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• Will high reputation in Programmers help to get a good job?

  - by Lorenzo

  In reference to this question, do you think that having a high reputation on this site will help to get a good job? Aside silly and humorous questions, on Programmers we can see a lot of high quality theory questions. I think that, if Stack Overflow will eventually evolve in "strictly programming related" (which usually is "strictly coding related"), the questions on Programmers will be much more interesting and meaningful ("Stack Overflow" = "I have this specific coding/implementation issue"; "Programmers" = "Best practices, team shaping, paradigms, CS theory"). So could high reputation on this site help (or at least be a good reference)? And then, more o less than Stack Overflow?

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• What is the advantage to hosting static resources on a separate domain?

  - by Michael Ekstrand

  I notice a lot of sites host their resources on a separate domain from the main site, e.g. StackExchange using sstatic.net, Barnes & Noble using imagesbn.com, etc. I understand that there are benefits to putting your static resources on a separate host, possibly with an efficient static-file web server like nginx, freeing up the main server to focus on serving dynamic content. Similarly, outsourcing to a shared CDN like cloudfront Akamai is logical. What is the benefit to using a separate domain otherwise, though? Why sstatic.net instead of static.stackexchange.com? Update: Several answers miss the core question. I understand that there is benefit to splitting between multiple hosts — parallel downloads, slimmer web server, etc. But what is more elusive is why multiple domains. Why sstatic.net rather than static.stackexchange.com as the host for shared resources? So far, only one answer has addressed that.

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• implementing a high level function in a script to call a low level function in the game engine

  - by eat_a_lemon

  In my 2d game engine I have a function that does pathfinding, find_shortest_path. It executes for each time step in the game loop and calculates the next coordinate pair in the series of coordinates to reach the destination object. Now I want to call this function in a scripting language and have it only return the last coordinate pair result. I want the game engine to go about the business of rendering the incremental steps but I don't want the high level script to care about the rendering. The high level script is only for ai game logic. Now I know how to bind a method from C to python but how can I signal and coordinate the wait time between the incremental steps without the high level function returning until its time for the last step?

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• How to Determine VPS Hosting Resources Needs for my upcoming Wordpress blog? How much resources should i purchase? [closed]

  - by Ishwar dixit

  Possible Duplicate: How to find web hosting that meets my requirements? Decided to purchase VPS hosting but Getting confused on amount of Resources i need? Wordpress will be used as platform, The blog i want to setup is assumed to have a traffic between 20k - 25k Visits per day with a rate of 5 pageviews per visit... there is No Download Facility provided...the content of the blog will be Text, Images & videos (will be used rarely)... The main question is? For the above requirement: How much RAM will be enough? How much CPU usage i will need? How much Bandwidth will be enough? How much Disk Space? Any other Requirement? Thanx in Advance..

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• Language+IDE for teaching high school students?

  - by daveagp

  I'm investigating languages and IDEs for a project involving teaching high-school students (around grade 11). It will teach basics of programming as an introduction to computer science (e.g., including how numbers/strings/characters are represented, using procedures and arrays, control flow, a little bit of algorithms, only very basic I/O). The non-negotiable requirements for this project are: a free up-to-date cross-platform IDE (Win & Mac incl. 64-bit) with debug a compiler where it's easy to learn from your mistakes together with the IDE, a gentle installation+learning curve So far, the best options I see are the following. Are there others I should know about? I am giving a short explanation with each one to generally show what I am looking for. In order from most to least promising: Pascal + FreePascal IDE (it seems a little buggy but actively developed?) Python + Eclipse + PyDev (good but features are overwhelming/hard to navigate) Groovy + Eclipse ('') Python + IDLE (looks unnatural to do debugging, to me) Pascal + Lazarus (IDE overwhelming, e.g. not obvious how to "start from scratch") Preferably, as a rule of thumb, the language should be direct enough that you don't need to wrap every program in a class, don't need to reference a System object to println, etc. I tried a little bit to see if there is something in JavaScript or (non-Visual) Basic along the lines of what I want, but found nothing so far. I would say that C/C++/C#, Java, Ruby, Lisp, VB do not fit my criteria for languages for this project. To reiterate my questions: are any of those 5 options really awesome or un-awesome? Are there other options which are even MORE awesome? Anything for Basic or JavaScript which meets all of the criteria? Thanks!

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• QWebView not loading external resources

  - by Nick

  Hi. I'm working on a kiosk web browser using Qt and PyQt4. QWebView seems to work quite well except for one quirk. If a URL fails to load for any reason, I want to redirect the user to a custom error page. I've done this using the loadFinished() signal to check the result, and change the URL to the custom page if necessary using QWebView.load(). However, any page I attempt to load here fails to pull in external resources like CSS or images. Using QWebView.load() to set the initial page at startup seems to work fine, and clicking any link on the custom error page will result in the destination page loading fine. It's just the error page that doesn't work. I'm really not sure where to go next. I've included the source for an app that will replicate the problem below. It takes a URL as a command line argument - a valid URL will display correctly, a bad URL (eg. DNS resolution fails) will redirect to Google, but with the logo missing. import sys from PyQt4 import QtGui, QtCore, QtWebKit class MyWebView(QtWebKit.QWebView): def __init__(self, parent=None): QtWebKit.QWebView.__init__(self, parent) self.resize(800, 600) self.load(QtCore.QUrl(sys.argv[1])) self.connect(self, QtCore.SIGNAL('loadFinished(bool)'), self.checkLoadResult) def checkLoadResult(self, result): if (result == False): self.load(QtCore.QUrl('http://google.com')) app = QtGui.QApplication(sys.argv) main = MyWebView() main.show() sys.exit(app.exec_()) If anyone could offer some advice it would be greatly appreciated.

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• Where should I declare my CDI resources?

  - by Laird Nelson

  JSR-299 (CDI) introduces the (unfortunately named) concept of a resource: http://docs.jboss.org/weld/reference/1.0.0/en-US/html/resources.html#d0e4373 You can think of a resource in this nomenclature as a bridge between the Java EE 6 brand of dependency injection (@EJB, @Resource, @PersistenceContext and the like) and CDI's brand of dependency injection. The general gist seems to be that somewhere (and this will be the root of my question) you declare what amounts to a bridge class: it contains fields annotated both with Java EE's @EJB or @PersistenceContext or @Resource annotations and with CDI's @Produces annotations. The net effect is that Java EE 6 injects a persistence context, say, where it's called for, and CDI recognizes that injected PersistenceContext as a source for future injections down the line (handled by @Inject). My question is: what is the community's consensus--or is there one--on: what this bridge class should be named where this bridge class should live whether it's best to localize all this stuff into one class or make several of them ...? Left to my own devices, I was thinking of declaring a single class called CDIResources and using that as the One True Place to link Java EE's DI with CDI's DI. Many examples do something similar, but I'm not clear on whether they're "just" examples or whether that's a good way to do it. Thanks.

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• Problems with MediaPlayer, raw resources, stop and start

  - by arakn0

  Hello everybody, I'm new in Android development and I have the next question/problem. I'm playing around with the MediaPlayer class to reproduce some sounds/music. I am playing raw resources (res/raw) and it looks kind of easy. To play a raw resource, the MediaPlayer has to be initialized like this: MediaPlayer mp = MediaPlayer.create(appContext, R.raw.song); mp.start(); Until here there is no problem. The sound is played, and everything works fine. My problem appears when I want to add more options to my application. Specifically when I add the "Stop" button/option. Basically, what I want to do is...when I press "Stop", the music stops. And when I press "Start", the song/sound starts over. (pretty basic!) To stop the media player, you only have to call stop(). But to play the sound again, the media player has to be reseted and prepared. mp.reset(); mp.setDataSource(params); mp.prepare(); The problem is that the method setDataSource() only accepts as params a file path, Content Provider URI, streaming media URL path, or File Descriptor. So, since this method doesn't accept a resource identifier, I don't know how to set the data source in order to call prepare(). In addition, I don't understand why you can't use a Resouce identifier to set the data source, but you can use a resource identifier when initializing the MediaPlayer. I guess that I'm missing something. I wonder if I am mixing concepts, and the method stop() doesn't have to be called in the "Stop" button. Any help? Thanks in advanced!!!

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• java distributed cache for low latency, high availability

  - by Shahbaz

  I've never used distributed caches/DHTs like memcached, jboss cache, ehcache, etc. I'm wondering which, if any, is appropriate for my use. First, I'm not doing web applications (as most of these project seem to be geared towards web apps). I write servers (Order Management Systems actually) for financial trading firms. The servers themselves are not too complicated. They need to receive information (market data, orders, executions, etc.) rout them to their destination while possibly transforming some of these messages. I am looking at these products to solve the following problems: * Safe repository of the state of the server. I'd rather build the logic of my application as a bunch of transformers (similar to Apache Camel) and store the state in a 'safe' place * This repository should be distributed: in case one of these data stores crashes, one or two more should be up and I should be able to switch to them seamlessly * This repository should be fast. Single digits milliseconds count here, in other words, systems which consume/process this data are automated systems, not humans clicking on links. This system needs to have high-throughput and low latency. By sending my data outside the process, I am necessarily slowing performance, but I am trying to balance absolute raw speed and absolute protection of data. * This repository should be safe. Similar to the point about several on-line backups, this system needs to write data to disk (potentially more than one disk). I'd really like to stop writing my own 'transaction servers.' Am I correct to be looking into projects such as jboss cache, ehcache, etc.? Thanks

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• Common JNDI resources in Tomcat

  - by Lehane

  Hi, I’m running a couple of servlet applications in Tomcat (5.5). All of the servlets use a common factory resource that is shared out using JNDI. At the moment, I can get everything working by including the factory resource as a GlobalNamingResource in the /conf/server.xml file, and then having each servlet’s META-INF/context.xml file include a ResourceLink to the resource. Snippets from the XML files are included below. NOTE: I’m not that familiar with tomcat, so I’m not saying that this is a good configuration!!! However, I now want to be able install these servlets into multiple tomcat instances automatically using an RPM. The RPM will firstly copy the WARs to the webapps directory, and the jars for the factory into the common/lib directory (which is fine). But it will also need to make sure that the factory resource is included as a resource for all of the servlets. What is the best way add the resource globally? I’m not too keen on writing a script that goes into the server.xml file and adds in the resource that way. Is there any way for me to add in multiple server.xml files so that I can write a new server-app.xml file and it will concatenate my settings to server.xml? Or, better still to add this JNDI resource to all the servlets without using server.xml at all? p.s. Restarting the server will not be an issue, so I don’t mind if the changes don’t get picked up automatically. Thanks Snippet from server.xml <!-- Global JNDI resources --> <GlobalNamingResources> <Resource name="bean/MyFactory" auth="Container" type="com.somewhere.Connection" factory="com.somewhere.MyFactory"/> </GlobalNamingResources> The entire servlet’s META-INF/context.xml file <?xml version="1.0" encoding="UTF-8"?> <Context> <ResourceLink global="bean/MyFactory" name="bean/MyFactory" type="com.somewhere.MyFactory"/> </Context>

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• Optimising RSS parsing on App Engine to avoid high CPU warnings

  - by Danny Tuppeny

  I'm pulling some RSS feeds into a datastore in App Engine to serve up to an iPhone app. I use cron to schedule updating the RSS every x minutes. Each task only parses one RSS feed (which has 15-20 items). I frequently get warnings about high CPU usage in the App Engine dashboard, so I'm looking for ways to optimise my code. Currently, I use minidom (since it's already there on App Engine), but I suspect it's not very efficient! Here's the code: dom = minidom.parseString(urlfetch.fetch(url).content) if dom: items = [] for node in dom.getElementsByTagName('item'): item = RssItem( key_name = self.getText(node.getElementsByTagName('guid')[0].childNodes), title = self.getText(node.getElementsByTagName('title')[0].childNodes), description = self.getText(node.getElementsByTagName('description')[0].childNodes), modified = datetime.now(), link = self.getText(node.getElementsByTagName('link')[0].childNodes), categories = [self.getText(category.childNodes) for category in node.getElementsByTagName('category')] ); items.append(item); db.put(items); def getText(self, nodelist): rc = '' for node in nodelist: if node.nodeType == node.TEXT_NODE: rc = rc + node.data return rc There isn't much going on, but the scripts often take 2-6 seconds CPU time, which seems a bit excessive for looping through 20ish items and reading a few attributes. What can I do to make this faster? Is there anything particularly bad in the above code, or should I change to another way of parsing? Are there are any libraries (that work on App Engine) that would be better, or would I be better parsing the RSS myself?

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• Threads, Sockets, and Designing Low-Latency, High Concurrency Servers

  - by lazyconfabulator

  I've been thinking a lot lately about low-latency, high concurrency servers. Specifically, http servers. http servers (fast ones, anyway) can serve thousands of users simultaneously, with very little latency. So how do they do it? As near as I can tell, they all use events. Cherokee and Lighttpd use libevent. Nginx uses it's own event library performing much the same function of libevent, that is, picking a platform optimal strategy for polling events (like kqueue on *bsd, epoll on linux, /dev/poll on Solaris, etc). They all also seem to employ a strategy of multiprocess or multithread once the connection is made - using worker threads to handle the more cpu intensive tasks while another thread continues to listen and handle connections (via events). This is the extent of my understanding and ability to grok the thousand line sources of these applications. What I really want are finer details about how this all works. In examples of using events I've seen (and written) the events are handling both input and output. To this end, do the workers employ some sort of input/output queue to the event handling thread? Or are these worker threads handling their own input and output? I imagine a fixed amount of worker threads are spawned, and connections are lined up and served on demand, but how does the event thread feed these connections to the workers? I've read about FIFO queues and circular buffers, but I've yet to see any implementations to work from. Are there any? Do any use compare-and-swap instructions to avoid locking or is locking less detrimental to event polling than I think? Or have I misread the design entirely? Ultimately, I'd like to take enough away to improve some of my own event-driven network services. Bonus points to anyone providing solid implementation details (especially for stuff like low-latency queues) in C, as that's the language my network services are written in.

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• .net c# cannot find img resources when open with exe

  - by okuryazar

  Hello, My exe processes text documents and I want to be able to right click on documents, select open with and point to my exe file. I can double click on my exe and choose a file to process with OpenFileDialog and it works fine. However, when I do open with, I get FileNotFound error. Here is the error log: System.IO.FileNotFoundException: attention.jpg at System.Drawing.Image.FromFile(String filename, Boolean useEmbeddedColorManagement) at System.Drawing.Image.FromFile(String filename) at ImzaDogrulamaUygulamasi.frmCertificate.FillTreeView() in D:\VSS\SOURCE\VS2008\EGA\ImzaDogrulamaUygulamasi\ImzaDogrulamaUygulamasi\frmCertificate.cs:line 76 at ImzaDogrulamaUygulamasi.frmCertificate.Form2_Load(Object sender, EventArgs e) in D:\VSS\SOURCE\VS2008\EGA\ImzaDogrulamaUygulamasi\ImzaDogrulamaUygulamasi\frmCertificate.cs:line 244 at System.Windows.Forms.Form.OnLoad(EventArgs e) at System.Windows.Forms.Form.OnCreateControl() at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible) at System.Windows.Forms.Control.CreateControl() at System.Windows.Forms.Control.WmShowWindow(Message& m) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.ScrollableControl.WndProc(Message& m) at System.Windows.Forms.ContainerControl.WndProc(Message& m) at System.Windows.Forms.Form.WmShowWindow(Message& m) at System.Windows.Forms.Form.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) and this is how I add my images in my code, all resources are in the same directory with the exe file: ImageList myImageList = new ImageList(); myImageList.Images.Add(Image.FromFile("attention.jpg")); myImageList.Images.Add(Image.FromFile("sandglass.jpg")); myImageList.Images.Add(Image.FromFile("11.JPG")); myImageList.Images.Add(Image.FromFile("checkGif.jpg")); treeView1.ImageList = myImageList; Any help is much appreciated. Thanks

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• JSFiddle external resources not working

  - by Ahmed Kato

  I am new to jsfiddle and I am trying to link my external resources. I added them using the tab on the left side and then paste my code on the panes Here is my JSFiddle project but only html is shown without linking to javascript and css in the output what I am doing wrong ? this is my original <head> <link href="css/bootstrap.min.css" rel="stylesheet"> <link href="css/bootstrap-responsive.min.css" rel="stylesheet"> <link href="css/style.css" rel="stylesheet"> <script type="text/javascript" src="js/jquery.min.js"></script> <script type="text/javascript" src="js/bootstrap.min.js"></script> <script type="text/javascript" src="js/scripts.js"></script> <script type="text/javascript" src="js/bootstrap-datepicker.js"></script> <link rel="stylesheet" href="bootstrap-tagsinput.css"> <link rel="stylesheet" type="text/css" href="css/datepicker.css"> </head>

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• Which linear programming package should I use for high numbers of constraints and "warm starts"

  - by davidsd

  I have a "continuous" linear programming problem that involves maximizing a linear function over a curved convex space. In typical LP problems, the convex space is a polytope, but in this case the convex space is piecewise curved -- that is, it has faces, edges, and vertices, but the edges aren't straight and the faces aren't flat. Instead of being specified by a finite number of linear inequalities, I have a continuously infinite number. I'm currently dealing with this by approximating the surface by a polytope, which means discretizing the continuously infinite constraints into a very large finite number of constraints. I'm also in the situation where I'd like to know how the answer changes under small perturbations to the underlying problem. Thus, I'd like to be able to supply an initial condition to the solver based on a nearby solution. I believe this capability is called a "warm start." Can someone help me distinguish between the various LP packages out there? I'm not so concerned with user-friendliness as speed (for large numbers of constraints), high-precision arithmetic, and warm starts. Thanks!

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• trying to read a delimited text file from resources - but it wont run

  - by Bigfatty

  I'm having a problem where instead of reading a text file from the location string, I changed it to read the text file from the resource location and it messes up my program. I've also used the insert snippet method to get most of this code, so it is safe to say I don't know what is going on. Could some one please help? 'reads the text out of a delimited text file and puts the words and hints into to separate arrays ' this works and made the program run ' Dim filename As String = Application.StartupPath + "\ProggramingList.txt" 'this dosnt work and brings back a Illegal characters in path error. dim filename as string = My.Resources.GamesList Dim fields As String() 'my text files are delimited Dim delimiter As String = "," Using parser As New TextFieldParser(filename) parser.SetDelimiters(delimiter) While Not parser.EndOfData ' Read in the fields for the current line fields = parser.ReadFields() ' Add code here to use data in fields variable. 'put the result into two arrays (the fields are the arrays im talking about). one holds the words, and one holds the corresponding hint Programingwords(counter) = Strings.UCase(fields(0)) counter += 1 'this is where the hint is at Programingwords(counter) = (fields(1)) counter += 1 End While End Using

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• PHP: tips/resources/patterns for learning to implement a basic ORM

  - by BoltClock

  I've seen various MVC frameworks as well as standalone ORM frameworks for PHP, as well as other ORM questions here; however, most of the questions ask for existing frameworks to get started with, which is not what I'm looking for. (I have also read this SO question but I'm not sure what to make of it, and the answers are vague.) Instead, I figured I'd learn best by getting my hands dirty and actually writing my own ORM, even a simple one. Except I don't really know how to get started, especially since the code I see in other ORMs is so complicated. With my PHP 5.2.x (this is important) MVC framework I have a basic custom database abstraction layer, that has: Very simple methods like connect($host, $user, $pass, $base), query($sql, $binds), etc Subclasses for each DBMS that it supports A class (and respective subclasses) to represent SQL result sets But does not have: Active Record functionality, which I assume is an ORM thing (correct me if I'm wrong) I've read up a little about ORM, and from my understanding they provide a means to further abstract data models from the database itself by representing data as nothing more than PHP-based classes/objects; again, correct me if I am wrong or have missed out in any way. Still, I'd like some simple tips from anyone else who's dabbled more or less with ORM frameworks. Is there anything else I need to take note of, simple example code for me to refer to, or resources I can read? Thanks a lot in advance!

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• Cobol web development/hosting resources

  - by felixm

  Hello, I'm employed at a fairly big company here in Germany and got the job to create the main website for it which will feature: Static contents; Information and Presentations An employee area (around 6000 employees) featuring various things from calenders, job descriptions, some sort of groups Too many other dynamic things I can't list here I have decided to use COBOL for the job, it may be very underrated but it is a very powerful language, especially for business apps and, as my co-workers say, web (2.0) development too. I also need to use COBOL because all the backend and transactions system of the company is programmed in it (some small parts were programmed in LISP too, idk exactly why). I also have received an API that makes it possible to use COBOL with MySQL easily. This is a big project and it will probably take more than 2 months programming it. What do I have to expect when building a huge web app in COBOL? Are there web frameworks for COBOL available? Some sort of MVC? Are there any good resources for practical web-development with COBOL? Thanks in advance

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• Where in maven project's path should I put configuration files that are not considered resources

  - by Paralife

  I have a simple java maven project. One of my classes when executing needs to load an xml configuration file from the classpath. I dont want to package such xml file when producing the jar but I want to include a default xml file in a zip assemply under a conf subfolder and I also want this default xml to be available in the unit tests to test against it. As I see it there are 2 possible places of this default xml: src/main/resources/conf/default.xml src/main/conf/default.xml Both solutions demand special pom actions: In solution 1, I get the auto copy to target folder during build which means it is available in testing but I also get it in the produced jar which i dont want. In solution 2, I get the jar as I want it(free of the xml) but I manually have to copy the xml to the target folder to be available for testing. (I dont want to add src's subfolders in test classpath. I think it is bad practice). The question is what is the best solution of the two? If the correct is 2, what is the best way to copy it to target folder? Is there any other solution better and more common than those two? (I also read http://stackoverflow.com/questions/465001/where-should-i-put-application-configuration-files-for-a-maven-project but I would like to know the most "correct solution" from the "convention over configuration" point of view and this link provides some configuration type solutions but not any convention oriented. Maybe there isnt one but I ask anyway. Also the solutions provided include AntRun plugin and appAssembler plugin and I wonder if I could do it with out them.)

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• Alternatives to LINQ To SQL on high loaded pages

  - by Alex

  To begin with, I LOVE LINQ TO SQL. It's so much easier to use than direct querying. But, there's one great problem: it doesn't work well on high loaded requests. I have some actions in my ASP.NET MVC project, that are called hundreds times every minute. I used to have LINQ to SQL there, but since the amount of requests is gigantic, LINQ TO SQL almost always returned "Row not found or changed" or "X of X updates failed". And it's understandable. For instance, I have to increase some value by one with every request. var stat = DB.Stats.First(); stat.Visits++; // .... DB.SubmitChanges(); But while ASP.NET was working on those //... instructions, the stats.Visits value stored in the table got changed. I found a solution, I created a stored procedure UPDATE Stats SET Visits=Visits+1 It works well. Unfortunately now I'm getting more and more moments like that. And it sucks to create stored procedures for all cases. So my question is, how to solve this problem? Are there any alternatives that can work here? I hear that Stackoverflow works with LINQ to SQL. And it's more loaded than my site.

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• Disposing ActiveX resources owned by another thread

  - by Stefan Teitge

  I've got a problem problem with threading and disposing resources. I've got a C# Windows Forms application which runs expensive operation in a thread. This thread instantiates an ActiveX control (AxControl). This control must be disposed as it uses a high amount of memory. So I implemented a Dispose() method and even a destructor. After the thread ends the destructor is called. This is sadly called by the UI thread. So invoking activexControl.Dispose(); fails with the message "COM object that has been separated from its underlying RCW", as the object belongs to another thread. How to do this correctly or is it just a bad design I use? (I stripped the code down to the minimum including removing any safety concerns.) class Program { [STAThread] static void Main() { // do stuff here, e.g. open a form new Thread(new ThreadStart(RunStuff); // do more stuff } private void RunStuff() { DoStuff stuff = new DoStuff(); stuff.PerformStuff(); } } class DoStuff : IDisposable { private AxControl activexControl; DoStuff() { activexControl = new AxControl(); activexControl.CreateControl(); // force instance } ~DoStuff() { Dispose(); } public void Dispose() { activexControl.Dispose(); } public void PerformStuff() { // invent perpetuum mobile here, takes time } }

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• Should I use IDisposable for purely managed resources?

  - by John Gietzen

  Here is the scenario: I have an object called a Transaction that needs to make sure that only one entity has permission to edit it at any given time. In order to facilitate a long-lived lock, I have the class generating a token object that can be used to make the edits. You would use it like this: var transaction = new Transaction(); using (var tlock = transaction.Lock()) { transaction.Update(data, tlock); } Now, I want the TransactionLock class to implement IDisposable so that its usage can be clear. But, I don't have any unmanaged resources to dispose. however, the TransctionLock object itself is a sort of "unmanaged resource" in the sense that the CLR doesn't know how to properly finalize it. All of this would be fine and dandy, I would just use IDisposable and be done with it. However, my issue comes when I try to do this in the finalizer: ~TransactionLock() { this.Dispose(false); } I want the finalizer to release the transaction from the lock, if possible. How, in the finalizer, do I detect if the parent transaction (this.transaction) has already been finalized? Is there a better pattern I should be using? The Transaction class looks something like this: public sealed class Transaction { private readonly object lockMutex = new object(); private TransactionLock currentLock; public TransactionLock Lock() { lock (this.lockMutex) { if (this.currentLock != null) throw new InvalidOperationException(/* ... */); this.currentLock = new TransactionLock(this); return this.currentLock; } } public void Update(object data, TransactionLock tlock) { lock (this.lockMutex) { this.ValidateLock(tlock); // ... } } internal void ValidateLock(TransactionLock tlock) { if (this.currentLock == null) throw new InvalidOperationException(/* ... */); if (this.currentLock != tlock) throw new InvalidOperationException(/* ... */); } internal void Unlock(TransactionLock tlock) { lock (this.lockMutex) { this.ValidateLock(tlock); this.currentLock = null; } } }

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• node.js UDP data lost at high package rates

  - by koleto

  I am observing a significant data-lost on a UDP connection with node.js 0.6.18 and 0.8.0 . It appears at high packet rates about 1200 packet per second with frames about 1500 byte limit. Each data packages has a incrementing number so it easy to track the number of lost packages. var server = dgram.createSocket("udp4"); server.on("message", function (message, rinfo) { //~processData(message); //~ writeData(message, null, 5000); }).bind(10001); On the receiving callback I tested two cases I first saved 5000 packages in a file. The result ware no dropped packages. After I have included a data processing routine and got about 50% drop rate. What I expected was that the process data routine should be completely asynchronous and should not introduce dead time to the system, since it is a simple parser to process binary data in the package and to emits events to a further processing routine. It seems that the parsing routine introduce dead time in which the event handler is unable to handle each packets. At the low package rates (< 1200 packages/sec) there are no data lost observed! Is this a bug or I am doing something wrong?

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• How to convert string with double high/wide characters to normal string [VC++6]

  - by Shaitan00

  My application typically recieves a string in the following format: " Item $5.69 " Some contants I always expect: - the LENGHT always 20 characters - the start index of the text always [5] - and most importantly the index of the DECIMAL for the price always [14] In order to identify this string correctly I validate all the expected contants listed above .... Some of my clients have now started sending the string with Doube-High / Double-Wide values (pair of characters which represent a single readable character) similar to the following: " Item $x80x90.x81x91x82x92 " For testing I simply scan the string character-by-character, compare char[i] and char[i+1] and replace these pairs with their corresponding single character when a match is found (works fine) as follows: [Code] for (int i=0; i < sData.length(); i++) { char ch = sData[i] & 0xFF; char ch2 = sData[i+1] & 0xFF; if (ch == '\x80' && ch2 == '\x90') zData.replace("\x80\x90", "0"); else if (ch == '\x81' && ch2 == '\x91') zData.replace("\x81\x91", "1"); else if (ch == '\x82' && ch2 == '\x92') zData.replace("\x82\x92", "2"); ... ... ... } [/Code] But the result is something like this: " Item $5.69 " Notice how this no longer matches my expectation: the lenght is now 17 (instead of 20) due to the 3 conversions and the decimal is now at index 13 (instead of 14) due to the conversion of the "5" before the decimal point. Ideally I would like to convert the string to a normal readable format keeping the constants (length, index of text, index of decimal) at the same place (so the rest of my application is re-usable) ... or any other suggestion (I'm pretty much stuck with this)... Is there a STANDARD way of dealing with these type of characters? Any help would be greatly appreciated, I've been stuck on this for a while now ... Thanks,

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• Differences in accessing resources between Simulator and Device?

  - by Tony

  Is there some difference between the way that bundle resources can be accessed on the iPhone simulator versus a device (in my case, an iPad)? I am able to access a file on the former, but not the latter. NSString *filePath = [NSString stringWithFormat:@"%@%@",[[NSBundle mainBundle] bundlePath], @"/AppResources/html/pages/quickHelp.html"]; BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:filePath]; // fileExists == YES in the debugger on both the simulator and the device NSString *path = [NSString stringWithFormat:@"AppResources/html/pages/%@", contentsFileName]; NSString *pathForURL = [[NSBundle mainBundle] pathForResource:path ofType:@"html"]; NSURL *url = [NSURL fileURLWithPath:pathForURL isDirectory:NO]; The code above works fine in the simulator, but on the device pathForResource:path returns nil, so the last line throws a 'nil string parameter' exception. Am I missing something obvious? edit: Of course, in the above @"quickHelp" is being passed in the contentsFileName var. edit2: if it makes any difference, in my build settings "Base SDK" is set to "iPhone Device 4.0", and "iPhone OS Deployment Target" is set to "iPhone OS 3.1.3". Any other settings that might have an influence?

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