3 Encapsulation and Information Hiding Free Online FlashCards

What is encapsulation?

Encapsulation groups an object’s state and behavior together while controlling how other code interacts with them.

What is information hiding?

Information hiding conceals implementation details that clients do not need to know and exposes a small, meaningful public interface.

Why does encapsulation matter?

It protects state from invalid changes, centralizes rules, hides complexity, reduces dependencies, and permits internal representation changes without changing clients.

What does access control determine?

Access control determines which code can use a type or one of its members.

What is a useful default for access levels?

Choose the most restrictive access level that still supports the required design.

What is a property?

A property presents an object characteristic through a field-like interface while allowing code to run when the value is read or written.

What does a private property setter provide?

A public getter with a private setter lets clients read the value while preventing arbitrary replacement by client code.

What is an object invariant?

An invariant is a condition that remains true for every valid object, such as a nonnegative account balance.

Where should object validation occur?

Validate data at the boundary where it enters or changes the object, such as a constructor, setter, factory method, or domain operation.

How can a Playlist apply information hiding?

A Playlist can expose addSong, removeSong, and playNext without revealing whether songs use a list, queue, or database.

What should a clear public interface express?

A public interface should expose behavior that expresses the object’s responsibility rather than its internal representation.

Why avoid returning internal mutable collections?

Returning an internal mutable collection lets callers alter object state without validation; return a read-only view, a copy, or controlled operations instead.