I assume that with interface you mean a C++ class with only pure virtual methods (i.e. without any code), instead with abstract class you mean a C++ class with virtual methods that can be overridden, and some code, but at least one pure virtual method that makes the class not instantiable. e.g.: class MyInterface { … Read more
When the memory for the atribute 1 & 2 are allocated in the heap ? The memory for the object as a whole is allocated when the new operator is invoked, before the java.lang.Object constructor is entered. Memory is allocated for individual Integer instances in init, but there is no point when memory is allocated … Read more
The documentation does aim to give you an example. You don’t have to follow it. You could provide a default; subclasses are still free to use super() to call your implementation. This is what most of the collections.abc classes do; see the source code. Size for example, returns 0 for __len__: class Sized(metaclass=ABCMeta): # … … Read more
What we want First, let’s define the final class and the base abstract class. public class MyControl : AbstractControl … public abstract class AbstractControl : UserControl // Also works for Form … Now all we need is a Description provider. public class AbstractControlDescriptionProvider<TAbstract, TBase> : TypeDescriptionProvider { public AbstractControlDescriptionProvider() : base(TypeDescriptor.GetProvider(typeof(TAbstract))) { } public override … Read more
What we are having here is two different methods with individual type parameters each. public abstract <T extends AnotherClass> void getAndParse(Args… args); This is a method with a type parameter named T, and bounded by AnotherClass, meaning each subtype of AnotherClass is allowed as a type parameter. public <SpecificClass> void getAndParse(Args… args) This is a … Read more
Instead of calling PropertyInfo.GetCustomAttributes(…), you have to call the static method System.Attribute.GetCustomAttributes(pi,…), as in: PropertyInfo info = GetType().GetProperties(); // this gets only the attributes in the derived class and ignores the ‘true’ parameter object[] DerivedAttributes = info.GetCustomAttributes(typeof(MyAttribute),true); // this gets all of the attributes up the heirarchy object[] InheritedAttributes = System.Attribute.GetCustomAttributes(info,typeof(MyAttribute),true);
In Framework Design Guidelines p 174 states: Avoid naming base classes with a “Base” suffix if the class is intended for use in public APIs. Also : http://blogs.msdn.com/kcwalina/archive/2005/12/16/BaseSuffix.aspx
Without the designers of java.lang.Object telling us, we have to base our answers on opinion. There’s a few questions which can be asked which may help clear it up. Would any of the methods of Object benefit from being abstract? It could be argued that some of the methods would benefit from this. Take hashCode() … Read more
In C#, a class that implements an interface is required to define all members of that interface. In the case of an abstract class, you simply define those members with the abstract keyword: interface IFoo { void Bar(); } abstract class Foo : IFoo { public abstract void Bar(); } Or to put it another … Read more
ES2015 does not have Java-style classes with built-in affordances for your desired design pattern. However, it has some options which may be helpful, depending on exactly what you are trying to accomplish. If you would like a class that cannot be constructed, but whose subclasses can, then you can use new.target: class Abstract { constructor() … Read more