extends

Java Generics Extends Class Parameter

我是研究僧i 提交于 2019-12-20 03:15:05
问题 I received an error and I have this structure in my program public interface Shapes<T>{ //methods here } public class ShapeAction<T> implements Shapes<T>{ //Methods and implementations here } public class Circle extends ShapeAction<T>{ //Some methods here } The error is pointing at class Circle extends Shapes< T > where it says "T cannot be resolved to a type". If I set T to string the error will go away but that also means I can only use one datatype. What should I put inside the <> so that

Having 2 variables with the same name in a class that extends another class in Java

无人久伴 提交于 2019-12-18 14:54:27
问题 Following is a part of my code for a project: public class Body extends Point{ public double x, y, mass; public Body() { x = y = mass = 0; } public Body(double x, double y, double mass) { this.mass = mass; this.x = x; this.y = y; } } public class Point { public double x; public double y; public Point(double x, double y) { this.x = x; this.y = y; } } I quickly realized that doing this will create two variables inside the Body class called x and two other variables in Body called y. How is this

How to merge objects?

匆匆过客 提交于 2019-12-18 12:05:46
问题 For instance, from these two objects : var object1 = { "color": "yellow", "size": null, "age": 7, "weight": null } var object2 = { "color": "blue", "size": 51, "age": null } I want this ( object2 overrides object1 except for null properties or properties he doesn't have): { "color": "blue", "size": 51, "age": 7, "weight": null } 回答1: Copy var src = { name: 'Apple', price: 5}; var dst= angular.copy(src); deep copy Extend : var mergedObject = angular.extend(dst, src1, src2, ...) shallow copy

Javascript extends class [closed]

扶醉桌前 提交于 2019-12-18 10:11:45
问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 6 years ago . What is the right/best way to extend a javascript class so Class B inherits everything from the class A (class B extends A)? 回答1: Take a look at Simple JavaScript Inheritance and Inheritance Patterns in JavaScript. The simplest method is probably functional inheritance but

Struggling with understanding <? extends T> wildcard in Java

删除回忆录丶 提交于 2019-12-18 07:06:22
问题 I have a very basic question. The code below doesn't compile (assume Apple Extends Fruit): List<? extends Fruit> numbers = new ArrayList<>(); numbers.add(new Apple()); //compile time error When reading about why not, I understand the words but not the concept :). Let's assume first Fruit is NOT an abstract class. I understand that that since we're dealing with multiple subtypes all of which extend Fruit. Supposedly since we can't tell the exact type of fruit, we can't put anything in the

C#'s equivalent of Java's <? extends Base> in generics

我们两清 提交于 2019-12-17 15:35:03
问题 In Java, I can do the following: (assume Subclass extends Base ): ArrayList<? extends Base> aList = new ArrayList<Subclass>(); What is the equivalent in C# .NET? There is no ? extends keyword apparently and this does not work: List<Base> aList = new List<Subclass>(); 回答1: Actually there is an Equivalent(sort of), the where keyword. I don't know how "close" it is. I had a function I needed to do something similar for. I found an msdn page about it. I don't know if you can do this inline for a

Typescript: How to extend two classes?

落爺英雄遲暮 提交于 2019-12-17 06:36:10
问题 I want to save my time and to reuse common code across classes which extends PIXI classes (a 2d webGl renderer library). Object Interfaces: module Game.Core { export interface IObject {} export interface IManagedObject extends IObject{ getKeyInManager(key: string): string; setKeyInManager(key: string): IObject; } } My issue is that the code inside getKeyInManager and setKeyInManager will not change and I want to reuse it, not to duplicate it, here is the implementation: export class

CodeIgniter Dry Navigation

空扰寡人 提交于 2019-12-13 04:43:13
问题 My boss told me make dry navigation dont use repetitive code, for navigation i am trying to extend CI_Controler and with construct load header nav, body, footer files. My question is when i create new controller and when i try to load different view files, how to achive that??? my extended controler class MY_Controller extends CI_Controller { public function __construct() { parent::__construct(); $this->load->view('view_header'); $this->load->view('includes/nav_home'); $this->load->view('view

Use method from T class extending ArrayList<T>

痞子三分冷 提交于 2019-12-12 14:13:11
问题 Not sure if the title makes sense, I will try to explain. I have a CustomList extending ArrayList, T being let's say Class A1 and Class A2, both extending Class A which is a custom Class. I need to do this : public class CustomList<T> extends ArrayList<T> { public CustomList() { super(); } public boolean add(T obj) { /*The method getCustomBoolean() is not defined for the type T*/ if(obj.getCustomBoolean()) { super.add(obj); } return true; } } The method getCustomBoolean() is a Class A method,

How to implement a generic activity that can be extended by normal, List and Map Activities?

Deadly 提交于 2019-12-12 14:10:08
问题 I want to display the same options menu on all of my application's activities. I created a generic Activity that implements the menu, and all my further activies extend it. The problem: when I need to extend other specific activities, like ListActivity and MapActivity, I can't figure out how to extend the generic activity and add the List or Map behaviour to the new class. To deal with the issue I had to create three different generic activities, each extending Activity, ListActivity and