non-blocking-state-machine

This Spring Boot Java project extends the simple-state-machine project to make the processors asynchronous and non-blocking.

Usage

The first step in using the framework is to configure the state transitions. An online order processing system is considered as an example for the demo. The order processing system is assumed to have the following state transitions:

Initial State	Pre-event	Processor	Post-event	Final State
DEFAULT	submit	OrderProcessor	orderCreated	PMTPENDING
PMTPENDING	pay	PaymentProcessor	paymentError	PMTERROREMAILPENDING
PMTERROREMAILPENDING	errorEmail	PaymentErrorEmailProcessor	pmtErrorEmailSent	PMTPENDING
PMTPENDING	pay	PaymentProcessor	paymentSuccess	PMTSUCCESSEMAILPENDING
PMTSUCCESSEMAILPENDING	successEmail	PaymentSuccessEmailProcessor	pmtSuccessEmailSent	COMPLETED

where the PaymentProcessor is considered a long running process and made asynchronous and non-blocking. All other processors are assumed synchronous. The above state transitions are configured in Java enums, OrderState and OrderEvent.

The demo includes an OrderController with two APIs to test the following scenarios:

Testing

Build using:
$ ./gradlew build

Run using:
$ \gradlew bootRun

Submit an order

User submits an order
System responds with an order ID.
Log messages confirm the state transition.

$ curl -X POST http://localhost:8080/order/items

Submit an invalid payment (amount = 0.00)

User submits an invalid payment for the order
System responds with a message "We are processing your payment. Please check your email for the order confirmation number."
System also sends an email with an error message.
Log messages confirm the state transition.

$ curl -X POST http://localhost:8080/orders/1e6092da-3bef-4377-8a02-5a4cb93f4a96/payment/0

Submit a valid payment (amount > 0.00)

User submits a valid payment for the order
System responds with a message "We are processing your payment. Please check your email for the order confirmation number."
System also sends an email with a success message.
Log messages confirm the state transition.

$ curl -X POST http://localhost:8080/orders/1e6092da-3bef-4377-8a02-5a4cb93f4a96/payment/1

Submit a valid payment for an order which is already completed

User submits a valid payment for the order
System responds with a message "Order is completed for orderId=1e6092da-3bef-4377-8a02-5a4cb93f4a96."
No state transition occurs in this case.

$ curl -X POST http://localhost:8080/orders/1e6092da-3bef-4377-8a02-5a4cb93f4a96/payment/2

Interested readers can run the included Apache JMeter test plan to test for multiple simultaneous users placing orders and paying for the orders.

More Info

More info about this project is also available at: dzone

malaka / non-blocking-state-machine Goto Github PK