Object Invariants, Immutability & You

Making Objects Do Your Bidding Domcode 26-11-2014

Jeroen v.d. Gulik

• CTO / Founder Isset (http://isset.nl)

• Builder of Artificial Stupidity

• @n0x13

• Likes Cats … a lot

“Every Great talk should start with a Quote”

- Ross Tuck

Telephone Game

“People Lie, therefore Objects Lie”

- Jeroen v.d. Gulik

Objects as dumb data stores

This is our industry standard

Context and Intent get lost- Ronald Reagan

Objects should have behaviour attached to

them- Mao Zedong

Objects should tell a tale about its current state and all the possible

ways to change that state- Adolf Hitler

Objects should be responsible for their own

internal consistency

Schrödinger's cat- Michael Jackson

Make the Implicit, Explicit

UnpaidOrder PaidOrder

“Sounds like a State Machine”- Igor Wiedler

Immutability

UnpublishedArticle PublishedArticle

UnpublishedArticle PublishedArticleDraft Article

Draft Article RetractedArticle

Magic is bad, hmmmkay- Mahatma Ghandi

Objects should …

• Be responsible for their own internal state

• Have specific behaviour towards its responsibility

• Broadcast their state

• Only care about the state it’s currently in.

Questions?

Please rate my talk: https://joind.in/12818