Clean Code: A Handbook of Agile Software Craftsmanship - Granularity

[Tomasz Prus]

I see that functions are covered in the book. There is something about granularity? I have often problem what is good way for example in webservices:

login(Person person)

or

login(String userName, String password, String ip)

?

[Petr Shilkin]

Of course, Person is much better.

[Ilja Preuss]

Originally posted by Petr Shilkin:
Of course, Person is much better.

Why? I'm not sure it's that obvious - or even possible to decide without knowing more about the context.

[Alaa Nassef]

What I assumed from Petr's comment is that he favors the second style since it uses less parameters, and all the data are contained in one object which might seem more OO. I totally agree with Ilja that the context must be known upfront to be able to make a better decision

[Jeff Langr]

Kent Beck recently posted an article on the topic: http://www.threeriversinstitute.org/AbstractVsConcreteParameters.html

[Robert Martin]

Originally posted by Tomasz Prus:
I see that functions are covered in the book. There is something about granularity? I have often problem what is good way for example in webservices:

login(Person person)

or

login(String userName, String password, String ip)

?

The fewer arguments you pass into a function the better. If there are more than three, you should turn them into an object. Even three is a lot, and probably should be turned into an object.