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  • ClassLoader exceptions being memoized

    - by Jim
    Hello, I am writing a classloader for a long-running server instance. If a user has not yet uploaded a class definition, I through a ClassNotFoundException; seems reasonable. The problem is this: There are three classes (C1, C2, and C3). C1 depends on C2, C2 depends on C3. C1 and C2 are resolvable, C3 isn't (yet). C1 is loaded. C1 subsequently performs an action that requires C2, so C2 is loaded. C2 subsequently performs an action that requires C3, so the classloader attempts to load C3, but can't resolve it, and an exception is thrown. Now C3 is added to the classpath, and the process is restarted (starting from the originally-loaded C1). The issue is, C2 seems to remember that C3 couldn't be loaded, and doesn't bother asking the classloader to find the class... it just re-throws the memoized exception. Clearly I can't reload C1 or C2 because other classes may have linked to them (as C1 has already linked to C2). I tried throwing different types of errors, hoping the class might not memoize them. Unfortunately, no such luck. Is there a way to prevent the loaded class from binding to the exception? That is, I want the classloader to be allowed to keep trying if it didn't succeed the first time. Thanks!

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  • How to Force an Exception from a Task to be Observed in a Continuation Task?

    - by Richard
    I have a task to perform an HttpWebRequest using Task<WebResponse>.Factory.FromAsync(req.BeginGetRespone, req.EndGetResponse) which can obviously fail with a WebException. To the caller I want to return a Task<HttpResult> where HttpResult is a helper type to encapsulate the response (or not). In this case a 4xx or 5xx response is not an exception. Therefore I've attached two continuations to the request task. One with TaskContinuationOptions OnlyOnRanToCompletion and the other with OnlyOnOnFaulted. And then wrapped the whole thing in a Task<HttpResult> to pick up the one result whichever continuation completes. Each of the three child tasks (request plus two continuations) is created with the AttachedToParent option. But when the caller waits on the returned outer task, an AggregateException is thrown is the request failed. I want to, in the on faulted continuation, observe the WebException so the client code can just look at the result. Adding a Wait in the on fault continuation throws, but a try-catch around this doesn't help. Nor does looking at the Exception property (as section "Observing Exceptions By Using the Task.Exception Property" hints here). I could install a UnobservedTaskException event handler to filter, but as the event offers no direct link to the faulted task this will likely interact outside this part of the application and is a case of a sledgehammer to crack a nut. Given an instance of a faulted Task<T> is there any means of flagging it as "fault handled"? Simplified code: public static Task<HttpResult> Start(Uri url) { var webReq = BuildHttpWebRequest(url); var result = new HttpResult(); var taskOuter = Task<HttpResult>.Factory.StartNew(() => { var tRequest = Task<WebResponse>.Factory.FromAsync( webReq.BeginGetResponse, webReq.EndGetResponse, null, TaskCreationOptions.AttachedToParent); var tError = tRequest.ContinueWith<HttpResult>( t => HandleWebRequestError(t, result), TaskContinuationOptions.AttachedToParent |TaskContinuationOptions.OnlyOnFaulted); var tSuccess = tRequest.ContinueWith<HttpResult>( t => HandleWebRequestSuccess(t, result), TaskContinuationOptions.AttachedToParent |TaskContinuationOptions.OnlyOnRanToCompletion); return result; }); return taskOuter; } with: private static HttpDownloaderResult HandleWebRequestError( Task<WebResponse> respTask, HttpResult result) { Debug.Assert(respTask.Status == TaskStatus.Faulted); Debug.Assert(respTask.Exception.InnerException is WebException); // Try and observe the fault: Doesn't help. try { respTask.Wait(); } catch (AggregateException e) { Log("HandleWebRequestError: waiting on antecedent task threw inner: " + e.InnerException.Message); } // ... populate result with details of the failure for the client ... return result; } (HandleWebRequestSuccess will eventually spin off further tasks to get the content of the response...) The client should be able to wait on the task and then look at its result, without it throwing due to a fault that is expected and already handled.

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  • WebClient.DownloadDataAsync is freezing my UI

    - by Matías
    Hi, I have in my Form constructor, after the InitializeComponent the following code: using (WebClient client = new WebClient()) { client.DownloadDataCompleted += new DownloadDataCompletedEventHandler(client_DownloadDataCompleted); client.DownloadDataAsync("http://example.com/version.txt"); } When I start my form, the UI doesn't appears till client_DownloadDataCompleted is raised. The client_DownloadDataCompleted method is empty, so there's no problem there. What I'm doing wrong? How is supposed to do this without freezing the UI? Thanks for your time. Best regards. FULL CODE: Program.cs using System; using System.Windows.Forms; namespace Lala { static class Program { /// <summary> /// The main entry point for the application. /// </summary> [STAThread] static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(new Form1()); } } } Form1.cs using System; using System.Net; using System.Windows.Forms; namespace Lala { public partial class Form1 : Form { WebClient client = new WebClient(); public Form1() { client.DownloadDataCompleted += new DownloadDataCompletedEventHandler(client_DownloadDataCompleted); client.DownloadDataAsync(new Uri("http://www.google.com")); InitializeComponent(); } void client_DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e) { textBox1.Text += "A"; } } partial class Form1 { /// <summary> /// Required designer variable. /// </summary> private System.ComponentModel.IContainer components = null; /// <summary> /// Clean up any resources being used. /// </summary> /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param> protected override void Dispose(bool disposing) { if (disposing && (components != null)) { components.Dispose(); } base.Dispose(disposing); } #region Windows Form Designer generated code /// <summary> /// Required method for Designer support - do not modify /// the contents of this method with the code editor. /// </summary> private void InitializeComponent() { this.button1 = new System.Windows.Forms.Button(); this.textBox1 = new System.Windows.Forms.TextBox(); this.SuspendLayout(); // // button1 // this.button1.Location = new System.Drawing.Point(12, 12); this.button1.Name = "button1"; this.button1.Size = new System.Drawing.Size(75, 23); this.button1.TabIndex = 0; this.button1.Text = "button1"; this.button1.UseVisualStyleBackColor = true; // // textBox1 // this.textBox1.Location = new System.Drawing.Point(12, 41); this.textBox1.Multiline = true; this.textBox1.Name = "textBox1"; this.textBox1.Size = new System.Drawing.Size(468, 213); this.textBox1.TabIndex = 1; // // Form1 // this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F); this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font; this.ClientSize = new System.Drawing.Size(492, 266); this.Controls.Add(this.textBox1); this.Controls.Add(this.button1); this.Name = "Form1"; this.Text = "Form1"; this.ResumeLayout(false); this.PerformLayout(); } #endregion private System.Windows.Forms.Button button1; private System.Windows.Forms.TextBox textBox1; } }

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  • jQuery modal dialog on ajaxStart event

    - by bdl
    I'm trying to use a jQuery UI modal dialog as a loading indicator via the ajaxStart, ajaxStop / ajaxComplete events. When the page fires, an Ajax handler loads some data, and the modal dialog shows just fine. However, it never hides or closes the dialog when the Ajax event is complete. It's a very small bit of code from the local server that is returned, so the actual Ajax event is very quick. Here's my actual code for the modal div: $("#modalwindow").dialog({ modal: true, height: 50, width: 200, zIndex: 999, resizable: false, title: "Please wait..." }) .bind("ajaxStart", function(){ $(this).show(); }) .bind("ajaxStop", function(){ $(this).hide(); }); The Ajax event is just a plain vanilla $.ajax({}) GET method call. Based on some searching here and Google, I've tried altering the ajaxStop handler to use $("#modalwindow").close(), $("#modalwindow").destroy(), etc. (#modalwindow referred to here as to give explicit context). I've also tried using the standard $("#modalwindow").dialog({}).ajaxStart(... as well. Should I be binding the events to a different object? Or calling them from within the $.ajax() complete event? I should mention, I'm testing on the latest IE8, FF 3.6 and Chrome. All have the same / effect.

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  • Ladder-like word game in Java

    - by sasquatch90
    I've found this question http://stackoverflow.com/questions/2844190/choosing-design-method-for-ladder-like-word-game and I would also like to do this kind of program. I've written some code but already have two issues. Here's what I already have : GRID : public class Grid { public Grid(){} public Grid( Element e ){} } ELEMENT : public class Element { final int INVISIBLE = 0; final int EMPTY = 1; final int FIRST_LETTER = 2; final int OTHER_LETTER = 3; private int state; private String letter; public Element(){} //empty block public Element(int state){ this("", 0); } //filled block public Element(String s, int state){ this.state = state; this.letter = s; } public static void changeState(int s){ } public int getState(){ return state; } public boolean equalLength(){ return true; } public boolean equalValue(){ return true; } @Override public String toString(){ return "["+letter+"]"; } } MAIN: import java.util.Scanner; public class Main { public static void main(String[] args){ Scanner sc = new Scanner(System.in); System.out.println("Height: "); while (!sc.hasNextInt()) { System.out.println("int, please!"); sc.next(); } final int height = sc.nextInt(); Grid[] game = new Grid[height]; for(int i = 1; i <= height; i++) { String s; do { System.out.println("Length " + i + ", please!"); s = sc.next(); } while (s.length() != i); Element[] line = new Element[s.length()+1]; Element single = null; String[] temp = null; //issue here temp = s.split(""); System.out.println("s.length: "+s.length()); System.out.println("temp.length: "+temp.length); // for(String str : temp){ System.out.println("str:"+str); } for (int k = 0 ; k < temp.length ; k++) { if( k == 0 ){ single = new Element(temp[k], 2); System.out.println("single1: "+single); } else{ single = new Element(temp[k], 3); System.out.println("single2: "+single); } line[k] = single; } for (Element l : line) { System.out.println("line:"+l); } //issue here game[i] = line; } // for (Grid g : game) { System.out.println(g); } } } And sample output for debug : Height: 3 Length 1, please! A s.length: 1 temp.length: 2 str: str:A single1: [] single2: [A] line:[] line:[A] Here's what I think it should work like. I grab a word from user. Next create Grid element for whole game. Then for each line I create Element[] array called line. I split the given text and here's the first problem. Why string.split() adds a whitespace ? You can see clearly in output that it is added for no reason. How can I get rid of it (now I had to add +1 to the length of line just to run the code). Continuing I'm throwing the splitted text into temporary String array and next from each letter I create Element object and throw it to line array. Apart of this empty space output looks fine. But next problem is with Grid. I've created constructor taking Element as an argument, but still I can't throw line as Grid[] elements because of 'incompatible types'. How can I fix that ? Am I even doing it right ? Maybe I should get rid of line as Element[] and just create Grid[][] ?

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  • WCF service consuming passively issued SAML token

    - by Neillyboy
    What is the best way to pass an existing SAML token from a website already authenticated via a passive STS? We have built an Identity Provider which is issuing passive claims to the website for authentication. We have this working. Now we would like to add some WCF services into the mix - calling them from the context of the already authenticated web application. Ideally we would just like to pass the SAML token on without doing anything to it (i.e. adding new claims / re-signing). All of the examples I have seen require the ActAs sts implementation - but is this really necessary? This seems a bit bloated for what we want to achieve. I would have thought a simple implementation passing the bootstrap token into the channel - using the CreateChannelActingAs or CreateChannelWithIssuedToken mechanism (and setting ChannelFactory.Credentials.SupportInteractive = false) to call the WCF service with the correct binding (what would that be?) would have been enough. We are using the Fabrikam example code as reference, but as I say, think the ActAs functionality here is overkill for what we are trying to achieve.

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  • Table header is not shown

    - by Vivien
    My error is that the table headers of my two tables are not shown. Right now I am setting the header with new JTable(data, columnNames). Here is an example which shows, my problem: public class Test extends JFrame { private static final long serialVersionUID = -4682396888922360841L; private JMenuBar menuBar; private JMenu mAbout; private JMenu mMain; private JTabbedPane tabbedPane; public SettingsTab settings = new SettingsTab(); private void addMenuBar() { menuBar = new JMenuBar(); mMain = new JMenu("Main"); mAbout = new JMenu("About"); menuBar.add(mMain); menuBar.add(mAbout); setJMenuBar(menuBar); } public void createTabBar() { tabbedPane = new JTabbedPane(JTabbedPane.TOP); tabbedPane.addTab("Settings", settings.createLayout()); add(tabbedPane); tabbedPane.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT); } private void makeLayout() { setTitle("Test"); setLayout(new BorderLayout()); setPreferredSize(new Dimension(1000, 500)); addMenuBar(); createTabBar(); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); pack(); setVisible(true); } public void start() { javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { makeLayout(); } }); } public static void main(String[] args) { Test gui = new Test(); gui.start(); } public class SettingsTab extends JPanel { public JScrollPane createLayout() { JPanel panel = new JPanel(new MigLayout("")); JScrollPane sp = new JScrollPane(panel); sp.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS); panel.add(table1(), "growx, wrap"); panel.add(Box.createRigidArea(new Dimension(0,10))); panel.add(table2()); // panel.add(Box.createRigidArea(new Dimension(0,10))); return sp; } public JPanel table1() { JPanel panel1 = new JPanel(); String[] columnNames = {"First Name", "Last Name"}; Object[][] data = { {"Kathy", "Smith"}, {"John", "Doe"}, {"Sue", "Black"}, {"Jane", "White"}, {"Joe", "Brown"}, {"John", "Doe"}, {"Sue", "Black"}, {"Jane", "White"}, {"Joe", "Brown"} }; final JTable table = new JTable(data, columnNames); tableProperties(table); panel1.add(table); panel1.setLayout(new BoxLayout(panel1, BoxLayout.Y_AXIS)); return panel1; } public JPanel table2() { JPanel panel1 = new JPanel(); String[] columnNames = {"First Name", "Last Name"}; Object[][] data = { {"Kathy", "Smith"}, {"John", "Doe"}, {"Sue", "Black"}, {"Jane", "White"}, {"Joe", "Brown"}, {"John", "Doe"}, {"Sue", "Black"}, {"Jane", "White"}, {"Joe", "Brown"} }; final JTable table = new JTable(data, columnNames); table.setPreferredScrollableViewportSize(new Dimension(500, 70)); table.setFillsViewportHeight(true); tableProperties(table); panel1.add(table); panel1.setLayout(new BoxLayout(panel1, BoxLayout.Y_AXIS)); return panel1; } public void tableProperties(JTable table) { table.setAutoResizeMode(JTable.AUTO_RESIZE_ALL_COLUMNS); table.repaint(); table.revalidate(); } } } Any recommendations what I am doing wrong?

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  • Editing list properties using DataGridview

    - by toom
    Ok, I have my custom class: public class FileItem : INotifyPropertyChanged { int id=0; string value=""; public int Id { get { return id; } set { id = value; Changed("Id"); } } public string Value { get { return value; } set { this.value = value; Changed("Value"); } } public event PropertyChangedEventHandler PropertyChanged; void Changed(string name) { if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs(name)); } } public BindingList<FileItem> FilesystemEntries = new BindingList<FileItem>(); And I have DatagridView1 with DataSource set to FilesystemEntries: binding.DataSource = FilesystemEntries; Already I can Add and remove rows - these chnages are reflected on collection. However, Value and Id are not saved into bidning list when i change them in DataGridView, id is always 0 and value is "". How can I make this work? Do I need to implement some interface to FileItem to allow editing properties? ReadOnly of DGV is set to false, same to all columns. Editing, Deleting and Changing are enabled.

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  • Databinding Textbox to Form.Text (title)

    - by MysticEarth
    I'm trying to bind a Textbox.Text to Form.Text (which sets the title of the form). The binding itself works. But, the title isn't updated until I move the entire form. How can I achieve Form.Text being updated without moving the form? I'd like Form.Text being updated directly when I type something in the Textbox. Edit; I set the title of the Form in a TextChanged event which is fired by a ToolStripTextbox: public partial class ProjectForm : Form { public ProjectForm() { // my code contains all sorts of code here, // but nothing that has something to do with the text. } } private void projectName_TextChanged_1(object sender, EventArgs e) { this.Text = projectName.TextBox.Text; } And the Databinding version: public partial class ProjectForm : Form { public ProjectForm() { this.projectName.TextBox.DataBindings.Add("Text", this, "Text", true, DataSourceUpdateMode.OnValidation); } } Edit 2: I see I forgot to mention something. Don't know if it adds anything, but my apllication is a MDI application. The part of the title that changes is: ApplicationName [THIS CHANGES, BUT ONLY AFTER MOVING/RESIZING]

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  • How do I create a selection list in ASP.NET MVC?

    - by Gary McGill
    I have a database table that records what publications a user is allowed to access. The table is very simple - it simply stores user ID/publication ID pairs: CREATE TABLE UserPublication (UserId INTEGER, PublicationID INTEGER) The presence of a record for a given user & publication means that the user has access; absence of a record implies no access. I want to present my admin users with a simple screen that allows them to configure which publications a user can access. I would like to show one checkbox for each of the possible publications, and check the ones that the user can currently access. The admin user can then check or un-check any number of publications and submit the form. There are various publication types, and I want to group the similarly-typed publications together - so I do need control over how the publications are presented (I don't want to just have a flat list). My view model obviously needs to have a list of all the publications (since I need to display them all regardless of the current selection), and I also need a list of the publications that the user currently has access to. (I'm not sure whether I'd be better off with a single list where each item includes the publication ID and a yes/no field?). But that's as far as I've got. I've really no idea how to go about binding this to some checkboxes. Where do I start?

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  • Simplest distributed persistent key/value store that supports primary key range queries

    - by StaxMan
    I am looking for a properly distributed (i.e. not just sharded) and persisted (not bounded by available memory on single node, or cluster of nodes) key/value ("nosql") store that does support range queries by primary key. So far closest such system is Cassandra, which does above. However, it adds support for other features that are not essential for me. So while I like it (and will consider using it of course), I am trying to figure out if there might be other mature projects that implement what I need. Specifically, for me the only aspect of value I need is to access it as a blob. For key, however, I need range queries (as in, access values ordered, limited by start and/or end values). While values can have structures, there is no need to use that structure for anything on server side (can do client-side data binding, flexible value/content types etc). For added bonus, Cassandra style storage (journaled, all sequential writes) seems quite optimal for my use case. To help filter out answers, I have investigated some alternatives within general domain like: Voldemort (key/value, but no ordering) and CouchDB (just sharded, more batch-oriented); and am aware of systems that are not quite distributed while otherwise qualifying (bdb variants, tokyo cabinet itself (not sure if Tyrant might qualify), redis (in-memory store only)).

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  • Service reference error when moving dev. environment from XP to W7

    - by Peter
    Hi, I am building an application and I am using web services for getting data from a server. It was working fine when I was developing on my XP machine but had to switch to Windows 7. On the new machine I grabbed the latest version of the code using sourcesafe. However, when I try to add a service reference in the solution or update an existing one I get the following error: There was an error downloading 'http://localhost:52490/Service/CustomerService.asmx'. The request failed with the error message: Server Error in '/' Application. Parser Error Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately. Parser Error Message: Could not create type 'Digital_Server.CustomerService'. Source Error <%@ WebService Language="vb" CodeBehind="CustomerService.asmx.vb" Class="Digital_Server.CustomerService" % Source File: /Service/CustomerService.asmxLine: 1 Version Information: Microsoft .NET Framework Version:2.0.50727.4927; ASP.NET Version:2.0.50727.4927 --. Metadata contains a reference that cannot be resolved: 'http://localhost:52490/Service/CustomerService.asmx'. An error occurred while receiving the HTTP response to http://localhost:52490/Service/CustomerService.asmx. This could be due to the service endpoint binding not using the HTTP protocol. This could also be due to an HTTP request context being aborted by the server (possibly due to the service shutting down). See server logs for more details. The underlying connection was closed: An unexpected error occurred on a receive. Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. An existing connection was forcibly closed by the remote host If the service is defined in the current solution, try building the solution and adding the service reference again. Does it has anything to do with the IIS or is it any configuration file I have to change in the solution? Any help is appreciated.

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  • Update UI from an event with a thread

    - by tyrone-tudehope
    Im working on a small application to try out an idea that I have. The idea is to periodically update the UI when event of some sort occurs. In the demo I've created, I'm updating a ProgressDialog every 2 seconds for 15 turns. The problem I am having, which I don't quite understand is that when an event is handled, I send a message to the handler which is supposed to update the message in the ProgressDialog. When this happens however, I get an exception which states that I can't update the UI from that thread. The following code appears in my Activity: ProgressDialog diag; String diagMessage = "Started loading..."; final static int MESSAGE_DATA_RECEIVED = 0; final static int MESSAGE_RECEIVE_COMPLETED = 1; final Handler handler = new Handler(){ @Override public void handleMessage(Message msg){ diag.setMessage(diagMessage); switch(msg.what){ case MESSAGE_DATA_RECEIVED: break; case MESSAGE_RECEIVE_COMPLETED: dismissDialog(); killDialog(); break; } } }; Boolean isRunning = false; /** * Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setupDialog(); if(isRunning){ showDialog(); } setContentView(R.layout.main); } void setupDialog(){ if(diag == null){ diag = new ProgressDialog(ThreadLoading.this); diag.setMessage(diagMessage); } } void showDialog(){ isRunning = true; if(diag != null && !diag.isShowing()){ diag.show(); } } void dismissDialog(){ if(diag != null && diag.isShowing()){ diag.dismiss(); } } void killDialog(){ isRunning = false; } public void onStart(){ super.onStart(); showDialog(); Thread background = new Thread(new Runnable(){ public void run(){ try{ final ThreadRunner tr = new ThreadRunner(); tr.setOnDataReceivedListener(new ThreadRunner.OnDataReceivedListener(){ public void onDataReceived(String message){ diagMessage = message; handler.handleMessage(handler.obtainMessage(MESSAGE_DATA_RECEIVED)); } }); tr.setOnDataDownloadCompletedEventListener(new ThreadRunner.OnDataDownloadCompletedListener(){ public void onDataDownloadCompleted(String message){ diagMessage = message; handler.handleMessage(handler.obtainMessage(MESSAGE_RECEIVE_COMPLETED)); } }); tr.runProcess(); } catch(Throwable t){ throw new RuntimeException(t); } } }); background.start(); } @Override public void onPause(){ super.onPause(); dismissDialog(); } For curiosity sake, here's the code for the ThreadRunner class: public interface OnDataReceivedListener { public void onDataReceived(String message); } public interface OnDataDownloadCompletedListener { public void onDataDownloadCompleted(String message); } private OnDataReceivedListener onDataReceivedEventListener; private OnDataDownloadCompletedListener onDataDownloadCompletedEventListener; int maxLoop = 15; int loopCount = 0; int sleepTime = 2000; public void setOnDataReceivedListener(OnDataReceivedListener onDataReceivedListener){ this.onDataReceivedEventListener = onDataReceivedListener; } public void setOnDataDownloadCompletedEventListener(OnDataDownloadCompletedListener onDataDownloadCompletedListener){ this.onDataDownloadCompletedEventListener = onDataDownloadCompletedListener; } public void runProcess(){ for(loopCount = 0; loopCount < maxLoop; loopCount++){ try{ Thread.sleep(sleepTime); onDataReceivedEventListener.onDataReceived(Integer.toString(loopCount)); } catch(Throwable t){ throw new RuntimeException(t); } } onDataDownloadCompletedEventListener.onDataDownloadCompleted("Download is completed"); } Am I missing something? The logic makes sense to me and it looks like everything should work, I'm using a handler to update the UI like it is recommended. Any help will be appreciated. Thanks, Tyrone P.S. I'm developing for Android 1.5

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  • Modern alternatives to Java

    - by Ralph
    I have been a Java developer for 14 years and have written an enterprise-level (~500 kloc) Swing application that uses most of the standard library APIs. Recently, I have become disappointed with the progress that the language has made to "modernize" itself, and am looking for an alternative for ongoing development. I have considered moving to the .NET platform, but I have issues with using something the only runs well in Windows (I know about Mono, but that is still far behind Microsoft). I also plan on buying a new Macbook Pro as soon as Apple releases their new rumored Arrandale-based machines and want to develop in an environment that will feel "at home" in Unix/Linux. I have considered using Python or Ruby, but the standard Java library is arguably the largest of any modern language. In JVM-based languages, I looked at Groovy, but am disappointed with its performance. Rumor has it that with the soon-to-be released JDK7, with its InvokeDynamic instruction, this will improve, but I don't know how much. Groovy is also not truly a functional language, although it provides closures and some of the "functional" features on collections. It does not embrace immutability. I have narrowed my search down to two JVM-based alternatives: Scala and Clojure. Each has its strengths and weaknesses. I am looking for opinions. I am not an expert at either of these languages; I have read 2 1/2 books on Scala and am currently reading Stu Halloway's book on Clojure. Scala is strongly statically typed. I know the dynamic language folks claim that static typing is a crutch for not doing unit testing, but it does provide a mechanism for compile-time location of a whole class of errors. Scala is more concise than Java, but not as much as Clojure. Scala's inter-operation with Java seems to be better than Clojure's, in that most Java operations are easier to do in Scala than in Clojure. For example, I can find no way in Clojure to create a non-static initialization block in a class derived from a Java superclass. For example, I like the Apache commons CLI library for command line argument parsing. In Java and Scala, I can create a new Options object and add Option items to it in an initialization block as follows (Java code): final Options options = new Options() { { addOption(new Option("?", "help", false, "Show this usage information"); // other options } }; I can't figure out how to the same thing in Clojure (except by using (doit...)), although that may reflect my lack of knowledge of the language. Clojure's collections are optimized for immutability. They rarely require copy-on-write semantics. I don't know if Scala's immutable collections are implemented using similar algorithms, but Rich Hickey (Clojure's inventor) goes out of his way to explain how that language's data structures are efficient. Clojure was designed from the beginning for concurrency (as was Scala) and with modern multi-core processors, concurrency takes on more importance, but I occasionally need to write simple non-concurrent utilities, and Scala code probably runs a little faster for these applications since it discourages, but does not prohibit, "simple" mutability. One could argue that one-off utilities do not have to be super-fast, but sometimes they do tasks that take hours or days to complete. I know that there is no right answer to this "question", but I thought I would open it up for discussion. Are there other JVM-based languages that can be used for enterprise level development?

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  • Problems manipulating strings through a stdcall to a dll

    - by ibiza
    I need to create a C++ dll that will be called from another program through stdcall. What is needed : the caller program will pass an array of string to the dll and the dll should change the string values in the array. The caller program will then continue to work with these string values that came from the dll. I made a simple test project and I am obviously missing something... Here is my test C++ dll : #ifndef _DLL_H_ #define _DLL_H_ #include <string> #include <iostream> struct strStruct { int len; char* string; }; __declspec (dllexport) int __stdcall TestFunction(strStruct* s) { std::cout << "Just got in dll" << std::endl; std::cout << s[0].string << std::endl; //////std::cout << s[1].string << std::endl; /* char str1[] = "foo"; strcpy(s[0].string, str1); s[0].len = 3; char str2[] = "foobar"; strcpy(s[1].string, str2); s[1].len = 6; */ //std::cout << s[0].string << std::endl; //std::cout << s[1].string << std::endl; std::cout << "Getting out of dll" << std::endl; return 1; } #endif and here is a simple C# program that I am using to test my test dll : using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Runtime.InteropServices; namespace TestStr { class Program { [DllImport("TestStrLib.dll", CharSet = CharSet.Ansi, CallingConvention = CallingConvention.StdCall)] public static extern int TestFunction(string[] s); static void Main(string[] args) { string[] test = new string[2] { "a1a1a1a1a1", "b2b2b2b2b2" }; Console.WriteLine(test[0]); Console.WriteLine(test[1]); TestFunction(test); Console.WriteLine(test[0]); Console.WriteLine(test[1]); Console.ReadLine(); } } } And here is the output produced : a1a1a1a1a1 b2b2b2b2b2 Just got in dll b2b2b2b2b2 Getting out of dll a1a1a1a1a1 b2b2b2b2b2 I have some questions : 1) Why is it outputting the element in the second position of the array rather than in the first position?? 2) If I uncomment the line commented with ////// in the dll file, the program crashes. Why? 3) Obviously I wanted to do more things in the dll (the parts in /* */) than what it does right now, but I am blocked by the first 2 questions... Thanks for all your help

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  • evaluating cost/benefits of using extension methods in C# => 3.0

    - by BillW
    Hi, In what circumstances (usage scenarios) would you choose to write an extension rather than sub-classing an object ? < full disclosure : I am not an MS employee; I do not know Mitsu Furota personally; I do know the author of the open-source Componax library mentioned here, but I have no business dealings with him whatsoever; I am not creating, or planning to create any commercial product using extensions : in sum : this post is from pure intellectal curiousity related to my trying to (continually) become aware of "best practices" I find the idea of extension methods "cool," and obviously you can do "far-out" things with them as in the many examples you can in Mitsu Furota's (MS) blog postslink text. A personal friend wrote the open-source Componax librarylink text, and there's some remarkable facilities in there; but he is in complete command of his small company with total control over code guidelines, and every line of code "passes through his hands." While this is speculation on my part : I think/guess other issues might come into play in a medium-to-large software team situation re use of Extensions. Looking at MS's guidelines at link text, you find : In general, you will probably be calling extension methods far more often than implementing your own. ... In general, we recommend that you implement extension methods sparingly and only when you have to. Whenever possible, client code that must extend an existing type should do so by creating a new type derived from the existing type. For more information, see Inheritance (C# Programming Guide). ... When the compiler encounters a method invocation, it first looks for a match in the type's instance methods. If no match is found, it will search for any extension methods that are defined for the type, and bind to the first extension method that it finds. And at Ms's link text : Extension methods present no specific security vulnerabilities. They can never be used to impersonate existing methods on a type, because all name collisions are resolved in favor of the instance or static method defined by the type itself. Extension methods cannot access any private data in the extended class. Factors that seem obvious to me would include : I assume you would not write an extension unless you expected it be used very generally and very frequently. On the other hand : couldn't you say the same thing about sub-classing ? Knowing we can compile them into a seperate dll, and add the compiled dll, and reference it, and then use the extensions : is "cool," but does that "balance out" the cost inherent in the compiler first having to check to see if instance methods are defined as described above. Or the cost, in case of a "name clash," of using the Static invocation methods to make sure your extension is invoked rather than the instance definition ? How frequent use of Extensions would affect run-time performance or memory use : I have no idea. So, I'd appreciate your thoughts, or knowing about how/when you do, or don't do, use Extensions, compared to sub-classing. thanks, Bill

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  • Cannot access resource defined in app.xaml

    - by DerKlaus
    I am using Visual Studio 2010 RC1. I define a resource "Brush2" in app.xaml_: <Application x:Class="VideoThumbnails.App" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" StartupUri="MainWindow.xaml"> <Application.Resources> <RadialGradientBrush x:Key="Brush2" RadiusX="1" RadiusY="1" GradientOrigin="0.3,0.3"> <GradientStop Color="White" Offset="0"/> <GradientStop Color="#ffc0c0" Offset="1"/> </RadialGradientBrush> </Application.Resources> </Application> In my Mainwindow I am trying to use that resource: ... <Border Margin="4,2" BorderBrush="Black" BorderThickness="2" CornerRadius="4" ToolTip="{Binding Path=FullPath}" HorizontalAlignment="Stretch" Background="{StaticResource Brush2}"> ... No matter what I do it always raises an exception at runtime (Resource not found). I changed build action without success. How can I use resources defined in app.xaml?

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  • Why doesn't keyboard input work for a ScrollViewer when the child control has input focus?

    - by Ashley Davis
    Why doesn't keyboard input work for a ScrollViewer when the child control has input focus? This is the scenario. A WPF window opens. It sets the focus to a control that is embedded in a ScrollViewer. I hit the up and down and left and right keys. The ScrollViewer doesn't seem to handle the key events, anyone know why? This is the simplest possible example: <Window x:Class="WpfApplication1.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Window1" Height="300" Width="300" FocusManager.FocusedElement="{Binding ElementName=control}" > <Grid> <ScrollViewer HorizontalScrollBarVisibility="Auto" > <ItemsControl x:Name="control" Width="1000" Height="1000" /> </ScrollViewer> </Grid> </Window> When you start the app that contains this window, "control" appears to have the focus as I intended. Pressing the key seems to result in bubbling key events reaching the ScrollViewer (I checked for this using WPF Snoop). I can't work out why it doesn't respond to the input.

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  • Validating collection elements in WPF

    - by Chris
    I would like to know how people are going about validating collections in WPF. Lets say for example that I have an observable collection of ViewModels that I am binding to the items source of a grid, and the user can add new rows to the grid and needs to fill them. First of all I need to validate on each row to ensure that required fields of each ViewModel are filled in. This is fine and simple to do for each row. However, the second level of validation is on the collection as a whole. For example i want to ensure that no two rows of the collection have the same identifier, or that no two rows have the same name. Im basically checking for duplicate properties within different rows. I also have more complex conditions where I must ensure that there is at least one item within the collection that has some property set. How do I get a validation rule that would allow me to check these rules, validating on the whole collection rather than the individual items. I also want to print any validation error above the datagrid so that the user can fix the problem and the message will update or disappear as the user fixes each different rule. Anyone have any experience of the proper way to do this? Thanks Chris

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  • How to set WS-SecurityPolicy in an inbound CXF service in Mule?

    - by Brakara
    When configuring the service for handling UsernameToken and signatures, it's setup like this: <service name="serviceName"> <inbound> <cxf:inbound-endpoint address="someUrl" protocolConnector="httpsConnector" > <cxf:inInterceptors> <spring:bean class="org.apache.cxf.binding.soap.saaj.SAAJInInterceptor" /> <spring:bean class="org.apache.cxf.ws.security.wss4j.WSS4JInInterceptor"> <spring:constructor-arg> <spring:map> <spring:entry key="action" value="UsernameToken Timestamp Signature" /> <spring:entry key="passwordCallbackRef" value-ref="serverCallback" /> <spring:entry key="signaturePropFile" value="wssecurity.properties" /> </spring:map> </spring:constructor-arg> </spring:bean> </cxf:inInterceptors> </cxf:inbound-endpoint> </inbound> </service> But how is it possible to create a policy of what algorithms that are allowed, and what parts of the message that should be signed?

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  • Using KnockoutJs templates with jQuery

    - by balteo
    I would like to end up with the following HTML in the DOM using jQuery and KnockoutJs templates: <div class="messageToAndFromOtherMember" id="13"> <span>the message</span> <span>2012-12-02 14:05:45.0</span> </div> I have started writing my KO template as follows: <div class="messageToAndFromOtherMember" data-bind="attr:{ id: messageId}"> <span data-bind="text: message"></span> <span data-bind="text: sendDateFmted"></span> </div> Upon a successful ajax request, the following js is executed: var messageViewModel = { message: response.message, sendDateFmted: response.sendDateFmted, messageId: response.messageId }; ko.applyBindings(messageViewModel); Now I am not sure how and where to actually do the binding: since my message does not exist before the ajax request is complete and I can have as several messages... Can anyone please suggest a solution? EDIT: I have added this to the html page: <div data-bind="template: { name: 'message-template', data: messageViewModel }"></div> I now get the following js error: Uncaught Error: Unable to parse bindings. Message: ReferenceError: $messageViewModel is not defined; Bindings value: template: { name: 'message-template', data: messageViewModel }

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  • Dataset bind to Gridview within WCF REST retrieval method and Linq to Sql

    - by user643794
    I used a WCF REST template to build a WCF service library to create PUT and GET calls. PUT method works fine sending my blob to a database. On the GET, I want to be able to access the web service directly and display the results from a stored procedure as a dataset and bind this to a gridview. The stored procedure is a simple select statement, returning three of the four columns from the table. I have the following: [WebGet(UriTemplate = "/?name={name}", ResponseFormat = WebMessageFormat.Xml)] public List<Object> GetCollection(string name) { try { db.OpenDbConnection(); // Call to SQL stored procedure return db.GetCustFromName(name); } catch (Exception e) { Log.Error("Stored Proc execution failed. ", e); } finally { db.CloseDbConnection(); } return null; } I also added Linq to SQL class to include my database table and stored procedures access. I also created the Default.aspx file in addition to the other required files. protected void Page_Load(object sender, EventArgs e) { ServiceDataContext objectContext = new ServiceDataContext(); var source = objectContext.GetCustFromName("Tiger"); Menu1.DataSource = source; Menu1.DataBind(); } But this gives me The entity type '' does not belong to any registered model. Where should the data binding be done? What should be the return type for GetCollection()? I am stuck with this. Please provide help on how to do this.

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  • How do you pass a BitmapImage from a background thread to the UI thread in WPF?

    - by DanM
    I have a background thread that generates a series of BitmapImage objects. Each time the background thread finishes generating a bitmap, I would like to show this bitmap to the user. The problem is figuring out how to pass the BitmapImage from the background thread to the UI thread. This is an MVVM project, so my view has an Image element: <Image Source="{Binding GeneratedImage}" /> My view-model has a property GeneratedImage: private BitmapImage _generatedImage; public BitmapImage GeneratedImage { get { return _generatedImage; } set { if (value == _generatedImage) return; _generatedImage= value; RaisePropertyChanged("GeneratedImage"); } } My view-model also has the code that creates the background thread: public void InitiateGenerateImages(List<Coordinate> coordinates) { ThreadStart generatorThreadStarter = delegate { GenerateImages(coordinates); }; var generatorThread = new Thread(generatorThreadStarter); generatorThread.ApartmentState = ApartmentState.STA; generatorThread.IsBackground = true; generatorThread.Start(); } private void GenerateImages(List<Coordinate> coordinates) { foreach (var coordinate in coordinates) { var backgroundThreadImage = GenerateImage(coordinate); // I'm stuck here...how do I pass this to the UI thread? } } I'd like to somehow pass backgroundThreadImage to the UI thread, where it will become uiThreadImage, then set GeneratedImage = uiThreadImage so the view can update. I've looked at some examples dealing with the WPF Dispatcher, but I can't seem to come up with an example that addresses this issue. Please advise.

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  • DataGridView with row-specific DataGridViewComboBoxColumn contents in C# Windows Forms 3.5

    - by XXXXX
    So I have something like the following data structure (constructors omitted) class Child { public string Name { get; set; } public int Age { get; set; } } class Parent { public string Name { get; set; } public List <Child> Children { get; private set; } // never null; list never empty public Child FavoriteChild { get; set; } // never null; always a reference to a Child in Children } List < Parent > Parents; What I want to do is show a DataGridView where each row is a Parent from Parent list. Each row should have two columns: a text box showing the parent's name and a DataGridViewComboBoxColumn containing that parent's children, from which the user can select the parent's favorite child. I suppose I could do the whole thing manually, but I'd like to do all this with more-or-less standard Data Binding. It's easy enough to bind the DataGridView to the list of parents, and easy enough to bind the selected child to the FavoriteChild property. The part that's giving me difficulty is that it looks like the Combo Box column wants to bind to one data source for all the combo-box's contents on all rows. I'd like each instance of the combo box to bind to the list of each parent's children. I'm fairly new to C#/Windows Forms, so I may well be missing something obvious. Or it could be that "you can't get there from here." It's not too tough to make a separate list of all the children and filter it by parent; I'm looking into that possibility right now. Is this feasible, or is there a better way?

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  • how to find a control inside ItemsPanelTemplate in wpf?

    - by kakopappa
    I am trying to access a Grid inside the DataTemplate while the ItemsControl is binded by ItemsSource. this is the full XMAL code, How do i find a certain element from outside? for (int i = 0; i < allViewControl.Items.Count; i++) { var container = allViewControl.ItemContainerGenerator.ContainerFromItem(allViewControl.Items[i]) as FrameworkElement; var grid = allViewControl.ItemTemplate.FindName("grid", container) as DataGrid; } i found this always returning null ? <ScrollViewer Grid.Row="0" HorizontalScrollBarVisibility="Disabled" VerticalScrollBarVisibility="Auto"> <ItemsControl x:Name="allViewControl" Focusable="False" HorizontalContentAlignment="Center" Grid.IsSharedSizeScope="true" ItemsSource="{Binding AllClassCharacters}" ItemTemplate="{StaticResource CharacterViewModelTemplate}" > <ItemsControl.ItemsPanel> <ItemsPanelTemplate> <Extensions:AnimatedWrapPanel IsItemsHost="true" /> </ItemsPanelTemplate> </ItemsControl.ItemsPanel> </ItemsControl> </ScrollViewer> <DataTemplate x:Key="CharacterViewModelTemplate" DataType="{x:Type ViewModel:CharacterViewModel}"> <Grid x:Name="grid" Width="200" Height="Auto" MinHeight="115" Margin="1" MinWidth="130" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" RenderTransformOrigin="0.5,0.5" Background="#66000000" > <Grid.RowDefinitions> <RowDefinition Height="70"/> <RowDefinition Height="*"/> </Grid.RowDefinitions> <Grid.ColumnDefinitions> <ColumnDefinition Width="*" /> <ColumnDefinition Width="*" /> </Grid.ColumnDefinitions> <ProgressBar x:Name="playerProgressBar" VerticalAlignment="Top" Background="Transparent" Height="5" Width="Auto" Value="0" Visibility="Collapsed" Grid.Column="0" Grid.Row="0" Grid.ColumnSpan ="2" Grid.RowSpan="2" Foreground="White" BorderThickness="0" Style="{DynamicResource ProgressBarStyle1}" /> </Grid>

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