Search Results

Search found 12445 results on 498 pages for 'memory fragmentation'.

Page 427/498 | < Previous Page | 423 424 425 426 427 428 429 430 431 432 433 434  | Next Page >

• Unknown Exception on trying to initialize the web service stub created by Axis C++

  - by Harsha Reddy

  Hi, I am trying out the sample calculator program given in the folder of axis c++. I am mainly interested in the client side. So I used the wsdl to create the stubs and my main is pretty much the same as given in the sample. However on executing the call Calculator ws (endpoint) I get an unknown exception "First-chance exception at 0x7c0024b9 in CalculatorClient.exe: 0xC0000005: Access violation reading location 0x00000000. First-chance exception at 0x7c812afb in CalculatorClient.exe: Microsoft C++ exception: [rethrow] at memory location 0x00000000.. Unhandled exception at 0x7c0024b9 in CalculatorClient.exe: 0xC0000005: Access violation reading location 0x00000000." and the exception causing code is Calculator::Calculator(const char* pchEndpointUri, AXIS_PROTOCOL_TYPE eProtocol) :Stub(pchEndpointUri, eProtocol) { } I had earlier tried to run a a webservice using Axis C++ but had received the same error. At that time my web service was a java ws on WAS. Then I later tried the calculator client (but this time I did not have any server hosting the ws as I just wanted to check if the Client could initialize). Is the problem caused due to the web service not being hosted on Apache in C++ (though I highly doubt it). Any help would be appreciated. Thanks, Harsha

  Read the article

• echo command not found while testing selenium with phpunit

  - by Bill Szerdy

  I am getting an ERROR: Unknown command: 'echo' executing a selenium script with phpunit. Based on the output that echo command should be included in my version of PHPUnit. The selenium script does execute successfully in the firefox selenium IDE. mkdir_build: phpunit: [exec] PHPUnit 3.4.12 by Sebastian Bergmann. [exec] [exec] . [exec] TestFull [exec] E [exec] [exec] Time: 11 seconds, Memory: 6.50Mb [exec] [exec] There was 1 error: [exec] [exec] 1) TestFull::testNumberOne [exec] PHPUnit_Framework_Exception: Response from Selenium RC server for testComplete(). [exec] ERROR: Unknown command: 'echo'. [exec] [exec] [exec] /directory/to/tests/TestFull.php:14 [exec] [exec] FAILURES! [exec] Tests: 1, Assertions: 0, Errors: 1. And the RC server output: $ java -jar selenium-server.jar -port 4445 -debug 13:23:08.426 INFO - Java: Sun Microsystems Inc. 14.2-b01 13:23:08.428 INFO - OS: Linux 2.6.28-15-server i386 13:23:08.439 INFO - v2.0 [a2], with Core v2.0 [a2] 13:23:08.439 INFO - Selenium server running in debug mode. 13:25:05.661 DEBUG - ---------retrieving CommandQueue for sel_93352 13:25:05.662 DEBUG - Browser 2c8b3b5657a640db9fb278ecbd01049e/:top sel_93352 posted ERROR: Unknown command: 'echo' 13:25:05.662 DEBUG - ---------retrieving CommandQueue for sel_93352 13:25:05.662 DEBUG - putting command: ERROR: Unknown command: 'echo' 13:25:05.662 DEBUG - ..command put?: true 13:25:05.662 DEBUG - sel_93352 commandHolder sel_93352 getCommand() called 13:25:05.662 DEBUG - waiting for data for at most 10 more s 13:25:05.662 DEBUG - data from polling: ERROR: Unknown command: 'echo' 13:25:05.662 DEBUG - sel_93352 commandResultHolder sel_93352 getResult() -> ERROR: Unknown command: 'echo' 13:25:05.663 DEBUG - Got result: ERROR: Unknown command: 'echo' on session 2c8b3b5657a640db9fb278ecbd01049e 13:25:05.663 INFO - Got result: ERROR: Unknown command: 'echo' on session 2c8b3b5657a640db9fb278ecbd01049e 13:25:05.663 DEBUG - Handled by org.openqa.selenium.server.SeleniumDriverResourceHandler in HttpContext[/selenium-server,/selenium-server] 13:25:05.663 DEBUG - RESPONSE: HTTP/1.1 200 OK Date: Wed, 07 Apr 2010 20:25:05 GMT Server: Jetty/5.1.x (Linux/2.6.28-15-server i386 java/1.6.0_16 Cache-Control: no-cache Pragma: no-cache Expires: Thu, 01 Jan 1970 00:00:00 GMT Content-Type: text/plain Connection: close

  Read the article

• Per-pixel per-component alpha blending in Windows

  - by Crend King

  I have a 24-bit bitmaps with R, G, B color channels and a 24-bit bitmap with R, G, B alpha channels. I want to alpha blend the first bitmap to a HDC in GDI or RenderTarget in Direct2D with the alpha channels respectively. For example, suppose for one pixel, the bitmap color is (192, 192, 192), the HDC color is (0, 255, 255) and the alpha channels are (30, 40, 50). The final HDC color should be (22, 245, 242). I know I can BitBlt the HDC to a memory HDC first, do alpha blending by manually calculating the color of each pixel and finally BitBlt back. I just want to avoid the additional blitting and leave APIs do their job (faster since they are in kernel space). The first idea comes to my mind is to split the source bitmap into 3 red-only, green-only and blue-only 8-bit bitmaps, do normal alpha blending, then composite the 3 output bitmaps into the HDC. But I don't find a way to do the splitting and composition natively in Windows (would Direct2D layer help?). Also, the splitting and compositing may require many additional copying. The performance overhead would be too high. Or maybe do the alpha blending in 3 passes. Each pass apply the blending for one channel, while maintaining the other 2 unchanged. Thanks for any comment. EDIT: I found this question, and the answer should be good reference to this problem. However, besides AC_SRC_OVER, there is no other blending operation supported. Why don't Microsoft improve their API?

  Read the article

• How can I build something like Amazon S3 in Perl?

  - by Joel G

  I am looking to code a file storage application in perl similar to amazon s3. I already have a amazon s3 clone that I found online called parkplace but its in ruby and is old also isn't built for high loads. I am not really sure what modules and programs I should use so id like some help picking them out. My requirements are listed below (yes I know there are lots but I could start simple then add more once I get it going): Easy API implementation for client side apps. (maybe REST (?) Centralized database server for the USERDB (maybe PostgreSQL (?). Logging of all connections, bandwidth used, well pretty much everything to a centralized server (maybe PostgreSQL again (?). Easy server side configuration (config file(s) stored on the servers). Web based control panel for admin(s) and user(s) to show logs. (could work just running queries from the databases) Fast High Uptime Low memory usage Some sort of load distribution/load balancer (maybe a dns based or pound or perlbal or something else (?). Maybe a cache of some sort (memcached or parlbal or something else (?). Thanks in advance

  Read the article

• Looking for a .Net ORM

  - by SLaks

  I'm looking for a .Net 3.5 ORM framework with a rather unusual set of requirements: I need to create and alter tables at runtime with schemas defined by my end-users. (Obviously, that wouldn't be strongly-typed; I'm looking for something like a DataTable there) I also want regular strongly-typed partial classes for rows in non-dynamic tables, with custom validation and other logic. (Like normal ORMs) I want to load the entire database (or some entire tables) once, and keep it in memory throughout the life of the (WinForms) GUI. (I have a shared SQL Server with a relatively slow connection) I also want regular LINQ support (like LINQ-to-SQL) for ASP.Net on the shared server (which has a fast connection to SQL Server) In addition to SQL Server, I also want to be able to use a single-file database that would support XCopy deployment (without installing SQL CE on the end-user's machine). (Probably Access or SQLite) Finally, it has to be free (unless it's OpenAccess) I'll probably have to write it myself, as I don't think there is an existing ORM that meets these requirements. However, I don't want to re-invent the wheel if there is one, hence this question. I'm using VS2010, but I don't know when my webhost (LFC) will upgrade to .Net 4.0

  Read the article

• Accessing frame info in gdb

  - by Maelstrom

  In gdb, is there a way to access the contents of info frame in a script? I'm debugging a problem somewhere between Apache, PHP, APC and my own code, and I have about a hundred cores to choose from. Following the instructions here http://bugs.php.net/bugs-generating-backtrace.php I end up with a stacktrace like: #0 0x0121a31a in do_bind_function (opline=0xa94dd750, function_table=0x9b9cf98, compile_time=0 '\0') at /usr/src/debug/php-5.2.7/Zend/zend_compile.c:2407 #1 0x0124bb2e in ZEND_DECLARE_FUNCTION_SPEC_HANDLER (execute_data=0xbfef7990) at /usr/src/debug/php-5.2.7/Zend/zend_vm_execute.h:498 #2 0x01249dfa in execute (op_array=0xb79d5d3c) at /usr/src/debug/php-5.2.7/Zend/zend_vm_execute.h:92 #3 0x01261e31 in ZEND_INCLUDE_OR_EVAL_SPEC_VAR_HANDLER (execute_data=0xbfef80d0) at /usr/src/debug/php-5.2.7/Zend/zend_vm_execute.h:7809 #4 0x01249dfa in execute (op_array=0xb79d55ec) at /usr/src/debug/php-5.2.7/Zend/zend_vm_execute.h:92 ... #26 0x09caa894 in ?? () #27 0x00000000 in ?? () The stack will always look similar, with function execute and ZEND_something interleaved several times. I need to go up to the last instance of execute (up 2 in this case) and print myVar. Obviously gdb knows the function names, but does it surface them in any user variables I could access? Typing frame 2 shows a one-line version, and info frame shows a single stackframe in detail. I want to do something like while ($current_frame.function_name != "execute") {up;} print myVar but I don't see how to do it strictly within gdb. Is there a variable / structure / special memory location / something that allows access to gdb's information on either the whole stack (like bt) or to the current stack frame (like info frame)?

  Read the article

• Ways std::stringstream can set fail/bad bit?

  - by Evan Teran

  A common piece of code I use for simple string splitting looks like this: inline std::vector<std::string> split(const std::string &s, char delim) { std::vector<std::string> elems; std::stringstream ss(s); std::string item; while(std::getline(ss, item, delim)) { elems.push_back(item); } return elems; } Someone mentioned that this will silently "swallow" errors occurring in std::getline. And of course I agree that's the case. But it occurred to me, what could possibly go wrong here in practice that I would need to worry about. basically it all boils down to this: inline std::vector<std::string> split(const std::string &s, char delim) { std::vector<std::string> elems; std::stringstream ss(s); std::string item; while(std::getline(ss, item, delim)) { elems.push_back(item); } if(ss.fail()) { // *** How did we get here!? *** } return elems; } A stringstream is backed by a string, so we don't have to worry about any of the issues associated with reading from a file. There is no type conversion going on here since getline simply reads until it sees a newline or EOF. So we can't get any of the errors that something like boost::lexical_cast has to worry about. I simply can't think of something besides failing to allocate enough memory that could go wrong, but that'll just throw a std::bad_alloc well before the std::getline even takes place. What am I missing?

  Read the article

• Using Word COM objects in .NET, InlineShapes not copied from template to document

  - by Keith

  Using .NET and the Word Interop I am programmatically creating a new Word doc from a template (.dot) file. There are a few ways to do this but I've chosen to use the AttachedTemplate property, as such: Dim oWord As New Word.Application() oWord.Visible = False Dim oDocuments As Word.Documents = oWord.Documents Dim oDoc As Word.Document = oDocuments.Add() oDoc.AttachedTemplate = sTemplatePath oDoc.UpdateStyles() (I'm choosing the AttachedTemplate means of doing this over the Documents.Add() method because of a memory leak issue I discovered when using Documents.Add() to open from templates.) This works fine EXCEPT when there is an image (represented as an InlineShape) in the template footer. In that case the image does not appear in the resulting document. Specifically the image should appear in the oDoc.Sections.Item(1).Footers.Item(WdHeaderFooterIndex.wdHeaderFooterPrimary).Range.InlineShapes collection but it does not. This is not a problem when using Documents.Add(), however as I said that method is not an option for me. Is there an extra step I have to take to get the images from the template? I already discovered that when using AttachedTemplate I have to explicitly call UpdateStyles() (as you can see in my code snippet) to apply the template styles to the document, whereas that is done automatically when using Documents.Add(). Or maybe there's some crazy workaround? Your help is much appreciated! :)

  Read the article

• Storing URLs while Spidering

  - by itemio

  I created a little web spider in python which I'm using to collect URLs. I'm not interested in the content. Right now I'm keeping all the visited URLs in a set in memory, because I don't want my spider to visit URLs twice. Of course that's a very limited way of accomplishing this. So what's the best way to keep track of my visited URLs? Should I use a database? * which one? MySQL, sqlite, postgre? * how should I save the URLs? As a primary key trying to insert every URL before visiting it? Or should I write them to a file? * one file? * multiple files? how should I design the file-structure? I'm sure there are books and a lot of papers on this or similar topics. Can you give me some advice what I should read?

  Read the article

• Array: mathematical sequence

  - by VaioIsBorn

  An array of integers A[i] (i 1) is defined in the following way: an element A[k] ( k 1) is the smallest number greater than A[k-1] such that the sum of its digits is equal to the sum of the digits of the number 4* A[k-1] . You need to write a program that calculates the N th number in this array based on the given first element A[1] . INPUT: In one line of standard input there are two numbers seperated with a single space: A[1] (1 <= A[1] <= 100) and N (1 <= N <= 10000). OUTPUT: The standard output should only contain a single integer A[N] , the Nth number of the defined sequence. Input: 7 4 Output: 79 Explanation: Elements of the array are as follows: 7, 19, 49, 79... and the 4th element is solution. I tried solving this by coding a separate function that for a given number A[k] calculates the sum of it's digits and finds the smallest number greater than A[k-1] as it says in the problem, but with no success. The first testing failed because of a memory limit, the second testing failed because of a time limit, and now i don't have any possible idea how to solve this. One friend suggested recursion, but i don't know how to set that. Anyone who can help me in any way please write, also suggest some ideas about using recursion/DP for solving this problem. Thanks.

  Read the article

• Beginning 3.2+ iPhone development

  - by Dinah

  I'm interested in learning Objective C for iPhone development. This is a topic which I realize has been covered to death. The qualifying difference is: I'd like to start learning beginning with the latest version (the most recent iPhone OS as of May, 2010 is ver. 3.2 and 4 beta is also out). I'd like to not have to wade through or unlearn legacy information. Using the links I've found throughout related topics on Stack Overflow, I'll read a blog post or tutorial which will say one thing, but then the comments will say, "this is different now in version xyz." For example, I've found this a few times regarding memory management/garbage collection. I assume that Apple's "getting started" doc.s will have the most recent info but many SO posts have said that those are not the most clear. The Stanford iPhone course looks great, but how do I know if it still applies to the most recent versions? Where should one start learning Objective C for iPhone development starting with version 3.2 or later without having as much exposure to legacy information?

  Read the article

• error while loadin applet in web application

  - by pallavi

  I want to run my applet on web application, but i got some error which i mentioned below please help me to get out of this problem ============================================================================================= Java Plug-in 1.7.0 Using JRE version 1.7.0-ea-b116 Java HotSpot(TM) Client VM User home directory = C:\Users\HONEY c: clear console window f: finalize objects on finalization queue g: garbage collect h: display this help message l: dump classloader list m: print memory usage o: trigger logging q: hide console r: reload policy configuration s: dump system and deployment properties t: dump thread list v: dump thread stack x: clear classloader cache 0-5: set trace level to java.lang.RuntimeException: java.lang.NoClassDefFoundError: mp3$1 at sun.plugin2.applet.Plugin2Manager.createApplet(Unknown Source) at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: java.lang.NoClassDefFoundError: mp3$1 at mp3.(mp3.java:93) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) at java.lang.reflect.Constructor.newInstance(Unknown Source) at java.lang.Class.newInstance0(Unknown Source) at java.lang.Class.newInstance(Unknown Source) at sun.plugin2.applet.Plugin2Manager$12.run(Unknown Source) at java.awt.event.InvocationEvent.dispatch(Unknown Source) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source) Caused by: java.lang.ClassNotFoundException: mp3$1 at sun.plugin2.applet.Applet2ClassLoader.findClass(Unknown Source) at sun.plugin2.applet.Plugin2ClassLoader.loadClass0(Unknown Source) at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source) at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) ... 16 more Caused by: java.io.IOException: open HTTP connection failed:http://viscous10.webng.com/mp3/mp3$1.class at sun.plugin2.applet.Applet2ClassLoader.getBytes(Unknown Source) at sun.plugin2.applet.Applet2ClassLoader.access$000(Unknown Source) at sun.plugin2.applet.Applet2ClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) ... 21 more Exception: java.lang.RuntimeException: java.lang.NoClassDefFoundError: mp3$1 ========================================================================================== but it happens only if i run applet with events and in simple applet i never occurred thanx

  Read the article

• Why can I run JUnit tests for my Spring project, but not a main method?

  - by FarmBoy

  I am using JDBC to connect to MySQL for a small application. In order to test without altering the real database, I'm using HSQL in memory for JUnit tests. I'm using Spring for DI and DAOs. Here is how I'm configuring my HSQL DataSource <bean id="mockDataSource" class="org.springframework.jdbc.datasource.SingleConnectionDataSource"> <property name="driverClassName" value="org.hsqldb.jdbcDriver"/> <property name="url" value="jdbc:hsqldb:mem:mockSeo"/> <property name="username" value="sa"/> </bean> This works fine for my JUnit tests which use the mock DB. But when I try to run a main method, I find the following error: Error creating bean with name 'mockDataSource' defined in class path resource [beans.xml]: Error setting property values; nested exception is org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are: PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'driverClassName' threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [org.hsqldb.jdbcDriver] I'm running from Eclipse, and I'm using the Maven plugin. Is there a reason why this would work as a Test, but not as a main()? I know that the main method itself is not the problem, because it works if I remove all references to the HSQL DataSource from my Spring Configuration file.

  Read the article

• How to use Common Table Expression and check no duplication in SQL Server

  - by vodkhang

  I have a table references to itself. User table: id, username, managerid and managerid links back to id Now, I want to get all the managers including direct manager, manager of direct manager, so on and so forth... The problem is that I do not want to have a unstop recursive sql. So, I want to check if an id alreay in a list, I will not include it anymore. Here is my sql for that: with all_managers (id, username, managerid, idlist) as ( select u1.id, u1.username, u1.managerid, ' ' from users u1, users u2 where u1.id = u2.managerid and u2.id = 6 UNION ALL select u.id, u.username, u.managerid, idlist + ' ' + u.id from all_managers a, users u where a.managerid = u.id and charindex(cast(u.id as nvarchar(5)), idlist) != 0 ) select id, username from all_managers; The problem is that in this line: select u1.id, u1.username, u1.managerid, ' ' The SQL Server complains with me that I can not put ' ' as the initialized for idlist. nvarchar(40) does not work as well. I do not know how to declare it inside a common table expression like this one. Usually, in db2, I can just put varchar(40) My sample data: ID UserName ManagerID 1 admin 1 2 a 1 3 b 1 4 c 2 What I want to do is that I want to find all managers of c guy. The result should be: admin, a, b. Some of the user can be his manager (like admin) because the ManagerID does not allow NULL and some does not have direct manager. With common table expression, it can lead to an infinite recursive. So, I am also trying to avoid that situation by trying to not include the id twice. For example, in the 1st iteration, we already have id : 1, so, in the 2nd iteration and later on, 1 should never be allowed. I also want to ask if my current approach is good or not and any other solutions? Because if I have a big database with a deep hierarchy, I will have to initialize a big varchar to keep it and it consumes memory, right?

  Read the article

• Updating multiple related tables in SQLite with C#

  - by PerryJ

  Just some background, sorry so long winded. I'm using the System.Data.SQLite ADO.net adapter to create a local sqlite database and this will be the only process hitting the database, so I don't need to worry about concurrency. I'm building the database from various sources and don't want to build this all in memory using datasets or dataadapters or anything like that. I want to do this using SQL (DdCommands). I'm not very good with SQL and complete noob in sqlite. I'm basically using sqlite as a local database / save file structure. The database has a lot of related tables and the data has nothing to do with People or Regions or Districts, but to use a simple analogy, imagine: Region table with auto increment RegionID, RegionName column and various optional columns. District table with auto increment DistrictID, DistrictName, RegionId, and various optional columns Person table with auto increment PersonID, PersonName, DistrictID, and various optional columns So I get some data representing RegionName, DistrictName,PersonName, and other Person related data. The Region, District and/or Person may or may not be created at this point. Once again, not being the greatest with this, my thoughts would be something like: Check to see if Region exists and if so get the RegionID else create it and get RegionID Check to see if District exists and if so get the DistrictID else create it adding in RegionID from above and get DistrictID Check to see if Person exists and if so get the PersonID else create it adding in DistrictID from above and get PersonID Update Person with rest of data. In MS SQL Server I would create a stored procedure to handle all this. Only way I can see to do this with sqlite is a lot of commands. So I'm sure I'm not getting this. I've spent hours looking around on various sites but just don't feel like I'm going down the right road. Any suggestions would be greatly appreciated.

  Read the article

• Safe to update separate regions of a BufferedImage in separate threads?

  - by finnw

  I have a collection of BufferedImage instances, one main image and some subimages created by calling getSubImage on the main image. The subimages do not overlap. I am also making modifications to the subimage and I want to split this into multiple threads, one per subimage. From my understanding of how BufferedImage, Raster and DataBuffer work, this should be safe because: Each instance of BufferedImage (and its respective WritableRaster) is accessed from only one thread. The shared ColorModel is immutable The DataBuffer has no fields that can be modified (the only thing that can change is elements of the backing array.) Modifying disjoint segments of an array in separate threads is safe. However I cannot find anything in the documentation that says that it is definitely safe to do this. Can I assume it is safe? I know that it is possible to work on copies of the child Rasters but I would prefer to avoid this because of memory constraints. Otherwise, is it possible to make the operation thread-safe without copying regions of the parent image?

  Read the article

• Implementing crossover in genetic programming

  - by Name

  Hi, I'm writing a genetic programming (GP) system (in C but that's a minor detail). I've read a lot of the literature (Koza, Poli, Langdon, Banzhaf, Brameier, et al) but there are some implementation details I've never seen explained. For example: I'm using a steady state population rather than a generational approach, primarily to use all of the computer's memory rather than reserve half for the interim population. Q1. In GP, as opposed to GA, when you perform crossover you select two parents but do you create one child or two, or is that a free choice you have? Q2. In steady state GP, as opposed to a generational system, what members of the population do the children created by crossover replace? This is what I haven't seen discussed. Is it the two parents, or is it two other, randomly-selected members? I can understand if it's the latter, and that you might use negative tournament selection to choose members to replace, but would that not create premature convergence? (After a crossover event the population contains the two original parents plus two children of those parents, and two other random members get removed. Elitism is inherent.) Q3. Is there a Web forum or mailing list focused on GP? Oddly I haven't found one. Yahoo's GP group is used almost exclusively for announcements, the Poli/Langdon Field Guide forum is almost silent, and GP discussions on general/game programming sites like gamedev.net are very basic. Thanks for any help you can provide!

  Read the article

• Help! I've learned jQuery... now I want to learn JavaScript

  - by Derek Adair

  I am a self-taught web developer/programmer. I started out about two years ago by learning how to make simple dynamic websites with HTML/CSS/PHP. Then I started dabbling with animation... Enter jQuery I've become quite proficient with jQuery over the last year and I've even started making my own plugins. I've spent most of my effort learning how to beautify websites with fancy effects and what not. Upon tackling my first full-blown application, I realized how under-developed my knowledge of JavaScript actually is. jQuery has allowed me to rely on its framework so heavily that I rarely use any interesting functions, techniques, or whatever that are 'native' to the JavaScript language. For example: I have a basic understanding of what a closure is... but I am unsure where this technique can actually benefit me. Although as I understand it, that's what my jQuery plugins do with (function ($){//plugin code here})(jQuery). I've seen many posts/blogs/whatever about memory leaks and circular references which is concerning. I'm frustrated because I can wrap my head around the basic concepts of what these are just by reading the articles, but I'm finding that the deeper I go the more I don't understand. The vocabulary alone is burdensome. Let alone how to actually use these techniques/functions/language features. I am trying to figure out what I don't know I'm looking to gather any advice, techniques, articles, books, videos, snippets, examples, potential pitfalls... really anything you have regarding application development with JavaScript/jQuery.

  Read the article

• jQuery performance

  - by jAndy

  Hi Folks, imagine you have to do DOM manipulation like a lot (in my case, it's kind of a dynamic list). Look at this example: var $buffer = $('<ul/>', { 'class': '.custom-example', 'css': { 'position': 'absolute', 'top': '500px' } }); $.each(pages[pindex], function(i, v){ $buffer.append(v); }); $buffer.insertAfter($root); "pages" is an array which holds LI elements as jQuery object. "$root" is an UL element What happens after this code is, both UL's are animated (scrolling) and finally, within the callback of animate this code is executed: $root.detach(); $root = $buffer; $root.css('top', '0px'); $buffer = null; This works very well, the only thing I'm pi**ed off is the performance. I do cache all DOM elements I'm laying a hand on. Without looking too deep into jQuery's source code, is there a chance that my performance issues are located there? Does jQuery use DocumentFragments to append things? If you create a new DOM element with var new = $('<div/>') it is only stored in memory at this point isnt it?

  Read the article

• Autodetect Presence of CSV Headers in a File

  - by banzaimonkey

  Short question: How do I automatically detect whether a CSV file has headers in the first row? Details: I've written a small CSV parsing engine that places the data into an object that I can access as (approximately) an in-memory database. The original code was written to parse third-party CSV with a predictable format, but I'd like to be able to use this code more generally. I'm trying to figure out a reliable way to automatically detect the presence of CSV headers, so the script can decide whether to use the first row of the CSV file as keys / column names or start parsing data immediately. Since all I need is a boolean test, I could easily specify an argument after inspecting the CSV file myself, but I'd rather not have to (go go automation). I imagine I'd have to parse the first 3 to ? rows of the CSV file and look for a pattern of some sort to compare against the headers. I'm having nightmares of three particularly bad cases in which: The headers include numeric data for some reason The first few rows (or large portions of the CSV) are null There headers and data look too similar to tell them apart If I can get a "best guess" and have the parser fail with an error or spit out a warning if it can't decide, that's OK. If this is something that's going to be tremendously expensive in terms of time or computation (and take more time than it's supposed to save me) I'll happily scrap the idea and go back to working on "important things". I'm working with PHP, but this strikes me as more of an algorithmic / computational question than something that's implementation-specific. If there's a simple algorithm I can use, great. If you can point me to some relevant theory / discussion, that'd be great, too. If there's a giant library that does natural language processing or 300 different kinds of parsing, I'm not interested.

  Read the article

• Implementing the ‘defer’ statement from Go in Objective-C?

  - by zoul

  Hello! Today I read about the defer statement in the Go language: A defer statement pushes a function call onto a list. The list of saved calls is executed after the surrounding function returns. Defer is commonly used to simplify functions that perform various clean-up actions. I thought it would be fun to implement something like this in Objective-C. Do you have some idea how to do it? I thought about dispatch finalizers, autoreleased objects and C++ destructors. Autoreleased objects: @interface Defer : NSObject {} + (id) withCode: (dispatch_block_t) block; @end @implementation Defer - (void) dealloc { block(); [super dealloc]; } @end #define defer(__x) [Defer withCode:^{__x}] - (void) function { defer(NSLog(@"Done")); … } Autoreleased objects seem like the only solution that would last at least to the end of the function, as the other solutions would trigger when the current scope ends. On the other hand they could stay in the memory much longer, which would be asking for trouble. Dispatch finalizers were my first thought, because blocks live on the stack and therefore I could easily make something execute when the stack unrolls. But after a peek in the documentation it doesn’t look like I can attach a simple “destructor” function to a block, can I? C++ destructors are about the same thing, I would create a stack-based object with a block to be executed when the destructor runs. This would have the ugly disadvantage of turning the plain .m files into Objective-C++? I don’t really think about using this stuff in production, I’m just interested in various solutions. Can you come up with something working, without obvious disadvantages? Both scope-based and function-based solutions would be interesting.

  Read the article

• Generic allocator class without variadic templates?

  - by rainer

  I am trying to write a generic allocator class that does not really release an object's memory when it is free()'d but holds it in a queue and returns a previously allocated object if a new one is requested. Now, what I can't wrap my head around is how to pass arguments to the object's constructor when using my allocator (at least without resorting to variadic templates, that is). The alloc() function i came up with looks like this: template <typename... T> inline T *alloc(const &T... args) { T *p; if (_free.empty()) { p = new T(args...); } else { p = _free.front(); _free.pop(); // to call the ctor of T, we need to first call its DTor p->~T(); p = new( p ) T(args...); } return p; } Still, I need the code to be compatible with today's C++ (and older versions of GCC that do not support variadic templates). Is there any other way to go about passing an arbitrary amount of arguments to the objects constructor?

  Read the article

• EJB3Unit testing no-tx-datasource

  - by justastefan

  Hello, I am doing tests on an ejb3-project using ejb3unit http://ejb3unit.sourceforge.net/Session-Bean.html for testing. All my Services long for @PersistenceContext (UnitName=bla). I set up the ejb3unit.properties like this: ejb3unit_jndi.1.isSessionBean=true ejb3unit_jndi.1.jndiName=ejb/MyServiceBean ejb3unit_jndi.1.className=com.company.project.MyServiceBean everything works with the in-memory-database. So now i want additionally test another servicebean with @PersistenceContext (UnitName=noTxDatasource) that goes for a defined in my datasources.xml: <datasources> <local-tx-datasource> ... </local-tx-datasource> <no-tx-datasource> <jndi-name>noTxDatasource</jndi-name> <connection-url>...</connection-url> <driver-class>oracle.jdbc.OracleDriver</driver-class> <user-name>bla</user-name> <password>bla</password> </no-tx-datasource> </datasources> How do I tell ejb3unit to make this work: Object object = InitialContext.doLookup("java:/noTxDatasource"); if (object instanceof DataSource) { return ((DataSource) object).getConnection(); } else { return null; } Currently it fails saying: javax.NamingException: Cannot find the name (noTxDataSource) in the JNDI tree Current bindings: (ejb/MyServiceBean=com.company.project.MyServiceBean) How can I add this no-tx-datasource to the jndi bindings?

  Read the article

• Enormous data and PHP errors

  - by salamis

  I am currently using the following HighCharts:HighStock:Charts: http://www.highcharts.com/stock/demo/data-grouping in order to display the data returned from the server. We retrieve the data from a MySQL database and is really big. We are storing sensor metrics every 1 second. After a while we got the following error: [Wed Sep 12 00:15:56 2012] [error] [client 127.0.0.1] PHP Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 4756882 bytes) in C:\\wamp\\www\\admin\\getTrends.php on line 156, referer: http://localhost/admin/trends.php [Wed Sep 12 00:15:56 2012] [error] [client 127.0.0.1] PHP Stack trace:, referer: http://localhost/admin/trends.php [Wed Sep 12 00:15:56 2012] [error] [client 127.0.0.1] PHP 1. {main}() C:\\wamp\\www\\admin\\getTrends.php:0, referer: http://localhost/admin/trends.php [Wed Sep 12 00:15:56 2012] [error] [client 127.0.0.1] PHP 2. getTrendsDataAI() C:\\wamp\\www\\admin\\getTrends.php:33, referer: http://localhost/admin/trends.php [Wed Sep 12 00:15:56 2012] [error] [client 127.0.0.1] PHP 3. printResults() C:\\wamp\\www\\admin\\getTrends.php:102, referer: http://localhost/admin/trends.php [Wed Sep 12 00:15:56 2012] [error] [client 127.0.0.1] PHP 4. createData() C:\\wamp\\www\\admin\\getTrends.php:230, referer: http://localhost/admin/trends.php [Wed Sep 12 00:15:56 2012] [error] [client 127.0.0.1] PHP 5. implode() C:\\wamp\\www\\admin\\getTrends.php:156, referer: http://localhost/admin/trends.php What is the best solution to return this data as JSON object to HighStocks for viewing? And how can we overcome the PHP limitation? Shall we return chunk of data each time? How do they usually present enormous amount of data to the users and creating charts and reports from this data? Another big problem that we need to overcome is that the returned JSON object is enormous. At this point is around 20-30 mbs and it will be much larger in the future. Is it ok to return this data to the user and perform everything client side? Any suggestions or thoughts welcome.

  Read the article

• Hibernate ScrollableResults Do Not Return The Whole Set of Results

  - by mlaverd

  Some of the queries we run have 100'000+ results and it takes forever to load them and then send them to the client. So I'm using ScrollableResults to have a paged results feature. But we're topping at roughly 50k results (never exactly the same amount of results). I'm on an Oracle9i database, using the Oracle 10 drivers and Hibernate is configured to use the Oracle9 dialect. I tried with the latest JDBC driver (ojdbc6.jar) and the problem was reproduced. We also followed some advice and added an ordering clause, but the problem was reproduced. Here is a code snippet that illustrates what we do: Criteria crit = sess.createCriteria(ABC.class); crit.add(Restrictions.eq("property", value)); crit.setFetchSize(pageSize); crit.addOrder(Order.asc("property")); ScrollableResults sr = crit.scroll(); ... ... do{ for (Object entry : page) sess.evict(entry); //to avoid having our memory just explode out of proportion page.clear(); for (int i =0 ; i < pageSize && ! metLastRow; i++){ if (resultSet.next()) page.add(sr.get(0)); else metLastRow = true; } metLastRow = metLastRow?metLastRow:sr.isLast(); sendToClient(page); }while(!metLastRow); So, why is it that I get the result set to tell me its at the end when it should be having so much more results?

  Read the article

< Previous Page | 423 424 425 426 427 428 429 430 431 432 433 434  | Next Page >