A simple state machine for Spring Boot projects
After importing into an IDE like STS can be run as Spring Boot application.
This project contains a framework and an illustration of the usage of the framework for a sample project like online order processing.
| Initial State | Pre-event | Processor | Post-event | Final State |
|---|---|---|---|---|
| DEFAULT -> | submit -> | orderProcessor() -> | orderCreated -> | PMTPENDING |
| PMTPENDING -> | pay -> | paymentProcessor() -> | paymentError -> | PMTPENDING |
| PMTPENDING -> | pay -> | paymentProcessor() -> | paymentSuccess -> | COMPLETED |
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To use this framework first create a state transitions table like above.
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Then implement the interfaces ProcessState and ProcessEvent. See OrderState and OrderEvent classes for examples
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Identify a primary key for the process. For the order process it would be orderId, for a time sheet application it would be userId-week-ending-date etc.
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Implement the StateTransitionsManager. See the OrderStateTransitionsManager class for an example.
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Implement the Processor class. See the OrderProcessor and the PaymentProcessor classes for examples.
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Create a controller class. See the OrderController for an example.
That is it.
For the order sample considered in this project, the following two APIs are created to test the state machine:
http://localhost:8080/order/cart?payment=123&orderId=123
(for quick testing in a browser both of the above are implemented as GET APIs)
When the above APIs are called the console log displays the state transitions that reflect the above table. (Note: payment=0 is used to mock payment error in this example)
A non-blocking version of this project is at: https://github.com/mapteb/non-blocking-state-machine
The technique used in this Java project can be easily adapted to Angular applications. Here is an Angular example.
More information about this project can be found at: https://dzone.com/articles/a-simple-state-machine-for-spring-boot-projects