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  • 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.

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  • RegistryKey ValueCount/SubKeyCount wrong

    - by Mark J Miller
    I am trying to query the following registry key values: HKLM\SOFTWARE\Microsoft\MSSQLServer\Client\SharedMemoryOn HKLM\SOFTWARE\Microsoft\MSSQLServer\Client\SuperSocketNetLib\ProtocolOrder But depending on which machine I'm running the program the query returns null. When I debug on my local machine and I inspect the value for ValueCount for: HKLM\SOFTWARE\Microsoft\MSSQLServer\Client HKLM\SOFTWARE\Microsoft\MSSQLServer\Client\SuperSocketNetLib The count is 0 and OpenSubKey returns null. I am a domain admin, in the local administrators group and have added the following to my app.manifest: <requestedExecutionLevel level="requireAdministrator" uiAccess="false" /> Any idea why? private static void ValidateSqlClientSettings() { Console.WriteLine("\r\n/////////////// LOCAL SQL CLIENT PROTOCOLS ////////////////"); RegistryKey keyHKLM = Registry.LocalMachine; ///TODO: nullreferenceexception - connect to remote machine and find out why RegistryKey sqlClientKey = keyHKLM.OpenSubKey(@"SOFTWARE\Microsoft\MSSQLServer\Client"); if (sqlClientKey == null) { WriteLine2Console(@"WARNING: unable to read registry key '{0}\SOFTWARE\Microsoft\MSSQLServer\Client'", ConsoleColor.Yellow); } var cliKeyNames = from k in sqlClientKey.GetSubKeyNames() where k == "SuperSocketNetLib" select k; ///TODO: find out why these values are always missing (even if I can see them in regedit) Console.Write("Shared Memory Disabled (cliconfg): "); if (Convert.ToBoolean(sqlClientKey.GetValue("SharedMemoryOn"))) WriteLine2Console("FAILED", ConsoleColor.Red); else if(sqlClientKey.GetValue("SharedMemoryOn") == null) WriteLine2Console(String.Format("WARNING - unable to read '{0}\\SharedMemoryOn'", sqlClientKey.Name), ConsoleColor.Yellow); else WriteLine2Console("PASS", ConsoleColor.Green); Console.Write("Client Protocol Order (cliconfg - tcp first): "); foreach (string cliKey in cliKeyNames) { RegistryKey subKey = sqlClientKey.OpenSubKey(cliKey); object order = subKey.GetValue("ProtocolOrder"); if (order != null && order.ToString().StartsWith("tcp") == false) { WriteLine2Console("FAILED", ConsoleColor.Red); } else if (order == null) { WriteLine2Console(String.Format("WARNING - unable to read '{0}\\ProtocolOrder'", subKey.Name), ConsoleColor.Yellow); } else { WriteLine2Console("PASS", ConsoleColor.Green); } subKey.Close(); } sqlClientKey.Close(); keyHKLM.Close(); }

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  • Mapping issue with multi-field primary keys using hibernate/JPA annotations

    - by Derek Clarkson
    Hi all, I'm stuck with a database which is using multi-field primary keys. I have a situation where I have a master and details table, where the details table's primary key contains fields which are also the foreign key's the the master table. Like this: Master primary key fields: master_pk_1 Details primary key fields: master_pk_1 details_pk_2 details_pk_3 In the Master class we define the hibernate/JPA annotations like this: @Id @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "idGenerator") @Column(name = "master_pk_1") private long masterPk1; @OneToMany(cascade=CascadeType.ALL) @JoinColumn(name = "master_pk_1", referencedColumnName = "master_pk_1") private List<Details> details = new ArrayList<Details>(); And in the details class I have defined the id and back reference like this: @EmbeddedId @AttributeOverrides( { @AttributeOverride( name = "masterPk1", column = @Column(name = "master_pk_1")), @AttributeOverride(name = "detailsPk2", column = @Column(name = "details_pk_2")), @AttributeOverride(name = "detailsPk2", column = @Column(name = "details_pk_2")) }) private DetailsPrimaryKey detailsPrimaryKey = new DetailsPrimaryKey(); @ManyToOne @JoinColumn(name = "master_pk_1", referencedColumnName = "master_pk_1", insertable=false) private Master master; The goal of all of this was that I could create a new master, add some details to it, and when saved, JPA/Hibernate would generate the new id for master in the masterPk1 field, and automatically pass it down to the details records, storing it in the matching masterPk1 field in the DetailsPrimaryKey class. At least that's what the documentation I've been looking at implies. What actually happens is that hibernate appears to corectly create and update the records in the database, but not pass the key to the details classes in memory. Instead I have to manually set it myself. I also found that without the insertable=true added to the back reference to master, that hibernate would create sql that had the master_pk_1 field listed twice in the insert statement, resulting in the database throwing an exception. My question is simply is this arrangement of annotations correct? or is there a better way of doing it?

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  • What are the primitive Forth operators?

    - by Barry Brown
    I'm interested in implementing a Forth system, just so I can get some experience building a simple VM and runtime. When starting in Forth, one typically learns about the stack and its operators (DROP, DUP, SWAP, etc.) first, so it's natural to think of these as being among the primitive operators. But they're not. Each of them can be broken down into operators that directly manipulate memory and the stack pointers. Later one learns about store (!) and fetch (@) which can be used to implement DUP, SWAP, and so forth (ha!). So what are the primitive operators? Which ones must be implemented directly in the runtime environment from which all others can be built? I'm not interested in high-performance; I want something that I (and others) can learn from. Operator optimization can come later. (Yes, I'm aware that I can start with a Turing machine and go from there. That's a bit extreme.) Edit: What I'm aiming for is akin to bootstrapping an operating system or a new compiler. What do I need do implement, at minimum, so that I can construct the rest of the system out of those primitive building blocks? I won't implement this on bare hardware; as an educational exercise, I'd write my own minimal VM.

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  • Using graphical ActiveX (COM) controls in WinForms project

    - by alex
    I have a collection (set) of ActiveX controls. I recieved them from our vendor company. I created a wrappers for them using tlbimp.exe and aximp.exe. All non-graphical controls work good. All graphical controls don't react on some methods. When I call their methods I get: TargetInvocativeException (InnerException is null). or Attempt to read/write protected memory. Our vendor company assure that their graphical activex controls work good. But they don't provide support service, so I have to find solution of my problem alone. And some more, All graphical activex controls don't react on mouseclick or any other mouse manipulations. But documentation says: it must change the color on mouse click. Maybe, someone have same symptoms and can help me ! I googled over that problem many pages but they don't help me. Maybe it's some Visual Studio settings or compiler options ? I use VS 2005.

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  • 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

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  • 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)?

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  • Hibernate: order multiple one-to-many relations

    - by Markos Fragkakis
    I have a search screen, using JSF, JBoss Seam and Hibernate underneath. There are columns for A, B and C, where the relations are as follows: A (1< -- ) B (1< -- ) C A has a List< B and B has a List< C (both relations are one-to-many). The UI table supports ordering by any column (ASC or DESC), so I want the results of the query to be ordered. This is the reason I used Lists in the model. However, I got an exception that Hibernate cannot eagerly fetch multiple bags (it considers both lists to be bags). There is an interesting blog post here, and they identify the following solutions: Use @IndexColumn annotation (there is none in my DB, and what's more, I want the position of results to be determined by the ordering, not by an index column) Fetch lazily (for performance reasons, I need eager fetching) Change List to Set So, I changed the List to Set, which by the way is more correct, model-wise. First, if don't use @OrderBy, the PersistentSet returned by Hibernate wraps a HashSet, which has no ordering. Second, If I do use @OrderBy, the PersistentSet wraps a LinkedHashSet, which is what I would like, but the OrderBy property is hardcoded, so all other ordering I perform through the UI comes after it. I tried again with Sets, and used SortedSet (and its implementation, TreeSet), but I have some issues: I want ordering to take place in the DB, and not in-memory, which is what TreeSet does (either through a Comparator, or through the Comparable interface of the elements). Second, I found that there is the Hibernate annotation @Sort, which has a SortOrder.UNSORTED and you can also set a Comparator. I still haven't managed to make it compile, but I am still not convinced it is what I need. Any advice?

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  • Haskell Linear Algebra Matrix Library for Arbitrary Element Types

    - by Johannes Weiß
    I'm looking for a Haskell linear algebra library that has the following features: Matrix multiplication Matrix addition Matrix transposition Rank calculation Matrix inversion is a plus and has the following properties: arbitrary element (scalar) types (in particular element types that are not Storable instances). My elements are an instance of Num, additionally the multiplicative inverse can be calculated. The elements mathematically form a finite field (??2256). That should be enough to implement the features mentioned above. arbitrary matrix sizes (I'll probably need something like 100x100, but the matrix sizes will depend on the user's input so it should not be limited by anything else but the memory or the computational power available) as fast as possible, but I'm aware that a library for arbitrary elements will probably not perform like a C/Fortran library that does the work (interfaced via FFI) because of the indirection of arbitrary (non Int, Double or similar) types. At least one pointer gets dereferenced when an element is touched (written in Haskell, this is not a real requirement for me, but since my elements are no Storable instances the library has to be written in Haskell) I already tried very hard and evaluated everything that looked promising (most of the libraries on Hackage directly state that they wont work for me). In particular I wrote test code using: hmatrix, assumes Storable elements Vec, but the documentation states: Low Dimension : Although the dimensionality is limited only by what GHC will handle, the library is meant for 2,3 and 4 dimensions. For general linear algebra, check out the excellent hmatrix library and blas bindings I looked into the code and the documentation of many more libraries but nothing seems to suit my needs :-(. Update Since there seems to be nothing, I started a project on GitHub which aims to develop such a library. The current state is very minimalistic, not optimized for speed at all and only the most basic functions have tests and therefore should work. But should you be interested in using or helping out developing it: Contact me (you'll find my mail address on my web site) or send pull requests.

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  • 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?

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  • Why calling Process.killProcess(Process.myPid()) is a bad idea?

    - by Tal Kanel
    I've read some posts saying using this method is "not good", shouldn't been use, it's not the right way to "close" the application and it's not how android works... I understand and accept the fact that Android OS knows better then me when it's the right time to terminate the process, but I didn't heard yet a good explanation why it's wrong using the killProcess() method?. after all - it's part of the android API... what I do know is that calling this method while other threads doing in potential an important work (operations on files, writing to DB, HTTP requests, running services..) can be terminated in the middle, and it's clearly not good. also I know I can benefit from the fact that "re-open" the application will be faster, cause the system maybe still "holds" in memory state from last time been used, and killProcess() prevents that. beside this reason, in assumption I don't have such operations, and I don't care my application will load from scratch each run, there are other reasons why not using the killProcess() method? I know about finish() method to close an Activity, so don't write me about that please.. finish() is only for Activity. not to all application, and I think I know exactly why and when to use it... and another thing - I'm developing also games with the Unity3D framework, and exporting the project to android. when I decompiled the generated apk, I was very suprised to find out that the java source code created from unity - implementing Unity's - Application.quit() method, with Process.killProcess(Process.myPid()). Application.quit() is suppose to be the right way to close game according to Unity3d guides (is it really?? maybe I'm wrong, and missed something), so how it happens that the Unity's framework developers which doing a very good work as it seems implemented this in native android to killProcess()? anyway - I wish to have a "list of reasons" why not using the killProcess() method, so please write down your answer - if you have something interesting to say about that. TIA

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  • 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.

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  • Looking for a smarter way to convert a Python list to a GList?

    - by Kingdom of Fish
    I'm really new to C - Python interaction and am currently writing a small app in C which will read a file (using Python to parse it) and then using the parsed information to execute small Python snippets. At the moment I'm feeling very much like I'm reinventing wheels, for example this function: typedef gpointer (list_func)(PyObject *obj); GList *pylist_to_glist(list_func func, PyObject *pylist) { GList *result = NULL; if (func == NULL) { fprintf(stderr, "No function definied for coverting PyObject.\n"); } else if (PyList_Check(pylist)) { PyObject *pIter = PyObject_GetIter(pylist); PyObject *pItem; while ((pItem = PyIter_Next(pIter))) { gpointer obj = func(pItem); if (obj != NULL) result = g_list_append(result, obj); else fprintf(stderr, "Could not convert PyObject to C object.\n"); Py_DECREF(pItem); } Py_DECREF(pIter); } return result; } I would really like to do this in a easier/smarter way less prone to memory leaks and errors. All comments and suggestions are appreciated.

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  • 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

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  • when long polling, Why are my other requests taking so long?

    - by Pascal
    The client makes 2 concurrent requests. (1 which takes 60 seconds - long polling) and another which is NOT long polling - supposed to return right away. It does return right away when I'm not doing long polling. But as soon as I start doing long polling with the other thread, the other one takes forever to execute. Firebug shows that the request is waiting for 10-50 seconds. On the server, I profiled ALL requests from the moment the php script starts to the time it goes back to the client, and it shows that each one only took 300ms or less. This problem started about the same time I started doing long polling (with the other XHR requests). I'm using jquery for both requests. The server shows that it is under very light load. CPU and memory less then 2%. 8 processes running out of a pool of 15. (it doesn't seem to deviate much from that number 8, even when I run more ajax requests). I guess each process can run multiple ajax threads concurrently. I made sure to EXIT from all processes as soon as their done executing. I don't see how the process pool has run out, if there are still 7 unused processes listed under prstat -J. Also, the problem happens somewhat intermittently. Firefox should be able to handle 2 concurrent ajax requests. i dont get what the problem is.

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  • 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.

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  • Why does perl crash with "*** glibc detected *** perl: munmap_chunk(): invalid pointer"?

    - by sid_com
    #!/usr/bin/env perl use warnings; use strict; use 5.012; use XML::LibXML::Reader; my $reader = XML::LibXML::Reader->new( location => 'http://www.heise.de/' ) or die $!; while ( $reader->read ) { say $reader->name; } At the end of the output from this script I get this error-messages: * glibc detected * perl: munmap_chunk(): invalid pointer: 0x0000000000b362e0 * ======= Backtrace: ========= /lib64/libc.so.6[0x7fb84952fc76] ... ======= Memory map: ======== 00400000-0053d000 r-xp 00000000 08:01 182002 /usr/local/bin/perl ... Is this due a bug? perl -V: Summary of my perl5 (revision 5 version 12 subversion 0) configuration: Platform: osname=linux, osvers=2.6.31.12-0.2-desktop, archname=x86_64-linux uname='linux linux1 2.6.31.12-0.2-desktop #1 smp preempt 2010-03-16 21:25:39 +0100 x86_64 x86_64 x86_64 gnulinux ' config_args='-Dnoextensions=ODBM_File' hint=recommended, useposix=true, d_sigaction=define useithreads=undef, usemultiplicity=undef useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef use64bitint=define, use64bitall=define, uselongdouble=undef usemymalloc=n, bincompat5005=undef Compiler: cc='cc', ccflags ='-fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64', optimize='-O2', cppflags='-fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include' ccversion='', gccversion='4.4.1 [gcc-4_4-branch revision 150839]', gccosandvers='' intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678 d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16 ivtype='long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8 alignbytes=8, prototype=define Linker and Libraries: ld='cc', ldflags =' -fstack-protector -L/usr/local/lib' libpth=/usr/local/lib /lib /usr/lib /lib64 /usr/lib64 /usr/local/lib64 libs=-lnsl -ldl -lm -lcrypt -lutil -lc perllibs=-lnsl -ldl -lm -lcrypt -lutil -lc libc=/lib/libc-2.10.1.so, so=so, useshrplib=false, libperl=libperl.a gnulibc_version='2.10.1' Dynamic Linking: dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E' cccdlflags='-fPIC', lddlflags='-shared -O2 -L/usr/local/lib -fstack-protector' Characteristics of this binary (from libperl): Compile-time options: PERL_DONT_CREATE_GVSV PERL_MALLOC_WRAP USE_64_BIT_ALL USE_64_BIT_INT USE_LARGE_FILES USE_PERLIO USE_PERL_ATOF Built under linux Compiled at Apr 15 2010 13:25:46 @INC: /usr/local/lib/perl5/site_perl/5.12.0/x86_64-linux /usr/local/lib/perl5/site_perl/5.12.0 /usr/local/lib/perl5/5.12.0/x86_64-linux /usr/local/lib/perl5/5.12.0 .

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  • 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.

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  • 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?

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  • 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?

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  • 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!

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  • Long running stateful service in .NET

    - by Asaf R
    Hi, I need to create a service in .NET that maintains (inner) state in-memory, spawns multiple threads and is generally long-running. There are a lot options - Good-old Windows Service Windows Communication Services Windows Workflow Foundation I really don't know which to choose. Most of the functionality is in a library used by this service, so the service itself is rather simple. On one hand, it's important the service host is as close to "simply working" as possible, which excludes Windows Service. On the other hand, it's important that the service is not taken down by the host just because there's no external activity, which makes WCF kind o' "scary". As for WF, it's strongest selling point is the ability to create processes as, um..., workflows, which is something I don't need nor want. To sum it up, the plethora of Microsoft technologies got me a bit confused. I'd appreciate help regarding the pros and cons of each solution (or other's I've failed to mention) for the problem of a stateful, long running service in .NET Thanks, Asaf P.S., I'm using .NET 4. EDIT: What I mean by the host "simply working" is, for example, that the service I create be reactivated if it crashes. I guess the reason for this question is that I've created Windows Services in the past (I think it was in plain C++ with Win32 API), and I don't want to miss out on something simpler if there's is such as thing. Thanks for all the replies thus far! Asaf.

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  • 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! :)

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  • 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.

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  • 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.

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