This question already has answers here: How to invoke the super constructor in Python? (7 answers) Closed 5 years ago. Consider this – a base class A, class B inheriting from A, class C inheriting from B. What is a generic way to call a parent class initialiser in an initialiser? If this still sounds … Read more
I’m thinking about how to represent a complex structure in a SQL Server database. Consider an application that needs to store details of a family of objects, which share some attributes, but have many others not common. For example, a commercial insurance package may include liability, motor, property and indemnity cover within the same policy … Read more
In the section about inheritance in the MDN article Introduction to Object Oriented Javascript, I noticed they set the prototype.constructor: // correct the constructor pointer because it points to Person Student.prototype.constructor = Student; Does this serve any important purpose? Is it okay to omit it? 14 Answers 14
Java 8 introduces default methods to provide the ability to extend interfaces without the need to modify existing implementations. I wonder if it’s possible to explicitly invoke the default implementation of a method when that method has been overridden or is not available because of conflicting default implementations in different interfaces. interface A { default … Read more
At work I’ve been tasked with turning a bunch of HTML files into a simple JSP project. It’s really all static, no serverside logic to program. I should mention I’m completely new to Java. JSP files seem to make it easy to work with common includes and variables, much like PHP, but I’d like to … Read more
I have this in my SCSS file: .class-a{ display: inline-block; //some other properties &:hover{ color: darken(#FFFFFF, 10%); } } .class-b{ //Inherite class-a here //some properties } In class-b, I would like to inherite all properties and nested declarations of class-a. How is this done? I tried using @include class-a, but that just throws an error … Read more
I have a Wicket page class that sets the page title depending on the result of an abstract method. public abstract class BasicPage extends WebPage { public BasicPage() { add(new Label(“title”, getTitle())); } protected abstract String getTitle(); } NetBeans warns me with the message “Overridable method call in constructor”, but what should be wrong with … Read more
How can I make a class or method abstract in Python? I tried redefining __new__() like so: class F: def __new__(cls): raise Exception(“Unable to create an instance of abstract class %s” %cls) but now if I create a class G that inherits from F like so: class G(F): pass then I can’t instantiate G either, … Read more
class A: def __init__(self): print(“world”) class B(A): def __init__(self): print(“hello”) B() # output: hello In all other languages I’ve worked with the super constructor is invoked implicitly. How does one invoke it in Python? I would expect super(self) but this doesn’t work. 7 Answers 7
In JavaScript, I want to create an object instance (via the new operator), but pass an arbitrary number of arguments to the constructor. Is this possible? What I want to do is something like this (but the code below does not work): function Something(){ // init stuff } function createSomething(){ return new Something.apply(null, arguments); } … Read more
