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  • What is the meaning of ": base" in the costructor definition ?

    - by DotNetBeginner
    What is the meaning of ": base" in the costructor of following class(MyClass) ? Please explain the concept behind constructor definition given below for class MyClass. public class MyClass: WorkerThread { public MyClass(object data): base(data) { // some code } } public abstract class WorkerThread { private object ThreadData; private Thread thisThread; public WorkerThread(object data) { this.ThreadData = data; } public WorkerThread() { ThreadData = null; } }

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  • C++ undefined reference

    - by klaus-johan
    Hi , My problem is the following : I have a class A that inherits from an abstract base class. I override all the virtual functions from the base class, and I have a constructor like this : A::A(B* b) { this->b=b; } In the constructor of class B , I have the following piece of code: A* a=new A(this) However this line of code gives the error : undefined reference to 'A::A(B*)' I have absolutly no idea why could this be happening , so any suggestion would be greatly appreciated !

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  • N2Cms, Adding a new property to a ContentPageBase class, corrupts the already entered data.

    - by Nour Sabouny
    i want to modify the ContentPageBase, in a functional site, i tried to add a property called for example (weight), but if there is an existing page in the database, the site will malfunction, and throws an Exception, of (Object reference not set to an instance of an object). how can i correct the already entered data ? public abstract class ContentPageBase : PageBase, ICommentable { [EditableTextBox("Weight", 10, ContainerName = Tabs.Details)] //newly added property. public virtual int Weight { get { return (int)GetDetail("Weight"); } set { SetDetail("Weight", value); } } }

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  • How to implement table-per-concrete-type strategy using entity framework

    - by SDReyes
    Hello Guys! I'm mapping a set of tables that share a common set of fields: So as you can see I'm using a table-per-concrete-type strategy to map the inheritance. But... I have not could to relate them to an abstract type containing these common properties. It's possible to do it using EF? BONUS: The only non documented Entity Data Model Mapping Scenario is Table-per-concrete-type inheritance http://msdn.microsoft.com/en-us/library/cc716779.aspx : P

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  • PHP OOP Design Patterns: Should I Create two seperate classes for registration and form validation?

    - by Joshua Poshua
    So here's my problem: I have two types of registration, registration A and registration B, each will have some of the same fields and some different fields. I was going to create abstract class registration and both A and B would have their own classes that extend from registration. My question is, should I create a seperate Validation class with seperate A and B validation classes that extend? or is there a better pattern to use for something like this? Thanks

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  • FluentNHibernate: mapping a Version property

    - by Brian
    How do I map a Version property using conventions (e.g. IClassConvention, AutomapperConfiguration)? public abstract class Entity { ... public virtual int? Version { get; protected set; } ... } <class ...> <version name="Version" column="version" generated="never" type="Int32" unsaved-value="0" /> </class>

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  • implementing java interface with scala class - type issue

    - by paintcan
    Why on earth won't this compile? Scala 2.8.0RC3: Java public interface X { void logClick(long ts, int cId, String s, double c); } Scala class Y extends X { def logClick(ts: Long, cId: Int,sid: java.lang.String,c: Double) : Unit = { ... } } Error class Y needs to be abstract, since method logClick in trait X of type (ts: Long,cId: Int,s: java.lang.String,c: Double)Unit is not defined

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  • Uploading multiple files using Spring MVC 3.0.2 after HiddenHttpMethodFilter has been enabled

    - by Tiny
    I'm using Spring version 3.0.2. I need to upload multiple files using the multiple="multiple" attribute of a file browser such as, <input type="file" id="myFile" name="myFile" multiple="multiple"/> (and not using multiple file browsers something like the one stated by this answer, it indeed works I tried). Although no versions of Internet Explorer supports this approach unless an appropriate jQuery plugin/widget is used, I don't care about it right now (since most other browsers support this). This works fine with commons fileupload but in addition to using RequestMethod.POST and RequestMethod.GET methods, I also want to use other request methods supported and suggested by Spring like RequestMethod.PUT and RequestMethod.DELETE in their own appropriate places. For this to be so, I have configured Spring with HiddenHttpMethodFilter which goes fine as this question indicates. but it can upload only one file at a time even though multiple files in the file browser are chosen. In the Spring controller class, a method is mapped as follows. @RequestMapping(method={RequestMethod.POST}, value={"admin_side/Temp"}) public String onSubmit(@RequestParam("myFile") List<MultipartFile> files, @ModelAttribute("tempBean") TempBean tempBean, BindingResult error, Map model, HttpServletRequest request, HttpServletResponse response) throws IOException, FileUploadException { for(MultipartFile file:files) { System.out.println(file.getOriginalFilename()); } } Even with the request parameter @RequestParam("myFile") List<MultipartFile> files which is a List of type MultipartFile (it can always have only one file at a time). I could find a strategy which is likely to work with multiple files on this blog. I have gone through it carefully. The solution below the section SOLUTION 2 – USE THE RAW REQUEST says, If however the client insists on using the same form input name such as ‘files[]‘ or ‘files’ and then populating that name with multiple files then a small hack is necessary as follows. As noted above Spring 2.5 throws an exception if it detects the same form input name of type file more than once. CommonsFileUploadSupport – the class which throws that exception is not final and the method which throws that exception is protected so using the wonders of inheritance and subclassing one can simply fix/modify the logic a little bit as follows. The change I’ve made is literally one word representing one method invocation which enables us to have multiple files incoming under the same form input name. It attempts to override the method protected MultipartParsingResult parseFileItems(List fileItems, String encoding) {} of the abstract class CommonsFileUploadSupport by extending the class CommonsMultipartResolver such as, package multipartResolver; import java.io.UnsupportedEncodingException; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; import javax.servlet.ServletContext; import org.apache.commons.fileupload.FileItem; import org.springframework.util.StringUtils; import org.springframework.web.multipart.MultipartException; import org.springframework.web.multipart.MultipartFile; import org.springframework.web.multipart.commons.CommonsMultipartFile; import org.springframework.web.multipart.commons.CommonsMultipartResolver; final public class MultiCommonsMultipartResolver extends CommonsMultipartResolver { public MultiCommonsMultipartResolver() { } public MultiCommonsMultipartResolver(ServletContext servletContext) { super(servletContext); } @Override @SuppressWarnings("unchecked") protected MultipartParsingResult parseFileItems(List fileItems, String encoding) { Map<String, MultipartFile> multipartFiles = new HashMap<String, MultipartFile>(); Map multipartParameters = new HashMap(); // Extract multipart files and multipart parameters. for (Iterator it = fileItems.iterator(); it.hasNext();) { FileItem fileItem = (FileItem) it.next(); if (fileItem.isFormField()) { String value = null; if (encoding != null) { try { value = fileItem.getString(encoding); } catch (UnsupportedEncodingException ex) { if (logger.isWarnEnabled()) { logger.warn("Could not decode multipart item '" + fileItem.getFieldName() + "' with encoding '" + encoding + "': using platform default"); } value = fileItem.getString(); } } else { value = fileItem.getString(); } String[] curParam = (String[]) multipartParameters.get(fileItem.getFieldName()); if (curParam == null) { // simple form field multipartParameters.put(fileItem.getFieldName(), new String[] { value }); } else { // array of simple form fields String[] newParam = StringUtils.addStringToArray(curParam, value); multipartParameters.put(fileItem.getFieldName(), newParam); } } else { // multipart file field CommonsMultipartFile file = new CommonsMultipartFile(fileItem); if (multipartFiles.put(fileItem.getName(), file) != null) { throw new MultipartException("Multiple files for field name [" + file.getName() + "] found - not supported by MultipartResolver"); } if (logger.isDebugEnabled()) { logger.debug("Found multipart file [" + file.getName() + "] of size " + file.getSize() + " bytes with original filename [" + file.getOriginalFilename() + "], stored " + file.getStorageDescription()); } } } return new MultipartParsingResult(multipartFiles, multipartParameters); } } What happens is that the last line in the method parseFileItems() (the return statement) i.e. return new MultipartParsingResult(multipartFiles, multipartParameters); causes a compile-time error because the first parameter multipartFiles is a type of Map implemented by HashMap but in reality, it requires a parameter of type MultiValueMap<String, MultipartFile> It is a constructor of a static class inside the abstract class CommonsFileUploadSupport, public abstract class CommonsFileUploadSupport { protected static class MultipartParsingResult { public MultipartParsingResult(MultiValueMap<String, MultipartFile> mpFiles, Map<String, String[]> mpParams) { } } } The reason might be - this solution is about the Spring version 2.5 and I'm using the Spring version 3.0.2 which might be inappropriate for this version. I however tried to replace the Map with MultiValueMap in various ways such as the one shown in the following segment of code, MultiValueMap<String, MultipartFile>mul=new LinkedMultiValueMap<String, MultipartFile>(); for(Entry<String, MultipartFile>entry:multipartFiles.entrySet()) { mul.add(entry.getKey(), entry.getValue()); } return new MultipartParsingResult(mul, multipartParameters); but no success. I'm not sure how to replace Map with MultiValueMap and even doing so could work either. After doing this, the browser shows the Http response, HTTP Status 400 - type Status report message description The request sent by the client was syntactically incorrect (). Apache Tomcat/6.0.26 I have tried to shorten the question as possible as I could and I haven't included unnecessary code. How could be made it possible to upload multiple files after Spring has been configured with HiddenHttpMethodFilter? That blog indicates that It is a long standing, high priority bug. If there is no solution regarding the version 3.0.2 (3 or higher) then I have to disable Spring support forever and continue to use commons-fileupolad as suggested by the third solution on that blog omitting the PUT, DELETE and other request methods forever. Just curiously waiting for a solution and/or suggestion. Very little changes to the code in the parseFileItems() method inside the class MultiCommonsMultipartResolver might make it to upload multiple files but I couldn't succeed in my attempts (again with the Spring version 3.0.2 (3 or higher)).

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  • C#/.NET Project - Am I setting things up correctly?

    - by JustLooking
    1st solution located: \Common\Controls\Controls.sln and its project: \Common\Controls\Common.Controls\Common.Controls.csproj Description: This is a library that contains this class: public abstract class OurUserControl : UserControl { // Variables and other getters/setters common to our UserControls } 2nd solution located: \AControl\AControl.sln and its project: \AControl\AControl\AControl.csproj Description: Of the many forms/classes, it will contain this class: using Common.Controls; namespace AControl { public partial class AControl : OurUserControl { // The implementation } } A note about adding references (not sure if this is relevant): When I add references (for projects I create), using the names above: 1. I add Common.Controls.csproj to AControl.sln 2. In AControl.sln I turn off the build of Common.Controls.csproj 3. I add the reference to Common.Controls (by project) to AControl.csproj. This is the (easiest) way I know how to get Debug versions to match Debug References, and Release versions to match Release References. Now, here is where the issue lies (the 3rd solution/project that actually utilizes the UserControl): 3rd solution located: \MainProj\MainProj.sln and its project: \MainProj\MainProj\MainProj.csproj Description: Here's a sample function in one of the classes: private void TestMethod<T>() where T : Common.Controls.OurUserControl, new() { T TheObject = new T(); TheObject.OneOfTheSetters = something; TheObject.AnotherOfTheSetters = something_else; // Do stuff with the object } We might call this function like so: private void AnotherMethod() { TestMethod<AControl.AControl>(); } This builds, runs, and works. No problem. The odd thing is after I close the project/solution and re-open it, I have red squigglies everywhere. I bring up my error list and I see tons of errors (anything that deals with AControl will be noted as an error). I'll see errors such as: The type 'AControl.AControl' cannot be used as type parameter 'T' in the generic type or method 'MainProj.MainClass.TestMethod()'. There is no implicit reference conversion from 'AControl.AControl' to 'Common.Controls.OurUserControl'. or inside the actual method (the properties located in the abstract class): 'AControl.AControl' does not contain a definition for 'OneOfTheSetters' and no extension method 'OneOfTheSetters' accepting a first argument of type 'AControl.AControl' could be found (are you missing a using directive or an assembly reference?) Meanwhile, I can still build and run the project (then the red squigglies go away until I re-open the project, or close/re-open the file). It seems to me that I might be setting up the projects incorrectly. Thoughts?

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  • Error "Create a concrete instance!"

    - by dododedodonl
    Hey All, I've got another problem in the same code... I'm getting this error: *** initialization method -initWithFormat:locale:arguments: cannot be sent to an abstract object of class NSString_RegEx: Create a concrete instance! But I don't understand the error or what I should do...

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  • C++ - Breaking code implementation into different parts

    - by Kotti
    Hi! The question plot (a bit abstract, but answering this question will help me in my real app): So, I have some abstract superclass for objects that can be rendered on the screen. Let's call it IRenderable. struct IRenderable { // (...) virtual void Render(RenderingInterface& ri) = 0; virtual ~IRenderable() { } }; And suppose I also have some other objects that derive from IRenderable, e.g. Cat and Dog. So far so good. I add some Cat and Dog specific methods, like SeekForWhiskas(...) and Bark(...). After that I add specific Render(...) method for them, so my code looks this way: class Cat : public IRenderable { public: void SeekForWhiskas(...) { // Implementation could be here or moved // to a source file (depends on me wanting // to inline it or not) } virtual void Render(...) { // Here comes the rendering routine, that // is specific for cats SomehowDrawAppropriateCat(...); } }; class Dog : public IRenderable { public: void Bark(...) { // Same as for 'SeekForWhiskas(...)' } virtual void Render(...) { // Here comes the rendering routine, that // is specific for dogs DrawMadDog(...); } }; And then somewhere else I can do drawing the way that an appropriate rendering routine is called: IRenderable* dog = new Dog(); dog->Render(...); My question is about logical wrapping of such kind of code. I want to break apart the code, that corresponds to rendering of the current object and it's own methods (Render and Bark in this example), so that my class implementation doesn't turn into a mess (imagine that I have 10 methods like Bark and of course my Render method doesn't fit in their company and would be hard to find). Two ways of making what I want to (as far as I know) are: Making appropriate routines that look like RenderCat(Cat& cat, RenderInterface* ri), joining them to render namespace and then the functions inside a class would look like virtual void Render(...) { RenderCat(*this, ...); }, but this is plain stupid, because I'll lose access to Cat's private members and friending these functions looks like a total design disaster. Using visitor pattern, but this would also mean I have to rebuild my app's design and looks like an inadequate way to make my code complicated from the very beginning. Any brilliant ideas? :)

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  • Problem when subClassing NSDate

    - by iFloh
    Hi, I first time tried to subClassed an NSDate to give it 2 methods that I need. Compiles fine, but in runtime I try to access it I get an error. Lets say I just want the current date which is unmodified in the subClass: [myNSDate date]; I get the error -[NSDate initWithTimeIntervalSinceReferenceDate:]: method only defined for abstract class. Define -[myNSDate initWithTimeIntervalSinceReferenceDate:]! what is different?

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  • GA Framework for Virtual Machines

    - by PeanutPower
    Does anyone know of any .NET genetic algorithm frameworks for evolving instructions sets in virtual machines to solve abstract problems? I would be particularly interested in a framework which allows virtual machines to self propagate within a pool and evolve against a fitness function determined by a data set with "good" outputs given expected inputs.

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  • C++ game designing & polymorphism question

    - by Kotti
    Hi! I'm trying to implement some sort of 'just-for-me' game engine and the problem's plot goes the following way: Suppose I have some abstract interface for a renderable entity, e.g. IRenderable. And it's declared the following way: interface IRenderable { // (...) // Suppose that Backend is some abstract backend used // for rendering, and it's implementation is not important virtual void Render(Backend& backend) = 0; }; What I'm doing right now is something like declaring different classes like class Ball : public IRenderable { virtual void Render(Backend& backend) { // Rendering implementation, that is specific for // the Ball object // (...) } }; And then everything looks fine. I can easily do something like std::vector<IRenderable*> items, push some items like new Ball() in this vector and then make a call similiar to foreach (IRenderable* in items) { item->Render(backend); } Ok, I guess it is the 'polymorphic' way, but what if I want to have different types of objects in my game and an ability to manipulate their state, where every object can be manipulated via it's own interface? I could do something like struct GameState { Ball ball; Bonus bonus; // (...) }; and then easily change objects state via their own methods, like ball.Move(...) or bonus.Activate(...), where Move(...) is specific for only Ball and Activate(...) - for only Bonus instances. But in this case I lose the opportunity to write foreach IRenderable* simply because I store these balls and bonuses as instances of their derived, not base classes. And in this case the rendering procedure turns into a mess like ball.Render(backend); bonus.Render(backend); // (...) and it is bad because we actually lose our polymorphism this way (no actual need for making Render function virtual, etc. The other approach means invoking downcasting via dynamic_cast or something with typeid to determine the type of object you want to manipulate and this looks even worse to me and this also breaks this 'polymorphic' idea. So, my question is - is there some kind of (probably) alternative approach to what I want to do or can my current pattern be somehow modified so that I would actually store IRenderable* for my game objects (so that I can invoke virtual Render method on each of them) while preserving the ability to easily change the state of these objects? Maybe I'm doing something absolutely wrong from the beginning, if so, please point it out :) Thanks in advance!

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  • Improving MVP in Scala

    - by Alexey Romanov
    The classical strongly typed MVP pattern looks like this in Scala: trait IView { } trait Presenter[View <: IView] { // or have it as an abstract type member val view : View } case class View1(...) extends IView { ... } case object Presenter1 extends Presenter[View1] { val view = View1(...) } Now, I wonder if there is any nice way to improve on it which I am missing...

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  • How best can I extract a logical model from a physical DB model

    - by Dean
    We have made substantial changes to our physical DB, now as it is the ne dof the project I would like to abstract a logical model from this, to allow me to generate schemas for both Oracle and SQL Server. Can anyone guide me as to the best way to achieve this. I was hoping TOAD data modeller would help but I can't seem to see any options to do what I require?

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  • How i change the Enabled= attribute via a preloaded field

    - by user1904656
    I want to modify the PXUIField Enabled=false/true using an existing boolean field #region LastBatNbr public abstract class lastBatNbr : PX.Data.IBqlField { } protected String _LastBatNbr; [PXDBString(10, IsFixed = true)] [PXUIField(DisplayName = "Last Batch Nbr")] public virtual String LastBatNbr { get { return this._LastBatNbr; } set { this._LastBatNbr = value; } } #endregion

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  • Binding Jar Library

    - by Juliano
    I'm trying to bind a jar library (jCIFS) on MFA, but i'm stuck on some errors, like this one: 'Jcifs.Util.MD4' does not implement inherited abstract member 'Java.Security.MessageDigestSpi.EngineDigest() After some research, i found some topics about this, telling to edit the metadata to change the permissions of the classes, like this: <attr path="/api/package[@name='java.security']/class[@name='MessageDigestSpi']/method[@name='engineDigest']" name="visibility">public</attr> But the error didn't change, and a still won't get what this error means. Anyone ? Thanks.

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  • Mapping One-to-One subclass in Fluent NHibernate

    - by Mike C.
    I have the following database structure: Event table Id - Guid (PK) Name - NVarChar Description - NVarChar SpecialEvent table Id - Guid (PK) StartDate - DateTime EndDate - DateTime I have an abstract Event class, and a SpecialEvent class that inherits from it. Eventually I will have a RecurringEvent class which will inherit from the Event class also. I'd like to map the SpecialEvent class while preserving a one-to-one relationship mapped with the Ids, if possible. Can anybody point me in the correct direction? Thanks!

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  • Eclipse "Add unimplemented methods" method ordering

    - by Steve Kuo
    Eclipse has a feature "Add unimplemented methods" that adds the unimplemented methods for a class (such as when implementing an interface). When Eclipse adds the methods it adds them in alphabetical order. Is there a way to configure Eclipse to add them in the order that they appear in the interface (or abstract class)?

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  • ACL implementation

    - by Kirzilla
    First question Please, could you explain me how simpliest ACL could be implemented in MVC. Here is the first approach of using Acl in Controller... <?php class MyController extends Controller { public function myMethod() { //It is just abstract code $acl = new Acl(); $acl->setController('MyController'); $acl->setMethod('myMethod'); $acl->getRole(); if (!$acl->allowed()) die("You're not allowed to do it!"); ... } } ?> It is very bad approach, and it's minus is that we have to add Acl piece of code into each controller's method, but we don't need any additional dependencies! Next approach is to make all controller's methods private and add ACL code into controller's __call method. <?php class MyController extends Controller { private function myMethod() { ... } public function __call($name, $params) { //It is just abstract code $acl = new Acl(); $acl->setController(__CLASS__); $acl->setMethod($name); $acl->getRole(); if (!$acl->allowed()) die("You're not allowed to do it!"); ... } } ?> It is better than previous code, but main minuses are... All controller's methods should be private We have to add ACL code into each controller's __call method. The next approach is to put Acl code into parent Controller, but we still need to keep all child controller's methods private. What is the solution? And what is the best practice? Where should I call Acl functions to decide allow or disallow method to be executed. Second question Second question is about getting role using Acl. Let's imagine that we have guests, users and user's friends. User have restricted access to viewing his profile that only friends can view it. All guests can't view this user's profile. So, here is the logic.. we have to ensure that method being called is profile we have to detect owner of this profile we have to detect is viewer is owner of this profile or no we have to read restriction rules about this profile we have to decide execute or not execute profile method The main question is about detecting owner of profile. We can detect who is owner of profile only executing model's method $model-getOwner(), but Acl do not have access to model. How can we implement this? I hope that my thoughts are clear. Sorry for my English. Thank you.

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