被文档的一个例子弄糊涂了
代码如下
// These abstract contracts are only provided to make the
// interface known to the compiler. Note the function
// without body. If a contract does not implement all
// functions it can only be used as an interface.
abstract contract Config {
function lookup(uint id) public virt
如果我有两个接口:
interface IGrandparent
{
void DoSomething();
}
interface IParent : IGrandparent
{
void DoSomethingElse();
}
然后有两个实现:
//only includes last interface from the inheritance chain
public class Child1 : IParent
{
public void DoSomething()
{
问题的主要部分是使用CRTP和一个基于策略的设计和可变模板。从策略中无法到达主/派生类中的受保护成员或私有成员。由于使用了各种模板,所以我不能像朋友一样声明策略。
问题是,如何将所有策略类设置为派生类的朋友。
考虑到这个CRTP解决方案,什么是支持多个继承级别,并解决了钻石问题,没有虚拟继承。
// Derived - We would like to obtain access to this type of instance
// BaseDerived - Helper type to avoid the diamond problem without virtual inher
背景:给定的接口、实现和使用者
public interface IDoer {
int DoIt(string arg);
}
public class LengthDoer : IDoer {
int _internalState;
public LengthDoer(IDependency dep) { _internalState = dep.GetInitialValue(); }
public int DoIt(string arg) {
_internalState++;
return arg.Length;
在我尝试编写更好的Model方法的过程中,我失败得很厉害。反过来,这也让我在这里提出了我的问题。
这是我的模型:
class Group < ActiveRecord::Base
# Because of inheritance issues with ActiveRecord
# We tell this Relation to use a "false" column to persuade
# The relation to push forward without worrying about Inheritance
self.inheritanc
我在文档中找到了这个例子:
pragma solidity ^0.4.22;
contract owned {
constructor() { owner = msg.sender; }
address owner;
}
// Use `is` to derive from another contract. Derived
// contracts can access all non-private members including
// internal functions and state variables. These cannot be
// access
我有个有趣的问题。考虑以下代码:
public class GenericsTest
{
// An interface with a generic type.
public interface IObject<K>{}
// An class with a generic type
public static class ObjectA<K>
{
// An inner class without generic type, but implementing the interface with generi
public class Test implements X, Y { //X.Y interface are shown below
public void myMethod() {
System.out.println(" Multiple inheritance example using interfaces");
}
public static void main(String[]args) {
Test t=new Test();
让我描述一下情况。我有一堆继承已经实现的表单。
示例:
Form A - Form A1 (inheritance)
- Form A2 (inheritance)
Form B - Form B1 (inheritance)
- Form B2 - FormB21 (inheritance)
- FormB22 (inheritance)
- Form B3 (inheritance)
Interface 1 - Form 1A
我面临的一个问题是,来自包含(外文)头文件的声明类名与我自己的头文件的声明类名发生冲突。但基本上我想用包含的类来组成我的班级。在Golang中,解决方案是使用名为的功能。
我怎样才能做到这一点:
- without renaming my own declaration (or modifying the consumers of my own declaration)?
- and without using inheritance (prefer composition over inheritance)?
- and without altering the foreign
我遇到了final关键字,它显然锁定在一个值中,因此以后不能更改它。但是,当我尝试使用它时,变量x仍然会被更改。我哪里出问题了吗?
public class Class {
// instance variable
private int x;
public Class() {
// initialise instance variables
final int x = 123;
}
public void sampleMethod() {
// trying to change it using final again
final in
我已经阅读了一些关于约束的内容,并且正在尝试在我的存储库模式中实现它。
我想要像下面这样的东西,但不能完全编译它。
public interface IRepository<T>
{
void GetAllData<T>();
}
//This needs to inherit from IRepository
//T has to be a model class
//V has to be a class that implements IEmployeeRepo
public interface IEmployeeRepo<T, V&
我正在使用这个来处理实体继承。我有扩展用户实体的个人和公司实体。
@Entity
@Inheritance
public abstract class User {
@Id
private long id;
@NotNull
private String email;
// getters and settres
}
@Entity
public class Person extends User {
private int age;
// getters and settres and other attributs
}
@Entity
public class Company
考虑以下情况:
(省略了以下内容:构造函数、Getters和Setters、@列注释、@Basic注释、@Table注释、导入和包声明。其余的和我想要的完全一样(甚至是空的注释)
@Inheritance(strategy=InheritanceType.JOINED)
@Entity
public class A {
@Id @GeneratedValue
private long id;
private String aValue;//There are getters and setters for this, but I omitted them
}
@Ent
我知道有一些关于case类的更改计划,比如禁止它们之间的继承:
scala> case class Foo()
defined class Foo
scala> case class Bar() extends Foo()
<console>:9: warning: case class `class Bar' has case ancestor `class Foo'. Case-to-case inheritance has potentially dangerous bugs which are unlikely to be fixed. Y
下面有一个防火墙过滤器,如果带宽阈值未超过,则将ICMP通信量设置为assured-forwarding类:
root@vmx> show configuration firewall filter example | display inheritance no-comments
term policer-example {
from {
protocol icmp;
}
then {
policer class-example;
forwarding-class assured-forwarding;
我有一个有几个片段的应用程序和一个管理它们的活动。为了避免片段之间的耦合,所有的交互和更改都通过活动(但下面是我的问题)在下面的场景中得到循环继承编译时错误:
简言之:
class A extends Z implements B.listenerB, C.listenerC // cyclic inheritance involving A
class B extends Y implements A.listenerA //cyclic inheritance involving B
class C extends Y implements A.listenerA // cycl
我正面临一个问题(由于我的无知),当使用Obj C中的父类的对象实例化时,我无法调用子类中定义的方法
超类
#import <Foundation/Foundation.h>
@interface Automobile : NSObject
-(void)startVehicle;
@end
Sub Class
#import "Automobile.h"
@interface Car : Automobile
-(void)startCar;
@end
Main Class
//Works
Car *myCar = [[Car alloc]in
我是一个硬编码甲骨文的家伙,并试图学习面向对象的概念。我已经用OOPS映射了我对Oracle概念的理解。你能帮我验证一下我的理解吗?
Table definition --> Class
Records/Rows --> Objects
Default value of columns --> Constructor
Creating a Type and assigning to a column --> Inheritance
Package --> Package
Package Spec --> Interface
还有--还有没有其他可以轻松映射
当我试图创建视图模型工厂类时,会出现此错误。我不知道怎么解决这个问题。有人能帮我吗?
Inheritance from an interface with '@JvmDefault' members is only allowed with -Xjvm-default option
class NewTagViewModelFactory(private val repository: PomodoroRepository) : ViewModelProvider.Factory {
override fun <T : ViewModel> create(mod