Should i use thread safe or non thread safe for my Singleton class for my purpose?

Question

I want to implement Singleton and found this acrticle from MSDN with several examples:

http://msdn.microsoft.com/en-us/library/ff650316.aspx

I have application that host WCF service. the application get String from Client, and sent this string to my Singleton. And from Singleton class i am open my Job class that do my stuff (open process..). The job class contain Event that each time process started to ends update my UI. and Singleton class should subscribe to this event. Also i am open new Singleton instance when my application start.

My service ServiceBehavior defined as ConcurrencyMode.Multiple and InstanceContextMode.PerSession so every client message create new instance:

[ServiceBehavior(
    ConcurrencyMode = ConcurrencyMode.Multiple,
    InstanceContextMode = InstanceContextMode.PerSession)]

so my only qustion is shold i use thread safe or non thread safe in my Singleton class ?

Make it thread safe, there are no drawbacks in make it thread safe and you can avoid future headache. — Alessandro D'Andria, Oct 04 '13 at 08:41

score 2 · Accepted Answer · edited May 23 '17 at 11:50

2

Yes, a singleton should be thread safe.

edited May 23 '17 at 11:50

Community

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answered Oct 04 '13 at 08:41

tom redfern

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So Multithreaded Singleton from the above link with my event will do the job ? – user2813889 Oct 04 '13 at 08:43
@hugh take a look at [Implementing the Singleton Pattern in C#](http://csharpindepth.com/articles/general/singleton.aspx). – Alessandro D'Andria Oct 04 '13 at 08:45
What version should i use ? – user2813889 Oct 04 '13 at 08:58
What version of what now? – tom redfern Oct 04 '13 at 09:11
what version, i can see six verions – user2813889 Oct 04 '13 at 10:18
Version 4 looks nice. I would use that. – tom redfern Oct 04 '13 at 10:33

score 1 · Answer 2 · answered Oct 04 '13 at 08:46

You should always opt for the thread-safe version when you are building something that can be modified. If it is a read-only collection then thread safety is not important.

Thread safety will incur a small performance cost usually due to locking, but it will save you a lot of potential pain later as race conditions are usually hard to debug.

score 1 · Answer 3 · answered Oct 04 '13 at 08:54

Thread unsafe may end up with weird results, possible to create more than 1 instance, which violates the singleton pattern. Thread Safe singleton is a good way to go.

Take a look to Jon Skeet's article, with different approach like Thread Safety, lazy instantiation etc.

http://csharpindepth.com/articles/general/singleton.aspx

Should i use thread safe or non thread safe for my Singleton class for my purpose?

3 Answers3