Slide Deck from Presentations to WITDevs (April 2021) and Cleveland Developer Group (6/28/2023) on using Rock, Paper, Scissors to learn the Map construct in Salesforce Apex development.

1. Lynda Kane
@labboopanda
RPS: An Apex Map
Learning Journey

3. Knowledge Gaps
A knowledge gap
is a discrepancy
between what is
known and what
should be known
Example 1:
Lynda the Human GPS
Despite going to
Parmatown Mall
hundreds of times, I still
don’t know how to get
there!
Example 2:
Imaginary Numbers
Knowledge Gap + Imposter Syndrome =
😨 😱 😭 😕 😣 🤢 🤔 😰

4. My Apex Knowledge Gap
Confession:
If I have to review
code, I try to get
away with ignoring or
skipping over any
code that uses Map.
What I Know:
● Key - Value Pair
● Key is unique
● Often see/used
with triggers
● Common is id
with query
results
What I Want to
Know:
● How to create
● How to get the
data
● Can I actually
use one
successfully?

5. My Apex Map Learning Plan
● Rock, Paper, Scissors
● Screen flow for user to play the game with Apex Action(s)
● Apex to pick computer’s random weapon choice
● Apex to determine who won
● Apex to determine what action the weapon did to win (cut,
smash, cover)
● Test class

6. Apex Map
Notes:
● Keys and Values
can by ANY data
type (primitive,
collection, sObject,
user-defined, Apex
built-in)
● If key is a string, it
is case-sensitive
(Rock ≠ rock)
Constructor:
● Map<type, type>()
Methods:
● put(key, value) - add pairs
● get(key) - returns value for specified key
● keySet() - returns a Set of the keys (unique, unordered)
● values() - returns List of all values
● size() - # of pairs
● isEmpty() - check for no pairs
● containsKey(key) - is this key in the map? Boolean
● clear() - remove all pairs
https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/a
pex_methods_system_map.htm

7. Rock, Paper, Scissors
Weapon This Wins Over: This Wins By:
Rock Scissors smashes
Paper Rock covers
Scissors Paper cuts
Map<String, List<String>>

8. Apex Actions in Flows (aka Surprises)
● Only 1 Method per Class can be invocable
● Parameters passed MUST be a List
● Return MUST be a List

9. Let’s Code

10. Code Recap
● Random Weapon Select - Map was overkill, use List
● Make the Weapons Map
● Get what chosen Weapon can beat
● Get how the chosen Weapon wins (action)
● Bring it all together
● Code Coverage

11. Screen Flow

12. Screen Flow Recap
● 1st Screen: User selects weapon from picklist
● Apex Action: run the code!
○ Pass in the User’s selection
○ Store the result
● 2nd Screen: Show the result

13. Lifelong Learning
● Error handling (what if user chose Spatula or Lizard as the
weapon?) (use containsKey(key))
● Use keySet() instead of List to randomly pick computer
weapon choice
● Add images to Flow (visual appeal)
● Improve code coverage
● Documentation
● LC or LWC instead for UI

14. What about Rock, Paper, Scissors, Lizard, Spock
● How to handle 2 possible weapons that can win over
selection (Map<String,List<String>>)
● How to get the action that wins (Map<List<String>,String>)
● Modify the Flow for additional choices

15. Questions/Comments?
Want to make this: Instructions
Contact:
Email: labboo.gc@gmail.com
Twitter: @labboopanda
LinkedIn: https://www.linkedin.com/in/lynda-kane-71379610/
Trailblazer.me: https://trailblazer.me/id/labboo