singleton

Singletons: Pros,Cons, Design Concerns [closed]

由 别来无恙 提交于 2019-12-08 04:55:53
问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 8 years ago . I admit it. I am using singletons. I know what you may all say, and frankly, seeing all these answers on the Internet, saying about

Make Singleton class in Multiprocessing

由 北城余情 提交于 2019-12-08 04:14:22
I create Singleton class using Metaclass , it working good in multithreadeds and create only one instance of MySingleton class but in multiprocessing, it creates always new instance import multiprocessing class SingletonType(type): # meta class for making a class singleton def __call__(cls, *args, **kwargs): try: return cls.__instance except AttributeError: cls.__instance = super(SingletonType, cls).__call__(*args, **kwargs) return cls.__instance class MySingleton(object): # singleton class __metaclass__ = SingletonType def __init__(*args,**kwargs): print "init called" def task(): # create

how to implement Singleton Pattern in my IPhone project?

由 匆匆过客 提交于 2019-12-08 03:49:38
问题 i am working on a project in wich i want to use Singleton Pattern model. i want to any data model of my this project fallow Singleton Pattern. i study the apple documentation regarding this http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/CocoaFundamentals/CocoaDesignPatterns/CocoaDesignPatterns.html#//apple_ref/doc/uid/TP40002974-CH6-SW6 and http://www.oodesign.com/singleton-pattern.html http://www.daveoncode.com/2011/12/19/fundamental-ios-design-patterns-sharedinstance

Android - using Singleton to access hold application settings, and Context

由 ぃ、小莉子 提交于 2019-12-08 03:26:04
问题 I need to access settings from various activities in my Android app. Rather than messing around with SharedPreferences in various activities I want to create a Singleton class, and grab all the settings at once using SharedPreferences in the Singleton. I also want a method in the Singleton to save settings where required, again using SharedPreferences. The trouble with this is that I need an Activity context to use SharedPreferences. Could I pass this into the Singleton.. I've read about

Android Invalid use of SingleClientConnManager: connection still allocated

由 岁酱吖の 提交于 2019-12-08 03:23:50
问题 Please note this question is unique for my HTTP call. I have look around and some ppl say httpResponse.getEntity().consumeContent(); but I can use it, because I need to provide a return data. I call my API doInBackground.... as return api.post("analytics", params); How can I fix the invalid SingleClientConnManager into this http post : public String post(String url, List<NameValuePair> params) { HttpPost request = new HttpPost(BASEURL + url); HttpResponse response; try { request.setEntity(new

Using Singleton in different classes

由 Deadly 提交于 2019-12-08 02:51:23
问题 How do you create a instance of a singleton that can be used in other classes? For Example: //Singleton_Class.h #ifndef Singleton_Class #define Singleton_Class class Singleton { private: static Singleton _instance; Singleton() {} ~Singleton() {} Singleton(const Singleton &); Singleton & operator=(const Singleton &); public: static Singleton &getInstance(){return _instance;} }; Singleton Singleton::_instance; #endif //Main.cpp #include "Singleton_Class.h" int main() { Singleton &s = Singleton:

Memory-leak free Singleton with context

由 蹲街弑〆低调 提交于 2019-12-08 02:27:56
问题 I am trying to implement the following singleton pattern: SingletonClass.getInstance(context).callMethod() While there are a variety of tutorials that explain how to make singletons in Kotlin, none of them address the fact that holding a context in a static field will cause memory leaks in Android. How do I create the above pattern without creating a memory leak? Update: Here is my implementation of CommonsWare's solution #2. I used Koin. Singleton class: class NetworkUtils(val context:

C++ Singleton class getInstance (as java) [duplicate]

由 拟墨画扇 提交于 2019-12-08 01:28:37
问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: Can any one provide me a sample of Singleton in c++? C++ Singleton design pattern C++ different singleton implementations I need some example of Singleton in c++ class because i have never wrote such class. For an example in java I can declare d a static field which is private and it's initialize in the constructor and a method getInstance which is also static and return the already initialize field instance.

Singleton design pattern with double-check lock

由 邮差的信 提交于 2019-12-08 01:21:05
问题 Consider you have the following code: 1. Why do we use double check lock, why single lock is not good enough, please provide detailed example. 2. What are the main drawbacks with this implementation? and how should I prove it? Thanks. public sealed class SomeSingleton5 { private static SomeSingleton5 s_Instance = null; private static object s_LockObj = new Object(); private SomeSingleton5() { } public static SomeSingleton5 Instance { get { if (s_Instance == null) { lock (s_LockObj) { if (s

How do I debug singletons in Objective-C

由 与世无争的帅哥 提交于 2019-12-08 01:04:23
问题 My app contains several singletons (following from this tutorial). I've noticed however, when the app crashes because of a singleton, it becomes nearly impossible to figure out where it came from. The app breakpoints at the main function giving an EXEC_BAD_ACCESS even though the problem lies in one of the Singleton objects. Is there a guide to how would I debug my singleton objects if they were problematic? 回答1: I scanned the article, and while it had some good ideas it also had some bad
订阅 singleton