Search Results

Search found 42993 results on 1720 pages for 'static method'.

Page 379/1720 | < Previous Page | 375 376 377 378 379 380 381 382 383 384 385 386  | Next Page >

  • Communication between layers in an application

    - by Petar Minchev
    Hi guys! Let's assume we have the following method in the business layer. What's the best practice to tell the UI layer that something went wrong and give also the error message? Should the method return an empty String when it was OK, otherwise the error message, or should it throw another exception in the catch code wrapping the caught exception? If we choose the second variant then the UI should have another try,catch which is too much try,catch maybe. Here is a pseudocode for the first variant. public String updateSomething() { try { //Begin transaction here dataLayer.do1(); dataLayer.do2(); dataLayer.doN(); } catch(Exception exc) { //Rollback transaction code here return exc.message; } return ""; } Is this a good practice or should I throw another exception in the catch(then the method will be void)?

    Read the article

  • Find the right parameters for an event without using Design Mode in Visual Studio 2010

    - by Jason
    Is there a way to know what parameters are needed by an event in Visual Studio 2010? Let's say I have a DropDownList control and I want to bind a method to the "OnSelectedIndexChanged", I would do something like this In the ASPX File: <asp:DropDownList ID="lstMyList" runat="server" OnSelectedIndexChanged="lstMyList_SelectedIndexChanged"></asp:DropDownList> In the codebehind: protected void lstMyList_SelectedIndexChanged(object sender, EventArgs e) { ... } Is there a way to know what parameters the method needs? (In this case, an object for the sender and an EventArgs parameter for the event.) I know you can easily create the method by double-clicking the right event in Design Mode, but it does a mess with your code so I prefer not to use it. Thanks!

    Read the article

  • UIViewScrollviw UITableView subview scrolling. IOS

    - by user1484810
    I have a UIScrollview with a UITableview subview. The UIScrollview scrolls the UITableView horizontally. The UITable view naturally scrolls up and down. If a user places their finger on the UitableView, and moves (swipes) horizontally, The delegate method below is invoked (void)scrollViewDidScroll:(UIScrollView *)scrollView with scrollView isEqual theUIScrollView If the user lifts their finger and places it back down on the UITableView and moves in a vertical direction The delegate method below is invoked (void)scrollViewDidScroll:(UIScrollView *)scrollView with scrollView isEqual = theUITable If however the user places their finger and moves in a horizontally (void)scrollViewDidScroll:(UIScrollView *)scrollView with scrollView isEqual theUIScrollView If the user then moves the finger (without lifting it) in a vertical direction. delegate method scrollViewDidScroll is not invoked at all. (The reverse is true too.) I note that the "Pulse News" app seems to behave in the above manner.. Ultimately I want to figure out how to get the UITableView and UIScrollview moving in a "unidirectional" fashion, with one finger kept on the screen. Thanks...

    Read the article

  • How bad is opening and closing a SQL connection for several times? What is the exact effect?

    - by Eren
    For example, I need to fill lots of DataTables with SQLDataAdapter's Fill() method: DataAdapter1.Fill(DataTable1); DataAdapter2.Fill(DataTable2); DataAdapter3.Fill(DataTable3); DataAdapter4.Fill(DataTable4); DataAdapter5.Fill(DataTable5); .... .... Even all the dataadapter objects use the same SQLConnection, each Fill method will open and close the connection unless the connection state is already open before the method call. What I want to know is how does unnecessarily opening and closing SQLConnections affect the performance of the application. How much does it need to scale to see the bad effects of this problem (100,000s of concurrent users?). In a mid-size website (daily 50000 users) does it worth bothering and searching for all the Fill() calls, keeping them together in the code and opening the connection before any Fill() call and closing afterwards?

    Read the article

  • Limit TCP requests per IP

    - by asmo
    Hello! I'm wondering how to limit the TCP requests per client (per specific IP) in Java. For example, I would like to allow a maximum of X requests per Y seconds for each client IP. I thought of using static Timer/TimerTask in combination with a HashSet of temporary restricted IPs. private static final Set<InetAddress> restrictedIPs = Collections.synchronizedSet(new HashSet<InetAddress>()); private static final Timer restrictTimer = new Timer(); So when a user connects to the server, I add his IP to the restricted list, and start a task to unrestrict him in X seconds. restrictedIPs.add(socket.getInetAddress()); restrictTimer.schedule(new TimerTask() { public void run() { restrictedIPs.remove(socket.getInetAddress()); } }, MIN_REQUEST_INTERVAL); My problem is that at the time the task will run, the socket object may be closed, and the remote IP address won't be accessible anymore... Any ideas welcomed! Also, if someone knows a Java-framework-built-in way to achieve this, I'd really like to hear it.

    Read the article

  • printing using one '\n'

    - by Alex
    I am pretty sure all of you are familiar with the concept of the Big4, and I have several stuffs to do print in each of the constructor, assignment, destructor, and copy constructor. The restriction is this: I CAN'T use more than one newline (e.g., ƒn or std::endl) in any method I can have a method called print, so I am guessing print is where I will put that precious one and only '\n', my problem is that how can the method print which prints different things on each of the element I want to print in each of the Big4? Any idea? Maybe overloading the Big4?

    Read the article

  • java: "downcasting" to new object / opposite of slicing

    - by rhavin
    Sorry, i really dont know how to make a headline for that question; maybe there is a name for what im trying to do that i dont know, but i can explain it with some code: Guess you have a class that unfortunately neither has a copy-constructor nor a public static copy method. class A { private int i; // <- private, cant access String x; // <- even worse: cant access unless in same pkg! /* … other stuff, ctor, etc. … */ public A clone() { A a = new A(); a.i = i; a.x = x; return x; } } Guess further, there is some function that returns an object of that class: public static A someFn(x,y,z); Now the problem: I want to derive from that class to add some functionality. Unfortunately, i neither have a sizeof in java nor a cc or static copy method. So when i do a class B extends A { protected w; public B clone() { /* as usual */ } } then i can clone my B and get a new one, but how can i convert the returned A from someFn() into a B. Is there anyway to do the opposite of slicing in java? if i clone it, it's still an A, and i cant copy it field by field. This is all simple in c++, but how to do this in Java?

    Read the article

  • Java - how to tell class of an object?

    - by lkm
    Given a method that accepts as a parameter a certain supertype. Is there any way, within that method, to determine the actual class of the object that was passed to it? I.e. if a subtype of the allowable parameter was actually passed, is there a way to find out which type it is? If this isn't possible can someone explain why not (from a language design perspective)? Thanks Update: just to make sure I was clear void doSomething(MyType myType) { //determine if myType is MyType OR one of its subclasses } Since the method signature specifies the parameter as being MyType, then how can one tell if the object is actually a subtype of MyType (and which one).

    Read the article

  • rspec mocks: verify expectations in it "should" methods?

    - by Derick Bailey
    I'm trying to use rspec's mocking to setup expectations that I can verify in the it "should" methods... but I don't know how to do this... when i call the .should_receive methods on the mock, it verifies the expected call as soon as the before :all method exits. here's a small example: describe Foo, "when doing something" do before :all do Bar.should_recieve(:baz) foo = Foo.new foo.create_a_Bar_and_call_baz end it "should call the bar method" do # ??? what do i do here? end end How can i verify the expected call in the 'it "should"' method? do i need to use mocha or another mocking framework instead of rspec's? or ???

    Read the article

  • How do we name test methods where we are checking for more than one condition?

    - by Sandbox
    I follow the technique specified in Roy Osherove's The Art Of Unit Testing book while naming test methods - MethodName_Scenario_Expectation. It suits perfectly well for my 'unit' tests. But,for tests that I write in 'controller' or 'coordinator' class, there isn't necessarily a method which I want to test. For these tests, I generate multiple conditions which make up one scenario and then I verify the expectation. For example, I may set some properties on different instances, generate an event and then verify that my expectation from controller/coordinator is being met. Now, my controller handles events using a private event handler. Here my scenario is that, I set some properties, say 3 condition1,condition2 and condition3 Also, my scenario includes an event is raised I don't have a method name as my event handler is private. How do I name such a test method?

    Read the article

  • How to avoid automatic renaming of sub signature parameters in visual basic 6.

    - by systempuntoout
    In Visual basic 6, i declare a sub like this: Private Sub test1(ByRef XmlFooOutput As String) ... End Sub after that, i declare another sub like the following one: Private Sub test2(ByRef xmlFooOutput As String) ... End Sub automagically, the first method is transformed in: Private Sub test1(ByVal xmlFooOutput As String) ... End Sub so the XmlFooOutput parameter is transformed in xmlFooOutput. This is a pretty dangerous feature because, method like those could be mapped to different XSL presentation files that read XML values through Xpath. So when test1 parameter is renamed, XSL bound to test1 method goes broken because Xpath point to XmlFooOuput but the correct value is now in xmlFooOutput. Is it possible to remove this weird feature? I'm using microsoft visual basic 6.0 (SP6). This question has some duplicate: http://stackoverflow.com/questions/1064858/stop-visual-basic-6-from-changing-my-casing http://stackoverflow.com/questions/248760/vb6-editor-changing-case-of-variable-names from what i see, there's no practical solution to disable this Intellisense evil feature.

    Read the article

  • What is the easiest way to get the property value from a passed lambda expression in an extension me

    - by Andrew Siemer
    I am writing a dirty little extension method for HtmlHelper so that I can say something like HtmlHelper.WysiwygFor(lambda) and display the CKEditor. I have this working currently but it seems a bit more cumbersome than I would prefer. I am hoping that there is a more straight forward way of doing this. Here is what I have so far. public static MvcHtmlString WysiwygFor<TModel, TProperty>(this HtmlHelper<TModel> helper, Expression<Func<TModel, TProperty>> expression) { return MvcHtmlString.Create(string.Concat("<textarea class=\"ckeditor\" cols=\"80\" id=\"", expression.MemberName(), "\" name=\"editor1\" rows=\"10\">", GetValue(helper, expression), "</textarea>")); } private static string GetValue<TModel, TProperty>(HtmlHelper<TModel> helper, Expression<Func<TModel, TProperty>> expression) { MemberExpression body = (MemberExpression)expression.Body; string propertyName = body.Member.Name; TModel model = helper.ViewData.Model; string value = typeof(TModel).GetProperty(propertyName).GetValue(model, null).ToString(); return value; } private static string MemberName<T, V>(this Expression<Func<T, V>> expression) { var memberExpression = expression.Body as MemberExpression; if (memberExpression == null) throw new InvalidOperationException("Expression must be a member expression"); return memberExpression.Member.Name; } Thanks!

    Read the article

  • How should I declare default values for instance variables in Python?

    - by int3
    Should I give my class members default values like this: class Foo: num = 1 or like this? class Foo: def __init__(self): self.num = 1 In this question I discovered that in both cases, bar = Foo() bar.num += 1 is a well-defined operation. I understand that the first method will give me a class variable while the second one will not. However, if I do not require a class variable, but only need to set a default value for my instance variables, are both methods equally good? Or one of them more 'pythonic' than the other? One thing I've noticed is that in the Django tutorial, they use the second method to declare Models. Personally I think the second method is more elegant, but I'd like to know what the 'standard' way is.

    Read the article

  • Get more error information from unhandled error

    - by Andrew Simpson
    I am using C# in a desktop application. I am calling a DLL written in C that I do not have the source code for. Whenever I call this DLL I get an untrapped error which I trap in an UnhandledException event/delegate. The error is : object reference not set to an instance of an object But the stack trace is empty. When I Googled this the info back was that the error was being hanlded eleswhere and then rethrown. But this can only be in the DLL I do not have the source code for. So, is there anyway I can get more info about this error? This is my code... in program.cs... AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(CurrentDomain_UnhandledException); static void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e) { try { Exception _ex = (Exception)e.ExceptionObject; //the stact trace property is empty here.. } finally { Application.Exit(); } } My DLL... [DllImport("AutoSearchDevice.dll", EntryPoint = "Start", ExactSpelling = false, CallingConvention = CallingConvention.StdCall)] public static extern int Start(int ASD_HANDLE); An I call it like so: public static void AutoSearchStart() { try { Start(m_pASD); } catch (Exception ex) { } }

    Read the article

  • Objetive C - Calling Methods in objects.

    - by Mace
    I'm new to Objective C, and I seem to be struggling with accessing a method of an object I created. I'm checking out the documentation , but I'm not entirely sure tha tthis is a job for a delegate. For example I have an object (1) that creates another object (2). I can access a method of the object (2) after I create it, but I can't access it from a method of object (1). I get a error that the object was not defined in this scope. If anyone can help I greatly appreciate it. I just need a nudge in the right direction so that I can at least get a grasp on how to think about the interaction between the objects.

    Read the article

  • Exception Handling in MVP Passive View

    - by ilmatte
    Hello, I'm wondering what's the preferred way to manage exceptions in an MVP implemented with a Passive View. There's a discussion in my company about putting try/catch blocks in the presenter or only in the view. In my opinion the logical top level caller is the presenter (even if the actual one is the view). Moreover I can test the presenter and not the view. This is the reason why I prefer to define a method in the view interface: IView.ShowError(error) and invoke it from the catch blocks in the presenter: try { } catch (Exception exception) { ...log exception... view.ShowError("An error occurred") } In this way the developers of future views can safely forget to implement exception handling but the IView interface force them to implement a ShowError method. The drawback is that if I want to feel completely safe I need to add redundant try/catch blocks in the view. The other way would be to add try catch blocks only in the views and not introducing the showerror method in the view interface. What do you suggest?

    Read the article

  • Dynamically adding @property in python

    - by rz
    I know that I can dynamically add an instance method to an object by doing something like: import types def my_method(self): # logic of method # ... # instance is some instance of some class instance.my_method = types.MethodType(my_method, instance) Later on I can call instance.my_method() and self will be bound correctly and everything works. Now, my question: how to do the exact same thing to obtain the behavior that decorating the new method with @property would give? I would guess something like: instance.my_method = types.MethodType(my_method, instance) instance.my_method = property(instance.my_method) But, doing that instance.my_method returns a property object.

    Read the article

  • Proper structure for many test cases in Python with unittest

    - by mellort
    I am looking into the unittest package, and I'm not sure of the proper way to structure my test cases when writing a lot of them for the same method. Say I have a fact function which calculates the factorial of a number; would this testing file be OK? import unittest class functions_tester(unittest.TestCase): def test_fact_1(self): self.assertEqual(1, fact(1)) def test_fact_2(self): self.assertEqual(2, fact(2)) def test_fact_3(self): self.assertEqual(6, fact(3)) def test_fact_4(self): self.assertEqual(24, fact(4)) def test_fact_5(self): self.assertFalse(1==fact(5)) def test_fact_6(self): self.assertRaises(RuntimeError, fact, -1) #fact(-1) if __name__ == "__main__": unittest.main() It seems sloppy to have so many test methods for one method. I'd like to just have one testing method and put a ton of basic test cases (ie 4! ==24, 3!==6, 5!==120, and so on), but unittest doesn't let you do that. What is the best way to structure a testing file in this scenario? Thanks in advance for the help.

    Read the article

  • Sharing a COM port over TCP

    - by guinness
    What would be a simple design pattern for sharing a COM port over TCP to multiple clients? For example, a local GPS device that could transmit co-ordinates to remote hosts in realtime. So I need a program that would open the serial port and accept multiple TCP connections like: class Program { public static void Main(string[] args) { SerialPort sp = new SerialPort("COM4", 19200, Parity.None, 8, StopBits.One); Socket srv = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); srv.Bind(new IPEndPoint(IPAddress.Any, 8000)); srv.Listen(20); while (true) { Socket soc = srv.Accept(); new Connection(soc); } } } I would then need a class to handle the communication between connected clients, allowing them all to see the data and keeping it synchronized so client commands are received in sequence: class Connection { static object lck = new object(); static List<Connection> cons = new List<Connection>(); public Socket socket; public StreamReader reader; public StreamWriter writer; public Connection(Socket soc) { this.socket = soc; this.reader = new StreamReader(new NetworkStream(soc, false)); this.writer = new StreamWriter(new NetworkStream(soc, true)); new Thread(ClientLoop).Start(); } void ClientLoop() { lock (lck) { connections.Add(this); } while (true) { lock (lck) { string line = reader.ReadLine(); if (String.IsNullOrEmpty(line)) break; foreach (Connection con in cons) con.writer.WriteLine(line); } } lock (lck) { cons.Remove(this); socket.Close(); } } } The problem I'm struggling to resolve is how to facilitate communication between the SerialPort instance and the threads. I'm not certain that the above code is the best way forward, so does anybody have another solution (the simpler the better)?

    Read the article

  • Multiple Asserts in a Unit Test

    - by whatispunk
    I've just finished reading Roy Osherove's "The Art of Unit Testing" and I am trying to adhere to the best practices he lays out in the book. One of those best practices is to not use multiple asserts in a test method. The reason for this rule is fairly clear to me, but it makes me wonder... If I have a method like: public Foo MakeFoo(int x, int y, int z) { Foo f = new Foo(); f.X = x; f.Y = y; f.Z = z; return f; } Must I really write individual unit tests to assert each separate property of Foo is initialized with the supplied value? Is it really all that uncommon to use multiple asserts in a test method? FYI: I am using MSTest.

    Read the article

  • Custom button with property as StaticResource

    - by alin
    I am trying to achieve the following thing: use an svg image into a custom button. In order to do this I created a Custom button: public class MainButton : Button { static MainButton() { DefaultStyleKeyProperty.OverrideMetadata(typeof(MainButton), new FrameworkPropertyMetadata(typeof(MainButton))); } public string Text { get { return (string)GetValue(TextProperty); } set { SetValue(TextProperty, value); } } public static readonly DependencyProperty TextProperty = DependencyProperty.Register("Text", typeof(string), typeof(MainButton), new UIPropertyMetadata("")); public object Image { get { return (object)GetValue(ImageProperty); } set { SetValue(ImageProperty, value); } } public static readonly DependencyProperty ImageProperty = DependencyProperty.Register("Image", typeof(object), typeof(MainButton), new UIPropertyMetadata("")); } I took a svg file, opened it in inkscape and saved it as xaml file. I opened Themes.xaml and added the created xaml image as a ControlTemplate And the button style is: Style TargetType="{x:Type local:MainButton}" <StackPanel Canvas.Top="12" Canvas.Left="0" Canvas.ZIndex="2" Width="80"> <ContentControl x:Name="Img" Template="{StaticResource Home}" /> </StackPanel> <StackPanel x:Name="spText" Canvas.Top="45" Canvas.Left="1" Canvas.ZIndex="1" Width="80"> <TextBlock x:Name="Txt" Text="{Binding Path=(local:MainButton.Text), RelativeSource ={RelativeSource FindAncestor, AncestorType ={x:Type Button}}}" VerticalAlignment="Center" HorizontalAlignment="Center" Foreground="White" FontSize="14"/> </StackPanel> ... As you can see I have hardcoded the StaticResource name I want to be able to have a binding with property Image on this Template, something like So that I can set the Image property of the button with the name of the StaticResource I want. For example, having beside "Home" image, another one "Back" I would have two buttons in MainWindow declared like this: Any advice is kindly taken. Thank you for your time.

    Read the article

  • Determining filetype of file in assets folder

    - by ChaimKut
    Question: How do you programmatically distinguish between directories and regular files in the assets folder? When using AssetManager to access files in the assets folder, it seems impossible to determine if a file is in fact a file or a directory. You get the list of files from the list method and then open the file using the open method. I thought perhaps using the openFd method to get the asset file descriptor (and then subsequently requesting the normal file descriptor) would provide me some information. But requesting the file descriptor for a directory results in an IOException (which makes sense since what would it mean for a directory to have a file descriptor...?). Currently I'm relying on that IOException (resulting from attemptng to open a directory in the assets folder) in order to determine if a file is in fact a directory. (Opening a regular file works just fine). This seems like a bad idea. Any other suggestions to distinguish between a file and a directory?

    Read the article

  • view is not rendered when returning ModelAndView

    - by adancu
    Hi, I have the following problem. I need to export a PDF in a controller The code below, where I return a View, works as expected. @RequestMapping(method = RequestMethod.GET) public View exportReport( @RequestParam(value = "userName", required = true) String userName, @RequestParam(value = "startDate", required = true) Date startDate, @RequestParam(value = "endDate", required = true) Date endDate) { /////////////////////////////////////////// return new TimeSheetReportPdfView(); } The problem occurs if I change the method to return a ModelAndView: @RequestMapping(method = RequestMethod.GET) public ModelAndView exportReport( @RequestParam(value = "userName", required = true) String userName, @RequestParam(value = "startDate", required = true) Date startDate, @RequestParam(value = "endDate", required = true) Date endDate) { /////////////////////////////////////////// return new ModelAndView(new TimeSheetReportPdfView(), model); } Now, the PDF is not exported, all I get is a blank page and nothing in the logs. Any help appreciated. Thanks.

    Read the article

  • Get annotations of return type in Java

    - by Apropos
    I'm using Spring MVC and am using aspects to advise my controllers. I'm running into one issue: controllers that return a value annotated with the @ResponseBody type. How are you able to find the annotations applied to the return type? @Around("myPointcut()") private Object checkAnnotations(ProceedingJoinPoint pjp) throws Throwable { Object result = pjp.proceed(); Method method = ((MethodSignature)pjp.getSignature()).getMethod(); System.out.println("Checking return type annotations."); for(Annotation annotation : method.getReturnType().getAnnotations()){ System.out.println(annotation.toString()); } System.out.println("Checking annotations on returned object."); for(Annotation annotation : result.getClass().getAnnotations()){ System.out.println(annotation.toString()); } return result; } Unfortunately, neither of these methods seem to have the desired effect. I can retrieve annotations on the type of object being returned, but not the ones being added at return time.

    Read the article

  • Java Concurrency in practice sample question

    - by andy boot
    I am reading "Java Concurrency in practice" and looking at the example code on page 51. This states that if a thread has references to a shared object then other threads may be able to access that object before the constructor has finished executing. I have tried to put this into practice and so I wrote this code thinking that if I ran it enough times a RuntimeException("World is f*cked") would occur. But it isn't doing. Is this a case of the Java spec not guaranting something but my particular implementation of java guaranteeing it for me? (java version: 1.5.0 on Ubuntu) Or have I misread something in the book? Code: (I expect an exception but it is never thrown) public class Threads { private Widgit w; public static void main(String[] s) throws Exception { while(true){ Threads t = new Threads(); t.runThreads(); } } private void runThreads() throws Exception{ new Checker().start(); w = new Widgit((int)(Math.random() * 100) + 1); } private class Checker extends Thread{ private static final int LOOP_TIMES = 1000; public void run() { int count = 0; for(int i = 0; i < LOOP_TIMES; i++){ try { w.checkMe(); count++; } catch(NullPointerException npe){ //ignore } } System.out.println("checked: "+count+" times out of "+LOOP_TIMES); } } private static class Widgit{ private int n; private int n2; Widgit(int n) throws InterruptedException{ this.n = n; Thread.sleep(2); this.n2 = n; } void checkMe(){ if (n != n2) { throw new RuntimeException("World is f*cked"); } } } }

    Read the article

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