Primitive Obsession

Question 1

What is the Primitive obsession?

Answer 1

The anti pattern in which developers are too focused on using primitive data types like vanilla ints, characters and floats as opposed to well-defined domain specific objects

Question 2

What are entities?

Answer 2

An object defined primarily by its identity

Question 3

What are value objects?

Answer 3

Objects lacking the concept of identity. They are defined and their attributes are immutable. Eg. Math.Pi object

Question 4

Effects of primitive obsession

Answer 4

1. Resulting code is cluttered and hard to read
2. Can lead to a lack of type safety, no inherent structure or validation with primitive data types (think of the compare or equals overriding methods)

Question 5

How do entities stay persistent?

Answer 5

The entity object will maintain the identity from its id (think databases)

They have life cycles which can change over time however the id keeps their identity

Question 6

Entity Considerations

Question 7

What is the difference between Value objects and entities

Answer 7

Value objects and entities are complete opposites, one lacks the concept of identity and the other is defined primarily by the identity.