Question

我想检查通用变量T是User还是Post的类型，它们都符合协议LiveObject

class LiveManager<T:LiveObject> {
    var resources = Dictionary<Int, T>()
    init(){
    }
    func something(){
        //How can I check whether T is a User or a Post?
    }
}

这是我的全班：

import Foundation
import Firebase

protocol LiveObject {
    init(data:JSON)
    func startListeningToFirebase(clientName: String) -> Void
    func stopListeningToFirebase(clientName: String) -> Void
}

class LiveManager<T:LiveObject> {
    let center = NSNotificationCenter.defaultCenter()
    let queue = NSOperationQueue.mainQueue()

    var resources = Dictionary<Int, T>()
    var clients = Dictionary<Int, Set<String>>()

    init(){

    }

    private func addToClientMap(id: Int, clientName: String){
        if clients[id] == nil {
            clients[id] = Set<String>()
            clients[id]!.insert(clientName)
        }else{
            clients[id]!.insert(clientName)
        }
    }

    func getResource(id: Int, clientName: String) -> T?{
        if let resource = resources[id] {
            addToClientMap(id, clientName: clientName)
            return resource
        }else{
            return nil
        }
    }

    func createResource(data:JSON, clientName: String, listenToFirebase: Bool) -> T? {
        if let id = data["id"].int {
            if let resource = resources[id] {
                addToClientMap(id, clientName: clientName)
                if listenToFirebase { resource.startListeningToFirebase(clientName) }
                return resource
            }else{
                resources[id] = T(data: data)
                addToClientMap(id, clientName: clientName)
                if listenToFirebase { resources[id]!.startListeningToFirebase(clientName) }
                return resources[id]
            }
        }
        return nil
    }

    func createResource(id: Int, clientName: String, listenToFirebase: Bool, completion:(resource: T?) -> Void)  {

    }


    func releaseResource(id: Int, clientName: String){
        print(clientName + " -- release resource")
        print(clients)
        if clients[id] != nil {
            clients[id]!.remove(clientName)
            if clients[id]!.count == 0 {
                print("Client count is zero - remove this from resources")
                resources.removeValueForKey(id)
                clients.removeValueForKey(id)
            }
        }
    }

    func startListeningToFirebase(id: Int, clientName: String) -> Bool{
        if let resource = resources[id] {
            resource.startListeningToFirebase(clientName)
            return true
        }else{
            return false
        }
    }

    func stopListeningToFirebase(id: Int, clientName: String) -> Bool{
        if let resource = resources[id] {
            resource.stopListeningToFirebase(clientName)
            return true
        }else{
            return false
        }
    }
}

Answer 1

你可以这样说：

init() {
    if T.self == User.self {
        print("T is User")
    }
    else if T.self == Post.self {
        print("T is Post")
    }
}

然而，虽然你可以做到这一点，但我觉得这样做会破坏使用泛型的目的。

Answer 2

检查isKindOfClass和其他相关检查器，具体取决于您要检查的具体内容。

如何检查我的通用变量的类型？

2 个答案: