Possible Duplicate: In Scala, how can I subclass a Java class with multiple constructors? Hello all clever people I'm currently having a little problem where I need to invoke different super methods based on which constructor I invoke. In short it is something like this: class HelpfulJList(model: ListModel) extends JList(mo...
I have a constructor attempting to initialize a field in a base class. The compiler complains. The field is protected, so derived classes should have access. //The base class: class BaseClass { public: BaseClass(std::string); BaseClass(const BaseClass& orig); virtual ~BaseClass(); const std::string GetData() const; ...
Which are the guidelines for choosing between template duck-typing and pure virtual base class inheritance? Examples: // templates class duck { void sing() { std::cout << "quack\n"; } }; template<typename bird> void somefunc(const bird& b) { b.sing(); } // pure virtual base class class bird { virtual void sing() = 0; }; c...
Possible Duplicate: Performing Inheritance in Javascript What are the ways to implement inheritance in JavaScript Which one is the best and why? ...
Hi everyone, One way to hack limited form of polymorphism in C is to do something like this: typedef struct { int x; } base; typedef struct { base super; int y; } derived; Now you can refer to a derived instance as a base instance, depending on how the variable is cast, ie: derived my_derived; my_derived.y = 10; my_der...
In my game I have a base class of Loot which has methods universal to anything which can be picked up by the player and stored in his inventory. This would include potions, equipment, ammo, etc. I can equip arrows, but not potions. So Arrow would be a subclass of Ammo, which would ultimately derive from Loot. I can drink a potion but not...
I'm so confused with the output of the following code: #include <iostream> using namespace std; class Parent { public: Parent() : x(2) { } virtual ~Parent() { } void NonVirtual() { cout << "Parent::NonVirtual() x = " << x << endl; } private: int x; }; class Child : public Parent { public: Child() : x(1) { } ...
Hello All I'm currently working on a port of a jEdit plugin to write all code in Scala. However Im forced at a certain point to implement my own Comparator. My simplified code is as follows: class compare extends MiscUtilities.Compare { def compare(obj1: AnyRef, obj2: AnyRef): Int = 1 } The MiscUtilities.Compare has the following ...
Possible Duplicate: Multiple Inheritance in C# In the following example, I want the Shirt to automatically inherit the properties of both the Material and Pigment classes. Is this even possible in C#? public class Material { public enum FabricTypes { Cotton, Wool, Polyester, Nylon } public FabricTypes Fabric { get; se...
Simple example: class A end class B < A end Then, how can I judge whether class B is inherited from class A? Is there a method somehow like is_a? or maybe called is_child_of?? I can't find one. ...
Please refer to the Java code below: class Base{ Base(){ System.out.println("Base Constructor"); method(); } void method(){} } class Derived extends Base{ int var = 2; Derived(){ System.out.println("Derived Constructor"); } @Override void method(){ System.ou...
I am trying to get a list of all objects in the database of a specified type. I have done this before when the type was known at compile time, but now I am trying to pass a type into the method and have the method return all the records of that specified type, and I can't get it working. I have tried the following: public IList<W...
I am trying to make a script in which different classes (e.g. Database, Utilities, Config) are all used to form one central Main class. I have tried extending a chain of them: Main -> Utilities -> Database -> Configuration But how can I set the different parts so that they can be called like this: <?php $this->db->select("WAFFLE...
Dear friends, I need your help in the following matter : in my django models, the following classes exist : class QItem(models.Model) class Question(QItem) class QuestionSet(QItem): items = models.ManyToManyField(QItem, blank=True, null=True, through='Ordering', related_name="contents") class Ordering(models.Model): item ...
I have multiple constructor in a Java class. public class A{ public A(){...} public A(String param){...} public A(String param, Object value} } Now I want to create a Scala class that inherit from that class class B extends A{ super("abc") } But this syntax is invalid. Scala is complaining that '.' expected but '(' found. ...
I can't do this interface InterfaceA { void MethodA(); } class ClassA : InterfaceA { virtual void InterfaceA.MethodA() // Error: The modifier 'virtual' is not valid for this item { } } Where the following works class ClassA : InterfaceA { public virtual void MethodA() { } } Why? How to circumvent th...
I've been using Codeigniter to construct the front end of a moderately sized application, and have run into an issue with--what I think may be--inheritance in PHP. Here is what I am trying to do: In following the MVC architecture, I found that I was duplicating a lot of code across models, and decided to create a common Model from which...
Say I have two Activities in an Android application, EditPerson and EditEmployee. It would seem natural to have the EditPerson Activity be a base class for the EditEmployee Activity and define methods that marshal data to and from the Views defined in the layout. The EditPerson Activity's implementation would push (for example) the "Na...
I have created a type like this: TypeBuilder tb = moduleBuilder.DefineType(myname, TypeAttributes.Class | TypeAttributes.Public, typeof(BaseClass), new Type[] { typeof(ImyInterface) }); Then lots of ilgenerating code follows for constructors, methods etc. When I start using the class I noticed something strange. I want to check...
Why do I get a compilation error when I call a base-class function with a pointer to a pointer to an inherited class? Example: class cFoo {}; class cBar : public cFoo {}; void func1(cFoo *) {} // base class void func2(cFoo **) {} // base class void main(void) { cBar bar, *pbar; // inherited class func1(&bar); // compiles ...