constructor

Is there a way to @Autowire a bean that requires constructor arguments?

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You need the @Value annotation. A common use case is to assign default field values using “#{systemProperties.myProp}” style expressions. public class SimpleMovieLister { private MovieFinder movieFinder; private String defaultLocale; @Autowired public void configure(MovieFinder movieFinder, @Value(“#{ systemProperties[‘user.region’] }”) String defaultLocale) { this.movieFinder = movieFinder; this.defaultLocale = defaultLocale; } // … } See: Expression Language > Annotation … Read more

How to call Base Class’s __init__ method from the child class? [duplicate]

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You could use super(ChildClass, self).__init__() class BaseClass(object): def __init__(self, *args, **kwargs): pass class ChildClass(BaseClass): def __init__(self, *args, **kwargs): super(ChildClass, self).__init__(*args, **kwargs) Your indentation is incorrect, here’s the modified code: class Car(object): condition = “new” def __init__(self, model, color, mpg): self.model = model self.color = color self.mpg = mpg class ElectricCar(Car): def __init__(self, battery_type, model, color, … Read more

Javascript “Not a Constructor” Exception while creating objects

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The code as posted in the question cannot generate that error, because Project is not a user-defined function / valid constructor. function x(a,b,c){} new x(1,2,3); // produces no errors You’ve probably done something like this: function Project(a,b,c) {} Project = {}; // or possibly Project = new Project new Project(1,2,3); // -> TypeError: Project is … Read more

C# Error: Parent does not contain a constructor that takes 0 arguments

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Since you don’t explicitly invoke a parent constructor as part of your child class constructor, there is an implicit call to a parameterless parent constructor inserted. That constructor does not exist, and so you get that error. To correct the situation, you need to add an explicit call: public Child(int i) : base(i) { Console.WriteLine(“child”); … Read more

async constructor functions in TypeScript?

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A constructor must return an instance of the class it ‘constructs’. Therefore, it’s not possible to return Promise<…> and await for it. You can: Make your public setup async. Do not call it from the constructor. Call it whenever you want to ‘finalize’ object construction. async function run() { let topic; debug(“new TopicsModel”); try { … Read more

Initialize parent’s protected members with initialization list (C++)

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It is not possible in the way you describe. You’ll have to add a constructor (could be protected) to the base class to forward it along. Something like: class Parent { protected: Parent( const std::string& something ) : something( something ) {} std::string something; } class Child : public Parent { private: Child() : Parent(“Hello, … Read more

Kotlin secondary constructor

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Update: Since M11 (0.11.*) Kotlin supports secondary constructors. For now Kotlin supports only primary constructors (secondary constructors may be supported later). Most use cases for secondary constructors are solved by one of the techniques below: Technique 1. (solves your case) Define a factory method next to your class fun C(s: String) = C(s.length) class C(a: … Read more

Is a `=default` move constructor equivalent to a member-wise move constructor?

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Yes both are the same. But struct Example { string a, b; Example(Example&& mE) = default; Example& operator=(Example&& mE) = default; } This version will permits you to skip the body definition. However, you have to follow some rules when you declare explicitly-defaulted-functions : 8.4.2 Explicitly-defaulted functions [dcl.fct.def.default] A function definition of the form: attribute-speciļ¬er-seqopt … Read more