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  • Programming logic best practice - redundant checks

    - by eldblz
    I'm creating a large PHP project and I've a trivial doubt about how to proceed. Assume we got a class books, in this class I've the method ReturnInfo: function ReturnInfo($id) { if( is_numeric($id) ) { $query = "SELECT * FROM books WHERE id='" . $id . "' LIMIT 1;"; if( $row = $this->DBDrive->ExecuteQuery($query, $FetchResults=TRUE) ) { return $row; } else { return FALSE; } } else { throw new Exception('Books - ReturnInfo - id not valid.'); } } Then i have another method PrintInfo function PrintInfo($id) { print_r( $this->ReturnInfo($id) ); } Obviously the code sample are just for example and not actual production code. In the second method should I check (again) if id is numeric ? Or can I skip it because is already taken care in the first method and if it's not an exception will be thrown? Till now I always wrote code with redundant checks (no matter if already checked elsewhere i'll check it also here) Is there a best practice? Is just common sense? Thank you in advance for your kind replies.

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  • Why does this code leak? (simple codesnippet)

    - by Ela782
    Visual Studio shows me several leaks (a few hundred lines), in total more than a few MB. I traced it down to the following "helloWorld example". The leak disappears if I comment out the H5::DataSet.getSpace() line. #include "stdafx.h" #include <iostream> #include "cpp/H5Cpp.h" int main(int argc, char *argv[]) { _CrtSetDbgFlag ( _CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF ); // dump leaks at return H5::H5File myfile; try { myfile = H5::H5File("C:\\Users\\yyy\\myfile.h5", H5F_ACC_RDONLY); } catch (H5::Exception& e) { std::string msg( std::string( "Could not open HDF5 file.\n" ) + e.getCDetailMsg() ); throw msg; } H5::Group myGroup = myfile.openGroup("/so/me/group"); H5::DataSet myDS = myGroup.openDataSet("./myfloatvec"); hsize_t dims[1]; //myDS.getSpace().getSimpleExtentDims(dims, NULL); // <-- here's the leak H5::DataSpace dsp = myDS.getSpace(); // The H5::DataSpace seems to leak dsp.getSimpleExtentDims(dims, NULL); //dsp.close(); // <-- doesn't help either std::cout << "Dims: " << dims[0] << std::endl; // <-- Works as expected return 0; } Any help would be appreciated. I've been on this for hours, I hate unclean code...

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  • issue with keychain and updates from app store

    - by xonegirlz
    I am having a very frustrating error. I have tested for an app upgrade by first installing the previous version (1.0.1) and then running version (1.0.2). Everything worked fine. I submitted the app and then I am getting issues people are getting crashes when they upgrade. I tried doing the same thing, which is installing the 1.0.1 and then install the binary on the app store, then it crashed. I looked at the console and crash logs and I get this: Jul 7 08:07:45 unknown MyApp[1429] <Warning>: KeychainUtils keychainValueForKey: - Error finding keychain value for key. Status code = -25300 Jul 7 08:07:45 unknown MyApp[1429] <Warning>: AccountSession readUserDataFromDisk - Error finding keychain value for key /var/mobile/Applications/997B32E7-6FFC-4696-9CAA-129BADE2FE64/Documents/instagram_json Jul 7 08:07:45 unknown MyApp[1429] <Warning>: UISegmentedControlStyleBezeled is deprecated. Please use a different style. Jul 7 08:07:45 unknown MyApp[1429] <Error>: *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFDictionary setObject:forKey:]: attempt to insert nil value (key: username)' *** First throw call stack: (0x33ee688f 0x367e7259 0x33ee6789 0x33ee67ab 0x33e5368b 0x14fd99 0x152319 0x1530bb 0x170299 0x3270ec59 0x32711817 0x354e7dfb 0x354e7cd0) Jul 7 08:07:45 unknown UIKitApplication:com.firesnakelabs.pinstagram[0x14e4][1429] <Notice>: terminate called throwing an exception >

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  • How can I [simply] consume JSON Data in a Line of Business Web Application

    - by Atomiton
    I usually use JSON with jQuery to just return a string with html. However, I want to start to use Javascript objects in my code. What's the simplest way to get started using json objects on my page? Here's a sample Ajax call ( after $(document).ready( { ... }) of course: $('#btn').click(function(event) { event.preventDefault(); var out = $('#result'); $.ajax({ url: "CustomerServices.asmx/GetCustomersByInvoiceCount", success: function(msg) { // // Iterate through the json results and spit them out to a page? // }, data: "{ 'invoiceCount' : 100 }" }); }); My WebMethod: [WebMethod(Description="Gets customers with more than n invoices")] public List<Customer> GetCustomersByInvoiceCount(int? invoiceCount) { using (dbDataContext db = new dbDataContext()) { return db.Customers.Where(c => c.InvoiceCount >= invoiceCount); } } What gets returned: {"d":[{"__type":"Customer","Account":"1116317","Name":"SOME COMPANY","Address":"UNit 1 , 392 JOHN ST. ","LastTransaction":"\/Date(1268294400000)\/","HighestBalance":13922.34},{"__type":"Customer","Account":"1116318","Name":"ANOTHER COMPANY","Address":"UNIT #345 , 392 JOHN ST. ","LastTransaction":"\/Date(1265097600000)\/","HighestBalance":549.42}]} What I'd LIKE to know, is what are people generally doing with this returned json? Do you iterate through the properties and create an html table on the fly? Is there way to "bind" JSON data using a javascript version of reflection ( something like the .Net GridView Control ) Do you throw this returned data into a Javascript Object and then do something with it? An example of what I want to achieve is to have an plain ol' html page ( on a mobile device )with a list of a Salesperson's Customers. When one of those customers are clicked, the customer id gets sent to a webservice which retrieves the customer details that are relevant to a sales person. I know the SO talent pool is quite deep so I figured you all here would be able to guide in the right direction and give me a few ideas on the best way to approach this.

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  • Merging two arrays in PHP

    - by Industrial
    Hi everyone, I am trying to create a new array from two current arrays. Tried array_merge, but it will not give me what I want. $array1 is a list of keys that I pass to a function. $array2 holds the results from that function, but doesn't contain any non-available resuls for keys. So, I want to make sure that all requested keys comes out with 'null':ed values, as according to the shown $result array. It goes a little something like this: $array1 = array('item1', 'item2', 'item3', 'item4'); $array2 = array( 'item1' => 'value1', 'item2' => 'value2', 'item3' => 'value3' ); Here's the result I want: $result = array( 'item1' => 'value1', 'item2' => 'value2', 'item3' => 'value3', 'item4' => '' ); It can be done this way, but I don't think that it's a good solution - I really don't like to take the easy way out and suppress PHP errors by adding @:s in the code. This sample would obviously throw errors since 'item4' is not in $array2, based on the example. foreach ($keys as $k => $v){ @$array[$v] = $items[$v]; } So, what's the fastest (performance-wise) way to accomplish the same result?

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  • Could this be considered a well-written class (am I using OOP correctly)?

    - by Ben Dauphinee
    I have been learning OOP principals on my own for a while, and taken a few cracks at writing classes. What I really need to know now is if I am actually using what I have learned correctly, or if I could improve as far as OOP is concerned. I have chopped a massive portion of code out of a class that I have been working on for a while now, and pasted it here. To all you skilled and knowledgeable programmers here I ask: Am I doing it wrong? class acl extends genericAPI{ // -- Copied from genericAPI class protected final function sanityCheck($what, $check, $vars){ switch($check){ case 'set': if(isset($vars[$what])){return(1);}else{return(0);} break; } } // --------------------------------- protected $db = null; protected $dataQuery = null; public function __construct(Zend_Db_Adapter_Abstract $db, $config = array()){ $this->db = $db; if(!empty($config)){$this->config = $config;} } protected function _buildQuery($selectType = null, $vars = array()){ // Removed switches for simplicity sake $this->dataQuery = $this->db->select( )->from( $this->config['table_users'], array('tf' => '(CASE WHEN count(*) > 0 THEN 1 ELSE 0 END)') )->where( $this->config['uidcol'] . ' = ?', $vars['uid'] ); } protected function _sanityRun_acl($sanitycheck, &$vars){ switch($sanitycheck){ case 'uid_set': if(!$this->sanityCheck('uid', 'set', $vars)){ throw new Exception(ERR_ACL_NOUID); } $vars['uid'] = settype($vars['uid'], 'integer'); break; } } private function user($action = null, $vars = array()){ switch($action){ case 'exists': $this->_sanityRun_acl('uid_set', $vars); $this->_buildQuery('user_exists_idcheck', $vars); return($this->db->fetchOne($this->dataQuery->__toString())); break; } } public function user_exists($uid){ return($this->user('exists', array('uid' => $uid))); } } $return = $acl_test->user_exists(1);

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  • Get class constant names in php?

    - by user151841
    I have a php class with some class constants that indicate the status of an instance. When I'm using the class, after I run some methods on it, I do some checks to make sure that the status is what I expect it to be. For instance, after calling some methods, I expect the status to be MEANINGFUL_STATUS_NAME. $objInstance->method1(); $objInstance->method2(); if ( $objInstance->status !== class::MEANINGFUL_STATUS_NAME ) { throw new Exception("Status is wrong, should not be " . class::MEANINGFUL_STATUS_NAME . "."); } However, this gives me the exception message "Status is wrong, should not be 2" when what I really want to see is "Status is wrong, should not be MEANINGFUL_STATUS_NAME" So I've lost the meaningfulness of the constant name. I was thinking of making an 'translation table' array, so I can take the constant values and translate them back into their name, but this seems cumbersome. How should I translate this back, so I get an error message that gives me a better idea of what went wrong?

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  • Why my linux signal handler run only once

    - by Henry Fané
    #include <iostream> #include <signal.h> #include <fenv.h> #include <string.h> void signal_handler(int sig, siginfo_t *siginfo, void* context) { std::cout << " signal_handler " << fetestexcept(FE_ALL_EXCEPT) << std::endl; throw "exception"; } void divide() { float a = 1000., b = 0., c, f = 1e-300; c = a / b; std::cout << c << " and f = " << f << std::endl; } void init_sig_hanlder() { feenableexcept(FE_ALL_EXCEPT); struct sigaction sa, initial_sa; sa.sa_sigaction = &signal_handler ; sigemptyset( &sa.sa_mask ) ; sa.sa_flags = SA_SIGINFO; // man sigaction(3) // allows for void(*)(int,siginfo_t*,void*) handler sigaction(SIGFPE, &sa, &initial_sa); } int main(int argc, char** argv) { init_sig_hanlder(); while(true) { try { sleep(1); divide(); } catch(const char * a) { std::cout << "Exception in catch: " << a << std::endl; } catch(...) { std::cout << "Exception in ..." << std::endl; } } return 0; } Produce the following results on Linux/g++4.2: signal_handler 0 Exception in catch: exception inf and f = 0 inf and f = 0 inf and f = 0 inf and f = 0 So, signal handler is executed the first time but the next fp exception does not trigger the handler again. Where am I wrong ?

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  • Does Spring MVC form submit data bind children objects automagically?

    - by predhme
    I have a data model that is something like this: public class Report { // report owner private User user; ... typical getter setter ... } public class User { ... omitted for clarity } What happens is when a report is created, the current user is set to the report user object. When the report is edited, the spring controller handling the POST request is receiving a report where the user object is null. Here is what my controller looks like: @Controller @RequestMapping("/report") public class ReportController { @RequestMapping(value = "/edit/{id}", method = RequestMethod.GET) public String editReport(@PathVariable Long id, Model model) { Report r = backend.getReport(id); // fully loads object model.addAttribute("report", report); return "report/edit"; } @RequestMapping(value = "/edit/{id}", method = RequestMethod.POST) public String process(@ModelAttribute("report") Report r) { backend.save(r); return "redirect:/report/show" + r.getId(); } } I ran things throw the debugger and it looks like in the editReport method the model object is storing the fully loaded report object (I can see the user inside the report). On the form jsp I can do the following: ${report.user.username} and the correct result is rendered. However, when I look at the debugger in the process method, the passed in Report r has a null user. I don't need to do any special data binding to ensure that information is retained do I?

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  • What is a good "Error Checking" Pattern (Java)?

    - by Jack
    I'll explain what I mean by input error checking. Say you have a function doSomething(x). If the function completes successfully doSomething does something and returns nothing. However, if there are errors I'd like to be notified. That is what I mean by error checking. I'm looking for, in general, the best way to check for errors. I've thought of the following solutions, each with a potential problem. Flag error checking. If doSomething(x) completes successfully return null. Otherwise, it returns a boolean or an error string. Problem: Side effects. Throwing an exception. Throw an exception if doSomething(x) encounters an error. Problem: If you are performing error checking for parameters only, throwing an IllegalArgumentExceptionseems inappropriate. Validating input prior to function call. If the error checking is only meant for the parameters of the function, then you can call a validator function before calling the doSomething(x) function. Problem: What if a client of the class forgets to call the validator function before calling doSomething(x)? I often encounter this problem and any help or a point in the right direction would be much appreciated.

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  • WCF - Return object without serializing?

    - by Mayo
    One of my WCF functions returns an object that has a member variable of a type from another library that is beyond my control. I cannot decorate that library's classes. In fact, I cannot even use DataContractSurrogate because the library's classes have private member variables that are essential to operation (i.e. if I return the object without those private member variables, the public properties throw exceptions). If I say that interoperability for this particular method is not needed (at least until the owners of this library can revise to make their objects serializable), is it possible for me to use WCF to return this object such that it can at least be consumed by a .NET client? How do I go about doing that? Update: I am adding pseudo code below... // My code, I have control [DataContract] public class MyObject { private TheirObject theirObject; [DataMember] public int SomeNumber { get { return theirObject.SomeNumber; } // public property exposed private set { } } } // Their code, I have no control public class TheirObject { private TheirOtherObject theirOtherObject; public int SomeNumber { get { return theirOtherObject.SomeOtherProperty; } set { // ... } } } I've tried adding DataMember to my instance of their object, making it public, using a DataContractSurrogate, and even manually streaming the object. In all cases, I get some error that eventually leads back to their object not being explicitly serializable.

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  • My java program seems to be skipping over the try{}, executing the catch{} and then throwing a NullPointerException. What should I do?

    - by Matt Bolopue
    I am writing a program that calculates the number of words, syllables, and sentences in any given text file. I don't need help finding those numbers, however my program (which currently should only find the number of words in the text file) will not import the text file even when I type in the name of the file correctly. The text file is in the same folder as the source code. Instead it tells me every time that what I typed in has the wrong file extension (see my catch{}) and then proceeds to throw a null pointer. I am at a loss for what could be causing it. Any suggestions? import java.io.*; import java.util.*; public class Reading_Lvl_Calc { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int words = 0; String fileName; Scanner scan; Scanner keyread = new Scanner(System.in); System.out.println("Please enter a file name (or QUIT to exit)"); fileName = keyread.nextLine(); File doc = new File(fileName); //while(scan.equals(null)){ try { scan = new Scanner(doc); } catch(Exception e) { if(fileName.substring(fileName.indexOf(".")) != ".txt") System.out.println("I'm sorry, the file \"" + fileName + "\" has an invalid file extension."); else System.out.println("I am sorry, the file \"" + fileName + " \" cannot be found.\n The file must be in the same directory as this program"); scan = null; } // } while(scan.hasNext()){ words++; scan.next(); } System.out.println(words); } }

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  • Criteria for triggering garbage collection in .Net

    - by Kennet Belenky
    I've come across some curious behavior with regard to garbage collection in .Net. The following program will throw an OutOfMemoryException very quickly (after less than a second on a 32-bit, 2GB machine). The Foo finalizer is never called. class Foo { static Dictionary<Guid, WeakReference> allFoos = new Dictionary<Guid, WeakReference>(); Guid guid = Guid.NewGuid(); byte[] buffer = new byte[1000000]; static Random rand = new Random(); public Foo() { // Uncomment the following line and the program will run forever. // rand.NextBytes(buffer); allFoos[guid] = new WeakReference(this); } ~Foo() { allFoos.Remove(guid); } static public void Main(string args[]) { for (; ; ) { new Foo(); } } } If the rand.nextBytes line is uncommented, it will run ad infinitum, and the Foo finalizer is regularly invoked. Why is that? My best guess is that in the former case, either the CLR or the Windows VMM is lazy about allocating physical memory. The buffer never gets written to, so the physical memory is never used. When the address space runs out, the system crashes. In the latter case, the system runs out of physical memory before it runs out of address space, the GC is triggered and the objects are collected. However, here's the part I don't get. Assuming my theory is correct, why doesn't the GC trigger when the address space runs low? If my theory is incorrect, then what's the real explanation?

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  • How can this Ambient Context become null?

    - by Mark Seemann
    Can anyone help me explain how TimeProvider.Current can become null in the following class? public abstract class TimeProvider { private static TimeProvider current = DefaultTimeProvider.Instance; public static TimeProvider Current { get { return TimeProvider.current; } set { if (value == null) { throw new ArgumentNullException("value"); } TimeProvider.current = value; } } public abstract DateTime UtcNow { get; } public static void ResetToDefault() { TimeProvider.current = DefaultTimeProvider.Instance; } } Observations All unit tests that directly reference TimeProvider also invokes ResetToDefault() in their Fixture Teardown. There is no multithreaded code involved. Once in a while, one of the unit tests fail because TimeProvider.Current is null (NullReferenceException is thrown). This only happens when I run the entire suite, but not when I just run a single unit test, suggesting to me that there is some subtle test interdependence going on. It happens approximately once every five or six test runs. When a failure occurs, it seems to be occuring in the first executed tests that involves TimeProvider.Current. More than one test can fail, but only one fails in a given test run. FWIW, here's the DefaultTimeProvider class as well: public class DefaultTimeProvider : TimeProvider { private readonly static DefaultTimeProvider instance = new DefaultTimeProvider(); private DefaultTimeProvider() { } public override DateTime UtcNow { get { return DateTime.UtcNow; } } public static DefaultTimeProvider Instance { get { return DefaultTimeProvider.instance; } } } I suspect that there's some subtle interplay going on with static initialization where the runtime is actually allowed to access TimeProvider.Current before all static initialization has finished, but I can't quite put my finger on it. Any help is appreciated.

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  • BackgroundWorker acting bizarrely...

    - by vdh_ant
    Hi guys I'm working on some code that calls a service. This service call could fail and if it does I want the system to try again until it works or too much time has passed. I am wondering where I am going wrong as the following code doesn't seem to be working correctly... It randomly only does one to four loops... protected virtual void ProcessAsync(object data, int count) { var worker = new BackgroundWorker(); worker.DoWork += (sender, e) => { throw new InvalidOperationException("oh shiznit!"); }; worker.RunWorkerCompleted += (sender, e) => { //If an error occurs we need to tell the data about it if (e.Error != null) { count++; System.Threading.Thread.Sleep(count * 5000); if (count <= 10) { if (count % 5 == 0) this.Logger.Fatal("LOAD ERROR - The system can't load any data", e.Error); else this.Logger.Error("LOAD ERROR - The system can't load any data", e.Error); this.ProcessAsync(data, count); } } }; worker.RunWorkerAsync(); } Cheers Anthony

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  • In ArrayBlockingQueue, why copy final member field into local final variable?

    - by mjlee
    In ArrayBlockingQueue, any method that requires lock will get set 'final' local variable before calling 'lock()'. public boolean offer(E e) { if (e == null) throw new NullPointerException(); final ReentrantLock lock = this.lock; lock.lock(); try { if (count == items.length) return false; else { insert(e); return true; } } finally { lock.unlock(); } } Is there any reason to set a local variable 'lock' from 'this.lock' when field 'this.lock' is final also. Additionally, it also set local variable of E[] before acting on. private E extract() { final E[] items = this.items; E x = items[takeIndex]; items[takeIndex] = null; takeIndex = inc(takeIndex); --count; notFull.signal(); return x; } Is there any reason for copying to local final variable?

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  • Implementing a Version check between an Abstract class and it's implementation

    - by Michael Stum
    I have this abstract class and concrete implementation (they are in different assemblies): public abstract class MyAbstractClass { private static readonly int MyAbstractClassVersion = 1; public abstract int ImplementedVersion { get; } protected MyAbstractClass() { CheckVersion(); } private void CheckVersion() { var message = string.Format( "MyAbstractClass implements Version {0}, concrete is Version {1}", RepositoryVersion, ImplementedVersion); if (!MyAbstractClassVersion.Equals(ImplementedVersion)) throw new InvalidOperationException(message); } } public class ConcreteClass : MyAbstractClass { public ConcreteClass() : base() { // ConcreteClass is guaranteed to have // a constructor that calls the base constructor // I just simplified the example } public override int ImplementedVersion { get { return 2; } } } As you see, I call CheckVersion() from the abstract constructor, to get rid of the "virtual member call in base constructor" message, but I am not sure if that's really the way to do it. Sure, it works, but that doesn't mean it will always work, will it? Also, I wonder if I can get the name of the Concrete Type from the CheckVersion() function? I know that adding new abstract members will force an error anyway (System.TypeLoadException) and I'm not sure if I want this type of strict Versioning, but I'm just curious how it would be done properly given only the abstract class and an implementation (I know I could do it by using interfaces and/or a Factory pattern).

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  • Stored procedure or function expects parameter which is not supplied

    - by user2920046
    I am trying to insert data into a SQL Server database by calling a stored procedure, but I am getting the error Procedure or function 'SHOWuser' expects parameter '@userID', which was not supplied. My stored procedure is called "SHOWuser". I have checked it thoroughly and no parameters is missing. My code is: public void SHOWuser(string userName, string password, string emailAddress, List preferences) { SqlConnection dbcon = new SqlConnection(conn); try { SqlCommand cmd = new SqlCommand(); cmd.Connection = dbcon; cmd.CommandType = System.Data.CommandType.StoredProcedure; cmd.CommandText = "SHOWuser"; cmd.Parameters.AddWithValue("@userName", userName); cmd.Parameters.AddWithValue("@password", password); cmd.Parameters.AddWithValue("@emailAddress", emailAddress); dbcon.Open(); int i = Convert.ToInt32(cmd.ExecuteScalar()); cmd.Parameters.Clear(); cmd.CommandText = "tbl_pref"; foreach (int preference in preferences) { cmd.Parameters.Clear(); cmd.Parameters.AddWithValue("@userID", Convert.ToInt32(i)); cmd.Parameters.AddWithValue("@preferenceID", Convert.ToInt32(preference)); cmd.ExecuteNonQuery(); } } catch (Exception) { throw; } finally { dbcon.Close(); } and the stored procedure is: ALTER PROCEDURE [dbo].[SHOWuser] -- Add the parameters for the stored procedure here ( @userName varchar(50), @password nvarchar(50), @emailAddress nvarchar(50) ) AS BEGIN INSERT INTO tbl_user(userName,password,emailAddress) values(@userName,@password,@emailAddress) select tbl_user.userID,tbl_user.userName,tbl_user.password,tbl_user.emailAddress, stuff((select ',' + preferenceName from tbl_pref_master inner join tbl_preferences on tbl_pref_master.preferenceID = tbl_preferences.preferenceID where tbl_preferences.userID=tbl_user.userID FOR XML PATH ('')),1,1,' ' ) AS Preferences from tbl_user SELECT SCOPE_IDENTITY(); END Pls help, Thankx in advance...

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  • Better way to catch trouble points

    - by mac
    User submits a CSV file which is consumed by a program. Values which are used throughout the program come from the CSV, natually if values are missed it is a problem. Below is my solution. Ip on top private List<String> currentFieldName = new ArrayList<String>(); As part of the method: try { setCurrentFieldName("Trim Space"); p.setTrimSpace(currentLineArray[dc.getTRIM_POSITION()].equals("yes") ? true : false); setCurrentFieldName("Ignore Case"); p.setIgnoreCase(currentLineArray[dc.getIGNORE_CASE_POSITION()].equals("yes") ? true : false); } catch (NullPointerException e) { throw new InputSpreadsheetValueUnassignedException("\"Type\" field not set: " + currentFieldName); } And the method which keeps track of a current field being looked at: private void setCurrentFieldName(String fieldName) { currentFieldName.clear(); currentFieldName.add(fieldName); } The idea there is that if user fails to submit value and i will end up getting null, before throwing an exception, i will know what value was not assigned. So, this being said, specific questions: Is what i have shown below an acceptable solution? Can you suggest something more elegant?

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  • Controlling race condition at startup.

    - by Will Hartung
    I have some code that I want to have some one time initialisation performed. But this code doesn't have a definite lifecycle, so my logic can be potentially invoked by multiple threads before my initialisation is done. So, I want to basically ensure that my logic code "waits" until initialisation is done. This is my first cut. public class MyClass { private static final AtomicBoolean initialised = new AtomicBoolean(false); public void initialise() { synchronized(initialised) { initStuff(); initialised.getAndSet(true); initialised.notifyAll(); } } public void doStuff() { synchronized(initialised) { if (!initialised.get()) { try { initialised.wait(); } catch (InterruptedException ex) { throw new RuntimeException("Uh oh!", ex); } } } doOtherStuff(); } } I basically want to make sure this is going to do what I think it's going to do -- block doStuff until the initialised is true, and that I'm not missing a race condition where doStuff might get stuck on a Object.wait() that will never arrive. Edit: I have no control over the threads. And I want to be able to control when all of the initialisation is done, which is why doStuff() can't call initialise(). I used an AtomicBoolean as it was a combination of a value holder, and an object I could synchronize. I could have also simply had a "public static final Object lock = new Object();" and a simple boolean flag. AtomicBoolean conveniently gave me both. A Boolean can not be modified. The CountDownLatch is exactly what I was looking for. I also considered using a Sempahore with 0 permits. But the CountDownLatch is perfect for just this task.

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  • Replacing/Adding resources (icon) programmatically in c#?

    - by reverendo
    I am trying to replace (or add in the case it doesn't exists) icons from .exe files using c#. So far I got this: string filename = "c:\\test.exe"; IntPtr hResource = BeginUpdateResource(filename, true); if (hResource.ToInt32() == 0) throw new Exception("File Not Found"); byte[] ico = System.IO.File.ReadAllBytes("C:\\icon.ico"); IntPtr unmanagedPointer = Marshal.AllocHGlobal(ico.Length); Marshal.Copy(ico, 0, unmanagedPointer, ico.Length); if (UpdateResource(hResource, "Icon", "1", 1033, unmanagedPointer, Convert.ToUInt32(ico.Length)) != false) { MessageBox.Show("Updated"); EndUpdateResource(hResource, false); } Marshal.FreeHGlobal(unmanagedPointer); "Icon", "1", 1033 <- I got this data by opening test.exe with Resource Hacker. I do get the messagebox "Updated", and if I open the resulting exe in Resource Hacker the resource gets replaced but the icon doesn't appear, its just empty. Also that code wont replace, the type "Icon" in the resource, it will delete everything and add that "Icon" and if I use BeginUpdateResource(path, false); it will not replace it neither but it will add ANOTHER "Icon". Where can I find an example to replace/add the icon using c# disregarding the name the resource use for the icon or if the resource doesn't exist?

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  • Excel I have a .Net object compiled as a tlb but cant not access any methods apart from Dispose.

    - by Mark O'Grady
    Hi This is ongoing issue to something I posted yesterday. I have a .net object that I want to use in Excel. I have an existing VBA script that i need to alter to call this the object from. I have then converted the object to a TLB. I've not really touched on this area before so any help will be appreciated. I have created an interface [Guid("0F700B48-E0CA-446b-B87E-555BCC317D74"),InterfaceType(ComInterfaceType.InterfaceIsDual)] [ComVisible(true)] public interface IOfficeCOMInterface { [DispId(1)] void ResetOrder(); [DispId(2)] void SetDeliveryAddress(string PostalName, string AddressLine1, string AddressLine2, string AddressLine3, string AddressLine4, string PostCode, string CountryCode, string TelephoneNo, string FaxNo, string EmailAddress); } I have also created an class that inherits that object. [ClassInterface(ClassInterfaceType.None), ProgId("NAMESPACE.OfficeCOMInterface"), Guid("9D9723F9-8CF1-4834-BE69-C3FEAAAAB530"), ComVisible(true)] public class OfficeCOMInterface : IOfficeCOMInterface, IDisposable { public void ResetSOPOrder() { } public void SetDeliveryAddress(string PostalName, string AddressLine1, string AddressLine2, string AddressLine3, string AddressLine4, string PostCode, string CountryCode, string TelephoneNo, string FaxNo, string EmailAddress) { try { SalesOrder.AmendDeliveryAddress(PostalName, AddressLine1, AddressLine2, AddressLine3, AddressLine4, PostCode); MessageBox.Show("Delivery address set"); } catch (Exception ex) { throw ex; } } } I can't access the object methods apart from dispose, I guess IDisposable is working fine. Is there anything I need to my Interface?

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  • JavaScript sleep

    - by Diazath
    yes, i know - that question has thousands of answers. please, don't tell me about "setTimeout" method becasuse - yes, everything is possible with that but not so easy as using sleep() method. for example: function fibonacci(n) { console.log("Computing Fibonacci for " + n + "..."); var result = 0; //wait 1 second before computing for lower n sleep(1000); result = (n <= 1) ? 1 : (fibonacci(n - 1) + fibonacci(n - 2)); //wait 1 second before announcing the result sleep(1000); console.log("F(" + n + ") = " + result); return result; } if you know how to get the same result using setTimeout - tell me ;) fibanacci is pretty easy task, because there not more than 2 recursions, but how about n-recursions (like fib(1) + fib(2) + .. + fib(n) and sleep after every "+"? nah, sleep would be muuuuuch easier. but still i can't get working example of implementing it. while (curr - start < time) { curr = (...) } is tricky, but it won't work (just stops my browser and then throw all console.logs at once).

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  • How to get from JRuby a correctly typed ruby implementation of a Java interface?

    - by Guss
    I'm trying to use JRuby (through the JSR233 interface included in JRuby 1.5) from a Java application to load a ruby implementation of a Java interface. My sample implementation looks like this: Interface: package some.package; import java.util.List; public interface ScriptDemoIf { int fibonacci(int d); List<String> filterLength(List<String> source, int maxlen); } Ruby Implementation: require 'java' include Java class ScriptDemo java_implements some.package.ScriptDemoIf java_signature 'int fibonacci(int d)' def fibonacci(d) d < 2 ? d : fibonacci(d-1) + fibonacci(d-2) end java_signature 'List<String> filterLength(List<String> source, int maxlen)' def filterLength(source, maxlen) source.find_all { |str| str.length <= maxlen } end end Class loader: public ScriptDemoIf load(String filename) throws ScriptException { ScriptEngine engine = new ScriptEngineManager().getEngineByName("jruby"); FileReader script = new FileReader(filename); try { engine.eval(new FileReader(script)); } catch (FileNotFoundException e) { throw new ScriptException("Failed to load " + filename); } return (ScriptDemoIf) m_engine.eval("ScriptDemo.new"); } (Obviously the loader is a bit more generic in real life - it doesn't assume that the implementation class name is "ScriptDemo" - this is just for simplicity). Problem - I get a class cast exception in the last line of the loader - the engine.eval() return a RubyObject type which doesn't cast down nicely to my interface. From stuff I read all over the web I was under the impression that the whole point of use java_implements in the Ruby section was for the interface implementations to be compiled in properly. What am I doing wrong?

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  • How to pass XML from C# to a stored procedure in SQL Server 2008?

    - by Geetha
    I want to pass xml document to sql server stored procedure such as this: CREATE PROCEDURE BookDetails_Insert (@xml xml) I want compare some field data with other table data and if it is matching that records has to inserted in to the table. Requirements: How do I pass XML to the stored procedure? I tried this, but it doesn’t work:[Working] command.Parameters.Add( new SqlParameter("@xml", SqlDbType.Xml) { Value = new SqlXml(new XmlTextReader(xmlToSave.InnerXml, XmlNodeType.Document, null)) }); How do I access the XML data within the stored procedure? Edit: [Working] String sql = "BookDetails_Insert"; XmlDocument xmlToSave = new XmlDocument(); xmlToSave.Load("C:\\Documents and Settings\\Desktop\\XML_Report\\Books_1.xml"); SqlConnection sqlCon = new SqlConnection("..."); using (DbCommand command = sqlCon.CreateCommand()) { **command.CommandType = CommandType.StoredProcedure;** command.CommandText = sql; command.Parameters.Add( new SqlParameter("@xml", SqlDbType.Xml) { Value = new SqlXml(new XmlTextReader(xmlToSave.InnerXml , XmlNodeType.Document, null)) }); sqlCon.Open(); DbTransaction trans = sqlCon.BeginTransaction(); command.Transaction = trans; try { command.ExecuteNonQuery(); trans.Commit(); sqlCon.Close(); } catch (Exception) { trans.Rollback(); sqlCon.Close(); throw; } Edit 2: How to create a select query to select pages, description based on some conditions. <booksdetail> <isn_13>700001048</isbn_13> <isn_10>01048B</isbn_10> <Image_URL>http://www.landt.com/Books/large/00/7010000048.jpg</Image_URL> <title>QUICK AND FLUPKE</title> <Description> PRANKS AND JOKES QUICK AND FLUPKE </Description> </booksdetail>

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