Search and Replace in MVC

my first suggestion would be - instead of thinking about the parts of the search methods - sketch out the people using the tool that you are building. give them specific names depending on their "Role". use those names in your design. Determine their needs -- what does the tool need to do for them? Determine their responsibilities -- what will they need to provide? From that determine what the application requirements are for that user.

Your class structure will then clearly represent the people using the application. you will automatically have the correct separation of concerns which will make it much easier to grow the application.

usually a search app would include some kind of admin role as well as end user role -- and since those two "Roles" are completely different, the class structure should reflect that. so like for a product search app - there might be a "Product Browser" role - the person who submits a search term and browses the results. and there could also be a "Product Admin" role who is taking care of the products that are getting searched on. by defining that separation of roles at the start, you can save a lot of time when building out your app.

• first you determine the Roles - who are the actors on the application?
• then write out the Use Cases - what are the actions that the actors make on the application? what are the results?
• then there are Business Assets that are being acted upon, in this case a list of words.
• and finally Implementation - how are you creating your application?

notice that implementation is last - the Roles and Use Cases drive the application - not the language, database type, etc. those are 'implementation details' that should not be part of the primary application design.

Like the above answer, I also think that you put the cart before the horse in this case. It sounds like you first thought about your architecture before having any requirements.

The usual way of developing software is to derive your architecture from the requirements you have, not only from the functional ones (in your case the Search/Replace functionality) but also - and mainly in most of the projects - from the non-functional ones (quality attributes) since those are the ones which cost you most of the money in the end if you missjudge them.

In your case the question is: Because you cannot perfectly implement every quality, what are the quality attributes you have to take care of most? As long as this question is not answered, nobody can give you a "blueprint" for a professional architecture that solves the search/replace functionality best.

Some of these quality attributes could be:

Performance: Do you have constraints regarding to the performance of the search/replace functionality?

Maintainablity: Should it be easy to change the searching/replacing algorithm? Should it be easy to change the UI which accesses your algorithms? (Possible hint to MVC)

MSDN has a nice summary on quality attributes: http://msdn.microsoft.com/en-us/library/ee658094.aspx