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  • Any tips on reducing wxWidgets application code size?

    - by Billy ONeal
    I have written a minimal wxWidgets application: stdafx.h #define wxNO_REGEX_LIB #define wxNO_XML_LIB #define wxNO_NET_LIB #define wxNO_EXPAT_LIB #define wxNO_JPEG_LIB #define wxNO_PNG_LIB #define wxNO_TIFF_LIB #define wxNO_ZLIB_LIB #define wxNO_ADV_LIB #define wxNO_HTML_LIB #define wxNO_GL_LIB #define wxNO_QA_LIB #define wxNO_XRC_LIB #define wxNO_AUI_LIB #define wxNO_PROPGRID_LIB #define wxNO_RIBBON_LIB #define wxNO_RICHTEXT_LIB #define wxNO_MEDIA_LIB #define wxNO_STC_LIB #include <wx/wxprec.h> Minimal.cpp #include "stdafx.h" #include <memory> #include <wx/wx.h> class Minimal : public wxApp { public: virtual bool OnInit(); }; IMPLEMENT_APP(Minimal) DECLARE_APP(Minimal) class MinimalFrame : public wxFrame { DECLARE_EVENT_TABLE() public: MinimalFrame(const wxString& title); void OnQuit(wxCommandEvent& e); void OnAbout(wxCommandEvent& e); }; BEGIN_EVENT_TABLE(MinimalFrame, wxFrame) EVT_MENU(wxID_ABOUT, MinimalFrame::OnAbout) EVT_MENU(wxID_EXIT, MinimalFrame::OnQuit) END_EVENT_TABLE() MinimalFrame::MinimalFrame(const wxString& title) : wxFrame(0, wxID_ANY, title) { std::auto_ptr<wxMenu> fileMenu(new wxMenu); fileMenu->Append(wxID_EXIT, L"E&xit\tAlt-X", L"Terminate the Minimal Example."); std::auto_ptr<wxMenu> helpMenu(new wxMenu); helpMenu->Append(wxID_ABOUT, L"&About\tF1", L"Show the about dialog box."); std::auto_ptr<wxMenuBar> bar(new wxMenuBar); bar->Append(fileMenu.get(), L"&File"); fileMenu.release(); bar->Append(helpMenu.get(), L"&Help"); helpMenu.release(); SetMenuBar(bar.get()); bar.release(); CreateStatusBar(2); SetStatusText(L"Welcome to wxWidgets!"); } void MinimalFrame::OnAbout(wxCommandEvent& e) { wxMessageBox(L"Some text about me!", L"About", wxOK, this); } void MinimalFrame::OnQuit(wxCommandEvent& e) { Close(); } bool Minimal::OnInit() { std::auto_ptr<MinimalFrame> mainFrame( new MinimalFrame(L"Minimal wxWidgets Application")); mainFrame->Show(); mainFrame.release(); return true; } This minimal program weighs in at 2.4MB! (Executable compression drops this to half a MB or so but that's still HUGE!) (I must statically link because this application needs to be single-binary-xcopy-deployed, so both the C runtime and wxWidgets itself are set for static linking) Any tips on cutting this down? (I'm using Microsoft Visual Studio 2010)

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  • Custom Class to store the properties and passing the class object across the pages - ASP.NEt

    - by NLV
    Hello I've a requirement where i need to pass some objects across the pages. So i created a custom class with all the properties required and created a instance of it and assigned all the properties appropriately. I then put that object in the session and took it the other page. The problem is that even when i set the properties values to the class it is coming as null. I set a breakpoint in the getter-setter and saw that the value itself is coming as null. Code - public class GetDataSetForReports { private Table m_aspTable; private int m_reportID; private string m_accountKey; private string m_siteKey; private string m_imUserName; /// <summary> /// Asp Table containing the filters /// </summary> public Table aspTable { get { return m_aspTable; } set { m_aspTable = aspTable; } } /// <summary> /// Report ID /// </summary> public int reportID { get { return m_reportID; } set { m_reportID = reportID; } } /// <summary> /// All the accounts selected /// </summary> public string accountKey { get { return m_accountKey; } set { m_accountKey = accountKey; } } /// <summary> /// All the sites selected /// </summary> public string siteKey { get { return m_siteKey; } set { m_siteKey = siteKey; } } /// <summary> /// Current User Name /// </summary> public string imUserName { get { return m_imUserName; } set { m_imUserName = imUserName; } } } This is how i'm creating an instance in the page1 and trying to get it in the page2. Page1 Code //Add the objects to the GetDataSetForReports Class GetDataSetForReports oGetDSForReports = new GetDataSetForReports(); oGetDSForReports.aspTable = aspTable; oGetDSForReports.reportID = iReportID; oGetDSForReports.accountKey = AccountKey; oGetDSForReports.siteKey = Sitekey; oGetDSForReports.imUserName = this.imUserName.ToString(); But the values are not getting set at all. The values are not passing to the class (to the setter) at all. Am i making any OOPS blunder? Any ideas? NLV

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  • How does java implement inner class closures?

    - by thecoop
    In Java an anonymous inner class can refer to variables in it's local scope: public class A { public void method() { final int i = 0; doStuff(new Action() { public void doAction() { Console.printf(i); // or whatever } }); } } My question is how is this actually implemented? How does i get to the anonymous inner doAction implementation, and why does it have to be final?

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  • C++ vs. C++/CLI: Const qualification of virtual function parameters

    - by James McNellis
    [All of the following was tested using Visual Studio 2008 SP1] In C++, const qualification of parameter types does not affect the type of a function (8.3.5/3: "Any cv-qualifier modifying a parameter type is deleted") So, for example, in the following class hierarchy, Derived::Foo overrides Base::Foo: struct Base { virtual void Foo(const int i) { } }; struct Derived : Base { virtual void Foo(int i) { } }; Consider a similar hierarchy in C++/CLI: ref class Base abstract { public: virtual void Foo(const int) = 0; }; ref class Derived : public Base { public: virtual void Foo(int i) override { } }; If I then create an instance of Derived: int main(array<System::String ^> ^args) { Derived^ d = gcnew Derived; } it compiles without errors or warnings. When I run it, it throws the following exception and then terminates: An unhandled exception of type 'System.TypeLoadException' occurred in ClrVirtualTest.exe Additional information: Method 'Foo' in type 'Derived'...does not have an implementation. That exception seems to indicate that the const qualification of the parameter does affect the type of the function in C++/CLI (or, at least it affects overriding in some way). However, if I comment out the line containing the definition of Derived::Foo, the compiler reports the following error (on the line in main where the instance of Derived is instantiated): error C2259: 'Derived': cannot instantiate abstract class If I add the const qualifier to the parameter of Derived::Foo or remove the const qualifier from the parameter of Base::Foo, it compiles and runs with no errors. I would think that if the const qualification of the parameter affects the type of the function, I should get this error if the const qualification of the parameter in the derived class virtual function does not match the const qualification of the parameter in the base class virtual function. If I change the type of Derived::Foo's parameter from an int to a double, I get the following warning (in addition to the aforementioned error, C2259): warning C4490: 'override': incorrect use of override specifier; 'Derived::Foo' does not match a base ref class method So, my question is, effectively, does the const qualification of function parameters affect the type of the function in C++/CLI? If so, why does this compile and why are there no errors or warnings? If not, why is an exception thrown?

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  • COMException Problem

    - by Jack Harvin
    Wondering if anyone could help with my problem. Below is the code, and after the code an explination of where the exception is thrown. using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Web; using WatiN.Core; using System.Threading; using System.IO; namespace WindowsFormsApplication1 { public partial class Form1 : System.Windows.Forms.Form { public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { } private void button1_Click(object sender, EventArgs e) { Thread t = new Thread(createApplications); Settings.AutoStartDialogWatcher = false; t.SetApartmentState(System.Threading.ApartmentState.STA); t.Start(); } private void createApplications() { createApp("username", "password", "Test App", "This is just a test description", "http:/mysite.com"); } private void createApp(String username, String password, String appName, String description, String appUrl) { var currentBrowser = new IE("http://mysite.com/login/php"); currentBrowser.TextField(Find.ById("username")).TypeText(username); currentBrowser.TextField(Find.ById("password")).TypeText(password); currentBrowser.Button(Find.ById("submit")).Click(); currentBrowser.GoTo("http://mysite.com/createmusicapp.php"); currentBrowser.TextField(Find.ById("application_name")).TypeText(appName); currentBrowser.TextField(Find.ById("application_description")).TypeText(description); currentBrowser.TextField(Find.ById("application_url")).TypeText(appUrl); currentBrowser.RadioButton(Find.ById("client_application_desktop_1")).Click(); currentBrowser.RadioButton(Find.ById("client_application_is_writable_1")).Click(); WatiN.Core.Image captchaImage = currentBrowser.Div(Find.ById("recaptcha_image")).Image(Find.ByStyle("display", "block")); Form2 captcha = new Form2(captchaImage.Src); captcha.ShowDialog(); } } } The exception is thrown on this line: currentBrowser.TextField(Find.ById("username")).TypeText(username); BUT, it's thrown when it gets to this line: captcha.ShowDialog(); It logs in, and fills in the app details and Form2 loads fine, but once loaded, after around 2-3 seconds the exception happens. I am wondering if it's anything to do with the threads? But I wouldn't know how to solve it if it was. The complete exception thrown is: The object invoked has disconnected from its clients. (Exception from HRESULT: 0x80010108 (RPC_E_DISCONNECTED))

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  • Mocking a concrete class : templates and avoiding conditional compilation

    - by AshirusNW
    I'm trying to testing a concrete object with this sort of structure. class Database { public: Database(Server server) : server_(server) {} int Query(const char* expression) { server_.Connect(); return server_.ExecuteQuery(); } private: Server server_; }; i.e. it has no virtual functions, let alone a well-defined interface. I want to a fake database which calls mock services for testing. Even worse, I want the same code to be either built against the real version or the fake so that the same testing code can both: Test the real Database implementation - for integration tests Test the fake implementation, which calls mock services To solve this, I'm using a templated fake, like this: #ifndef INTEGRATION_TESTS class FakeDatabase { public: FakeDatabase() : realDb_(mockServer_) {} int Query(const char* expression) { MOCK_EXPECT_CALL(mockServer_, Query, 3); return realDb_.Query(); } private: // in non-INTEGRATION_TESTS builds, Server is a mock Server with // extra testing methods that allows mocking Server mockServer_; Database realDb_; }; #endif template <class T> class TestDatabaseContainer { public: int Query(const char* expression) { int result = database_.Query(expression); std::cout << "LOG: " << result << endl; return result; } private: T database_; }; Edit: Note the fake Database must call the real Database (but with a mock Server). Now to switch between them I'm planning the following test framework: class DatabaseTests { public: #ifdef INTEGRATION_TESTS typedef TestDatabaseContainer<Database> TestDatabase ; #else typedef TestDatabaseContainer<FakeDatabase> TestDatabase ; #endif TestDatabase& GetDb() { return _testDatabase; } private: TestDatabase _testDatabase; }; class QueryTestCase : public DatabaseTests { public: void TestStep1() { ASSERT(GetDb().Query(static_cast<const char *>("")) == 3); return; } }; I'm not a big fan of that compile-time switching between the real and the fake. So, my question is: Whether there's a better way of switching between Database and FakeDatabase? For instance, is it possible to do it at runtime in a clean fashion? I like to avoid #ifdefs. Also, if anyone has a better way of making a fake class that mimics a concrete class, I'd appreciate it. I don't want to have templated code all over the actual test code (QueryTestCase class). Feel free to critique the code style itself, too. You can see a compiled version of this code on codepad.

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  • How does this Singleton-like web class persists session data, even though session is not updated in

    - by Micah Burnett
    Ok, I've got this singleton-like web class which uses session to maintain state. I initially thought I was going to have to manipulate the session variables on each "set" so that the new values were updated in the session. However I tried using it as-is, and somehow, it remembers state. For example, if run this code on one page: UserContext.Current.User.FirstName = "Micah"; And run this code in a different browser tab, FirstName is displayed correctly: Response.Write(UserContext.Current.User.FirstName); Can someone tell me (prove) how this data is getting persisted in the session? Here is the class: using System; using System.Collections.Generic; using System.Linq; using System.Web; public class UserContext { private UserContext() { } public static UserContext Current { get { if (System.Web.HttpContext.Current.Session["UserContext"] == null) { UserContext uc = new UserContext(); uc.User = new User(); System.Web.HttpContext.Current.Session["UserContext"] = uc; } return (UserContext)System.Web.HttpContext.Current.Session["UserContext"]; } } private string HospitalField; public string Hospital { get { return HospitalField; } set { HospitalField = value; ContractField = null; ModelType = null; } } private string ContractField; public string Contract { get { return ContractField; } set { ContractField = value; ModelType = string.Empty; } } private string ModelTypeField; public string ModelType { get { return ModelTypeField; } set { ModelTypeField = value; } } private User UserField; public User User { get { return UserField; } set { UserField = value; } } public void DoSomething() { } } public class User { public int UserId { get; set; } public string FirstName { get; set; } } I added this to a watch, and can see that the session variable is definitely being set somewhere: (UserContext)System.Web.HttpContext.Current.Session["UserContext"]; As soon as a setter is called the Session var is immediately updated: set { HospitalField = value; //<--- here ContractField = null; ModelType = null; }

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  • CLR 4.0 inlining policy? (maybe bug with MethodImplOptions.NoInlining)

    - by ControlFlow
    I've testing some new CLR 4.0 behavior in method inlining (cross-assembly inlining) and found some strage results: Assembly ClassLib.dll: using System.Diagnostics; using System; using System.Reflection; using System.Security; using System.Runtime.CompilerServices; namespace ClassLib { public static class A { static readonly MethodInfo GetExecuting = typeof(Assembly).GetMethod("GetExecutingAssembly"); public static Assembly Foo(out StackTrace stack) // 13 bytes { // explicit call to GetExecutingAssembly() stack = new StackTrace(); return Assembly.GetExecutingAssembly(); } public static Assembly Bar(out StackTrace stack) // 25 bytes { // reflection call to GetExecutingAssembly() stack = new StackTrace(); return (Assembly) GetExecuting.Invoke(null, null); } public static Assembly Baz(out StackTrace stack) // 9 bytes { stack = new StackTrace(); return null; } public static Assembly Bob(out StackTrace stack) // 13 bytes { // call of non-inlinable method! return SomeSecurityCriticalMethod(out stack); } [SecurityCritical, MethodImpl(MethodImplOptions.NoInlining)] static Assembly SomeSecurityCriticalMethod(out StackTrace stack) { stack = new StackTrace(); return Assembly.GetExecutingAssembly(); } } } Assembly ConsoleApp.exe using System; using ClassLib; using System.Diagnostics; class Program { static void Main() { Console.WriteLine("runtime: {0}", Environment.Version); StackTrace stack; Console.WriteLine("Foo: {0}\n{1}", A.Foo(out stack), stack); Console.WriteLine("Bar: {0}\n{1}", A.Bar(out stack), stack); Console.WriteLine("Baz: {0}\n{1}", A.Baz(out stack), stack); Console.WriteLine("Bob: {0}\n{1}", A.Bob(out stack), stack); } } Results: runtime: 4.0.30128.1 Foo: ClassLib, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null at ClassLib.A.Foo(StackTrace& stack) at Program.Main() Bar: ClassLib, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null at ClassLib.A.Bar(StackTrace& stack) at Program.Main() Baz: at Program.Main() Bob: ClassLib, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null at Program.Main() So questions are: Why JIT does not inlined Foo and Bar calls as Baz does? They are lower than 32 bytes of IL and are good candidates for inlining. Why JIT inlined call of Bob and inner call of SomeSecurityCriticalMethod that is marked with the [MethodImpl(MethodImplOptions.NoInlining)] attribute? Why GetExecutingAssembly returns a valid assembly when is called by inlined Baz and SomeSecurityCriticalMethod methods? I've expect that it performs the stack walk to detect the executing assembly, but stack will contains only Program.Main() call and no methods of ClassLib assenbly, to ConsoleApp should be returned.

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  • remove duplicate code in java

    - by Anantha Kumaran
    class A extends ApiClass { public void duplicateMethod() { } } class B extends AnotherApiClass { public void duplicateMethod() { } } I have two classes which extend different api classes. The two class has some duplicate methods(same method repeated in both class) and how to remove this duplication? Edit The ApiClass is not under my control

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  • Android - OPENGL cube is NOT in the display

    - by Marc Ortiz
    I'm trying to display a square on my display and i can't. Whats my problem? How can I display it on the screen (center of the screen)? I let my code below! Here's my render class: public class GLRenderEx implements Renderer { private GLCube cube; Context c; GLCube quad; // ( NEW ) // Constructor public GLRenderEx(Context context) { // Set up the data-array buffers for these shapes ( NEW ) quad = new GLCube(); // ( NEW ) } // Call back when the surface is first created or re-created. @Override public void onSurfaceCreated(GL10 gl, EGLConfig config) { // NO CHANGE - SKIP } // Call back after onSurfaceCreated() or whenever the window's size changes. @Override public void onSurfaceChanged(GL10 gl, int width, int height) { // NO CHANGE - SKIP } // Call back to draw the current frame. @Override public void onDrawFrame(GL10 gl) { // Clear color and depth buffers using clear-values set earlier gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT); gl.glLoadIdentity(); // Reset model-view matrix ( NEW ) gl.glTranslatef(-1.5f, 0.0f, -6.0f); // Translate left and into the // screen ( NEW ) // Translate right, relative to the previous translation ( NEW ) gl.glTranslatef(3.0f, 0.0f, 0.0f); quad.draw(gl); // Draw quad ( NEW ) } } And here is my square class: public class GLCube { private FloatBuffer vertexBuffer; // Buffer for vertex-array private float[] vertices = { // Vertices for the square -1.0f, -1.0f, 0.0f, // 0. left-bottom 1.0f, -1.0f, 0.0f, // 1. right-bottom -1.0f, 1.0f, 0.0f, // 2. left-top 1.0f, 1.0f, 0.0f // 3. right-top }; // Constructor - Setup the vertex buffer public GLCube() { // Setup vertex array buffer. Vertices in float. A float has 4 bytes ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length * 4); vbb.order(ByteOrder.nativeOrder()); // Use native byte order vertexBuffer = vbb.asFloatBuffer(); // Convert from byte to float vertexBuffer.put(vertices); // Copy data into buffer vertexBuffer.position(0); // Rewind } // Render the shape public void draw(GL10 gl) { // Enable vertex-array and define its buffer gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer); // Draw the primitives from the vertex-array directly gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, vertices.length / 3); gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); } } Thanks!!

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  • How to change method signature in Netbeans Form Editor?

    - by Dzmitry Zhaleznichenka
    I create GUI in Netbeans Form Editor and want to change an auto-generated signature of one method, namely to add throws to it. How to do it? For instance, I have private void btOpenFileActionPerformed(java.awt.event.ActionEvent evt) {} And want to make it private void btOpenFileActionPerformed(java.awt.event.ActionEvent evt) throws AssertionError{} As the method signature is auto-generated, I cannot change it manually.

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  • Using auto-generated event handler in both class and it's superclass

    - by abatishchev
    I have a abstract class: public abstract class MySuperControl : UserControl { protected void Page_PreRender(object sender, EventArgs e) { // do something in super } } and a class that is code-behind for a designed UserControl: public partial class MyControl : MySuperControl { protected void Page_PreRender(object sender, EventArgs e) { // do something in class } } how do declare both of them to nest automated call?

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  • Can you pass by reference in Java?

    - by dbones
    Hi. Sorry if this sounds like a newbie question, but the other day a Java developer mentioned about passing a paramter by reference (by which it was ment just pass a Reference object) From a C# perspective I can pass a reference type by value or by reference, this is also true to value types I have written a noddie console application to show what i mean.. can i do this in Java? namespace ByRefByVal { class Program { static void Main(string[] args) { //Creating of the object Person p1 = new Person(); p1.Name = "Dave"; PrintIfObjectIsNull(p1); //should not be null //A copy of the Reference is made and sent to the method PrintUserNameByValue(p1); PrintIfObjectIsNull(p1); //the actual reference is passed to the method PrintUserNameByRef(ref p1); //<-- I know im passing the Reference PrintIfObjectIsNull(p1); Console.ReadLine(); } private static void PrintIfObjectIsNull(Object o) { if (o == null) { Console.WriteLine("object is null"); } else { Console.WriteLine("object still references something"); } } /// <summary> /// this takes in a Reference type of Person, by value /// </summary> /// <param name="person"></param> private static void PrintUserNameByValue(Person person) { Console.WriteLine(person.Name); person = null; //<- this cannot affect the orginal reference, as it was passed in by value. } /// <summary> /// this takes in a Reference type of Person, by reference /// </summary> /// <param name="person"></param> private static void PrintUserNameByRef(ref Person person) { Console.WriteLine(person.Name); person = null; //this has access to the orginonal reference, allowing us to alter it, either make it point to a different object or to nothing. } } class Person { public string Name { get; set; } } } If it java cannot do this, then its just passing a reference type by value? (is that fair to say) Many thanks Bones

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  • Impossible to use ref and out in Extension methods?

    - by Hun1Ahpu
    Why is it forbidden to call Extension method with ref modifier? This one is possible: public static void Change(ref TestClass testClass, TestClass testClass2) { testClass = testClass2; } And this one not: public static void ChangeWithExtensionMethod(this ref TestClass testClass, TestClass testClass2) { testClass = testClass2; } But why?

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  • Constructor versus setter injection

    - by Chris
    Hi, I'm currently designing an API where I wish to allow configuration via a variety of methods. One method is via an XML configuration schema and another method is through an API that I wish to play nicely with Spring. My XML schema parsing code was previously hidden and therefore the only concern was for it to work but now I wish to build a public API and I'm quite concerned about best-practice. It seems that many favor javabean type PoJo's with default zero parameter constructors and then setter injection. The problem I am trying to tackle is that some setter methods implementations are dependent on other setter methods being called before them in sequence. I could write anal setters that will tolerate themselves being called in many orders but that will not solve the problem of a user forgetting to set the appropriate setter and therefore the bean being in an incomplete state. The only solution I can think of is to forget about the objects being 'beans' and enforce the required parameters via constructor injection. An example of this is in the default setting of the id of a component based on the id of the parent components. My Interface public interface IMyIdentityInterface { public String getId(); /* A null value should create a unique meaningful default */ public void setId(String id); public IMyIdentityInterface getParent(); public void setParent(IMyIdentityInterface parent); } Base Implementation of interface: public abstract class MyIdentityBaseClass implements IMyIdentityInterface { private String _id; private IMyIdentityInterface _parent; public MyIdentityBaseClass () {} @Override public String getId() { return _id; } /** * If the id is null, then use the id of the parent component * appended with a lower-cased simple name of the current impl * class along with a counter suffix to enforce uniqueness */ @Override public void setId(String id) { if (id == null) { IMyIdentityInterface parent = getParent(); if (parent == null) { // this may be the top level component or it may be that // the user called setId() before setParent(..) } else { _id = Helpers.makeIdFromParent(parent,getClass()); } } else { _id = id; } } @Override public IMyIdentityInterface getParent() { return _parent; } @Override public void setParent(IMyIdentityInterface parent) { _parent = parent; } } Every component in the framework will have a parent except for the top level component. Using the setter type of injection, then the setters will have different behavior based on the order of the calling of the setters. In this case, would you agree, that a constructor taking a reference to the parent is better and dropping the parent setter method from the interface entirely? Is it considered bad practice if I wish to be able to configure these components using an IoC container? Chris

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  • Implementing a robust async stream reader for a console

    - by Jon
    I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a Stream in an event-based manner. The stream, in my scenario, is guaranteed to be a FileStream and there is also an associated StreamReader already present to leverage. The public interface of the class is this: public class MyStreamManager { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } Obviously this specific scenario has to do with a console's standard output. StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Since we are only handing off data from the stream to a consumer, and that consumer may well have inside knowledge about the size and/or format of these chunks, I want to call event subscribers exactly once for each chunk. Otherwise the abstraction breaks down and the subscribers have to buffer the incoming data and reconstruct the chunks themselves using said knowledge. This is much less convenient to the calling code, and detracts from the usefulness of my class. Edit: There are comments below correctly stating that since the data is coming from a stream, there is absolutely nothing that the receiver can infer about the structure of the data unless it is fully prepared to parse it. What I am trying to do here is leverage the "flush the output" "structure" that the owner of the console imparts while writing on it. I am prepared to assume (better: allow my caller to have the option to assume) that the OS will pass me the data written between two flushes of the stream in exactly one piece. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream (thus preserving the chunks). private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer, all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Maintains the "chunkiness" of the data; this allows the calling code to use inside knowledge of the data without doing any extra work Is almost agnostic to the buffer size (it will work correctly with any size buffer irrespective of the data being read) The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this.

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  • Ajax post request, an object that includes an array and other objects, can't be parsed correctly int

    - by Waheedi
    what i want is to get a proper parameter, if you see the parameter been logged you would tell there is something wrong my javasript: first run the runMe function Ajax: function() { var xmlhttp, bComplete = false; try { xmlhttp = new ActiveXObject("Msxml2.XMLHTTP"); } catch (e) { try { xmlhttp = new ActiveXObject("Microsoft.XMLHTTP"); } catch (e) { try { xmlhttp = new XMLHttpRequest(); } catch (e) { xmlhttp = false; }}} if (!xmlhttp) return null; this.connect = function(sURL, sMethod, sVars, fnDone) { if (!xmlhttp) return false; bComplete = false; sMethod = sMethod.toUpperCase(); try { if (sMethod == "GET") { xmlhttp.open(sMethod, sURL+"?"+sVars, true); sVars = ""; } else { xmlhttp.open(sMethod, sURL); xmlhttp.setRequestHeader("Method", "POST "+sURL+" HTTP/1.1"); xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded"); xmlhttp.setRequestHeader("Content-length", sVars.length); } xmlhttp.onreadystatechange = function(){ if (xmlhttp.readyState == 4 && !bComplete) { bComplete = true; fnDone(xmlhttp); }}; xmlhttp.send(sVars); } catch(z) { return false; } return true; }; return this; }, tOrigin: function(origin){ this.origin = origin; }, tObject: function(origins,url,apik){ this.origins=origins; //this is an array this.url=url; this.apik=apik; this.host= "http://localhost:3000/";//window.location.hostname; } runMe: function(){ var t = new tObject(['this','word','word me please','and me please','word','word','okay','word','go','go'],window.location.href,"helloapik"); // console.log(t); ajax = new Ajax(); ajax.connect("http://localhost:3000/","POST",JSON.stringify(t), callBackFunc) } this is what I'm getting in my rails server log Parameters: {"{\"origins\":"={"{\"origin\":\"this\"},{\"origin\":\"word\"},{\"origin\":\"word me please\"},{\"origin\":\"and me please\"},{\"origin\":\"word\"},{\"origin\":\"word\"},{\"origin\":\"word\"},{\"origin\":\"okay\"},{\"origin\":\"word\"},{\"origin\":\"go\"},{\"origin\":\"go\"}"={",\"url\":\"file:///Users/waheed/Desktop/untitled.html\",\"apik\":\"helloapik\",\"host\":\"http://localhost:3000/\"}"=nil}}}

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  • Sockets, Threads and Services in android, how to make them work together ?

    - by Spredzy
    Hi all, I am facing a probleme with threads and sockets I cant figure it out, if someone can help me please i would really appreciate. There are the facts : I have a service class NetworkService, inside this class I have a Socket attribute. I would like it be at the state of connected for the whole lifecycle of the service. To connect the socket I do it in a thread, so if the server has to timeout, it would not block my UI thread. Problem is, into the thread where I connect my socket everything is fine, it is connected and I can talk to my server, once this thread is over and I try to reuse the socket, in another thread, I have the error message Socket is not connected. Questions are : - Is the socket automatically disconnected at the end of the thread? - Is their anyway we can pass back a value from a called thread to the caller ? Thanks a lot, Here is my code public class NetworkService extends Service { private Socket mSocket = new Socket(); private void _connectSocket(String addr, int port) { Runnable connect = new connectSocket(this.mSocket, addr, port); new Thread(connect).start(); } private void _authentification() { Runnable auth = new authentification(); new Thread(auth).start(); } private INetwork.Stub mBinder = new INetwork.Stub() { @Override public int doConnect(String addr, int port) throws RemoteException { _connectSocket(addr, port); _authentification(); return 0; } }; class connectSocket implements Runnable { String addrSocket; int portSocket; int TIMEOUT=5000; public connectSocket(String addr, int port) { addrSocket = addr; portSocket = port; } @Override public void run() { SocketAddress socketAddress = new InetSocketAddress(addrSocket, portSocket); try { mSocket.connect(socketAddress, TIMEOUT); PrintWriter out = new PrintWriter(mSocket.getOutputStream(), true); out.println("test42"); Log.i("connectSocket()", "Connection Succesful"); } catch (IOException e) { Log.e("connectSocket()", e.getMessage()); e.printStackTrace(); } } } class authentification implements Runnable { private String constructFirstConnectQuery() { String query = "toto"; return query; } @Override public void run() { BufferedReader in; PrintWriter out; String line = ""; try { in = new BufferedReader(new InputStreamReader(mSocket.getInputStream())); out = new PrintWriter(mSocket.getOutputStream(), true); out.println(constructFirstConnectQuery()); while (mSocket.isConnected()) { line = in.readLine(); Log.e("LINE", "[Current]- " + line); } } catch (IOException e) {e.printStackTrace();} } }

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  • iphone Odd Problem when using a custom cell

    - by Brodie4598
    Please note where I have the NSLOG. All it is displaying in the log is the first three items in the nameSection. After some testing, I discovered it is displaying how many keys there are because if I add a key to the plist, it will log a fourth item in log. nameSection should be an array of the strings that make up the key array in the plist file. the plist file has 3 dictionaries, each with several arrays of strings. The code picks the dictionary I am working with correctly, then should use the array names as sections in the table and the strings en each array as what to display in each cell. so if the dictionary i am working with has 3 arrays, NSLOG will display 3 strings from the first array: 2010-05-01 17:03:26.957 Checklists[63926:207] string0 2010-05-01 17:03:26.960 Checklists[63926:207] string1 2010-05-01 17:03:26.962 Checklists[63926:207] string2 then stop with: 2010-05-01 17:03:26.963 Checklists[63926:207] * Terminating app due to uncaught exception 'NSRangeException', reason: '* -[NSCFArray objectAtIndex:]: index (3) beyond bounds (3)' if i added an array to the dictionary, it log 4 items instead of 3. I hope this explanation makes sense... -(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{ return [keys count]; } -(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger) section { NSString *key = [keys objectAtIndex:section]; NSArray *nameSection = [names objectForKey:key]; return [nameSection count]; } -(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { NSUInteger section = [indexPath section]; NSString *key = [keys objectAtIndex: section]; NSArray *nameSection = [names objectForKey:key]; static NSString *SectionsTableIdentifier = @"SectionsTableIdentifier"; static NSString *ChecklistCellIdentifier = @"ChecklistCellIdentifier "; ChecklistCell *cell = (ChecklistCell *)[tableView dequeueReusableCellWithIdentifier: SectionsTableIdentifier]; if (cell == nil) { NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"ChecklistCell" owner:self options:nil]; for (id oneObject in nib) if ([oneObject isKindOfClass:[ChecklistCell class]]) cell = (ChecklistCell *)oneObject; } NSUInteger row = [indexPath row]; NSDictionary *rowData = [self.keys objectAtIndex:row]; NSString *tempString = [[NSString alloc]initWithFormat:@"%@",[nameSection objectAtIndex:row]]; NSLog(@"%@",tempString); cell.colorLabel.text = [tempArray objectAtIndex:0]; cell.nameLabel.text = [tempArray objectAtIndex:1]; return cell; return cell; } - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath]; if (cell.accessoryType == UITableViewCellAccessoryNone) { cell.accessoryType = UITableViewCellAccessoryCheckmark; } else if (cell.accessoryType == UITableViewCellAccessoryCheckmark) { cell.accessoryType = UITableViewCellAccessoryNone; } [tableView deselectRowAtIndexPath:indexPath animated:NO]; } -(NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section{ NSString *key = [keys objectAtIndex:section]; return key; }

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  • Cpp some basic problems

    - by DevAno1
    Hello. My task was as follows : Create class Person with char*name and int age. Implement contructor using dynamic allocation of memory for variables, destructor, function init and friend function show. Then transform this class to header and cpp file and implement in other program. Ok so I've almost finished my Person class, but I get error after destructor. First question is how to write this properly ? #include <iostream> using namespace std; class Person { char* name; int age; public: int * take_age(); Person(){ int size=0; cout << "Give length of char*" << endl; cin >> size; name = new char[size]; age = 0; } ~Person(){ cout << "Destroying resources" << endl; delete *[] name; delete * take_age(); } friend void(Person &p); int * Person::take_age(){ return age; } void init(char* n, int a) { name = n; age = a; } void show(Person &p){ cout << "Name: " << p.name << "," << "age: " << p.age << endl; } }; int main(void) { Person *p = new Person; p->init("Mary", 25); p.show(); system("PAUSE"); return 0; } And now with header/implementation part : - do I need to introduce constructor in header/implementation files ? If yes - how? - my show() function is a friendly function. Should I take it into account somehow ? I already failed to return this task on my exam, but still I'd like to know how to implement it.

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  • Mouse event in Java

    - by Harish
    I am trying to move a JComponent say a label over a table.I am tracking this event using MouseMotionListener's mouseDragged method.This method perfectly helps me in tracking the item.Is there a way to track the mouse release after dragging is complete(.ie the dropping event). tktLabel1.addMouseMotionListener(new MouseMotionListener() { public void mouseDragged(MouseEvent arg0) { tktLabel1.setBounds(tktLabel1.getX() + arg0.getX(), tktLabel1.getY() + arg0.getY(), width, height); } public void mouseMoved(MouseEvent arg0) { } });

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  • Extending Enums, Overkill?

    - by CkH
    I have an object that needs to be serialized to an EDI format. For this example we'll say it's a car. A car might not be the best example b/c options change over time, but for the real object the Enums will never change. I have many Enums like the following with custom attributes applied. public enum RoofStyle { [DisplayText("Glass Top")] [StringValue("GTR")] Glass, [DisplayText("Convertible Soft Top")] [StringValue("CST")] ConvertibleSoft, [DisplayText("Hard Top")] [StringValue("HT ")] HardTop, [DisplayText("Targa Top")] [StringValue("TT ")] Targa, } The Attributes are accessed via Extension methods: public static string GetStringValue(this Enum value) { // Get the type Type type = value.GetType(); // Get fieldinfo for this type FieldInfo fieldInfo = type.GetField(value.ToString()); // Get the stringvalue attributes StringValueAttribute[] attribs = fieldInfo.GetCustomAttributes( typeof(StringValueAttribute), false) as StringValueAttribute[]; // Return the first if there was a match. return attribs.Length > 0 ? attribs[0].StringValue : null; } public static string GetDisplayText(this Enum value) { // Get the type Type type = value.GetType(); // Get fieldinfo for this type FieldInfo fieldInfo = type.GetField(value.ToString()); // Get the DisplayText attributes DisplayTextAttribute[] attribs = fieldInfo.GetCustomAttributes( typeof(DisplayTextAttribute), false) as DisplayTextAttribute[]; // Return the first if there was a match. return attribs.Length > 0 ? attribs[0].DisplayText : value.ToString(); } There is a custom EDI serializer that serializes based on the StringValue attributes like so: StringBuilder sb = new StringBuilder(); sb.Append(car.RoofStyle.GetStringValue()); sb.Append(car.TireSize.GetStringValue()); sb.Append(car.Model.GetStringValue()); ... There is another method that can get Enum Value from StringValue for Deserialization: car.RoofStyle = Enums.GetCode<RoofStyle>(EDIString.Substring(4, 3)) Defined as: public static class Enums { public static T GetCode<T>(string value) { foreach (object o in System.Enum.GetValues(typeof(T))) { if (((Enum)o).GetStringValue() == value.ToUpper()) return (T)o; } throw new ArgumentException("No code exists for type " + typeof(T).ToString() + " corresponding to value of " + value); } } And Finally, for the UI, the GetDisplayText() is used to show the user friendly text. What do you think? Overkill? Is there a better way? or Goldie Locks (just right)? Just want to get feedback before I intergrate it into my personal framework permanently. Thanks.

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