I am trying to refactor the following code from my render view: <Button href=”#” active={!this.state.singleJourney} onClick={this.handleButtonChange.bind(this,false)} >Retour</Button> to a version where the bind is within the constructor. The reason for that is that bind in the render view will give me performance issues, especially on low end mobile phones. I have created the following code, … Read more
I need to have a class constructor in PHP call its parent’s parent’s (grandparent?) constructor without calling the parent constructor. // main class that everything inherits class Grandpa { public function __construct() { } } class Papa extends Grandpa { public function __construct() { // call Grandpa’s constructor parent::__construct(); } } class Kiddo extends Papa … Read more
I would like to use Class.newInstance() but the class I am instantiating does not have a nullary constructor. Therefore I need to be able to pass in constructor arguments. Is there a way to do this? 8 Answers 8
I have a struct and I would like it to be initialised with some sensible default values. Typically, the thing to do here is to use a constructor but since go isn’t really OOP in the traditional sense these aren’t true objects and it has no constructors. I have noticed the init method but that … Read more
So since I’ve been using Spring, if I were to write a service that had dependencies I would do the following: @Component public class SomeService { @Autowired private SomeOtherService someOtherService; } I have now run across code that uses another convention to achieve the same goal @Component public class SomeService { private final SomeOtherService someOtherService; … Read more
Is there any difference at all between these classes besides the name? class WithClass (): def __init__(self): self.value = “Bob” def my_func(self): print(self.value) class WithoutClass (): value = “Bob” def my_func(self): print(self.value) Does it make any difference if I use or don’t use the __init__ method for declaring the variable value? My main worry is … Read more
Suppose I have two C++ classes: class A { public: A() { fn(); } virtual void fn() { _n = 1; } int getn() { return _n; } protected: int _n; }; class B : public A { public: B() : A() {} virtual void fn() { _n = 2; } }; If I write … Read more
Why does C++ not have a virtual constructor? 23 Answers 23
This question already has answers here: Closed 12 years ago. Possible Duplicate: What is a clean, pythonic way to have multiple constructors in Python? Is it not possible to define multiple constructors in Python, with different signatures? If not, what’s the general way of getting around it? For example, let’s say you wanted to define … Read more
Why does this code: class A { public: explicit A(int x) {} }; class B: public A { }; int main(void) { B *b = new B(5); delete b; } Result in these errors: main.cpp: In function ‘int main()’: main.cpp:13: error: no matching function for call to ‘B::B(int)’ main.cpp:8: note: candidates are: B::B() main.cpp:8: note: … Read more
