Question

 private Obj CacheSomething()
    {
       Obj retVal = (Obj)System.Web.HttpRuntime.Cache["key"];

        if (retVal == null)
        {
            retVal = new Obj();
            System.Web.HttpRuntime.Cache["key"] = retVal;
        }
        return retVal;
    }

This is probably a stupid question but is it stored in Server memory or client memory?

Also, what is the difference between doing the above and using a Singleton?

for example:

myObj= GenericSingleton<Obj>.GetInstance();

and

myObj= CacheSomething();

When I declare a new object every time it takes longer obviously, but both the above methods are faster than not caching and not using a singleton. Is using a singleton basically caching?

Answer 1

1. System.Web.HttpRuntime.Cache is server-side.

2. When using a Singleton pattern you usually write code expecting the singleton instance to exist. With cached item you can never rely on its existence and should write code accordingly. For example, if retVal creation is a time/resource consuming, you should lock to prevent other threads doing the same work of constructing it.