For the longest time now, I thought that the two functions above were the same. But in actuality, while they may do exactly the same thing between open and closed braces (which in this case is nothing at all), what’s going on behind the scenes is dif…

In this example: protocol MyProtocol { func testFuncA() } extension MyProtocol { func testFuncA() { print("MyProtocol's testFuncA") } } class MyClass : MyProtocol {} let object: MyClass = MyClass() object.testFuncA() static dispatch is used. The…

一.测试代码: //protocol DiceGameDelegate: AnyObject { //} // //@objc protocol OcProtocol{ //    @objc func OcFunc() //} protocol SeedProtocol { func NormalFunc() func ExtenImpFunc() //@objc func OcFunc() } extension SeedProtocol{ func ExtenImpFunc(){} fun…

简介 2014年,苹果公司在WWDC上发布Swift这一新的编程语言.经过几年的发展,Swift已经成为iOS开发语言的“中流砥柱”,Swift提供了非常灵活的高级别特性,例如协议.闭包.泛型等,并且Swift还进一步开发了强大的SIL(Swift Intermediate Language)用于对编译器进行优化,使得Swift相比Objective-C运行更快性能更优,Swift内部如何实现性能的优化,我们本文就进行一下解读,希望能对大家有所启发和帮助. 针对Swift性能提升这一问题,我们可…

简介 2014年,苹果公司在WWDC上发布Swift这一新的编程语言.经过几年的发展,Swift已经成为iOS开发语言的“中流砥柱”,Swift提供了非常灵活的高级别特性,例如协议.闭包.泛型等,并且Swift还进一步开发了强大的SIL(Swift Intermediate Language)用于对编译器进行优化,使得Swift相比Objective-C运行更快性能更优,Swift内部如何实现性能的优化,我们本文就进行一下解读,希望能对大家有所启发和帮助. 针对Swift性能提升这一问题,我们可…

Holding Your Objects In general, your programs will always be creating new objects based on some criteria that will be known only at run time. You can't rely on creating a named reference to hold each one of your objects. The compiler-supported type…

In this example: protocol MyProtocol { func testFuncA() } extension MyProtocol { func testFuncA() { print("MyProtocol's testFuncA") } } class MyClass : MyProtocol {} let object: MyClass = MyClass() object.testFuncA() static dispatch is used. The…

To solve the general programming problem, you need to create any number of objects, anytime, anywhere. So you can't rely on creating a named reference to hold each one of your objects. Java has several ways to hold objects: 1. the compiler-supported…

When a class literal is passed among methods to communicate both compile-time and runtime type information. Map<Class<T>, Object> Class's cast method The dynamic analog of Java's cast operator. It simply checks that its argument is an instance…

The beginning of this chapter introduced the idea of writing code that can be applied as generally as possible. To do this, we need ways to loosen the constraints on the types that our code works with, without losing the benefits of static type check…

AMQP 0-9-1 Model Explained — RabbitMQ http://next.rabbitmq.com/tutorials/amqp-concepts.html AMQP 0-9-1 Model Explained About This Guide This guide provides an overview of the the AMQP 0-9-1 protocol, one of the protocols supported by RabbitMQ. High-l…

Why Elixir   为什么要学习Elixir?答案很简单,为了更好的学习Erlang.这么无厘头的理由? Erlang语法设计几乎没有考虑过取悦开发者,所以学习之初的门槛略高.对于已经克服了最初语法障碍的同学,Elixir其实没有什么吸引力. 在Elixir之前已经有很多类似的项目,比如http://lfe.github.io Elixir类似思路的还有http://reia-lang.org 在前,但Elixir显然做得更好一些.看这些语言的时候,会有一种感觉:把这语言语法层面做优化调整…

上一篇介绍了在Bluemix Containers服务中使用docker hub镜像和container的高可用配置.接下来我们尝试如何在容器中使用持久存储. 在Bluemix的Containers服务中,文件共享(File Share)是持久的共享存储区域,每个docker容器的Volume都保存在File Share中.借用官网的一张图来说明Organization,Space,File Share, Volume和container之间的关系: 显然首先需要创建一个文件共享,但是通过web…

上一篇中介绍了Bluemix的Containers服务以及如何使用自定义的docker image创建一个容器实例并对外提供服务.除了自定义镜像之外,Bluemix Containers还可以使用Docker Hub上的image来创建容器实例,前提是这些image必须是公共的(public). Bluemix的CLI可以完成从Docker Hub复制镜像的任务. registry.ng.bluemix.net/htcn_us_south_1/tomcat: 执行上述命令后,就把一个tomcat…

国际版的Bluemix目前有三个region,US South,United Kingdom和Sydney.其中US South是功能最全的,UK其次,Sydney功能最少.Containers服务在US和UK两个region中都可以使用. 为了减少不必要的麻烦,我使用了一个在国外的安装了Ubuntu 16.04操作系统的虚拟机作为客户端,如果你想体验一把国内pull/push docker镜像的酸爽,同时还想测试一下在Windows 10自带的Linux环境中运行docker的话,那么可以放心…

Framework类库中的泛型 泛型可以使代码重用,提高开发效率 CLR允许在引用类型.值类型或接口中定义泛型方法: CLR允许创建泛型引用类型.泛型值类型(枚举不允许创建).泛型委托类型和泛型接口类型: System.Collections.Generics中定义了List<T>,<T>表示它操作的是一个未指定数据类型:定义泛型类型或方法时,T是一个变量名,在源代码中能够使用一个数据类型的任何位置都能用T,例如方法参数.返回值等等. 泛型参数变量要么称为T,要么以T开头(如Tke…

30.2 The Level Of Management Protocols Originally, many wide area networks included management protocols as part of their link level protocols. If a packet switch began misbehaving, the network manager could instruct a neighboring packet switch to se…

首先django-restframework是基于django的一个框架.   mixins.py中开头是这样写的: Basic building blocks for generic class based views. We don't bind bahaviour to http method handlers yet, whick allows mixin classes to be composed in interesting ways.   generics是把对数据库的增删改查都…

docker run -d -P --name web training/webapp python app.py # -name means give the to-be-run container a name 'web'. -P means connect web to default network space bridge docker network ls docker run -itd --name=networktest ubuntu #container named netwo…

yarn rm的管理页面中显示了集群的概况,其中有一个指标叫Containers Reserved . 预留的容器,为什么会预留,集群的资源使用饱合,新的app请求的资源一般会进入pending状态,为什么需要预留, 查阅资料说是,如果app申请的资源不太容易分配,比如新的app是一个计算密集型的,一个task需要6个vcores,其他任务需要一个, 则刚释放的资源如果不预留,就会被其他任务使用,而这样有失公平. 这也是yarn 公平调度器的一个特性,有关公平调度器的更多说明,请阅读: Fair…

Network containers Estimated reading time: 5 minutes If you are working your way through the user guide, you just built and ran a simple application. You've also built in your own images. This section teaches you how to network your containers. Launc…

Delphi 2009 新增了泛型容器单元: Generics.Collections, 同时还有一个 Generics.Defaults 单元做支持. Generics.Collections 包含了以下实用类:TList<T>TQueue<T>TStack<T>TDictionary<TKey,TValue>TObjectList<T>TObjectQueue<T>TObjectStack<T>TObjectDicti…

TQueue 和 TStack, 一个是队列列表, 一个是堆栈列表; 一个是先进先出, 一个是先进后出. TStack 主要有三个方法.一个属性:Push(压栈).Pop(出栈).Peek(查看下一个要出栈的元素);Count(元素总数). 本例效果图: 代码文件: unit Unit1; interface uses   Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,   Dialogs, S…

TQueue 和 TStack, 一个是队列列表, 一个是堆栈列表; 一个是先进先出, 一个是先进后出. TQueue 主要有三个方法.一个属性:Enqueue(入列).Dequeue(出列).Peek(查看下一个要出列的元素);Count(元素总数). 本例效果图: 代码文件: unit Unit1; interface uses   Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,   Dia…

正常运行以下命令 sudo docker run --rm busybox echo helloworld /var/log/upstart/docker.log 日志如下: // :: POST /v1./containers/create [339dd1d9] +job create() [339dd1d9] -job create() = OK () // :: POST /v1./containers/5abf93d6f3f8fc6166f12fb0682d3f4d8a056cb7a07…

In the Java community there's been a rush of lightweight containers that help to assemble components from different projects into a cohesive application. Underlying these containers is a common pattern to how they perform the wiring, a concept they r…

Category 要扩展一个不可修改的类,通常的做法是为该类创建一个子类,在子类中实现想要实现的方法,在Object-C中,可以通过category来实现,并且实现方式更为简单. 现在有如下定义:一个包含4个方法的Fraction类 @interface Fraction : NSObject @property int num, den; -(void) setTo:(int) n over:(int) d; -(void) reduce; -(double) converToNum; -(v…

The layout system is one of the most powerful parts of Ext JS. It handles the sizing and positioning of every Component in your application. This guide covers the basics of how to get started with layouts. 布局系统是 Ext JS 的最强大的部分之一.它可以处理您的应用程序中的每个组件的大小和…

Events, Protocols and Delegates   事件.协议和委托 This article presents the key iOS technologies used to receive callbacks and to populate user interface controls with data. These technologies are events, protocols, and delegates. This article explains what…

协议定义了一个蓝图,规定了用来实现某一特定工作或者功能所必须的方法和属性.类.结构体或者枚举类型都可以遵循协议,并提供具体实现来完成协议定义的方法和功能.任意能满足协议要求的类型被称为遵循conform这个协议. 除了遵循协议的类型必须实现那些指定的规定以外,还可以对协议进行扩展,实现一些特殊的规定或者一些附加的功能,使得遵循的类型能够受益. 协议的公式: protocol SomeProtocol { // 协议内容 } 要使类遵循某个协议,需要在类型名称后加上协议名称,中间以冒号:分隔,作为…