Java: Event Tickets

Your task is to fix the event tickets tool so that every command updates the data correctly and prints the correct success message or error reason. It reads the state from data/event.json and data/reservations.json, processes the reserve, release and transfer commands, and writes the updated state back.

Project Structure

├── data/
│   ├── event.json              # Read-only event limits (event, capacity, per_person_limit)
│   └── reservations.json       # Persistent reservations state (reservations)
├── src/
│   ├── main/java/com/tickets/
│   │   ├── Commands.java       # Command handlers
│   │   ├── FileIo.java         # State file load and save
│   │   ├── Main.java           # CLI entry point
│   │   ├── Models.java         # Data models
│   │   └── Parser.java         # JSON parsing
│   └── test/java/com/tickets/
│       └── CommandsTest.java
├── tickets                     # CLI launcher script
├── run.sh                      # Setup and run script
├── reset.sh                    # Restore data/reservations.json to its initial state
├── test.sh                     # Test script (writes junit.xml)
├── pom.xml                     # Maven build configuration
└── README.md

Commands

Install

mvn -B -ntp -DskipTests package

Run

bash run.sh

Test

bash test.sh

Reset

Restore data/reservations.json to its initial state.

bash reset.sh

Examples

Each example below runs independently against the initial data files. Park Movie Night has 27 tickets and a limit of 4 per person. Eight people hold 25 of them, in this order: sam 4, riley 2, jordan 4, casey 1, taylor 4, quinn 3, morgan 4, drew 3. That leaves 2.

Example 1: Reserving adds to what a person already holds

Command:

./tickets reserve casey 1

Output:

Reserved 1 for casey (2 held, 1 left)

casey afterwards:

{"person":"casey","qty":2}

casey held 1, so one more makes 2, and 1 ticket is left.

Example 2: Releasing gives tickets back to the event

Command:

./tickets release sam 1

Output:

Released 1 for sam (3 held, 3 left)

sam afterwards:

{"person":"sam","qty":3}

sam goes from 4 to 3 and the ticket returns to the pool, so 3 are left. A person who gives back everything they hold leaves the list: ./tickets release casey 1 prints Released 1 for casey (0 held, 3 left) and casey's entry is removed.

Example 3: Only tickets a person holds can be released

Commands:

./tickets release riley 3
./tickets release avery 1

Output:

Error: NOT_ENOUGH_HELD
Error: NO_RESERVATION

riley holds 2 and avery holds none. Neither command changes the file.

Example 4: A transfer moves tickets between two holders

Command:

./tickets transfer quinn riley 2

Output:

Transferred 2 from quinn to riley

The two records that change. quinn:

{"person":"quinn","qty":1}

riley:

{"person":"riley","qty":4}

quinn goes from 3 to 1 and riley from 2 to 4. No ticket leaves or enters the pool, so 2 are still left. ./tickets transfer quinn riley 3 would take riley to 5, over the limit of 4, and answers Error: PER_PERSON_LIMIT.

Example 5: A transfer needs a giver who holds tickets, and two different people

Commands:

./tickets transfer avery sam 1
./tickets transfer sam sam 1

Output:

Error: NO_RESERVATION
Error: SAME_PERSON

avery holds no tickets, and sam cannot transfer to sam. Neither command changes the file.