Value Objects

A Value Object is an object whose data serves as its identity. Put another way, a Value Object is identified by its data (a.k.a state a.k.a properties a.k.a attributes).

Conversely, Value Objects do not have a unique identifier associated with them, which could be used to reference them later.

Typical examples of Value Objects are strings, monies, points, or GPS coordinates. It is easy to see that two $5 notes are equivalent to each other and can easily be switched with one another. (To the federal reserve which tracks each note by its unique identifier, these notes would be Entities.)