[Newbies] Concrete classes... multiple users

[John Almberg]

One of the cool things, I think, about Smalltalk is that Classes are  
objects... i.e. concrete factories that can be modified at runtime to  
produce objects in different ways, depending on the runtime  
situation. I just find this so much more intuitive, compared to how  
classes are done in other languages...

But I think I may have used it in a naive way...

For example, I needed an Adapter class that could produce standard  
Item objects by connecting to a variety of legacy database tables,  
converting the non-standard item records into standard Item objects.  
This way, the consumer of those Item objects doesn't care where the  
items come from.

Originally, I thought I would only have to make these connections,  
one at a time. I.e., I'd program the Item class 'factory' with the  
legacy database hostname, username, password, and then just start  
asking for Items. The Item class would then go out to the database,  
fetch the proper row, create an Item object, initialize the instance  
variables, and return it to the Item object consumer.

This is intuitive, cool, and it works.

Then the requirements changed and I needed to connect to multiple  
database *at the same time*.

But there is only one Item class object!

This really muddles things up, because I basically have to update the  
Item class variables every time I need an Item object. No longer cool!

Did I just misuse this feature? Should I have built two Adapter  
Objects, instead? Am I missing something obvious? Is a little  
knowledge a dangerous thing? :-)

TIA... John

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.squeakfoundation.org/pipermail/beginners/attachments/20071026/d4b989ef/attachment.htm