protocols

问题 Within my app, I have multiple UIView subclasses that depend on a model. Each of the classes adopting ' Restorable ' protocol which holds the superclass of the model. Each sub-model describes the specific UIView not-common properties. // Super-model public protocol StoryItem { var id: Int64? { get } } // Parent protocol public protocol Restorable: AnyObject { var storyItem: StoryItem? { get set } } // Specific protocol public struct TextItem: StoryItem { public var id: Int64? public var text:

问题 I'm quite new to C# so please bear with me. I'm writing a relatively simple client server application in C# .NET 4.0. I am using TCP protocol, TCPListener and TCPClient to be more specific. I know how does TCP protocol work in theory. But I must be 100% sure that there will be no (unhandled) errors during data transfers. After I send data how do I know whether data was successfully received. Can I totally rely on the underlying implementation of TCP protocol? So there is no need that I

问题 I am building a server client application using netty and ios, I am facing a problem when the user just turns off WiFi on his/her ios device, the netty server does not know about it. The server needs to know to do cleanup for that user and set him/her offline, but now when the user tries to connect again, the server just tells him that he/she is already online. 回答1: If I understood your problem correctly: You want to listen for client channel closed events in server side and do some session

问题 I am trying to define a protocol "Repository" which requires de definition of a couple of properties (which implement a specific protocol "DataSource") But due to the complexity of my real scenario one of this properties need to be a subprotocol of "DataSource". I reduced the problem to this simple code: protocol DataSource { } protocol ExtraDataSouce: DataSource { func method1() -> String } struct MyDataSource: ExtraDataSouce { func method1() -> String { return "whatever" } } protocol

问题 I found an interesting behaviour which seems like a bug... Based on the behaviour described the following articles: https://medium.com/ios-os-x-development/swift-protocol-extension-method-dispatch-6a6bf270ba94 http://nomothetis.svbtle.com/the-ghost-of-swift-bugs-future The output is not what I expect, when I add SomeSuperclass , rather than directly adopting the protocol. protocol TheProtocol { func method1() } extension TheProtocol { func method1() { print("Called method1 from protocol

问题 More broadly this question is about various approaches to the expression problem. The idea is that your program is a combination of a datatype and operations over it. We want to be able to add new cases without recompiling the old classes. Now Haskell has some really awesome solutions to the expression problem with the TypeClass. In particular - we can do: class Eq a where (==) :: a -> a -> Bool (/=) :: a -> a -> Bool member :: (Eq a) => a -> [a] -> Bool member y [] = False member y (x:xs) =

问题 There are four common protocols for network access of SVN. svn://repos svn+ssh://repos https://repos http://repos The Wikipedia page doesn't say much about the differences of the four different protocols. I've always preferred svn:// , because it is the easiest to set up, but what is the difference and which one is "better"? 回答1: http:// has a serious overhead, especially when dealing with thousands of small files. I used svn for a website that had around 50,000 icons, all saved in SVN. With

问题 I'm a bit confused. What's the difference between protocol A : class { ... } and protocol A{ ... } , and which one we should use in swift? PS： we got an error when we wrote like this protocol A{ ... } weak var delegate: A error : 'weak' cannot be applied to non-class type 回答1: protocol A : class { ... } defines a "class-only protocol": Only class types (and not structures or enumerations) can adopt this protocol. Weak references are only defined for reference types . Classes are reference

问题 I have a homework question which confused me, really badly. Below is a brief explanation of a question. Imagine you are developing an application that stores contact information. The address book may contain many entity types e.g. Human being, a company or anything else that has a contact information. Now instead of explicitly checking every object type write a protocol that declares how an object must behave and successfully appear in your address book. My understanding and efforts of

问题 the question is as follows: if you take a look at any site using addthis (the share button)... once you float over the addthis button, and all of the required assets load take a look at the body of the document using firebug or chrome inspector (not the source, the actual document that is sitting on your screen... the object inspector). you will notice that the additional assets loaded automatically by addthis look something like this: <script type="text/javascript" src="//s7.addthis.com