Software Architect's Handbook

What needs to be exposed/hidden?

You and your team should really think about the properties and behaviors (methods) that need to be exposed for a module. Everything else can be hidden. Through the use of a public interface, we can define what we want to make available.

Information hiding assists with defining public interfaces. Rather than lazily exposing most of a class, it forces us to consider what really needs to be made public. The public interface defines a contract that the implementation must follow, and allows others to know what is available. It is up to the implementation to decide how it is accomplished.