following 7.2 of http://cran.r-project.org/doc/contrib/Genolini-S4tutorialV0-5en.pdf
apparently this is how to do mutators "right", it is still a bit goofy, but I don't mind it as much. Also, it might be a good idea to make a class of the algorithms rather than leave them as a list. That would prevent any generic list from being set here, though error handling in the initializeProcessInputs could probably handle that case.
example of mutator pattern