Like this: public class DerivedClass : BaseClass { public DerivedClass(int derivedParam, String baseParam):base(baseParam) { } } The base keyword here calls the base class constructor that matches the provided parameter overload.
Abstract methods means there is no default implementation for it and an implementing class will provide the details. Essentially, you would have abstract class AbstractObject { public abstract void method(); } class ImplementingObject extends AbstractObject { public void method() { doSomething(); } } So, it’s exactly as the error states: your abstract method can not … Read more
You can’t force a particular signature of constructor in your subclass – but you can force it to go through a constructor in your abstract class taking two integers. Subclasses could call that constructor from a parameterless constructor, passing in constants, for example. That’s the closest you can come though. Moreover, as you say, you … Read more
The reason you would use an abstract state is to keep your definition dry when you have a part of your url non-navigable. For example, say that you had a url scheme like the following: /home/index /home/contact However, for whatever reason in your design, this url was invalid (i.e. no purpose for a page): /home … Read more
You have two options: 1. Use a Protocol Define the superclass as a Protocol instead of a Class Pro: Compile time check for if each “subclass” (not an actual subclass) implements the required method(s) Con: The “superclass” (protocol) cannot implement methods or properties 2. Assert in the super version of the method Example: class SuperClass … Read more
It’ll have abstract as one of its modifiers when you call getModifiers() on the class object. This link should help. Modifier.isAbstract( someClass.getModifiers() ); Also: http://java.sun.com/javase/6/docs/api/java/lang/reflect/Modifier.html http://java.sun.com/javase/6/docs/api/java/lang/Class.html#getModifiers()
Before abc was introduced you would see this frequently. class Base(object): def go(self): raise NotImplementedError(“Please Implement this method”) class Specialized(Base): def go(self): print “Consider me implemented”
Yes, but you’ll need to use either pointers or smart pointers (I’d go with this). struct X { virtual ~X() {} //<— as pointed out in the comments // a virtual destructor is required // for correct deletion virtual void foo() = 0; }; struct Y : X { virtual void foo() { } }; … Read more
JavaScript Classes and Inheritance (ES6) According to ES6, you can use JavaScript classes and inheritance to accomplish what you need. JavaScript classes, introduced in ECMAScript 2015, are primarily syntactical sugar over JavaScript’s existing prototype-based inheritance. Reference: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes First of all, we define our abstract class. This class can’t be instantiated, but can be extended. We … Read more
The name property is marked as protected. This was added in TypeScript 1.3 and is now firmly established. The makeSound method is marked as abstract, as is the class. You cannot directly instantiate an Animal now, because it is abstract. This is part of TypeScript 1.6, which is now officially live. abstract class Animal { … Read more