inheritance

问题 I have these 3 classes public class Box<O> { public O getItem() {...} } public class CoolBox extends Box<Integer> { ... } public class AmazingBox extends CoolBox { ... } At one point in my code, I need to get the return Type of the method getItem() for the AmazingBox class, but when accessing its methods via reflection, I get Object as the return Type instead of Integer . Is there any way, (plain java or extra libraries) to get Integer as the return Type? This is the code I used to get the

问题 I am trying to write to write a program, but am getting some errors. Base Car Class current speed (property) – default value 0 accelerate (method) drive (method) brand (property) - default value ‘unknown’ max speed (property) - default value 0 Camaro Car Class Inherits Base Car brand (property) - default value ‘Chevy’ max speed (property) – default value 200 Code Scenario: In this example I need to create an instance of Camaro and tell it to drive, I will assume it’s moving in a straight line

问题 I am trying to write to write a program, but am getting some errors. Base Car Class current speed (property) – default value 0 accelerate (method) drive (method) brand (property) - default value ‘unknown’ max speed (property) - default value 0 Camaro Car Class Inherits Base Car brand (property) - default value ‘Chevy’ max speed (property) – default value 200 Code Scenario: In this example I need to create an instance of Camaro and tell it to drive, I will assume it’s moving in a straight line

问题 I am struggling to understand the constructor invocation pattern in Javascript. I have a base object Mammal ( would it be incorrect to use the term class ? ) and an inherited object Cat . In the following code the object Cat correctly inherits from the Mammal object. /* Mammal base Object */ var Mammal = function(name) { this.name = name; } Mammal.prototype.get_name = function() { return this.name; } Mammal.prototype.says = function () { return this.saying || ''; } /* Cat object */ var Cat =

问题 I have a library of classes that describe different pieces of connecting hardware such as nails, screws and bolts that we will call the ConnectorLibrary. I am attempting to build a library on top of that one that will handle analyzing the grip capacity of each class in that library that we will call ConnectorGripAnalysisLibrary. For this question we will work with the classes: Screw , Bolt , and Connector . Both Screw and Bolt inherit from Connector (which is an abstract class) and they are

问题 Base class: Public MustInherit Class Connector Public Event Changed as EventHandler End Class Interface: Public Interface IPlug Event Changed as EventHandler End Interface Derived class: Public Class OutputConnector Inherits Connector Implements IPlug Event Changed as EventHandler Implements IPlug.Changed End Class VB.Net Problem: The Changed event in OutputConnector conflicts with the Changed event in Connector , of course. But I have to implement it to satisfy the IPlug interface. How can I

问题 Has anyone noticed this? Whenever a model uses column_aggregation (inheritance), the schema.sql has 2 CREATE TABLE commands, one creates the basic table, and the other (apart from fields) adds an index on the inheritence column CREATE TABLE Prop (id INT AUTO_INCREMENT, opt_property_type SMALLINT UNSIGNED DEFAULT 251 NOT NULL, property_nature VARCHAR(255), INDEX opt_property_type_idx (opt_property_type), PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci ENGINE = InnoDB;

问题 I was messing around with inheritance in C++ and wanted to know if anyone had any insight on the way it functions. Code below #include <iostream> using namespace std; class AA { int aa; public: AA() {cout<<"AA born"<<endl;} ~AA(){cout<<"AA killed"<<endl;} virtual void print(){ cout<<"I am AA"<<endl;} }; class BB : public AA{ int bb; public: BB() {cout<<"BB born"<<endl;} ~BB() {cout<<"BB killed"<<endl;} void print() {cout<<"I am BB"<<endl;} }; class CC: public BB{ int cc; public: CC() {cout<<

问题 I am not able to access i in my derived class. m.i is not working. Why? public class MyClass { protected int i; public MyClass() { } public virtual void Display() { Console.WriteLine("Base dis"); } } public class MyCla : MyClass { public MyCla() { } int ij = 12; public new void Display() { MyClass m = new MyClass(); // m.i is inaccessible here Console.WriteLine("Derived dis"); } } 回答1: That is because protected variables and properties are only available to derived classes, within the derived

问题 @interface MySuperclass : NSObject { } @end @interface MySuperclass (MyCategory) - (void)myMethod; @end @interface MySubclass : MySuperclass { } @end @interface MySubclass (MyOtherCategory) - (void)myMethod; @end Is it defined which implementation of -myMethod will be called? Kochan states in Programming in Objective-C that: If more than one category declares a method with the same name for the same class, it is not defined which method will be executed when invoked. But I am not sure whether