Question

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Is it better to create a singleton to access unity container or pass it through the application?

We have an application that is processing various XML messages. We are using Dependency Injection along with a Singleton Factory to create instances of the related messages. We are using WCF to pick these messages off of a queue so when we launch the WCF Service it is spinning up multiple instances enabling us to process messages concurrently off of the queue.

We implemented our factory using a Singleton and just concerned we could encounter issues because we are processing multiple instances in parallel. (Issues like this is now a bottleneck, could encounter thread contention, etc)

Should we not make the Factory a Singleton? Just curious….wanted some more expert opinion on this as I am ignorant in this area.

Any suggestions / comments would be greatly appreciated.

thanks,

S

Answer 1

When you’re using DI, Singletons are almost never necessary.

Instead I would compose everything at the Composition Root and use appropriate lifetime management with Unity to create the equivalent of Singletons.