APIs

Question 1

GET

Answer 1

Read

http://www.example.com/customers/12345/orders

Question 2

PUT

Answer 2

Update/Replace

http://www.example.com/customers/12345/orders/98765

Question 3

PATCH

Answer 3

Update/Modify

http://www.example.com/customers/12345/orders/98765

Question 4

DELETE

Answer 4

Delete

http://www.example.com/customers/12345/orders

Question 5

POST

Answer 5

Create

http://www.example.com/customers/12345/orders

Question 6

Principles of Good API Design

Answer 6

• Do one thing and do it well
• APIs should be as small as possible because it can be difficult to remove features. Conceptual weight is more important than supporting a lot of endpoints. Think about it in terms of power to weight ratio.
• Don’t let implementation details leak into the API. (e.g.. on disk and serialization formats, tuning parameters.)
• Maximize information hiding so modules can be built, tested, and debugged separately
• Choose names carefully and be consistent
• Re-use requires good design and good documentation

Question 7

Performance Consequences of Poor API Design

Answer 7

Bad

• Making types mutable
• Providing a constructor instead of static factory. (Static factories are not required to create a new object every time they are called. Prevents the creation of unnecessary objects.)
• Using a concrete implementation type instead of an interface
• Example: Component.getSize() returns a dimension that is mutable. That means each call much create a new Dimension object, which results in millions of needless object allocations.