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  • c++ "interface"-like classes similar to Java?

    - by William the Coderer
    In Java, you can define an interface as a class with no actual code implementation, but only to define the methods that a class must implement. Those types can be passed as parameters to methods and returned from methods. In C++, a pure virtual class can't be used as a parameter or return type, from what I can tell. Any way to mimic Java's interface classes? I have a string class in C++, and several subclasses for different encodings (like UTFxxx, ISOxxx, etc) that derive from the base string class. However, since there are so many different encodings, the base class has no meaningful implementation. But it would serve well as an interface if I could handle it as its own object and calls to that object would call on the correct subclass it was inherited to.

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  • What version of mongodb was full $text query operator introduced?

    - by Marc Maxson
    Stupid question, right? But the official docs for 'text index' say: http://docs.mongodb.org/manual/core/index-text/ Text Indexes New in version 2.4. To perform queries that access the text index, use the $text query operator. Whereas if you click on the help for searching the index you created with the $text operator, it reads: http://docs.mongodb.org/manual/reference/operator/query/text/#op._S_text $text New in version 2.6. Seems to be 2.4 but still having problems wiht it.

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  • .NET Windows Service, threads and garbage collection (possible memory leaks)

    - by Evgeny
    I am developing a .NET Windows service that is creating a couple of threads and then uses these threads to send print jobs to printers (there is a thread for each printer). I have some issues which sometimes can be fixed by restarting the service. Some issues also arise when the service has been running for a while. This makes me suspect a possible memory leak. So, a couple of questions: Would a garbage collector collect an object if it was created inside a thread, or will the object exist until the thread is stopped/terminated? What tools can I use to monitor the amount of memory used by a Windows service and by a thread that I am starting programmatically?

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  • Rails: unexpected behavior updating a shared instance

    - by Pascal Lindelauf
    I have a User object, that is related to a Post object via two different association paths: Post --(has_many)-- comments --(belongs to)-- writer (of type User) Post --(belongs to)-- writer (of type User) Say the following hold: user1.name == "Bill" post1.comments[1].writer == user1 post1.writer == user1 Now when I retrieve the post1 and its comments from the database and I update post1.comments[1].writer like so: post1.comments[1].writer.name = "John" I would expect post1.writer to equal "John" too. But it doesn't! It still equals "Bill". So there seems to be some caching going on, but the kind I would not expect. I would expect Rails to be clever enough to load exactly one instance of the user with name "Bill"; instead is appears to load two individual ones: one for each association path. Can someone explain how this works exactly and how I am to handle these types of situations the "Rails way"?

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  • Storing GenericForeignKey content_type in another model?

    - by slypete
    I have a typical definition/instance situation in my data modeling. I'm trying to store the content_type of a GenericForeignKey in another model (the definition model) like so: class IndicatorFieldInstance(models.Model): definition = models.ForeignKey(IndicatorField) object_id = models.PositiveIntegerField() content_object = generic.GenericForeignKey(definition.content_type, 'object_id') indicator_instance = models.ForeignKey(IndicatorInstance) I've also tried it like this: content_object = generic.GenericForeignKey('definition__content_type', 'object_id') Neither of these methods seem to work. Is it possible to achieve this? For reference, here's the definition model: class IndicatorField(models.Model): name = models.CharField(max_length='255') content_type = models.ForeignKey(ContentType) indicator = models.ForeignKey(Indicator) Thanks, Pete

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  • How do file references within a PHP Objects work?

    - by bender
    I'm trying to create an PHP object that can load objects in other files on demand when needed. My problem is that when I reference the files based on file location for the class definition, it can not find the files. So file structure: /Test.php /os/os.php (extends kernel) /os/kernel.php /os/libraries/lib1.php /os/libraries/lib2.php /os/libraries/lib3.php In kernel.php, the libraries are referenced as 'libraries/lib1.php'. If I create an "os" object in Test.php. The lib files are not found.

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  • Converting JBOSS annotations to xml

    - by sixtyfootersdude
    Good Morning, I was just hoping that someone could point me to a reference that defines about what JBOSS annotations are equivalent to what xml tags. I am particularly interested in these tags: @WebContext in org.jboss.ws.annotation.WebContext and @SecurityDomain in org.jboss.annotation.security.SecurityDomain

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  • store data in asp.net pages (Not Sessions)

    - by ARB
    I am creating 4 asp.net pages. first three pages have 'CONTINUE' button and last page has 'SUBMIT' button. I am not allowed to use Sessions to store first three pages data. and i need to use 'BACK' button on last three pages. when i click 'BACK' button i need to maintain the previous page data entered by user. As my pages do some postbacks, i cannot use javascript.history function. My restrictions are: As the application is served from a web farm, a session object cannot be used. However, for the purpose of this excersise, consider session object as database-like persistent space where you can store your data. your code should show an easy way to switch to a different persistent space. What is databse like persistent space and how to write a code to switch to different persistent space?... Please give me some idea on how to proceed.... Thank you

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  • Active Record like functionality on array instance variable

    - by rube_noob
    I would like to write a module that provides active record like functionality on an array instance variable. Examples of its use would be x = Container.new x.include(ContainerModule) x.elements << Element.new x.elements.find id module ContainerModule def initialize(*args) @elements = [] class << @elements def <<(element) #do something with the Container... super(element) end def find(id) #find an element using the Container's id self #=> #<Array..> but I need #<Container..> end end super(*args) end end The problem is that I need the Container object within these methods. Any reference to self will return the Array, not the Container object. Is there any way to do this? Thanks!

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  • Manipulating individual rows of a datagrid

    - by pfranchise
    Hey, recently I started working on a webpage that has a datagrid. I understand how to add datasources and that sort of thing, or at least I am starting to get it. But my question is about manipulating individual rows or cells. Is that only possible during the databind event handler, that is the only place I have been able to do it so far. I am sure there is a more abstract way of doing the things I want to do, but there are times where I just want to say Datagrid.add(row). I mean, if the datagrid is made up of a certain object type, can I make a new object of that type and just chuck it on the end? I am still new to this stuff, so perhaps what I want to do would defeat the purpose of this added abstraction, but figured I would ask around. Thanks for any advice, tips, or tricks people feel like sharing. Edit: for clarification I am using c#, entity framework, asp.net, and an SQL database.

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  • Javascript: Passing large objects or strings between function considered a bad practice

    - by Mr. Smee
    Is it considered a bad practice to pass around a large string or object (lets say from an ajax response) between functions? Would it be beneficial in any way save the response in a variable and keep reusing that variable? So in the code it would be something like this: var response; $.post(url, function(resp){ response = resp; }) function doSomething() { // do something with the response here } vs $.post(url, function(resp){ doSomething(resp); }) function doSomething(resp) { // do something with the resp here } Assume resp is a large object or string and it can be passed around between multiple functions.

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  • Could not load file or assembly or one of its dependencies. The located assembly's manifest definiti

    - by kp
    Hello, I changed some names of nameapces, assemblies in one of exsisting project(C# and ASP.NET). But when I try to debug it; I get this error. Could not load file or assembly 'HR' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040). I have replced DFI with HR in the code. Please help, Thank you

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  • Removing a UIView from its superView and expanding its frame to full screen

    - by Magic Bullet Dave
    I have an object that is a subclass of UIView that can be added to a view hierarchy as a subView. I want to be able to remove the UIView from its superView and add it as a subView of the main window and then expand to full screen. Something along the lines of: // Remove from superView and add to mainWindow [self retain]; [self removeFromSuperView]; [self addSubView:mainWindow]; // Animate to full screen [UIView beginAnimations:@"expandToFullScreen" context:nil]; [UIView setAnimationDuration:1.0]; self.frame = [[UIScreen mainScreen] applicationFrame]; [UIView commitAnimations]; [self release]; Firstly am I on the right lines? Secondly, is there an easily way for the object to get a pointer to the mainWindow? Thanks Dave

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  • what is wrong: "value Parsers is not a member of package scala.util.parsing.combinator"?

    - by Nick Fortescue
    I've got the above odd error message that I don't understand "value Parsers is not a member of package scala.util.parsing.combinator". I'm trying to learn Parser combinators by writing a C parser step by step. I started at token, so I have the classes: import util.parsing.combinator.JavaTokenParsers object CeeParser extends JavaTokenParsers { def token: Parser[CeeExpr] = ident } abstract class CeeExpr case class Token(name: String) extends CeeExpr This is as simple as I could make it. The code below works fine, but if I uncomment the commented line I get the error message given above: object Play { def main(args: Array[String]) { //val parser: _root_.scala.util.parsing.combinator.Parsers.Parser[CeeExpr] CeeParser.token val x = CeeParser.token print(x) } } In case it is a problem with my setup, I'm using scala 2.7.6 via the scala-plugin for intellij. Can anyone shed any light on this? The message is wrong, Parsers is a member of scala.util.parsing.combinator.

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  • Problem with Models on Master Page View.

    - by user342514
    Have a problem with master page views and models. In the first image, I have a simple view in which I am trying to access the Model properties. None of the model properties are available at this time (this is the problem). If I use a <%= Model.blah % then you can see that the model properties are available. Second photo. In the last photo you will now see that I can access the Model properties that I was trying to access in the first photo. An error will be thrown if viewing this page if you don't first do <%= with the model. CS1061: 'object' does not contain a definition for 'User' and no extension method 'User' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?) http://yfrog.com/8b43656447p So why is this happening?

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  • Creating SVG map from geometry stored in MySQL

    - by Barnabe
    I have a group of geometries stored in MySQl (as polygon and as well-known text) representing counties. I can build a table of geometries and color codes after querying some county data (say GDP per capita). What is the best way to export this as an SVG map? I cannot find any reference to SVG conversion in the MySQL documentation.

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  • PHP Soap Error - Improper SOAP Request

    - by Mem
    Hey, The PHP SOAP client is constructing a soap request that uses "href" to reference other parts of the message. The web service i'm trying to consume does not like this. Is there a way to force it to construct the soap envelope without references? Thanks in advance

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  • Why calling ISet<dynamic>.Contains() compiles, but throws an exception at runtime?

    - by Andrey Breslav
    Please, help me to explain the following behavior: dynamic d = 1; ISet<dynamic> s = new HashSet<dynamic>(); s.Contains(d); The code compiles with no errors/warnings, but at the last line I get the following exception: Unhandled Exception: Microsoft.CSharp.RuntimeBinder.RuntimeBinderException: 'System.Collections.Generic.ISet<object>' does not contain a definition for 'Contains' at CallSite.Target(Closure , CallSite , ISet`1 , Object ) at System.Dynamic.UpdateDelegates.UpdateAndExecuteVoid2[T0,T1](CallSite site, T0 arg0, T1 arg1) at FormulaToSimulation.Program.Main(String[] args) in As far as I can tell, this is related to dynamic overload resolution, but the strange things are (1) If the type of s is HashSet<dynamic>, no exception occurs. (2) If I use a non-generic interface with a method accepting a dynamic argument, no exception occurs. Thus, it looks like this problem is related particularly with generic interfaces, but I could not find out what exactly causes the problem. Is it a bug in the compiler/typesystem, or legitimate behavior?

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  • ASP.NET Elements are null when assigning data source

    - by deccks
    For some reason, all of the objects in my ASP.NET markup are now null when I try to assign values to their properties in the code behind. My project was going fine and then now when I try to assign a data source to a GridView, I get a null reference error. I have no idea why it's doing this. I am not doing nothing special. I am just trying to assign a value to a property to an asp.net element in on the page. The intellisense knows that the element is there and I get no errors when I build the project. It's just when I am running the website I get the null reference. I have been trying to fix this issue for a couple weeks now. Please Help. Thanks. Here is the code: protected void Page_PreRender(object sender, EventArgs e) { LoadData(); } private void LoadData() { Entities context = new Entities(); var types = (from t in context.CustomerTypes select t).OrderBy(t => t.TypeName); gvCustomerTypes.DataSource = types; gvCustomerTypes.DataBind(); } and on in the markup the gridview looks like this: <asp:GridView ID="gvCustomerTypes" runat="server" ShowHeader="true" GridLines="Both" AutoGenerateColumns="false" AlternatingRowStyle-BackColor="AliceBlue" Width="100%"> <Columns> <asp:TemplateField HeaderText="Customer Type Name" HeaderStyle-HorizontalAlign="Left" ItemStyle-HorizontalAlign="Left"> <ItemTemplate> <asp:Label ID="lblType" runat="server" Text='<%# Eval("TypeName") %>' /> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Edit" HeaderStyle-HorizontalAlign="Center" ItemStyle-HorizontalAlign="Center"> <ItemTemplate> <asp:HyperLink ID="HyperLink1" NavigateUrl='<%#Eval("CustomerTypeID", "CreateEditCustomerType.aspx?ID={0}") %>' Text="Edit" runat="server" /> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Delete" HeaderStyle-HorizontalAlign="Center" ItemStyle-HorizontalAlign="Center"> <ItemTemplate> <asp:LinkButton ID="LinkButton1" CommandName='<%#Eval("CustomerTypeID") %>' OnClientClick="javascript:return confirm('Are you sure you want to delete this Customer Type?');" OnCommand="DeleteCustomerType" Text="Delete" runat="server" /> </ItemTemplate> </asp:TemplateField> </Columns> </asp:GridView>

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  • relating data stored in NoSQL DB to data stored in SQL DB

    - by seanbrant
    Whats the best way to use a SQL DB along side a NoSQL DB? I want to keep my users and other data in postgres but have some data that would be better suited for a NoSQL DB like redis. I see a lot of talk about switching to NoSQL but little talk on integrating it with existing systems. I think it would be foolish to throw the baby out with the bath water and ditch SQL all together, unless it makes things easier to maintain and develop. I'm wondering what the best approach is for relating data stored in SQL to my data in redis. I was thinking of something along the line of this. User object stored in SQL Book object in redis, key sh1 hash of value, value is a JSON string Relations stored in redis, key User.pk:books, value redis set of sha1's Anyone have experience, tips, better ways?

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  • Pure virtual destructor in interface

    - by ALOR
    Hello all. Here is my problem. I'm making C++ dll, which extensively relies on instance object exports. So i return my actual instances as a pointers to interface through some exported factory method. Interfaces i use are purely virtual, to avoid linking problame. So i need a pure virtual destructor too, and i implemented one (with empty body, as i googled it). All compiles perfectly well, except... I can't see, if the actual destructors are called or not - because when i added some std::cout << "hello destructor"; i never get to see it. I have some explicit "delete obj", that's not the problem. Am i missing something? Is there another way to delete my object through interface?

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  • how to define a structural type that refers to itself?

    - by IttayD
    I want to create a method sum that I can call on different types, specifically sum(1,2). def sum[A](a1: A, a2: A) = a1 + a2 This fails because the compiler can't tell if A has a method '+' I tried to define a structural type: type Addable = {def +(a: Addable)} This fails because of an illegal cyclic reference How can I achieve this in a type safe way without requiring A to extend a specific trait?

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  • Please Find the error :

    - by jagdeep
    using System; using System.Collections; using System.Configuration; using System.Data; using System.Linq; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.HtmlControls; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Xml.Linq; public partial class Expt : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected void Bttnadd_Click(object sender, EventArgs e) { FileUpload1.SaveAs(MapPath("~/img//"+DateTime.Now.ToString()+FileUpload1.FileName)); } } Exception Details: System.Web.HttpException: ~/img//1/1/2011 1:47:52 PMWinter.jpg is not a valid virtual path.

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