Design Patterns discussion

[A Rick Anderson <arick AT pobox.com>]

Chris Finlayson wrote:

> So, more specifically, what I'd propose to satisfy these requirements are:
>
> 1. Change the SortFactoryStrategy method by adding two  new Create methods.
> One that takes in a request of whether or not the user wants a stable or
> nonstable algorithm, and a default one is created and returned.  Another
> that allows the user to request a specific type of stable or nonstable sort.
>
> 2. The factory then returns it appropriately. If one is not found, a Null
> object is returned and a client has to check for that appropriately.
>
>
> This allows for the ability to create stable and non-stable versions of
> sorting routines (i.e. traditionally quicksort is non-stable, but a stable
> version can be created).

That's a reasonable solution for early binding languages.  However, if 
you look at how Gosling solved this in the examples that come with the 
JDK, you see how he was able to bypass the need for a factory class 
completely by passing in the name of the class he wanted to instantiate. 
 With Java, and some of the other languages, you can instantiate an 
object from the name of the class.

--
A. Rick Anderson

arick AT pobox.com
arick AT bea.com