inheritance

问题 I have been reading the answers to the question: Create instance of generic type in Java? I have implemented the approach suggested by Lars Bohl. I adapted his code as follows: import java.lang.reflect.ParameterizedType; import java.lang.reflect.Type; public class ParameterizedTypeEg<E> { public Class<E> getTypeParameterClass() { Type type = getClass().getGenericSuperclass(); ParameterizedType paramType = (ParameterizedType) type; return (Class<E>) paramType.getActualTypeArguments()[0]; }

问题 I a project of mine, written in Qt, I have a QWidget Widget that should display either a MyTreeWidget (inheriting from QTreeWidget ) or a MyTableWidget (inheriting from QTableWidget ) Constraints Widget shouldn't know who it is talking to. Therefore it must (??) own a class inherited by the My(Tree|Table)Widget MyTreeWidget and MyTableWidget share a lot of code and I don't want to copy paste this code. So I thought of making them inherit from a MyGenericView which inherit from

问题 This may be a strange question, but I don't understand how have I managed to get this to work. My intention was to access the super's field from an object that overrides the field. First, what did work (1): class Foo { protected int i = 0; } public class Bar extends Foo { int i = 1; Foo f() { return this; } public static void main (String[] args) { Bar b = new Bar(); System.out.println(b.i); System.out.println(b.f().i); } } I first tried to use something like (2): System.out.println(b.super.i

问题 I want to implement Table Per Type inheritance with Entity framework for an existing database. The database: The inheritance for ImageParagraphs works perfect, but I am not able to make a Table Per Type inheritance with LinkListParagraph because of the different primary keys (ParagraphID; ParagraphID+LinkID): Error 1 Error 3003: Problem in Mapping Fragment starting at line 113: All the key properties (Paragraphs.ParagraphID) of the EntitySet Paragraphs must be mapped to all the key properties

问题 Let's say I have the class A with member int number which has a getter and a setter. Then I make a subclass of A and call it B. Now in the class B I wish to keep the member number , but in this class I want to impose the restriction that number is read-only. How can I do this? 回答1: The need for that is usually a hint that your design is not optimal (as it violates the Liskov substitution principle). Therefore, C# does not really support it. However, here are two ways to kind of implement it:

问题 Why does the System.out.println(b.h + " " + b.getH()); prints the following: Beta 44 <br/> 4 44 (notice this is in the second line) I was expecting it to print something like this: 4 Beta 44 44 (this one is in one line) The reason why I thought it would print this way is because we call b.h first which is 4.Then we call b.getH() which will print Beta 44 44 Here is the code: class Baap{ int h = 4; public int getH(){ System.out.println("Beta " + h); return h; } } class Beta extends Baap{ int h

问题 Hello I have a global array of let's say array = ["A", "B", "C", "D", "E"] I want to design a parent class with 5 children classes like this Parent, Child1, Child2, Child3, Child4, Child5 The Parent class will have a method name getID(); How can i design such that this behavior occur Child1.getID() is array[0] gives "A" Child2.getID() is array[1] gives "B" Child3.getID() is array[2] gives "C" Child4.getID() is array[3] gives "D" Child5.getID() is array[4] gives "E" Is this possible? The

问题 I cannot get inheritance to work across CommonJS modules generated using typescript 1.0 ( tsc is run using --module commonjs ) This fails when two classes inheriting the same base class, call each other "through" the base class. What seems to hapeen is that the first class imports the Base Class, which imports the second class which also imports the Base Class but the last Base Class import is failing. An example illustrating this behaviour is provided below. Is there anything in the

问题 In the following sample class "SomeClass" does not implement "ISomeInterface". Why can't I implement this by passing a more derived interface which does implement the base requirement. Whatever instance would be passed it would still implement the base, am I missing something? namespace Test { public interface IBaseInterface { void DoBaseStuff(); } public interface IChildInterface : IBaseInterface { void DoChildStuff(); } public interface ISomeInterface { void DoSomething(IBaseInterface

问题 I can test normal controllers fine. I cannot test controllers that inherit a base controller. This is how we've been defining subclassed-controllers: app.NavController = app.BaseController.extend({ ... }); This is the base: app.BaseController = Class.extend({ $scope: null, init: function($scope) { this.$scope = $scope; this.defineListeners(); this.defineScope(); }, defineListeners: function() { // this.$scope.$on('$destroy',this.destroy.bind(this)); }, ... }); app.controller('BaseController',