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  • Is this code well-defined?

    - by Nawaz
    This code is taken from a discussion going on here. someInstance.Fun(++k).Gun(10).Sun(k).Tun(); Is this code well-defined? Is ++k Fun() evaluated before k in Sun()? What if k is user-defined type, not built-in type? And in what ways the above function calls order is different from this: eat(++k);drink(10);sleep(k); As far as I can say, in both situations, there exists a sequence point after each function call. If so, then why can't the first case is also well-defined like the second one? Section 1.9.17 of the C++ ISO standard says this about sequence points and function evaluation: When calling a function (whether or not the function is inline), there is a sequence point after the evaluation of all function arguments (if any) which takes place before execution of any expressions or statements in the function body. There is also a sequence point after the copying of a returned value and before the execution of any expressions outside the function.

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  • Print a JavaScript array to HTML, square brackets and quotation marks intact

    - by Mark Gia Bao Nguyen
    I'd like to set the attribute of an input form with an array of values (to use for autocomplete search). I have a JS array that looks a little something like this: var suggestions = ["value1", "value2", "value3"]; Using jQuery, I did this: $("#search-input").attr("data-source", suggestions); Desired output: <input type='search' data-source='["value1", "value2", "value3"]' /> Actual output: <input type='search' data-source='value1, value2, value3' /> This breaks the autocomplete as it requires an array (or at least something that looks like a JavaScript array).

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  • Activator.CreateInstance(string) and Activator.CreateInstance<T>() difference

    - by Juan Manuel Formoso
    No, this is not a question about generics. I have a Factory pattern with several classes with internal constructors (I don't want them being instantiated if not through the factory). My problem is that CreateInstance fails with a "No parameterless constructor defined for this object" error unless I pass "true" on the non-public parameter. Example // Fails Activator.CreateInstance(type); // Works Activator.CreateInstance(type, true); I wanted to make the factory generic to make it a little simpler, like this: public class GenericFactory<T> where T : MyAbstractType { public static T GetInstance() { return Activator.CreateInstance<T>(); } } However, I was unable to find how to pass that "true" parameter for it to accept non-public constructors (internal). Did I miss something or it isn't possible?

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  • ASP.NET MVC - Disable Html Helper control using boolean value from Model

    - by The Matt
    I am outputting a textbox to the page using the Html helpers. I want to add the disabled attribute dynamically based on whether or not a boolean value in my model is true or false. My model has a method that returns a boolean value: <% =Model.IsMyTextboxEnabled() %> I currently render the textbox like follows, but I want to now enabled or disable it: <% =Html.TextBox("MyTextbox", Model.MyValuenew { id = "MyTextbox", @class = "MyClass" })%> If the return value of Model.IsMyTextboxEnabled() == true I want the following to be output: <input class="MyClass" id="MyTextbox" name="MyTextbox" type="text" value="" /> If it == false, I want it to output as: <input class="MyClass" id="MyTextbox" name="MyTextbox" type="text" value="" disabled /> What is the cleanest way to do this?

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  • Make xargs execute the command once for each line of input

    - by Readonly
    How can I make xargs execute the command exactly once for each line of input given? It's default behavior is to chunk the lines and execute the command once, passing multiple lines to each instance. From http://en.wikipedia.org/wiki/Xargs: find /path -type f -print0 | xargs -0 rm In this example, find feeds the input of xargs with a long list of file names. xargs then splits this list into sublists and calls rm once for every sublist. This is more efficient than this functionally equivalent version: find /path -type f -exec rm '{}' \; I know that find has the "exec" flag. I am just quoting an illustrative example from another resource.

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  • DataSource or ConnectionPoolDataSource for Application Server JDBC resources

    - by Vinnie
    When creating JNDI JDBC connection pools in an application server, I always specified the type as javax.sql.ConnectionPoolDataSource. I never really gave it too much thought as it always seemed natural to prefer pooled connections over non-pooled. However, in looking at some examples (specifically for Tomcat) I noticed that they specify javax.sql.DataSource. Further, it seems there are settings for maxIdle and maxWait giving the impression that these connections are pooled as well. Glassfish also allows these parameters regardless of the type of data source selected. Are javax.sql.DataSource pooled in an application server (or servlet container)? What (if any) advantages are there for choosing javax.sql.ConnectionPoolDataSource over javax.sql.DataSource (or vice versa)?

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  • InvalidOperationException When XML Serializing Inherited Class

    - by Nick
    I am having an issue serializing a c# class to an XML file that has a base class... here is a simple example: namespace Domain { [Serializable] public class ClassA { public virtual int MyProperty { get; set; } } } namespace Derived { public class ClassA : Domain.ClassA { public override int MyProperty { get { return 1; } set { /* Do Nothing */ } } } } When I attempt to serialize an instance of Derived.ClassA, I receive the following exception: InvalidOperationException(Types 'Domain.ClassA' and 'Derived.ClassA' both use the XML type name 'ClassA', from the namespace ". Use XML attributes to specify a unique XML name and/or namespace for the type.) The problem is that I want to create a single base class that simply defines the structure of the XML file, and then allow anyone else to derive from that class to insert business rules, but that the formatting will come through from the base. Is this possible, and if so, how do I attribute the base class to allow this?

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  • Why is this simple file upload not working? JSF

    - by Nitesh Panchal
    Hello, Why is this code not working? I always get size() = 0, whenever i upload file. xhtml file :- <?xml version='1.0' encoding='UTF-8' ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://java.sun.com/jsf/html"> <h:head> <title>Abc</title> </h:head> <h:body> <center> <form method="post" enctype="multipart/form-data" id="form" action="/upload/uploadFile"> <input type="file"/> <br/> <input type="Submit" value="upload"/> </form> </center> </h:body> </html> This is my servlet :- package servlets; import java.io.IOException; import java.util.List; import java.util.logging.Level; import java.util.logging.Logger; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.fileupload.FileItem; import org.apache.commons.fileupload.FileUploadException; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; @WebServlet(name="uploadFile", urlPatterns={"/uploadFile"}) public class uploadFile extends HttpServlet { protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException, FileUploadException { System.out.println("executed!"); List<FileItem> items = new ServletFileUpload(new DiskFileItemFactory()).parseRequest(request); System.out.println(items.size()); for (FileItem item : items) { if (!item.isFormField()) { System.out.println("Name: " + item.getName()); System.out.println("Size: " + item.getSize()); System.out.println("Type: " + item.getContentType()); } } } @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { try { processRequest(request, response); } catch (FileUploadException ex) { ex.printStackTrace(); } } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { try { processRequest(request, response); } catch (FileUploadException ex) { ex.printStackTrace(); } } @Override public String getServletInfo() { return "Short description"; } }

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  • How to add/remove rows using SlickGrid

    - by lkahtz
    How to write such functions and bind them to two buttons like "add row" and "remove row": The now working example code only support adding new row by editing on the blank bottom line. <!DOCTYPE HTML> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <title>SlickGrid example 3: Editing</title> <link rel="stylesheet" href="../slick.grid.css" type="text/css"/> <link rel="stylesheet" href="../css/smoothness/jquery-ui-1.8.16.custom.css" type="text/css"/> <link rel="stylesheet" href="examples.css" type="text/css"/> <style> .cell-title { font-weight: bold; } .cell-effort-driven { text-align: center; } </style> </head> <body> <div style="position:relative"> <div style="width:600px;"> <div id="myGrid" style="width:100%;height:500px;"></div> </div> <div class="options-panel"> <h2>Demonstrates:</h2> <ul> <li>adding basic keyboard navigation and editing</li> <li>custom editors and validators</li> <li>auto-edit settings</li> </ul> <h2>Options:</h2> <button onclick="grid.setOptions({autoEdit:true})">Auto-edit ON</button> &nbsp; <button onclick="grid.setOptions({autoEdit:false})">Auto-edit OFF</button> </div> </div> <script src="../lib/firebugx.js"></script> <script src="../lib/jquery-1.7.min.js"></script> <script src="../lib/jquery-ui-1.8.16.custom.min.js"></script> <script src="../lib/jquery.event.drag-2.0.min.js"></script> <script src="../slick.core.js"></script> <script src="../plugins/slick.cellrangedecorator.js"></script> <script src="../plugins/slick.cellrangeselector.js"></script> <script src="../plugins/slick.cellselectionmodel.js"></script> <script src="../slick.formatters.js"></script> <script src="../slick.editors.js"></script> <script src="../slick.grid.js"></script> <script> function requiredFieldValidator(value) { if (value == null || value == undefined || !value.length) { return {valid: false, msg: "This is a required field"}; } else { return {valid: true, msg: null}; } } var grid; var data = []; var columns = [ {id: "title", name: "Title", field: "title", width: 120, cssClass: "cell-title", editor: Slick.Editors.Text, validator: requiredFieldValidator}, {id: "desc", name: "Description", field: "description", width: 100, editor: Slick.Editors.LongText}, {id: "duration", name: "Duration", field: "duration", editor: Slick.Editors.Text}, {id: "%", name: "% Complete", field: "percentComplete", width: 80, resizable: false, formatter: Slick.Formatters.PercentCompleteBar, editor: Slick.Editors.PercentComplete}, {id: "start", name: "Start", field: "start", minWidth: 60, editor: Slick.Editors.Date}, {id: "finish", name: "Finish", field: "finish", minWidth: 60, editor: Slick.Editors.Date}, {id: "effort-driven", name: "Effort Driven", width: 80, minWidth: 20, maxWidth: 80, cssClass: "cell-effort-driven", field: "effortDriven", formatter: Slick.Formatters.Checkmark, editor: Slick.Editors.Checkbox} ]; var options = { editable: true, enableAddRow: true, enableCellNavigation: true, asyncEditorLoading: false, autoEdit: false }; $(function () { for (var i = 0; i < 500; i++) { var d = (data[i] = {}); d["title"] = "Task " + i; d["description"] = "This is a sample task description.\n It can be multiline"; d["duration"] = "5 days"; d["percentComplete"] = Math.round(Math.random() * 100); d["start"] = "01/01/2009"; d["finish"] = "01/05/2009"; d["effortDriven"] = (i % 5 == 0); } grid = new Slick.Grid("#myGrid", data, columns, options); grid.setSelectionModel(new Slick.CellSelectionModel()); grid.onAddNewRow.subscribe(function (e, args) { var item = args.item; grid.invalidateRow(data.length); data.push(item); grid.updateRowCount(); grid.render(); }); }) </script> </body> </html>

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  • Double pointer const-correctness warnings in C

    - by Michael Koval
    You can obviously cast a pointer to non-const data to a a pointer of the same type to const data: int *x = NULL; int const *y = x; Adding additional const qualifiers to match the additional indirection should logically work the same way: int * *x = NULL; int *const *y = x; /* okay */ int const *const *z = y; /* warning */ Compiling this with GCC or Clang with the -Wall flag, however, results in the following warning: test.c:4:23: warning: initializing 'int const *const *' with an expression of type 'int *const *' discards qualifiers in nested pointer types int const *const *z = y; /* warning */ ^ ~ Why does adding an additional const qualifier "discard qualifiers in nested pointer types"?

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  • Would dynamically created JavaScript files be cached?

    - by venksster
    So my application uses a LOT of js files. thats a lot of http requests. I decided to combine them dynamically at the server in packs of 3-4 files clubbed by functionality. My client side request is: ...script type="text/javascript" src="http://mydomain.com/core-js.php" ... My server side does: --core-js.php-- header("Content-type: application/x-javascript"); include_once('file1.js'); include_once('file2.js'); include_once('file3.js'); include_once('file4.js'); I am setting a far future expire header on core-js.php. My question is, would core-js.php be cached at the client side? If it would be, could someone please explain how? Thanks!

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  • Android USB Host Communication

    - by Kip Russell
    I'm working on a project that utilizes the USB Host capabilities in Android 3.2. I'm suffering from a deplorable lack of knowledge and talent regarding USB/Serial communication in general. I'm also unable to find any good example code for what I need to do. I need to read from a USB Communication Device. Ex: When I connect via Putty (on my PC) I enter: >GO And the device starts spewing out data for me. Pitch/Roll/Temp/Checksum. Ex: $R1.217P-0.986T26.3*60 $R1.217P-0.986T26.3*60 $R1.217P-0.987T26.3*61 $R1.217P-0.986T26.3*60 $R1.217P-0.985T26.3*63 I can send the initial 'GO' command from the Android device at which time I receive an echo of 'GO'. Then nothing else on any subsequent reads. How can I: 1) Send the 'go' command. 2) Read in the stream of data that results. The USB device I'm working with has the following interfaces (endpoints). Device Class: Communication Device (0x2) Interfaces: Interface #0 Class: Communication Device (0x2) Endpoint #0 Direction: Inbound (0x80) Type: Intrrupt (0x3) Poll Interval: 255 Max Packet Size: 32 Attributes: 000000011 Interface #1 Class: Communication Device Class (CDC) (0xa) Endpoint #0 Address: 129 Number: 1 Direction: Inbound (0x80) Type: Bulk (0x2) Poll Interval (0) Max Packet Size: 32 Attributes: 000000010 Endpoint #1 Address: 2 Number: 2 Direction: Outbound (0x0) Type: Bulk (0x2) Poll Interval (0) Max Packet Size: 32 Attributes: 000000010 I'm able to deal with permission, connect to the device, find the correct interface and assign the endpoints. I'm just having trouble figuring out which technique to use to send the initial command read the ensuing data. I'm tried different combinations of bulkTransfer and controlTransfer with no luck. Thanks. I'm using interface#1 as seen below: public AcmDevice(UsbDeviceConnection usbDeviceConnection, UsbInterface usbInterface) { Preconditions.checkState(usbDeviceConnection.claimInterface(usbInterface, true)); this.usbDeviceConnection = usbDeviceConnection; UsbEndpoint epOut = null; UsbEndpoint epIn = null; // look for our bulk endpoints for (int i = 0; i < usbInterface.getEndpointCount(); i++) { UsbEndpoint ep = usbInterface.getEndpoint(i); Log.d(TAG, "EP " + i + ": " + ep.getType()); if (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) { if (ep.getDirection() == UsbConstants.USB_DIR_OUT) { epOut = ep; } else if (ep.getDirection() == UsbConstants.USB_DIR_IN) { epIn = ep; } } } if (epOut == null || epIn == null) { throw new IllegalArgumentException("Not all endpoints found."); } AcmReader acmReader = new AcmReader(usbDeviceConnection, epIn); AcmWriter acmWriter = new AcmWriter(usbDeviceConnection, epOut); reader = new BufferedReader(acmReader); writer = new BufferedWriter(acmWriter); }

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  • Retrieve Button value with jQuery

    - by Simon Hutton
    A simple one, I'm trying to retrieve the value attribute of a button when its been pressed using jQuery, here's what I have: <script type="text/javascript"> $(document).ready(function() { $('.my_button').click(function() { alert($(this).val()); }); }); </script> <button class="my_button" name="buttonName" value="buttonValue"> Button Label</button> In Firefox my alert displays 'buttonValue' which is great but in IE7 it displays 'Button Label'. What jQuery should I use to always get the button's value? Or should I be using a different approach? Many thanks. ANSWER: I'm now using <input class="my_button" type="image" src="whatever.png" value="buttonValue" />

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  • Scala match question

    - by javier
    Hello to everyone. I came across with an error on my Scala code that I cannot solve by myself (I am new at Scala). I have the following code: def myFunction(list: List[Any]): String = { var strItems : String = ""; list.foreach(item => { strItems += item match { case x:JsonSerializable => x.toJson() case y:String => ("\"" + y + "\"") case _ => item.toString } if(item != list.last) strItems += ","; }) strItems; } The error I am getting is: error: pattern type is incompatible with expected type; found : String required: Unit case y:String = ("\"" + y + "\"") Any idea why? PS: is there a more performant way to code myFunction

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  • How do I impliment a hidden field in a post form so users can't accidentally double post? (PHP/Mysql

    - by ggfan
    When users submit a form, they will sometimes click refresh or backspace then resubmit which causes multiple entries in mysql. How can i prevent mysql from allowing more than 1 of the same entry? People suggested a hidden field with a value, but how do I use that? <label for="state" class="styled">State:</label> <input type="text" id="state" name="state" value="<?php if (!empty($state)) echo $state; ?>" size="30" /><br /> //a hidden field of a certain value? ________________________________________ <input type="submit" value="Post Ad!" name="submit" /> //php to insert to mysql $query4 = "INSERT INTO posting (state) VALUES ('$state')"; mysqli_query($dbc, $query4);

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  • gcc, strict-aliasing, and horror stories

    - by Joseph Quinsey
    In http://stackoverflow.com/questions/2906365/gcc-strict-aliasing-and-casting-through-a-union I asked whether anyone had encountered problems with union punning through pointers. So far, the answer seems to be No. This question is broader: do you have any horror stories about gcc and strict-aliasing? Background: Quoting from AndreyT's answer in http://stackoverflow.com/questions/2771023/c99-strict-aliasing-rules-in-c-gcc/2771041#2771041: "Strict aliasing rules are rooted in parts of the standard that were present in C and C++ since the beginning of [standardized] times. The clause that prohibits accessing object of one type through a lvalue of another type is present in C89/90 (6.3) as well as in C++98 (3.10/15). ... It is just that not all compilers wanted (or dared) to enforce it or rely on it." Well, gcc is now daring to do so, with its -fstrict-aliasing switch. And this has caused some problems. See, for example, the excellent article http://davmac.wordpress.com/2009/10/ about a Mysql bug, and the equally excellent discussion in http://cellperformance.beyond3d.com/articles/2006/06/understanding-strict-aliasing.html. Some other less-relevant links: http://stackoverflow.com/questions/1225741/performance-impact-of-fno-strict-aliasing http://stackoverflow.com/questions/754929/strict-aliasing http://stackoverflow.com/questions/262379/when-is-char-safe-for-strict-pointer-aliasing http://stackoverflow.com/questions/725138/how-to-detect-strict-aliasing-at-compile-time So to repeat, do you have a horror story of your own? Problems not indicated by -Wstrict-aliasing would, of course, be preferred. And other C compilers are also welcome.

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  • idiomatic property changed notification in scala?

    - by Jeremy Bell
    I'm trying to find a cleaner alternative (that is idiomatic to Scala) to the kind of thing you see with data-binding in WPF/silverlight data-binding - that is, implementing INotifyPropertyChanged. First, some background: In .Net WPF or silverlight applications, you have the concept of two-way data-binding (that is, binding the value of some element of the UI to a .net property of the DataContext in such a way that changes to the UI element affect the property, and vise versa. One way to enable this is to implement the INotifyPropertyChanged interface in your DataContext. Unfortunately, this introduces a lot of boilerplate code for any property you add to the "ModelView" type. Here is how it might look in Scala: trait IDrawable extends INotifyPropertyChanged { protected var drawOrder : Int = 0 def DrawOrder : Int = drawOrder def DrawOrder_=(value : Int) { if(drawOrder != value) { drawOrder = value OnPropertyChanged("DrawOrder") } } protected var visible : Boolean = true def Visible : Boolean = visible def Visible_=(value: Boolean) = { if(visible != value) { visible = value OnPropertyChanged("Visible") } } def Mutate() : Unit = { if(Visible) { DrawOrder += 1 // Should trigger the PropertyChanged "Event" of INotifyPropertyChanged trait } } } For the sake of space, let's assume the INotifyPropertyChanged type is a trait that manages a list of callbacks of type (AnyRef, String) = Unit, and that OnPropertyChanged is a method that invokes all those callbacks, passing "this" as the AnyRef, and the passed-in String). This would just be an event in C#. You can immediately see the problem: that's a ton of boilerplate code for just two properties. I've always wanted to write something like this instead: trait IDrawable { val Visible = new ObservableProperty[Boolean]('Visible, true) val DrawOrder = new ObservableProperty[Int]('DrawOrder, 0) def Mutate() : Unit = { if(Visible) { DrawOrder += 1 // Should trigger the PropertyChanged "Event" of ObservableProperty class } } } I know that I can easily write it like this, if ObservableProperty[T] has Value/Value_= methods (this is the method I'm using now): trait IDrawable { // on a side note, is there some way to get a Symbol representing the Visible field // on the following line, instead of hard-coding it in the ObservableProperty // constructor? val Visible = new ObservableProperty[Boolean]('Visible, true) val DrawOrder = new ObservableProperty[Int]('DrawOrder, 0) def Mutate() : Unit = { if(Visible.Value) { DrawOrder.Value += 1 } } } // given this implementation of ObservableProperty[T] in my library // note: IEvent, Event, and EventArgs are classes in my library for // handling lists of callbacks - they work similarly to events in C# class PropertyChangedEventArgs(val PropertyName: Symbol) extends EventArgs("") class ObservableProperty[T](val PropertyName: Symbol, private var value: T) { protected val propertyChanged = new Event[PropertyChangedEventArgs] def PropertyChanged: IEvent[PropertyChangedEventArgs] = propertyChanged def Value = value; def Value_=(value: T) { if(this.value != value) { this.value = value propertyChanged(this, new PropertyChangedEventArgs(PropertyName)) } } } But is there any way to implement the first version using implicits or some other feature/idiom of Scala to make ObservableProperty instances function as if they were regular "properties" in scala, without needing to call the Value methods? The only other thing I can think of is something like this, which is more verbose than either of the above two versions, but is still less verbose than the original: trait IDrawable { private val visible = new ObservableProperty[Boolean]('Visible, false) def Visible = visible.Value def Visible_=(value: Boolean): Unit = { visible.Value = value } private val drawOrder = new ObservableProperty[Int]('DrawOrder, 0) def DrawOrder = drawOrder.Value def DrawOrder_=(value: Int): Unit = { drawOrder.Value = value } def Mutate() : Unit = { if(Visible) { DrawOrder += 1 } } }

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  • WCF extensions without including the assembly version

    - by Marc Gravell
    As discussed here, I'm trying to add a WCF endpoint-extension; I've got it working, but I need to include the full assembly details: <extensions> <behaviorExtensions> <add name="protobuf" type="ProtoBuf.ServiceModel.ProtoBehaviorExtension, protobuf-net, Version=1.0.0.275, Culture=neutral, PublicKeyToken=257b51d87d2e4d67"/> </behaviorExtensions> </extensions> What I would like to do (to avoid issues when updating etc, especially for samples) is to include just the names: <add name="protobuf" type="ProtoBuf.ServiceModel.ProtoBehaviorExtension, protobuf-net"/> (which is what you might expect from standard assembly-naming conventions) However, if I do this, I get a big error: Parser Error Message: An error occurred creating the configuration section handler for system.serviceModel/behaviors: Extension element 'protobuf' cannot be added to this element. Verify that the extension is registered in the extension collection at system.serviceModel/extensions/behaviorExtensions. Is it possible (and if so: how) to add an extension without having to specify the assembly-version?

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  • Constructor invocation returned null: what to do?

    - by strager
    I have code which looks like: private static DirectiveNode CreateInstance(Type nodeType, DirectiveInfo info) { var ctor = nodeType.GetConstructor(new[] { typeof(DirectiveInfo) }); if(ctor == null) { throw new MissingMethodException(nodeType.FullName, "ctor"); } var node = ctor.Invoke(new[] { info }) as DirectiveNode; if(node == null) { // ???; } return node; } I am looking for what to do (e.g. what type of exception to throw) when the Invoke method returns something which isn't a DirectiveNode or when it returns null (indicated by // ??? above). (By the method's contract, nodeType will always describe a subclass of DirectiveNode.) I am not sure when calling a constructor would return null, so I am not sure if I should handle anything at all, but I still want to be on the safe side and throw an exception if something goes wrong.

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  • mdadm: Win7-install created a boot partition on one of my RAID6 drives. How to rebuild?

    - by EXIT_FAILURE
    My problem happened when I attempted to install Windows 7 on it's own SSD. The Linux OS I used which has knowledge of the software RAID system is on a SSD that I disconnected prior to the install. This was so that windows (or I) wouldn't inadvertently mess it up. However, and in retrospect, foolishly, I left the RAID disks connected, thinking that windows wouldn't be so ridiculous as to mess with a HDD that it sees as just unallocated space. Boy was I wrong! After copying over the installation files to the SSD (as expected and desired), it also created an ntfs partition on one of the RAID disks. Both unexpected and totally undesired! . I changed out the SSDs again, and booted up in linux. mdadm didn't seem to have any problem assembling the array as before, but if I tried to mount the array, I got the error message: mount: wrong fs type, bad option, bad superblock on /dev/md0, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so dmesg: EXT4-fs (md0): ext4_check_descriptors: Block bitmap for group 0 not in group (block 1318081259)! EXT4-fs (md0): group descriptors corrupted! I then used qparted to delete the newly created ntfs partition on /dev/sdd so that it matched the other three /dev/sd{b,c,e}, and requested a resync of my array with echo repair > /sys/block/md0/md/sync_action This took around 4 hours, and upon completion, dmesg reports: md: md0: requested-resync done. A bit brief after a 4-hour task, though I'm unsure as to where other log files exist (I also seem to have messed up my sendmail configuration). In any case: No change reported according to mdadm, everything checks out. mdadm -D /dev/md0 still reports: Version : 1.2 Creation Time : Wed May 23 22:18:45 2012 Raid Level : raid6 Array Size : 3907026848 (3726.03 GiB 4000.80 GB) Used Dev Size : 1953513424 (1863.02 GiB 2000.40 GB) Raid Devices : 4 Total Devices : 4 Persistence : Superblock is persistent Update Time : Mon May 26 12:41:58 2014 State : clean Active Devices : 4 Working Devices : 4 Failed Devices : 0 Spare Devices : 0 Layout : left-symmetric Chunk Size : 4K Name : okamilinkun:0 UUID : 0c97ebf3:098864d8:126f44e3:e4337102 Events : 423 Number Major Minor RaidDevice State 0 8 16 0 active sync /dev/sdb 1 8 32 1 active sync /dev/sdc 2 8 48 2 active sync /dev/sdd 3 8 64 3 active sync /dev/sde Trying to mount it still reports: mount: wrong fs type, bad option, bad superblock on /dev/md0, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so and dmesg: EXT4-fs (md0): ext4_check_descriptors: Block bitmap for group 0 not in group (block 1318081259)! EXT4-fs (md0): group descriptors corrupted! I'm a bit unsure where to proceed from here, and trying stuff "to see if it works" is a bit too risky for me. This is what I suggest I should attempt to do: Tell mdadm that /dev/sdd (the one that windows wrote into) isn't reliable anymore, pretend it is newly re-introduced to the array, and reconstruct its content based on the other three drives. I also could be totally wrong in my assumptions, that the creation of the ntfs partition on /dev/sdd and subsequent deletion has changed something that cannot be fixed this way. My question: Help, what should I do? If I should do what I suggested , how do I do that? From reading documentation, etc, I would think maybe: mdadm --manage /dev/md0 --set-faulty /dev/sdd mdadm --manage /dev/md0 --remove /dev/sdd mdadm --manage /dev/md0 --re-add /dev/sdd However, the documentation examples suggest /dev/sdd1, which seems strange to me, as there is no partition there as far as linux is concerned, just unallocated space. Maybe these commands won't work without. Maybe it makes sense to mirror the partition table of one of the other raid devices that weren't touched, before --re-add. Something like: sfdisk -d /dev/sdb | sfdisk /dev/sdd Bonus question: Why would the Windows 7 installation do something so st...potentially dangerous? Update I went ahead and marked /dev/sdd as faulty, and removed it (not physically) from the array: # mdadm --manage /dev/md0 --set-faulty /dev/sdd # mdadm --manage /dev/md0 --remove /dev/sdd However, attempting to --re-add was disallowed: # mdadm --manage /dev/md0 --re-add /dev/sdd mdadm: --re-add for /dev/sdd to /dev/md0 is not possible --add, was fine. # mdadm --manage /dev/md0 --add /dev/sdd mdadm -D /dev/md0 now reports the state as clean, degraded, recovering, and /dev/sdd as spare rebuilding. /proc/mdstat shows the recovery progress: md0 : active raid6 sdd[4] sdc[1] sde[3] sdb[0] 3907026848 blocks super 1.2 level 6, 4k chunk, algorithm 2 [4/3] [UU_U] [>....................] recovery = 2.1% (42887780/1953513424) finish=348.7min speed=91297K/sec nmon also shows expected output: ¦sdb 0% 87.3 0.0| > |¦ ¦sdc 71% 109.1 0.0|RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR > |¦ ¦sdd 40% 0.0 87.3|WWWWWWWWWWWWWWWWWWWW > |¦ ¦sde 0% 87.3 0.0|> || It looks good so far. Crossing my fingers for another five+ hours :) Update 2 The recovery of /dev/sdd finished, with dmesg output: [44972.599552] md: md0: recovery done. [44972.682811] RAID conf printout: [44972.682815] --- level:6 rd:4 wd:4 [44972.682817] disk 0, o:1, dev:sdb [44972.682819] disk 1, o:1, dev:sdc [44972.682820] disk 2, o:1, dev:sdd [44972.682821] disk 3, o:1, dev:sde Attempting mount /dev/md0 reports: mount: wrong fs type, bad option, bad superblock on /dev/md0, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so And on dmesg: [44984.159908] EXT4-fs (md0): ext4_check_descriptors: Block bitmap for group 0 not in group (block 1318081259)! [44984.159912] EXT4-fs (md0): group descriptors corrupted! I'm not sure what do do now. Suggestions? Output of dumpe2fs /dev/md0: dumpe2fs 1.42.8 (20-Jun-2013) Filesystem volume name: Atlas Last mounted on: /mnt/atlas Filesystem UUID: e7bfb6a4-c907-4aa0-9b55-9528817bfd70 Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Filesystem features: has_journal ext_attr resize_inode dir_index filetype extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize Filesystem flags: signed_directory_hash Default mount options: user_xattr acl Filesystem state: clean Errors behavior: Continue Filesystem OS type: Linux Inode count: 244195328 Block count: 976756712 Reserved block count: 48837835 Free blocks: 92000180 Free inodes: 243414877 First block: 0 Block size: 4096 Fragment size: 4096 Reserved GDT blocks: 791 Blocks per group: 32768 Fragments per group: 32768 Inodes per group: 8192 Inode blocks per group: 512 RAID stripe width: 2 Flex block group size: 16 Filesystem created: Thu May 24 07:22:41 2012 Last mount time: Sun May 25 23:44:38 2014 Last write time: Sun May 25 23:46:42 2014 Mount count: 341 Maximum mount count: -1 Last checked: Thu May 24 07:22:41 2012 Check interval: 0 (<none>) Lifetime writes: 4357 GB Reserved blocks uid: 0 (user root) Reserved blocks gid: 0 (group root) First inode: 11 Inode size: 256 Required extra isize: 28 Desired extra isize: 28 Journal inode: 8 Default directory hash: half_md4 Directory Hash Seed: e177a374-0b90-4eaa-b78f-d734aae13051 Journal backup: inode blocks dumpe2fs: Corrupt extent header while reading journal super block

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  • edge case for selecting a checked radio input with jquery

    - by altvali
    Hi all! I have a problem selecting a checked radio button with jquery. The radio buttons are generated by a function from a MVC that i'd rather not change and its name is like id[number]. Simply put, I have to check if any of these buttons are checked: <input type="radio" name="id[1]" value="1"/ <input type="radio" name="id[1]" value="2"/ The problem is that jQuery('input:radio[name=id[1]]:checked').val() will select some function from the jQuery library. Any help will be much appreciated.

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  • HttpURLConnection does not read the whole respnse

    - by Peter Szanto
    I use HttpURLConnection to do HTTP POST but I dont always get back the full response. I wanted to debug the problem, but when I step through each line it worked. I thought it must be a timing issue so I added Thread.sleep and it really made my code work, but this is only a temporary workaround. I wonder why is this happening and how to solve. Here is my code: URL u = new URL(url); URLConnection c = u.openConnection(); InputStream in = null; String mediaType = null; if (c instanceof HttpURLConnection) { //c.setConnectTimeout(1000000); //c.setReadTimeout(1000000); HttpURLConnection h = (HttpURLConnection)c; h.setRequestMethod("POST"); //h.setChunkedStreamingMode(-1); setAccept(h, expectedMimeType); h.setRequestProperty("Content-Type", inputMimeType); for(String key: httpHeaders.keySet()) { h.setRequestProperty(key, httpHeaders.get(key)); if (logger.isDebugEnabled()) { logger.debug("Request property key : " + key + " / value : " + httpHeaders.get(key)); } } h.setDoOutput(true); h.connect(); OutputStream out = h.getOutputStream(); out.write(input.getBytes()); out.close(); mediaType = h.getContentType(); logger.debug(" ------------------ sleep ------------------ START"); try { Thread.sleep(2000); } catch (InterruptedException e) { e.printStackTrace(); } logger.debug(" ------------------ sleep ------------------ END"); if (h.getResponseCode() < 400) { in = h.getInputStream(); } else { in = h.getErrorStream(); } It genearates the following HTTP headers POST /emailauthentication/ HTTP/1.1 Accept: application/xml Content-Type: application/xml Authorization: OAuth oauth_consumer_key="b465472b-d872-42b9-030e-4e74b9b60e39",oauth_nonce="YnDb5eepuLm%2Fbs",oauth_signature="dbN%2FWeWs2G00mk%2BX6uIi3thJxlM%3D", oauth_signature_method="HMAC-SHA1", oauth_timestamp="1276524919", oauth_token="", oauth_version="1.0" User-Agent: Java/1.6.0_20 Host: test:6580 Connection: keep-alive Content-Length: 1107 In other posts it was suggested to turn off keep-alive by using the http.keepAlive=false system property, I tried that and the headers changed to POST /emailauthentication/ HTTP/1.1 Accept: application/xml Content-Type: application/xml Authorization: OAuth oauth_consumer_key="b465472b-d872-42b9-030e-4e74b9b60e39", oauth_nonce="Eaiezrj6X4Ttt0", oauth_signature="ND9fAdZMqbYPR2j%2FXUCZmI90rSI%3D", oauth_signature_method="HMAC-SHA1", oauth_timestamp="1276526608", oauth_token="", oauth_version="1.0" User-Agent: Java/1.6.0_20 Host: test:6580 Connection: close Content-Length: 1107 the Connection header is "close" but I still cannot read the whole response. Any idea what do I do wrong?

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