Why does the code above compile at all? Phone seems unrelated to Roamable to me? yes because Roamable is an interface it might cause a Run-time exception but not compile time exception, because even if Phone doesn’t implement Roamable, a subclass of Phone might, hence the compiler has no way to know it but at … Read more
As already mentioned this can’t be done with floats, they can’t inherit heights, they’re unaware of their siblings so for example the side two floats don’t know the height of the centre content, so they can’t inherit from anything. Usually inherited height has to come from either an element which has an explicit height or … Read more
It is definitely not good to inherint Child from Parent or Parent from Child. The correct way to do it is to make a base class, let’s say Person and inherit both Child and Parent from it. An advantage of doing this is to remove code repetition, at the moment you have only firstname / … Read more
Since your superclass Person doesn’t have a default constructor, in your subclasses (Student and Staff), you must call the superclass constructor as the first statement. You should define your sub-class constructors like this: Student() { super(“a_string_value”, an_int_value);// You have to pass String and int values to superclass } Staff() { super(“a_string_value”, an_int_value); // You have … Read more
I do so (this is just an example): using System.Reflection; public class DefaultObject { … } public class ExtendedObject : DefaultObject { …. public DefaultObject Parent { get; set; } public ExtendedObject() {} public ExtendedObject(DefaultObject parent) { Parent = parent; foreach (PropertyInfo prop in parent.GetType().GetProperties()) GetType().GetProperty(prop.Name).SetValue(this, prop.GetValue(parent, null), null); } } Using: DefaultObject default = … Read more
This is a variation on Paul McGuire’s DocStringInheritor metaclass. It inherits a parent member’s docstring if the child member’s docstring is empty. It inherits a parent class docstring if the child class docstring is empty. It can inherit the docstring from any class in any of the base classes’s MROs, just like regular attribute inheritance. … Read more
Liskov Substitution Principle Generally you don’t want you method signature to vary in derived types. This can cause problems if you want to swap the use of derived types. This is often referred to as the Liskov Substitution Principle. Benefits of Explicit Signatures At the same time I don’t think it’s correct for all your … Read more
You’ll want to use: Backbone.Model.prototype.clone.call(this); This will call the original clone() method from Backbone.Model with the context of this(The current model). From Backbone docs: Brief aside on super: JavaScript does not provide a simple way to call super — the function of the same name defined higher on the prototype chain. If you override a … Read more
Terminology, terminology… OK, what do we mean by “Foo is inherited”? We mean that if objects of class A have Foo in its interface, then objects of class B which is a subclass of A also have Foo in its interface. Constructors aren’t a part of objects’ interface. They belong directly to classes. Classes A … Read more
In the first situation, Num2 is extending the class Num and since you are not redefining the special method named __init__() in Num2, it gets inherited from Num. When a class defines an __init__() method, class instantiation automatically invokes __init__() for the newly-created class instance. In the second situation, since you are redefining __init__() in … Read more