I'm a fan of Dependency Injection, however I don't know how much both public and private methods inside a class should be loosely-coupled.
Just to picture it better, when I have both projectId and userId as private properties in my class, and both of them have their own decent setter methods which will do the input validation also -- throwing an error in case of unexpected input, then isn't it better that all the class' methods relies on these properties instead of getting them via method arguments' and repeat the whole validation, etc. again?
In this case the methods will tightly-bind to the class itself -- and probably the constructor as well, but the advantage is that all the methods can easily rely on the setter methods and they will always assume also that the proper data is always available for me to process -- because the setter should have thrown an exception otherwise.
This seems quite helpful to me and I can make all the classes and libraries loosely-coupled in a way they don't depend to each other, however my question is, can a method inside a class be dependent on the class properties itself or not? Is it considered as a bad-practice?