An object and an instance are the same thing. Personally I prefer to use the word “instance” when referring to a specific object of a specific type, for example “an instance of type Foo”. But when talking about objects in general I would say “objects” rather than “instances”. A reference either refers to a specific … Read more
There is a basic difference, which in short can be described as “the difference between the project of a house and the house itself”. For expert programmers I would just say that “new Backbone.Model” returns an object instance, but “Backbone.Model.extend” returns a constructor function FIRST: a new object (i.e. The house) var TestModel = new … Read more
The preferred syntax is: expect(@object).to be_a Shirt The older syntax is: @object.should be_an_instance_of Shirt Note that there is a very subtle difference between the two. If Shirt were to inherit from Garment then both of these expectations will pass: expect(@object).to be_a Shirt expect(@object).to be_a Garment If you do and @object is a Shirt, then the … Read more
There are several important uses, most of which are basically to disambiguate between instance methods, class methods, and variables. First, this is the best way to define class methods: class Foo def self.bar “class method bar” end def bar “instance method bar” end end Foo.bar #returns “class method bar” foo = Foo.new foo.bar #returns “instance … Read more
One way to bypass the restriction is to use reflections: import java.lang.reflect.Constructor; public class Example { public static void main(final String[] args) throws Exception { Constructor<Foo> constructor = Foo.class.getDeclaredConstructor(); constructor.setAccessible(true); Foo foo = constructor.newInstance(); System.out.println(foo); } } class Foo { private Foo() { // private! } @Override public String toString() { return “I’m a Foo … Read more
You can never instantiate an interface in java. You can, however, refer to an object that implements an interface by the type of the interface. For example, public interface A { } public class B implements A { } public static void main(String[] args) { A test = new B(); //A test = new A(); … Read more
‘self’ is only a reference to the object. ‘del self’ is deleting the ‘self’ reference from the local namespace of the kill function, instead of the actual object. To see this for yourself, look at what happens when these two functions are executed: >>> class A(): … def kill_a(self): … print self … del self … Read more
Yes, there is: var genericListType = typeof(List<>); var specificListType = genericListType.MakeGenericType(typeof(double)); var list = Activator.CreateInstance(specificListType);
I’m not entirely sure what use case you are trying to satisfy. But it is possible to have a factory return instances of an object. You should be able to modify this to suit your needs. var ExampleApplication = angular.module(‘ExampleApplication’, []); ExampleApplication.factory(‘InstancedService’, function(){ function Instance(name, type){ this.name = name; this.type = type; } return { … Read more
Every Activity you make is started through a sequence of method calls. onCreate() is the first of these calls. Each and every one of your Activities extends android.app.Activity either directly or by subclassing another subclass of Activity. In Java, when you inherit from a class, you can override its methods to run your own code … Read more