This GitHub Classroom lab teaches the basics of Spring Boot and Spring Data JPA using a simple 1v1 matching game server theme.

Students will work with:

• Spring Boot application structure
• REST controllers
• JPA entities and relationships
• Spring Data repositories
• a service layer
• an in-memory H2 database for local testing

By the end of this lab, you should be able to:

1. explain the role of @SpringBootApplication, @RestController, @Service, @Entity, and repository interfaces
2. model a simple domain using JPA relationships
3. save and query entities with Spring Data JPA
4. implement service-layer methods that support a small matchmaking workflow
5. run tests against an H2 in-memory database

The app models a simplified 1v1 matching server:

• PlayerAccount: a player with a username and rating
• QueueEntry: a player waiting in the matchmaking queue
• MatchRecord: a 1v1 match between two players, with an optional winner

Complete the TODO methods in:

• MatchmakingService.java

Required methods:

1. registerPlayer
2. enqueuePlayer
3. createMatch
4. finishMatch
5. findRecentMatchesForPlayer

• Do not rename classes or methods.
• Do not change package names.
• Do not modify the tests.
• Keep all code in edu.sdccd.cisc191.
• Use the repositories provided in the starter.
• Throw IllegalArgumentException when an ID does not exist or a winner is not part of the match.

mvn spring-boot:run

The app uses an in-memory H2 database.

mvn test

Register a player:

curl -X POST "http://localhost:8080/api/players?username=alpha&rating=1200"

Put a player in queue:

curl -X POST "http://localhost:8080/api/queue/1"

Create a match:

curl -X POST "http://localhost:8080/api/matches?playerOneId=1&playerTwoId=2&arenaName=Volcano"

Complete a match:

curl -X POST "http://localhost:8080/api/matches/1/finish?winnerId=2"

1. Why is the service layer useful even when repositories already exist?
2. What JPA relationship is used from QueueEntry to PlayerAccount?
3. Why does MatchRecord store references to player entities instead of only storing usernames?
4. What is the benefit of using H2 for a classroom lab?