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• killing a separate thread having a socket

  - by user311906

  Hi All I have a separate thread ListenerThread having a socket listening to info broadcasted by some remote server. This is created at the constructor of one class I need to develop. Because of requirements, once the separate thread is started I need to avoid any blocking function on the main thread. Once it comes to the point of calling the destructor of my class I cannot perform a join on the listener thread so the only thing I can do is to KILL it. My questions are: what happens to the network resoruces allocated by the function passed to the thead? Is the socket closed properly or there might be something pending? ( most worried about this ) is this procedure fast enough i.e. is the thread killed so that interrupt immediately ? I am working with Linux ...what command or what can I check to ensure that there is no networking resource left pending or that something went wrong for the Operating system I thank you very much for your help Regards MNSTN NOTE: I am using boost::thread in C++

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• Exception "Illegal attempt to associate a collection with two open sessions" when saving object

  - by Alex

  I am using CastleProject ActiveRecord and I use lazy load feature of this ORM. In order to make lazy load work, it is required to create SessionScope. I do this in Program.cs: public static SessionScope sessionScope; private static void InitializeActiveRecord() { ActiveRecordStarter.Initialize(); sessionScope = new SessionScope(); } This works fine for loading, however, when I try to save my objects, I get an exception saying "Illegal attempt to associate a collection with two open sessions". I guess this is due to the fact that I created one session myself. How to avoid this exception?

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• Question about joins and table with Millions of rows

  - by xRobot

  I have to create 2 tables: Magazine ( 10 millions of rows with these columns: id, title, genres, printing, price ) Author ( 180 millions of rows with these columns: id, name, magazine_id ) . Every author can write on ONLY ONE magazine and every magazine has more authors. So if I want to know all authors of Motors Magazine, I have to use this query: SELECT * FROM Author, Magazine WHERE ( Author.id = Magazine.id ) AND ( genres = 'Motors' ) The same applies to Printing and Price column. To avoid these joins with tables of millions of rows, I thought to use this tables: Magazine ( 10 millions of rows with this column: id, title, genres, printing, price ) Author ( 180 millions of rows with this column: id, name, magazine_id, genres, printing, price ) . and this query: SELECT * FROM Author WHERE genres = 'Motors' Is it a good approach ? I can use Postgresql or Mysql.

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• Bulding an multi-platform SWT application using Ant

  - by Mridang Agarwalla

  I'm writing an SWT application which can be used on Windows (32/64 bit) and Mac OSX (32/64 bit). Apart from the JRE I rely on the SWT library found here. I can find four versions of the SWT library depending upon my target platforms (as mentioned above). When building my application, how can I compile using the correct SWT Jar? If possible, I'd like to try and avoid hard-coding the Jar version, platform and architecture. The SWT Jars are named like this: swt-win32-x86_64.jar swt-win32-x86_32.jar swt-macosx-x86_32.jar swt-macosx-x86_64.jar (My project will be an open source project. I'd like people to be able to download the source and build it and therefore I've thought of including all the four versions of the SWT Jars in the source distribution. I hope this is the correct approach of publishing code relying on third-part libraries.) Thanks everyone.

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• Hashing a python method to regenerate output when method is modified

  - by Seth Johnson

  I have a python method that has a deterministic result. It takes a long time to run and generates a large output: def time_consuming_method(): # lots_of_computing_time to come up with the_result return the_result I modify time_consuming_method from time to time, but I would like to avoid having it run again while it's unchanged. [Time_consuming_method only depends on functions that are immutable for the purposes considered here; i.e. it might have functions from Python libraries but not from other pieces of my code that I'd change.] The solution that suggests itself to me is to cache the output and also cache some "hash" of the function. If the hash changes, the function will have been modified, and we have to re-generate the output. Is this possible or a ridiculous idea? If this isn't a terrible idea, is the best implementation to write f = """ def ridiculous_method(): a = # # lots_of_computing_time return a """ , use the hashlib module to compute a hash for f, and use compile or eval to run it as code?

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• c# multi threaded file processing

  - by user177883

  There is a folder that contains 1000 of small text files. I aim to parse and process all of them while more files are being populated in to the folder. My intention is to multithread this operation as the single threaded prototype took 6 minutes to process 1000 files. I like to have reader and writer thread(s) as following : while the reader thread(s) are reading the files, I d like to have writer thread(s) to process them. Once the reader is started reading a file, I d like to mark it as being processed, such as by renaming it, once it s read, rename it to completed. How to approach such multithreaded application ? Is it better to use a distributed hash table or a queue? Which data structure to use that would avoid locks? Would you have a better approach to this scheme that you like to share?

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• Caurina Tweener and Alpha

  - by Jk_

  Hi guys, Usually I work with TweenLite but I had to modify the code of someone else who worked with Caurina Tweener. I have a basic problem with it! On my scene, I have a simple movie clip filled with black. Into this movieclip a bitmap file (jpg). When I make a tween on the alpha of my mc, it seems that there is a delay (in the alpha) between this the black background and the image. Tweener.addTween(thisMc, { _autoAlpha:0, time:1 } ); I'm sure there is an easy way to avoid this problem but I can't find it out! Cheers, Jk_

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• Embed external images for use in HTML canvas?

  - by Philipp Lenssen

  I'm using JavaScript to load an image into my Canvas element in Firefox. This works fine for local images, but throws a security exception for external images. Is there any way to avoid this security exception, one that does not involve my server having to act as proxy to load the image locally (because that would stress my server)? PS: The current code is similar to this: var img = new Image(); var contextSource = canvasSource.getContext('2d'); contextSource.drawImage(img, 0, 0); // get image data to do stuff with pixels var imageDataSource = contextSource.getImageData(0, 0, width - 1, height - 1);

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• Can django lazy-load fields in a model?

  - by Leopd

  One of my django models has a large TextField which I often don't need to use. Is there a way to tell django to "lazy-load" this field? i.e. not to bother pulling it from the database unless I explicitly ask for it. I'm wasting a lot of memory and bandwidth pulling this TextField into python every time I refer to these objects. The alternative would be to create a new table for the contents of this field, but I'd rather avoid that complexity if I can.

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• Could not see memory being released on closing MFC modal dialog that hosts wpf user control using HW

  - by Naveen Chiluka

  This is in continuation with my last question posted "Continuous Memory leak while using WpfHWndSource" I have to load an WPF User Control in an MFC Modal Dialog that is being invoked from the ocx control. For this I have created a MFC Regular Dll(Mixed Mode Regular dll with clr option enabled), I have created a modal dialog which will host wpf user control using HWndSource. This exported dialog is placed as a child Dialog of the above MFC dialog that is being invoked from the ocx. Ny intermediate dialog uses C++/Cli code. When the main MFC dialog is closed, I am deleteing the ptr reference of the intermediate dialog created on the heap. In the the dipose of the .Net User Control, I have set most of the references that I have created to null, unsubscribed to the events (to avoid weak refernces), unbinded from the propertes(by using clear binding). Called delete on the HwndSource and the user control(which basically calls the dispose method). But I do not see complete memory being released. Any help would be greatful.

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• [PHP] Using cURL to download large XML files

  - by ndg

  I'm working with PHP and need to parse a number of fairly large XML files (50-75MB uncompressed). The issue, however, is that these XML files are stored remotely and will need to be downloaded before I can parse them. Having thought about the issue, I think using a system() call in PHP in order to initiate a cURL transfer is probably the best way to avoid timeouts and PHP memory limits. Has anyone done anything like this before? Specifically, what should I pass to cURL to download the remote file and ensure it's saved to a local folder of my choice?

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• How to convert a function that returns a int to a function that returns a bool using boost::bind?

  - by user814628

  I have something like the following: struct A{ virtual int derp(){ if(herp()) return 1; else return 0; } void slurp(){ boost::function<bool(int x, int y> purp = /** boost bind derp to match lvalue sig **/; } } Any ideas? I want to create the function prup which basically calls derp and ignores the (x,y) passed in. I need something like bool purp(int x, int y){ return derp(); } but want to avoid creating it as a member function, and rather just create it locally if possible?

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• Is it a solvable problem to generate a regular expression that matches some input set?

  - by Roman

  I provide some input set which contains known separated number of text blocks. I want to make a program that automatically generate 1 or more regular expressions each of which matches every text block in the input set. I see some relatively easy ways to implement a brute-force search. But I'm not an expert in compilers theory. That's why I'm curious: 1) is this problem solvable? or there are some principle impossibility to make such algorithm? 2) is it possible to achieve polynomial complexity for this algorithm and avoid brute forcing?

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• Locking a file to verify a single execution of a service. How reliable?

  - by Camilo Díaz

  Hello, I am deploying a little service to an UNIX(AIX) system. I want to check if there is no active instance of that service running when starting it. How reliable is to implement that check like this? Try to acquire a lock on a file (w/ FileChannel) If succeeds, keep lock and continue execution If fails, exit and refuse to run the main body I am aware of software like the Tanuki wrapper, however, I'm longing for a simpler(maybe not portable) solution. Regarding PIDFILE(s): I want to avoid using them if possible, as I don't have administrative rights on the machine, neither knowledge in AIX's shell programming.

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• TSQL ID generation

  - by Markus

  Hi. I have a question regarding locking in TSQL. Suppose I have a the following table: A(int id, varchar name), where id is the primary key, but is NOT an identity column. I want to use the following pseudocode to insert a value into this table: lock (A) uniqueID = GenerateUniqueID() insert into A values (uniqueID, somename) unlock(A) How can this be accomplished in terms of TSQL? The computation of the next id should be done with the table A locked in order to avoid other sessions to do the same operation at the same time and get the same id.

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• Retrieve entities with children per one sql call. ADO.NET Entity framework

  - by Andrew Florko

  Hello everybody, I have two tables: A & B B { B1: Field1, B2: Field2, ... } A { Children: List of B, A1: Field1, A2: Field2, } I want to retrieve "A" entities with related "B" entities like this: DataContext.A.Select( a = new MySubset( A1 = a.A1, Children = a.Children.Select(b = b.B1).ToList()); But EF can't translate ToList into SQL, so i have to call ToList() per each instance in query producing additional network call. How can I avoid this? Thank you in advance.

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• Setting the Cursor Position in a Win32 Console Application

  - by Jim Fell

  How can I set the cursor position in a Win32 Console application? Preferably, I would like to avoid making a handle and using the Windows Console Functions. (I spent all morning running down that dark alley; it creates more problems than it solves.) I seem to recall doing this relatively simply when I was in college using stdio, but I can't find any examples of how to do it now. Any thoughts or suggestions would be greatly appreciated. Thanks.

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• Strategies for generating Zend Cache Keys

  - by emeraldjava

  ATM i'm manually generating a cache key based on the method name and parameters, then follow to the normal cache pattern. This is all done in the Controller and i'm calling a model class that 'extends Zend_Db_Table_Abstract'. public function indexAction() { $cache = Zend_Registry::get('cache'); $individualleaguekey = sprintf("getIndividualLeague_%d_%s",$leagueid,$division->code); if(!$leaguetable = $cache->load($individualleaguekey)) { $table = new Model_DbTable_Raceresult(); $leaguetable = $table->getIndividualLeague($leagueid,$division,$races); $cache->save($leaguetable, $individualleaguekey); } $this->view->leaguetable = $leaguetable; .... I want to avoid the duplication of parameters to the cache creation method and also to the model method, so i'm thinking of moving the caching logic away from my controller class and into model class packaged in './model/DbTable', but this seems incorrect since the DB model should only handle SQL operations. Any suggestions on how i can implement a clean patterned solution?

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• How to stop GHC from generating intermediate files?

  - by unknown

  When compiling a haskell source file via ghc --make foo.hs GHC always leaves behind a variety of intermediate files other than foo.exe. These are foo.hi and foo.o. I often end up having to delete the .hi and .o files to avoid cluttering up the folders. Is there a command line option for GHC not to leave behind its intermediate files? (When asked on #haskell, the best answer I got was ghc --make foo.hs && rm foo.hi foo.o.

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• Using different versions of jQuery on the same page

  - by nimcap

  Users of my service includes a JS in their pages that I provide. I am hosting the script they are including. My script does some manipulation on their content. I am sick of writing my own DOM manipulators/selectors and wasting hours for jobs that can be done with 1 line of code if I can use jQuery. Some of the users of my service already uses jQuery (or Prototype etc.) on their pages, so if I include jQuery there will be a conflict. Because there will be version differences, I don't want to use their jQuery selectors, methods either in case jQuery exists. Keeping in mind that I have no control over their pages, how can I include jQuery and avoid conflict?

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• Position elements without overlap

  - by eWolf

  I have a number of rectangular elements that I want to position in a 2D space. I calculate an ideal position for each element. Now my problem is that many elements overlap as very often the ideal positions are concentrated in one region. I want to avoid overlap as much as possible (doesn't have to be perfect, though). How can I do this? I've heard physics simulations are suitable for this - is that correct? And can anyone provide an example/tutorial? By the way: I'm using XNA, if you know any .NET library that does exactly this job - tell me!

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• Dynamic dispatch and inheritance in python

  - by Bill Zimmerman

  Hi, I'm trying to modify Guido's multimethod (dynamic dispatch code): http://www.artima.com/weblogs/viewpost.jsp?thread=101605 to handle inheritance and possibly out of order arguments. e.g. (inheritance problem) class A(object): pass class B(A): pass @multimethod(A,A) def foo(arg1,arg2): print 'works' foo(A(),A()) #works foo(A(),B()) #fails Is there a better way than iteratively checking for the super() of each item until one is found? e.g. (argument ordering problem) I was thinking of this from a collision detection standpoint. e.g. foo(Car(),Truck()) and foo(Truck(), Car()) and should both trigger foo(Car,Truck) # Note: @multimethod(Truck,Car) will throw an exception if @multimethod(Car,Truck) was registered first? I'm looking specifically for an 'elegant' solution. I know that I could just brute force my way through all the possibilities, but I'm trying to avoid that. I just wanted to get some input/ideas before sitting down and pounding out a solution. Thanks

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• How to remove duplicate line in a file

  - by Abs

  Hi I'm using the below method to write to a file from the Jtextarea and I call this method every 30 second within a Timer but instead to add only new line in file it rewrite the entire lines contained in Jtextarea so then I have duplicate lines. I want to avoid this and update the file just with new lines. Could you help me please. public void loger() { FileWriter writer = null; try { writer = new FileWriter("MBM_Log_"+date()+".txt" , true); textArea.write(writer); } catch (IOException exception) { System.err.println("log error"); exception.printStackTrace(); } finally { if (writer != null) { try { writer.close(); } catch (IOException exception) { System.err.println("Error closing writer"); exception.printStackTrace(); } } } }

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• Avoiding "variable might not have been initialized"

  - by Mason Wheeler

  I recently ran across a routine that looks something like this: procedure TMyForm.DoSomething(list: TList<TMyObject>; const flag: boolean); var local: integer; begin if flag then //do something else local := ExpensiveFunctionCallThatCalculatesSomething; //do something else for i := 0 to list.Count do if flag then //do something else if list[i].IntValue > local then //WARNING HERE //do something else end; This gives Variable 'local' might not have been initialized even though you can tell by reading the code that you won't hit that line unless the code branch that initializes it has run. Now, I could get rid of this warning by adding a useless local := 0; at the top of the procedure, but I wonder if there might not be a better way to structure this to avoid the issue. Anyone have any ideas?

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• Why is there so much poorly indented code out there?

  - by dsimcha

  The more I browse the code to open source projects in languages that aren't Python, the more I realize that it seems a lot of programmers don't believe in proper indentation. (I won't mention any projects specifically to avoid having anyone take this question too personally.) Usually code is indented, but in a way just different enough from the standard style that it drives me crazy, especially in old/crufty code. I've noticed that when I write in C-like languages, I tend to indent correctly as religiously as when I'm writing in Python, with the exception of debugging code that I actually want to stick out like a sore thumb. Given how easy it is with a modern IDE to fix incorrect indentation, what are some rationales for not religiously keeping indentation in sync with braces?

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