want to do something like this.. For each record that matches that query, copy records 5134 - 5139 from wp_shopp_asset but change the id so it's unique and set the cell in column 'parent' to have the value of 'product' from the table wp_shopp_spec. This will mean 6 new records are created for each record matching the above query, all with the same value in 'parent' but with unique ids and every other column copied from the original (ie. records 5134-5139) Hope that's clear enough - any help greatly appreciated.

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• Jquery click bindings are not working correctly when binding multiple copies

  - by KallDrexx

  I seem to have an issue when creating copies of a template and tying the .click() method to them properly. Take the following javascript for example: var list; // Loop through all of the objects var topics = data.objects; for (x = 0; x < objects.length; x++) { // Clone the object list item template var item = $("#object_item_list_template").clone(); // Setup the click action and inner text for the link tag in the template var objectVal = objects[x].Value; item.find('a').click(function () { ShowObject(objectVal.valueOf(), 'T'); }).html(objects[x].Text); // add the html to the list if (list == undefined) list = item; else list.append(item.contents()); } // Prepend the topics to the topic list $("#object_list").empty().append(list.contents()); The problem I am seeing with this is that no matter which item the user clicks on in the #object_list, ShowObject() is called with the last value of objectVal. So for example, if the 3rd item's <a> is clicked, ShowObject(5,'T'); is called even though objects[2].Value is successfully being seen as 2. How can I get this to work? The main purpose of this code is to take a variable number of items gotten from a JSON AJAX request, make copies of the item template, and insert those copies into the correct spot on the html page. I decided to do it this way so that I can keep all my HTML in one spot for when I need to change the layout or design of the page, and not have to hunt for the html code in the javascript.

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• Cannot implicity convert type void to System.Threading.Tasks.Task<bool>

  - by sagesky36

  I have a WCF Service that contains the following method. All the methods in the service are asynchrounous and compile just fine. public async Task<Boolean> ValidateRegistrationAsync(String strUserName) { try { using (YeagerTechEntities DbContext = new YeagerTechEntities()) { DbContext.Configuration.ProxyCreationEnabled = false; DbContext.Database.Connection.Open(); var reg = await DbContext.aspnet_Users.FirstOrDefaultAsync(f => f.UserName == strUserName); if (reg != null) return true; else return false; } } catch (Exception) { throw; } } My client application was set to access the WCF service with the check box for the "Allow generation of asynchronous operations" and it generated the proxy just fine. I am receiving the above subject error when trying to call this WCF service method from my client with the following code. Mind you, I know what the error message means, but this is my first time trying to call an asynchronous task in a WCF service from a client. Task<Boolean> blnMbrShip = db.ValidateRegistrationAsync(FormsAuthentication.Decrypt(cn.Value).Name); What do I need to do to properly call the method so the design time compile error disappears? Thanks so much in advance...

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• Java inheritance and super() isn't working as expected

  - by dwwilson66

  For a homework assignment, I'm working with the following. It's an assigned class structure, I know it's not the best design by a long shot. Class | Extends | Variables -------------------------------------------------------- Person | None | firstName, lastName, streetAddress, zipCode, phone CollegeEmployee | Person | ssn, salary,deptName Faculty | CollegeEmployee | tenure(boolean) Student | person | GPA,major So in the Faculty class... public class Faculty extends CollegeEmployee { protected String booleanFlag; protected boolean tenured; public Faculty(String firstName, String lastName, String streetAddress, String zipCode, String phoneNumber,String ssn, String department,double salary) { super(firstName,lastName,streetAddress,zipCode,phoneNumber, ssn,department,salary); String booleanFlag = JOptionPane.showInputDialog (null, "Tenured (Y/N)?"); if(booleanFlag.equals("Y")) tenured = true; else tenured = false; } } It was my understanding that super() in Faculty would allow access to the variables in CollegeEmployee as well as Person. With the code above, it compiles fine when I ONLY include the Person variables. As soon as I try to use ssn, department, or salary I get the following compile errors. Faculty.java:15: error: constructor CollegeEmployee in class CollegeEmployee can not be applied to the given types: super(firstName,lastName,streetAddress,zipCode,phoneNumber,ssn,department,salary); ^ Required: String,String,String,String,String Found: String,String,String,String,String,String,String,String reason: actual and formal argument lists differ in length I'm completely confused by this error...which is the actual and formal? Person has five arguments, CollegeEmployee has 3, so my guess is that something's funky with how the parameters are being passed...but I'm not quite sure where to begin fixing it. What am I missing?

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