inheritance

问题 Hello I need to inherit my schemas in mongoose library. Are there complete plugins for that? Or how should I do that myself? I need to inherit all pre, post, init middleware from a Base schema also. 回答1: You may want to look at using a Mongoose Plugin: http://mongoosejs.com/docs/plugins.html A plugin that does what you want 'out of the box' is here: https://github.com/briankircho/mongoose-schema-extend 回答2: For others looking for this functionality, Mongoose 3.8 now has Schema Inheritance via

问题 I'm a little confused. Basically, I've got 2 different resource managers (AudioLibrary and VideoLibrary) that both inherit from a shared BaseLibrary class. This base class contains references to both audio and video. Both audio and video inherit from a parent class called Media. I'm keeping the data in a map, filled with unique_ptr. But, to my surprise, I've discovered when these pointers are eventually deleted via .erase, only the base destructor for Media is called. I guess I've missed

问题 I have an issue with Knockout where I prototype a user object where the observable properties of my object seem to be overwritten by the last occurrence. Therefore I cannot use the same object more than once otherwise it will be overwritten. Although this is hard to explain, see my fiddle. http://jsfiddle.net/RSEcj/1/ What am I doing wrong? (or is this a bug in Knockout?) How can I fix the problem. 回答1: Because observables are functions and not properties they are represented by a single

问题 Should a Singleton class be allowed to have children? Should we seal it? What are the pro's and con's? For being able to inherit from a Singleton class, we would have to make the constructor protected instead of private. Now, that will be fine in c#, but the protected word in java gives both child-classes and package-classes access to the constructor. Which means not only classes that inherit from our Singleton can access the constructor but other classes in the same package can do it. I'm a

问题 This answer seems to suggest it should work so why does my example kick up a compiler error: class Class1 { protected: long m_memberVar; }; class SubClass1: public Class1 { public: void PrintMember(Class1 memberToPrintFrom) { Console::Write("{0}", memberToPrintFrom.m_memberVar); // <-- Compiler error: error C2248: 'BaseClassMemberAccess::Class1::m_memberVar' : cannot access protected member declared in class 'BaseClassMemberAccess::Class1' } }; [Edit] - changed subclass to a public

问题 Let's start with another behavior: even if you declare a method/variable as private, another instance of the same class can access it. That's OK I can live with it. I call these class-private and not instance-private. Now the question part: For example, at runtime I want to be able to check that all String variables in this class are not null, and if they are null they should be changed to the string "NULL". I can run through the variables using reflection and get their values. But if I

问题 Here is my issue : I would like to use a subclass of SurfaceInkCanvas in my MyWindow. I created a C# class like this : namespace MyNamespace { public class SubSurfaceInkCanvas : SurfaceInkCanvas { private MyWindow container; public SubSurfaceInkCanvas() : base() { } public SubSurfaceInkCanvas(DrawingWindow d) : base() { container = d; } protected override void OnTouchDown(TouchEventArgs e) { base.OnTouchDown(e); } } } And I would like to use it in my XAML window. Is it something like this ?

问题 How do I properly extend a custom JavaFX component to add or modify its GUI components if it uses FXML for the view? As an example scenario, suppose I use the following approach of creating a custom JavaFX component: SpecializedButton.java (Controller) package test; import java.io.IOException; import javafx.fxml.FXML; import javafx.fxml.FXMLLoader; import javafx.scene.control.Button; import javafx.scene.control.Label; import javafx.scene.layout.HBox; public class SpecializedButton extends

问题 Every object in .NET inherits (directly or indirectly) from the common root base "Object". Is there such a common object root in C++? How do I pass any object to a function? public void DoSomeStuff(object o) { ... } EDIT: To clarify, the purpose: In that function I want to invoke a pointer to member function. For that I need the object instance and pointer to the required function. To simplify readability I want to make a wrapper containing the both required information. I'm not sure if that

问题 Every object in .NET inherits (directly or indirectly) from the common root base "Object". Is there such a common object root in C++? How do I pass any object to a function? public void DoSomeStuff(object o) { ... } EDIT: To clarify, the purpose: In that function I want to invoke a pointer to member function. For that I need the object instance and pointer to the required function. To simplify readability I want to make a wrapper containing the both required information. I'm not sure if that