I get the following error message (reduced to the important part) when I'm compiling my classes: reference to keySet is ambiguous, both method keySet() in java.util.SortedMap<E,capture#614 of ?> and method keySet() in test.ImmutableMap<E,capture#614 of ?> match return map.keySet().iterator(); ^ map is of type Immutab...
Hi All, As I am working as a C# developer, I know that we can implement multiple inheritance by use of Interface. Can anybody please provide me link OR code for how to achieve multiple inheritance with C#. I want code for how to achieve multiple inheritance in C# with the use of Interface. Thanks in advance. ...
When you have an UIViewController and UITableViewController classes and you wanted to let these two do some common stuff in their - (void)viewDidLoad how could you achieve this in Objective-C without actually duplicating your code? I tried to create MyUIViewController inheriting UIViewController and implement viewDidLoad in there. This ...
Aim To implement a proper and efficient view architecture for my project (with maximum reuse of repeated units) About my project My project involves classes taken by tutors and packs published by tutors. No framework has been used but object orientation and class hierarchies are present for model, controller part. I have the followin...
How do I access overridden members of base classes of base classes? #include <iostream> using namespace std; class A {public: char x; A(){x='A';};}; class B1 : public A {public: char x; B1(){x='B';};}; class B2 : public A {public: char x; B2(){x='B';};}; class C : public B1, public B2 {public: char x; C(){x='C';};}; int main(){ C ...
Hi, I've got a class mapping with two polymorphic inheritance : #test classes class AbstractA(Base): __tablename__ = "abstract_a" id = Column(Integer, primary_key=True) class_name = Column('class_name', String(50)) __mapper_args__ = { 'polymorphic_on': class_name, } #some stuff here class AbstractB(Abs...
I have the following 3 classes: class Node { public Node Parent; // Edit: to clarify, each of these classes has many fields and methods public void Method1() { /*...*/ } public void Method2() { /*...*/ } /* ... */ public void Method30() { /*...*/ } } class Element : Node { public Dictionary<string, string> Attri...
In a lot of my PHP classes, I have this code: private $strError = ""; private $intErrorCode = NULL; private $blnError = FALSE; public function isError() { return $this->blnError; } public function getErrorCode() { return $this->intErrorCode; } private function setError( $strError, $intErrorCode = NULL ) { $this->blnError...
I was pretty sure that the answer to that question was, "Never, ever can a template be the copy constructor." Unfortunately, I just spent 3 hours figuring out why I was getting a warning about recursion, tracked it to the copy constructor, watched the debugger go insane and not let me look at the recursive code, and finally tracked it d...
The dynamic_cast operator is returning zero (0) when I apply to a pointer that points to an instance of a multiply inherited object. I don't understand why. The hierarchy: class Field_Interface { public: virtual const std::string get_field_name(void) const = 0; // Just to make the class abstract. }; class Record_ID_Interface {...
Hi, (pardon the noob question in advance) I have 4 classes: class Person {}; class Student : public Person {}; class Employee : public Person {}; class StudentEmployee : public Student, public Employee {}; Essentially Person is the base class, which are directly subclassed by both Student and Employee. StudentEmployee employs multip...
Ok obviously I am fighting .net here ... and the answer is probably that i am barking up the wrong tree and should just get on with just using the kind of database design i would of 5 years ago. What I want is to have an abstract object Client and have 2 inherited objects Supplier and Customer. The relationship between client and both ...
I have a templated class that performs an action on the class that is given as template argument. For some of my classes I want to 'group' the functionality in one class, to make it easier for the caller. In fact the code looks something like this (names were changed): template<typename T> class DoSomeProcessing { public: process(T...
I'm trying to embed a browser control in my application (IWebBrowser2). I need to implement IDispatch, IDocHostShowUI, IDocHostUIHandler etc to make this work. I am doing this in pure C++/Win32 api. I'm not using ATL, MFC or any other framework. I have a main class, called TWebf, that creates a Win32 window to put the browser control in...
I have two Java class hierarchies that share a common ancestor and implement a common interface. I need to pass a pointer to one of these things to a method in another class. interface I { ... } class A extends java.awt.Component implements I { ... } class B extends java.awt.Component implements I { ... } class D { Component c; I ...
A very simple case of diamond-type inheritance: class Root: def f(self): print('Root') class A(Root): pass class B(Root): def f(self): print('B') class AB(A, B): pass AB().f() According to Python 3.1.2 documentation: For most purposes, in the simplest cases, you can think of the search for attribute...
Hi, I have a model like this: class Person(models.Model,Subject): name = .. The class Subject is not supposed to be in the Database so, it doesn't extends from models.Model: class Subject: def __init__(self,**kargs): _observers = [] my problem is that the constructor of Subject is never called, so i've tried adding ...
Hi, I've read the questions/answers explaining that there is no multiple inheritance in C#, that we don't even need it, and that it causes too much problems. Now, I'm working on a project where I don't really understand how can I do things without multiple inheritance, without duplicating code. Here's the situation. There is a website...
Hello, I have the following multi-table inheritance situation: from django.db import Models class Partner(models.Model): # this model contains common data for companies and persons code = models.CharField() name = models.CharField() class Person(Partner): # some person-specific data ssn = models.CharField() cla...
Invoking an extension method that works on a interface from an implementor seems to require the use of the this keyword. This seems odd. Does anyone know why? Is there an easier way to get shared implementation for an interface? This irks me as I'm suffering multiple inheritance/mixin withdrawl. Toy example: public interface ITest ...