java - Where is the proper place to put code that saves objects to sharedpreference file -

i guess generic object oriented question, coming conclusion don't think enough in terms of objects.

i have 2 classes, person class , people class. reading , writing these (from , sharedperferencesfile) several activities. right have persistdata class handles reading , writing. when want read or write these guys instance of persistdata class , call methods like, persistdata.write(person); or persistdata.write(people); way this, or should move read , write code person , people class?

i use class call settingsprovider, calling new settingsprovider(this).getperson(); , new settingsprovider(this).setperson(person); yes, how it.