Search Results

Search found 20401 results on 817 pages for 'null coalescing operator'.

Page 379/817 | < Previous Page | 375 376 377 378 379 380 381 382 383 384 385 386  | Next Page >

  • Problem with document.location.href

    - by novellino
    Hello, I am new to Javascript and Web development and I have a question regarding the document.location.href. I am using a cookie for storing the language the user prefers and then load the english or the swedish version depending on the language. The default language in the beginning is the same as the browser's language, and my index.jsp is the swedish one. The first time everything works fine. The problem is when the cookie exists already. The basic code is: if (language!=null && language!=""){ if (language=="en-US" || language=="en-us") document.location.href = "en/index.jsp"; } else{ //Explorer if (navigator.userLanguage) language = navigator.userLanguage; //other browsers else language = (navigator.language) ? navigator.language : navigator.userLanguage; if (language!=null && language!=""){ setCookie('language', language, 365, '/', 'onCheck'); if (language=="en-US" || language=="en-us") document.location.href = "en/index.jsp"; else if(language=="sv") document.location.href="index.jsp"; } } When the cookie exists we enter the first "if", and there, if the language is swedish it opens the default blabla/index.jsp page. When the language is set to engish it should open the blabla/en/index.jsp but instead it opens the blabla/en/en/index.jsp which of course is wrong. Does anyone know what I am doing wrong?? Thanks

    Read the article

  • Partially constructed object / Multi threading

    - by reto
    Heya! I'm using joda due to it's good reputation regarding multi threading. It goes great distances to make multi threaded date handling efficient, for example by making all Date/Time/DateTime objects immutable. But here's a situation where I'm not sure if Joda is really doing the right thing. It probably is correct, but I'd be very interested to see the explanation for it. When a toString() of a DateTime is being called Joda does the following: /* org.joda.time.base.AbstractInstant */ public String toString() { return ISODateTimeFormat.dateTime().print(this); } All formatters are thread safe, as they are as well ready-only. But what's about the formatter-factory: private static DateTimeFormatter dt; /* org.joda.time.format.ISODateTimeFormat */ public static DateTimeFormatter dateTime() { if (dt == null) { dt = new DateTimeFormatterBuilder() .append(date()) .append(tTime()) .toFormatter(); } return dt; } This is a common pattern in single threaded applications. I see the following dangers: Race condition during null check -- worst case: two objects get created. No Problem, as this is solely a helper object (unlike a normal singleton pattern situation), one gets saved in dt, the other is lost and will be garbage collected sooner or later. the static variable might point to a partially constructed object before the objec has been finished initialization (before calling me crazy, read about a similar situation in this Wikipedia article. So how does Joda ensure that not partially created formatter gets published in this static variable? Thanks for your explanations! Reto

    Read the article

  • what does this C++ line of code mean "sol<?=f((1<<n)-1,i,0)+abs(P[i])*price;"

    - by KItis
    Could anyone help me to understand following line of code. sol I am studying an algorithm written using c++ and it has following operator " following is the error message returned. Hello.cpp: In function ‘int main()’: Hello.cpp:115: error: ‘memset’ was not declared in this scope Hello.cpp:142: error: expected primary-expression before ‘?’ token Hello.cpp:142: error: expected primary-expression before ‘=’ token Hello.cpp:142: error: expected ‘:’ before ‘;’ token Hello.cpp:142: error: expected primary-expression before ‘;’ token may be " Thanks in advance for the time you spent reading this post.

    Read the article

  • Python/MySQL fails under Windows

    - by AP257
    I'm trying to get Python 2.6 to communicate with MySQL Server 5.1, under Windows XP, but I keep getting a strange error, "SystemError: NULL object passed to Py_BuildValue": >>> import MySQLdb as mysql >>> db = mysql.connect(user = "root", passwd="whatever", db="mysql", host="localh ost") >>> cu = db.cursor() >>> cu.execute("show tables") Traceback (most recent call last): File "<stdin>", line 1, in <module> File "C:\dirr\lib\site-packages\MySQLdb\cursors.py", line 173, in execu te self.errorhandler(self, exc, value) File "C:\ dirr\lib\site-packages\MySQLdb\connections.py", line 36, in de faulterrorhandler raise errorclass, errorvalue SystemError: NULL object passed to Py_BuildValue I thought it might be a character set problem, but I've tried setting and setting MySQL as UTF-8, and it hasn't made a difference. I guess there must be a problem with python-mysql. Can anyone help? UPDATE OK, python-mysql under windows is a bit of a nightmare, particularly with Python 2.6 it seems. Rather than installing python-mysql with pip, use this installer instead. That fixed it.

    Read the article

  • how to use cookies in HttpsURLConnection in android.

    - by sajjoo
    hello guys, actually i am new in Android and now i have to add the cookies in my project. i am using HttpsUrlConnection. here is how i am making request and getting response from a webserver and now i have to add cookies aswell. URL url = new URL(strUrl); HttpsURLConnection connection = (HttpsURLConnection) url.openConnection(); connection.setRequestMethod("POST"); connection.setRequestProperty("Content-Type", "application/soap+xml; charset=utf-8"); connection.setRequestProperty("Content-Length", ""+ Integer.toString(request.getBytes().length)); connection.setUseCaches (false); connection.setDoInput(true); connection.setDoOutput(true); // send Request... DataOutputStream wr = new DataOutputStream (connection.getOutputStream()); wr.writeBytes (request); wr.flush (); wr.close (); //Get response... DataInputStream is = new DataInputStream(connection.getInputStream()); String line; StringBuffer response = new StringBuffer(); while((line = is.readLine()) != null) { response.append(line); } is.close(); FileLogger.writeFile("Soap.txt", "RESPONSE: " + methodName + "\n" + response); HashMap<String, String> parameters = null; try { parameters = SoapRequest.responseParser(response.toString(), methodName); } catch (ParserConfigurationException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (SAXException e) { // TODO Auto-generated catch block e.printStackTrace(); } return parameters; any help will be appreciative, thanks

    Read the article

  • Start-job to call script from main

    - by Naveen
    I have three script , from main - 1-script , I am calling other two scripts. so that I can execute both scripts parallely because it's taking too much time in sequential order. Only variables are different in the script. How can I merge script 2 & 3 in a single script so that I can call from the main script and it will run as parallel. 1 CompareCtrlM... Completed False localhost ######################... 3 CompareCtrlM... Completed True localhost ######################... Main -1 Script Start-Job -Name "LoopComparectrlMasterModel" -filepath D:\tmp\naveen\Script\CompareCtrlMasterCtrlModel.ps1 Start-Job -Name "LoopCompareProdMasterModel" -filepath D:\idv\CA\rcm_data\tmp\work\CompareCtrlMasterProdModel.ps1 Wait-Job -Name "LoopComparectrlMasterModel" Receive-Job "LoopComparectrlMasterModel" Wait-Job -Name "LoopCompareProdMasterModel" Receive-Job "LoopCompareProdMasterModel" =============================================== Script 2- for ($i = 1 ; $i -lt 3; $i++){ $jobName = 'CompareCtrlMasterProdModelESS$i' echolog $THISSCRIPT $RCM_UPDATE_LOG_FILE $LLINFO ("Starting Ctrl Master-Prod Model comparison #" + $i + ", create SBT") $rc = CreateSbtFile $sbtCompareCtrlMasterProdModel[$i-1] $cfgProdModel $cfgCtrlMaster "" "" $SBT_MODE_COMPARE_CFGS_FULL $workDir Start-Job -Name "$jobName" -filepath $ExecuteSbtWithRcmClientTool -ArgumentList $sbtCompareCtrlMasterProdModel[$i-1],"",$true,$false | Out-Null Wait-Job -Name "$jobName" $results = Receive-Job -Name $jobName } ========================================================================== Script 3- for ($i = 1 ; $i -lt 3; $i++){ $jobName = 'CompareCtrlMasterCtrlModelESS$i' echolog $THISSCRIPT $RCM_UPDATE_LOG_FILE $LLINFO ("Starting Ctrl Master-Ctrl Model comparison #" + $i + ", create SBT") $rc = CreateSbtFile $sbtCompareCtrlMasterCtrlModel[$i-1] $cfgCtrlModel $cfgCtrlMaster "" "" $SBT_MODE_COMPARE_CFGS_FULL $workDir Start-Job -Name "$jobName" -filepath $ExecuteSbtWithRcmClientTool -ArgumentList $sbtCompareCtrlMasterCtrlModel[$i-1],"",$true,$false | Out-Null Wait-Job -Name "$jobName" $results = Receive-Job -Name $jobName } write-output $results Thanks a lot for help Regards Naven

    Read the article

  • Is there alternative way to write this query?

    - by Kugel
    I have tables A, B, C, where A represents items which can have zero or more sub-items stored in C. B table only has 2 foreign keys to connect A and C. I have this sql query: select * from A where not exists (select * from B natural join C where B.id = A.id and C.value > 10); Which says: "Give me every item from table A where all sub-items have value less than 10. Is there a way to optimize this? And is there a way to write this not using exists operator?

    Read the article

  • JavaFx 2.1, 2.2 TableView update issue

    - by Lewis Liu
    My application uses JPA read data into TableView then modify and display them. The table refreshed modified record under JavaFx 2.0.3. Under JavaFx 2.1, 2.2, the table wouldn't refresh the update anymore. I found other people have similar issue. My plan was to continue using 2.0.3 until someone fixes the issue under 2.1 and 2.2. Now I know it is not a bug and wouldn't be fixed. Well, I don't know how to deal with this. Following are codes are modified from sample demo to show the issue. If I add a new record or delete a old record from table, table refreshes fine. If I modify a record, the table wouldn't refreshes the change until a add, delete or sort action is taken. If I remove the modified record and add it again, table refreshes. But the modified record is put at button of table. Well, if I remove the modified record, add the same record then move the record to the original spot, the table wouldn't refresh anymore. Below is a completely code, please shine some light on this. import javafx.application.Application; import javafx.beans.property.SimpleStringProperty; import javafx.collections.FXCollections; import javafx.collections.ObservableList; import javafx.event.ActionEvent; import javafx.event.EventHandler; import javafx.geometry.HPos; import javafx.geometry.Insets; import javafx.geometry.Pos; import javafx.scene.Group; import javafx.scene.Scene; import javafx.scene.control.*; import javafx.scene.control.cell.PropertyValueFactory; import javafx.scene.layout.GridPane; import javafx.scene.layout.HBox; import javafx.scene.layout.VBox; import javafx.scene.text.Font; import javafx.stage.Modality; import javafx.stage.Stage; import javafx.stage.StageStyle; public class Main extends Application { private TextField firtNameField = new TextField(); private TextField lastNameField = new TextField(); private TextField emailField = new TextField(); private Stage editView; private Person fPerson; public static class Person { private final SimpleStringProperty firstName; private final SimpleStringProperty lastName; private final SimpleStringProperty email; private Person(String fName, String lName, String email) { this.firstName = new SimpleStringProperty(fName); this.lastName = new SimpleStringProperty(lName); this.email = new SimpleStringProperty(email); } public String getFirstName() { return firstName.get(); } public void setFirstName(String fName) { firstName.set(fName); } public String getLastName() { return lastName.get(); } public void setLastName(String fName) { lastName.set(fName); } public String getEmail() { return email.get(); } public void setEmail(String fName) { email.set(fName); } } private TableView<Person> table = new TableView<Person>(); private final ObservableList<Person> data = FXCollections.observableArrayList( new Person("Jacob", "Smith", "[email protected]"), new Person("Isabella", "Johnson", "[email protected]"), new Person("Ethan", "Williams", "[email protected]"), new Person("Emma", "Jones", "[email protected]"), new Person("Michael", "Brown", "[email protected]")); public static void main(String[] args) { launch(args); } @Override public void start(Stage stage) { Scene scene = new Scene(new Group()); stage.setTitle("Table View Sample"); stage.setWidth(535); stage.setHeight(535); editView = new Stage(); final Label label = new Label("Address Book"); label.setFont(new Font("Arial", 20)); TableColumn firstNameCol = new TableColumn("First Name"); firstNameCol.setCellValueFactory( new PropertyValueFactory<Person, String>("firstName")); firstNameCol.setMinWidth(150); TableColumn lastNameCol = new TableColumn("Last Name"); lastNameCol.setCellValueFactory( new PropertyValueFactory<Person, String>("lastName")); lastNameCol.setMinWidth(150); TableColumn emailCol = new TableColumn("Email"); emailCol.setMinWidth(200); emailCol.setCellValueFactory( new PropertyValueFactory<Person, String>("email")); table.setItems(data); table.getColumns().addAll(firstNameCol, lastNameCol, emailCol); //--- create a edit button and a editPane to edit person Button addButton = new Button("Add"); addButton.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent event) { fPerson = null; firtNameField.setText(""); lastNameField.setText(""); emailField.setText(""); editView.show(); } }); Button editButton = new Button("Edit"); editButton.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent event) { if (table.getSelectionModel().getSelectedItem() != null) { fPerson = table.getSelectionModel().getSelectedItem(); firtNameField.setText(fPerson.getFirstName()); lastNameField.setText(fPerson.getLastName()); emailField.setText(fPerson.getEmail()); editView.show(); } } }); Button deleteButton = new Button("Delete"); deleteButton.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent event) { if (table.getSelectionModel().getSelectedItem() != null) { data.remove(table.getSelectionModel().getSelectedItem()); } } }); HBox addEditDeleteButtonBox = new HBox(); addEditDeleteButtonBox.getChildren().addAll(addButton, editButton, deleteButton); addEditDeleteButtonBox.setAlignment(Pos.CENTER_RIGHT); addEditDeleteButtonBox.setSpacing(3); GridPane editPane = new GridPane(); editPane.getStyleClass().add("editView"); editPane.setPadding(new Insets(3)); editPane.setHgap(5); editPane.setVgap(5); Label personLbl = new Label("Person:"); editPane.add(personLbl, 0, 1); GridPane.setHalignment(personLbl, HPos.LEFT); firtNameField.setPrefWidth(250); lastNameField.setPrefWidth(250); emailField.setPrefWidth(250); Label firstNameLabel = new Label("First Name:"); Label lastNameLabel = new Label("Last Name:"); Label emailLabel = new Label("Email:"); editPane.add(firstNameLabel, 0, 3); editPane.add(firtNameField, 1, 3); editPane.add(lastNameLabel, 0, 4); editPane.add(lastNameField, 1, 4); editPane.add(emailLabel, 0, 5); editPane.add(emailField, 1, 5); GridPane.setHalignment(firstNameLabel, HPos.RIGHT); GridPane.setHalignment(lastNameLabel, HPos.RIGHT); GridPane.setHalignment(emailLabel, HPos.RIGHT); Button saveButton = new Button("Save"); saveButton.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent event) { if (fPerson == null) { fPerson = new Person( firtNameField.getText(), lastNameField.getText(), emailField.getText()); data.add(fPerson); } else { int k = -1; if (data.size() > 0) { for (int i = 0; i < data.size(); i++) { if (data.get(i) == fPerson) { k = i; } } } fPerson.setFirstName(firtNameField.getText()); fPerson.setLastName(lastNameField.getText()); fPerson.setEmail(emailField.getText()); data.set(k, fPerson); table.setItems(data); // The following will work, but edited person has to be added to the button // // data.remove(fPerson); // data.add(fPerson); // add and remove refresh the table, but now move edited person to original spot, // it failed again with the following code // while (data.indexOf(fPerson) != k) { // int i = data.indexOf(fPerson); // Collections.swap(data, i, i - 1); // } } editView.close(); } }); Button cancelButton = new Button("Cancel"); cancelButton.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent event) { editView.close(); } }); HBox saveCancelButtonBox = new HBox(); saveCancelButtonBox.getChildren().addAll(saveButton, cancelButton); saveCancelButtonBox.setAlignment(Pos.CENTER_RIGHT); saveCancelButtonBox.setSpacing(3); VBox editBox = new VBox(); editBox.getChildren().addAll(editPane, saveCancelButtonBox); Scene editScene = new Scene(editBox); editView.setTitle("Person"); editView.initStyle(StageStyle.UTILITY); editView.initModality(Modality.APPLICATION_MODAL); editView.setScene(editScene); editView.close(); final VBox vbox = new VBox(); vbox.setSpacing(5); vbox.getChildren().addAll(label, table, addEditDeleteButtonBox); vbox.setPadding(new Insets(10, 0, 0, 10)); ((Group) scene.getRoot()).getChildren().addAll(vbox); stage.setScene(scene); stage.show(); } }

    Read the article

  • C# implicit conversions

    - by Chris Boden
    Hello, I'm currently working on an application where I need to load data from an SQL database and then assign the retrieved values into the properties of an object. I'm doing this by using reflection since the property names and column names are the same. However, many of the properties are using a custom struct type that is basically a currency wrapper for the decimal type. I have defined an implicit conversion in my struct: public static implicit operator Currency(decimal d) { return new Currency(d); } This works fine when I use it in code. However, when I have this: foreach (PropertyInfo p in props) { p.SetValue(this, table.Rows[0][p.Name], null); } It throws an ArgumentException stating that it cannot convert from System.Decimal to Currency. I'm confused since it works fine in any other circumstance.

    Read the article

  • What is a good way to assign order #s to ordered rows in a table in Sybase

    - by DVK
    I have a table T (structure below) which initially contains all-NULL values in an integer order column: col1 varchar(30), col2 varchar(30), order int NULL I also have a way to order the "colN" columns, e.g. SELECT * FROM T ORDER BY some_expression_involving_col1_and_col2 What's the best way to assign - IN SQL - numeric order values 1-N to the order table, so that the order values match the order of rows returned by the above ORDER BY? In other words, I would like a single query (Sybase SQL syntax so no Oracle's rowcount) which assigns order values so that SELECT * FROM T ORDER BY order returns 100% same order of rows as the query above. The query does NOT necessarily need to update the table T in place, I'm OK with creating a copy of the table T2 if that'll make the query simpler. NOTE1: A solution must be real query or a set of queries, not involving a loop or a cursor. NOTE2: Assume that the data is uniquely orderable according to the order by above - no need to worry about situation when 2 rows can be assigned the same order at random. NOTE3: I would prefer a generic solution, but if you wish a specific example of ordering expression, let's say: SELECT * FROM T ORDER BY CASE WHEN col1="" THEN "AAAAAA" ELSE col1 END, ISNULL(col2, "ZZZ")

    Read the article

  • How to read from a method that returns a filehandle in perl?

    - by Ryan Thompson
    I have an object with a method that returns a filehandle, and I want to read from that handle. The following doesn't work, because the right angle bracket of the method call is interpreted as the closing angle bracket of the input reader: my $input = <$object->get_handle()>; That gets parsed as: my $input = ( < $object- > ) get_handle() >; which is obviously a syntax error. Is there any way I can perform a method call within an angle operator, or do I need to break it into two steps like this? my $handle = $object->get_handle(); my $input = <$handle>;

    Read the article

  • Does Android AsyncTaskQueue or similar exist?

    - by Ben L.
    I read somewhere (and have observed) that starting threads is slow. I always assumed that AsyncTask created and reused a single thread because it required being started inside the UI thread. The following (anonymized) code is called from a ListAdapter's getView method to load images asynchronously. It works well until the user moves the list quickly, and then it becomes "janky". final File imageFile = new File(getCacheDir().getPath() + "/img/" + p.image); image.setVisibility(View.GONE); view.findViewById(R.id.imageLoading).setVisibility(View.VISIBLE); (new AsyncTask<Void, Void, Bitmap>() { @Override protected Bitmap doInBackground(Void... params) { try { Bitmap image; if (!imageFile.exists() || imageFile.length() == 0) { image = BitmapFactory.decodeStream(new URL( "http://example.com/images/" + p.image).openStream()); image.compress(Bitmap.CompressFormat.JPEG, 85, new FileOutputStream(imageFile)); image.recycle(); } image = BitmapFactory.decodeFile(imageFile.getPath(), bitmapOptions); return image; } catch (MalformedURLException ex) { // TODO Auto-generated catch block ex.printStackTrace(); return null; } catch (IOException ex) { // TODO Auto-generated catch block ex.printStackTrace(); return null; } } @Override protected void onPostExecute(Bitmap image) { if (view.getTag() != p) // The view was recycled. return; view.findViewById(R.id.imageLoading).setVisibility( View.GONE); view.findViewById(R.id.image) .setVisibility(View.VISIBLE); ((ImageView) view.findViewById(R.id.image)) .setImageBitmap(image); } }).execute(); I'm thinking that a queue-based method would work better, but I'm wondering if there is one or if I should attempt to create my own implementation.

    Read the article

  • http-post request for a long String in iOS

    - by onkar
    I am looking to send a very long String, which is an image that is encoded into a String. I need to send that information using POST method. I have implemented the same in Android using key-value pair, I need to implement the same in iOS using key-value pair. Please help me with useful resources/approach. EDIT 1 What have I tried [dictionnary setObject:@"admin" forKey:@"username"]; [dictionnary setObject:@"123123" forKey:@"password"]; NSError *error = nil; NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dictionnary options:kNilOptions error:&error]; NSString *urlString = @"MY CALL URL"; NSURL *url = [NSURL URLWithString:urlString]; NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url]; [request setHTTPMethod:@"POST"]; [request setHTTPBody:jsonData]; NSURLResponse *response = NULL; NSError *requestError = NULL; NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&requestError]; NSLog(@"response is obtained"); NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding] ; NSLog(@"%@", responseString); EDIT 2 Error I am getting Request Error Error Domain=kCFErrorDomainCFNetwork Code=303 "The operation couldn’t be completed. (kCFErrorDomainCFNetwork error 303.)" UserInfo=0x7ba0120 {NSErrorFailingURLKey=http://yahoo.com/, NSErrorFailingURLStringKey=http://yahoo.com/}

    Read the article

  • Placement new in gcc

    - by Roman Prikhodchenko
    I need to find a workaround for a bug with placement new in g++. I now it was fixed in gcc-4.3 but I have to support versions 4.2 and 4.1. For example, following code compiles with an error "error: no matching function for call to 'operator new(long unsigned int, void*&)" template<class T, template<typename> class Alloc> inline void* type_ctor() { Alloc<T> a; void* p = a.allocate(1); new(p) T; return p; } ..... type_ctor<A, NewAllocator >();

    Read the article

  • how to get the size of a C global array into an assembly program written for the avr architecture co

    - by johannes
    I have a .c file with the following uint8_t buffer[32] I have a .S file where I want to do the following cpi r29, buffer+sizeof(buffer) The second argument for cpi muste be an imidiate value not a location. But unfortunetly sizeof() is a c operator. Both files, are getting compiled to seperate object files and linked afterwards. If I do avr-objdump -x file.c. Amongst other things, I get the size of the buffer. So it is already available in the object file. How do I access the size of the buffer in my assembly file at compile time?

    Read the article

  • I can not use Session In Page_Load and I got error bellow

    - by LostLord
    hi my dear friends .... why i got this error : Object reference not set to an instance of an object. when i put this code in my page_load.: protected void Page_Load(object sender, EventArgs e) { BackEndUtils.OverallLoader(); string Teststr = Session["Co_ID"].ToString(); } ========================================================================== this session is made when user logins to my web site and this session works in other areas... thanks for your attention ========================================================================== thanks for your answers i removed BackEndUtils.OverallLoader(); but error still exists i tried Teststr = Convert.ToString(Session["Co_ID"]); and error disappeared - but i don't know why that session is null in other areas that session works perfectly = such as a button in that form what is the matter? my web page markup is like this : <%@ Page Title="" Language="C#" MasterPageFile="~/Admin/AdminBackend.Master" AutoEventWireup="true" CodeBehind="Personel.aspx.cs" Inherits="Darman.Admin.Personel" Theme="DefaultTheme" %> ================================================================================= i put this code in a button like this : string Teststr = Convert.ToString(Session["Co_ID"]); when i press that button THIS code in page Load(POSTBACK) + IN Button_Click works perfectly and shows me 23 (my Co_ID) But when i run my page in browser (first time) this code in page load shows me null. why? thanks a lot

    Read the article

  • Are finalizers ever allowed to call other managed classes' methods?

    - by romkyns
    I used to be pretty sure the answer is "no", as explained in Overriding the Finalize method and Object.Finalize documentation. However, while randomly browsing through FileStream in Reflector, I found that it can actually call just such a method from a finalizer: private SafeFileHandle _handle; ~FileStream() { if (this._handle != null) { this.Dispose(false); } } protected override void Dispose(bool disposing) { try { ... } finally { if ((this._handle != null) && !this._handle.IsClosed) // <=== HERE { this._handle.Dispose(); // <=== AND HERE } [...] } } I started wondering whether this will always work due to the exact way in which it's written, and hence whether the "do not touch managed classes from finalizers" is just a guideline that can be broken given a good reason and the necessary knowledge to do it right. I dug a bit deeper and found out that the worst that can happen when the "rule" is broken is that the managed object being accessed had already been finalized, or may be getting finalized in parallel on a separate thread. So if the SafeFileHandle's finalizer didn't do anything that would cause a subsequent call to Dispose fail then the above should be fine... right? Question: so there might after all be situations in which a method on another managed class may be called reliably from a finalizer? I've always believed this to be false, but this code suggests that it's possible and that there can be good enough reasons to do it. Bonus: Observe that the SafeFileHandle will not even know it's being called from a finalizer, since this is just a normal call to Dispose(). The base class, SafeHandle, actually has two private methods, InternalDispose and InternalFinalize, and in this case InternalDispose will be called. Isn't this a problem? Why not?...

    Read the article

  • How does sizeof calculate the size of structures

    - by Gearoid Murphy
    I know that a char and an int are calculated as being 8 bytes on 32 bit architectures due to alignment, but I recently came across a situation where a structure with 3 shorts was reported as being 6 bytes by the sizeof operator. Code is as follows: #include <iostream> using namespace std ; struct IntAndChar { int a ; unsigned char b ; }; struct ThreeShorts { unsigned short a ; unsigned short b ; unsigned short c ; }; int main() { cout<<sizeof(IntAndChar)<<endl; // outputs '8' cout<<sizeof(ThreeShorts)<<endl; // outputs '6', I expected this to be '8' return 0 ; } Compiler : g++ (Debian 4.3.2-1.1) 4.3.2. This really puzzles me, why isn't alignment enforced for the structure containing 3 shorts?

    Read the article

  • InvalidOperationException when executing SqlCommand with transaction

    - by Serhat Özgel
    I have this code, running parallel in two separate threads. It works fine for a few times, but at some random point it throws InvalidOperationException: The transaction is either not associated with the current connection or has been completed. At the point of exception, I am looking inside the transaction with visual studio and verify its connection is set normally. Also command.Transaction._internalTransaction. _transactionState is set to Active and IsZombied property is set to false. This is a test application and I am using Thread.Sleep for creating longer transactions and causing overlaps. Why may the exception being thrown and what can I do about it? IDbCommand command = new SqlCommand("Select * From INFO"); IDbConnection connection = new SqlConnection(connectionString); command.Connection = connection; IDbTransaction transaction = null; try { connection.Open(); transaction = connection.BeginTransaction(); command.Transaction = transaction; command.ExecuteNonQuery(); // Sometimes throws exception Thread.Sleep(forawhile); // For overlapping transactions running in parallel transaction.Commit(); } catch (ApplicationException exception) { if (transaction != null) { transaction.Rollback(); } } finally { connection.Close(); }

    Read the article

  • Does std::multiset guarntee insertion order?

    - by Naveen
    I have a std::multiset which stores elements of class A. I have provided my own implementation of operator< for this class. My question is if I insert two equivalent objects into this multiset is their order guaranteed? For example, first I insert a object a1 into the set and then I insert an equivalent object a2 into this set. Can I expect the a1 to come before a2 when I iterate through the set? If no, is there any way to achieve this using multiset?

    Read the article

  • Java enums in generic type

    - by Marcin Cylke
    Hi, I'd like to create a generic enum-based mapper for IBatis. I'm doing this with the below code. This does have compile time errors, which I don't know how to fix. Maybe my solution is just plain wrong (keep in mind the use of IBatis), in such case please suggest something better. Any help appreciated. What I want to achieve is to define subsequent mappers as: public class XEnumTypeHandler extends CommonEnumTypeHandler<X> { } The current code: public class CommonEnumTypeHandler<T extends Enum> implements TypeHandlerCallback { public void setParameter(ParameterSetter ps, Object o) throws SQLException { if (o.getClass().isAssignableFrom(**T**)) { ps.setString(((**T**) o).value().toUpperCase()); } else throw new SQLException("Excpected ParameterType object than: " + o); } public Object getResult(ResultGetter rs) throws SQLException { Object o = valueOf(rs.getString()); if (o == null) throw new SQLException("Unknown parameter type: " + rs.getString()); return o; } public Object valueOf(String s) { for (T pt : T.**values()**) { if (pt.**value()**.equalsIgnoreCase(s)) return pt; } return null; } } I've added error markings to the above code, the error messages are in order: T cannot be resolved The method value() is undefined for the type T The method values() is undefined for the type T The method values() is undefined for the type T

    Read the article

  • Validating age field

    - by Marcelo
    Hi people, I'm trying to validate an age field in a form but I'm having some problem. First I tried to make sure that the field will not be send empty. I don't know JavaScript so I searched some scripts and adapted them to this: function isInteger (s) { var i; if (isEmpty(s)) if (isInteger.arguments.length == 1) return 0; else return (isInteger.arguments[1] == true); for (i = 0; i < s.length; i++) { var c = s.charAt(i); if (!isDigit(c)) return false; } return true; } function isEmpty(s) { return ((s == null) || (s.length == 0)) } function validate_required(field,alerttxt) { with (field) { if (value==null||value=="") { alert(alerttxt);return false; } else { return true; } } } function validate_form(thisform) { with (thisform) { if ((validate_required(age,"Age must be filled out!")==false) || isInteger(age,"Age must be and int number")==false)) {email.focus();return false;} } } //html part <form action="doador.php" onsubmit="return validate_form(this)" method="post"> It's working fine for empty fields, but if I type any letters or characters in age field, it'll be sent and saved a 0 in my database. Can anyone help me? Sorry for any mistake in English, and thanks in anvance for your help.

    Read the article

  • With NHibernate and Transaction do I rollback on commit failure or does it auto rollback on single c

    - by mattcodes
    I've built the following Dispose method for my Unit Of Work which essentially wraps the active NH session & transaction (transaction set as variable after opening session as to not be replaced if NH session gets new transaction after error) public void Dispose() { Func<ITransaction,bool> transactionStateOkayFunc = trans => trans != null && trans.IsActive && !trans.WasRolledBack; try { if(transactionStateOkayFunc(this.transaction)) { if (HasErrored) { transaction.Rollback(); } else { try { transaction.Commit(); } catch (Exception) { if(transactionStateOkayFunc(transaction)) transaction.Rollback(); throw; } } } } finally { if(transaction != null) transaction.Dispose(); if(session.IsOpen) session.Close(); } I can't help feeling that code is a little bloated, will a transaction automatically rollback is a discrete Commit fails in the case of non-nested transactions? Will Commit or Rollback automatically Dipose the transaction? If not will Session.Close() automatically dispose the associated transaction?

    Read the article

  • Scheme: what are the benefits of letrec?

    - by Ixmatus
    While reading "The Seasoned Schemer" I've begun to learn about letrec. I understand what it does (can be duplicated with a Y-Combinator) but the book is using it in lieu of recurring on the already defined function operating on arguments that remain static. An example of an old function using the defined function recurring on itself (nothing special): (define (substitute new old lat) (cond ((null? l) '()) ((eq? (car l) old) (cons new (substitute new old (cdr l)))) (else (cons (car l) (substitute new old (cdr l)))))) Now for an example of that same function but using letrec: (define (substitute new old lat) (letrec ((replace (lambda (l) (cond ((null? l) '()) ((eq? (car l) old) (cons new (replace (cdr l)))) (else (cons (car l) (replace (cdr l)))))))) (replace lat))) Aside from being slightly longer and more difficult to read I don't know why they are rewriting functions in the book to use letrec. Is there a speed enhancement when recurring over a static variable this way because you don't keep passing it?? Is this standard practice for functions with arguments that remain static but one argument that is reduced (such as recurring down the elements of a list)? Some input from more experienced Schemers/LISPers would help!

    Read the article

  • Cannot launch 16-bit application anymore

    - by Nick Bedford
    I'm trying to debug and resolve some issues with a Win32 macro application written C++ however I'm having the strangest issue. I have to launch a 16-bit program and then simulate entering data into and have been using ShellExecute for over two years now. I haven't touched this actual code at all, but now it doesn't work. I'm doing ShellExecute(NULL, "open", exe_path.c_str(), NULL, "", SW_SHOWDEFAULT);. This has worked flawlessly for years but all of sudden, it stopped working. It gives me an ACCESS_DENIED error code. I've Googled and apparently this is a pretty common issue with launching 16-bit apps. The workstation XP SP2 environment hasn't changed at all, and it was actually working until I rebuilt a little while ago (I've rebuilt it before many times). The code is inside a window procedure function and when I take it out and launch the program in the WinMain function it works, but the code has to be in the window procedure... I've tried numerous alternatives but they all give the same issue. The biggest issue with this is it was working then all of a sudden decided it wasn't going to with no change to both code and environment! In fact, it was about half way through testing changes that it thought it'd stop working. Please help as I cannot do anything without the program launching. It's the first step in the code that I'm debugging!

    Read the article

< Previous Page | 375 376 377 378 379 380 381 382 383 384 385 386  | Next Page >