A simple spring-boot and spring-statemachine rest-api example that handles the process involved in hiring an employee (with the statemachine utilizing different regions).

You can use regions to define nested states and transitions. In UML state machine diagrams, a region is a container inside a state that can hold states, pseudostates, and transitions, which you can add to state machines or states. Regions allow you to provide more detail about the internal transitions of a particular state.

After every execution, states are saved in the database for later usage.

Note: This is a sample, not a complete project to handle all the processes involved.

Scenario:

The allowed state transitions are:

ADDED -> IN-CHECK <-> APPROVED -> ACTIVE

Furthermore, IN-CHECK state is special and has the following orthogonal child substates:

• SECURITY_CHECK_STARTED

• SECURITY_CHECK_FINISHED

• WORK_PERMIT_CHECK_STARTED

• WORK_PERMIT_CHECK_FINISHED

with allowed state transitions:

• SECURITY_CHECK_STARTED -> SECURITY_CHECK_FINISHED
• WORK_PERMIT_CHECK_STARTED -> WORK_PERMIT_CHECK_FINISHED

This means that a complete state of an employee in the IN_CHECK state could look like (IN_CHECK, SECURITY_CHECK_STARTED, WORK_PERMIT_CHECK_FINISHED).

Examples of permitted transition:

• (IN_CHECK, SECURITY_CHECK_STARTED, WORK_PERMIT_CHECK_STARTED) -> (IN_CHECK, SECURITY_CHECK_FINISHED, WORK_PERMIT_CHECK_STARTED)
• (IN_CHECK, SECURITY_CHECK_STARTED, WORK_PERMIT_CHECK_STARTED) -> (IN_CHECK, SECURITY_CHECK_STARTED, WORK_PERMIT_CHECK_FINISHED)

Transition from IN_CHECK state to APPROVED state happens automatically when the complete state is (IN_CHECK, SECURITY_CHECK_FINISHED, WORK_PERMIT_CHECK_FINISHED). Transition from IN_CHECK state to APPROVED without meeting the condition above is not allowed.

How to run Note: EmployeeTerms table is populated automatically from a script in the resources forlder. This mock table serves as a table to hold contract and position details. There are 2 modes to run it.

1. The traditional way with java -jar
   • Change directory(cd) in to the folder of the application source code
   • Run mvn clean package
   • Issue java -jar ems-1.0.0.jar
   • Use the requests provided below.
2. From docker container
   • Build the applicaiton mvn clean package
   • Build docker image docker build -t ems .
   • Run the image docker run -d -it --name ems ems:latest
   • Get the ip of the container docker inspect ems | grep Address
   • Replace the ip address below with the address from the above command and do the calls

Requests: Create employee

curl -X 'POST'   'http://172.17.0.3:8080/v1/employee'   \
-H 'accept: application/json' \
-H 'Content-Type: application/json' -d '{
  "firstName": "string",
  "lastName": "string",
  "dob": "2021-12-16",
  "gender": "F",
  "passportNumber": "string",
  "employementTerms": {"id": 2}
}'

Sample response:

{
	"type": "ResponseBase",
	"success": true,
	"resultCode": 0,
	"transactionId": "b338a35e-9c1e-4a5f-bb87-7f3be0ce0475"
}

Change state with an event

curl -X 'PUT'   'http://172.17.0.3:8080/v1/employee/1'   -H 'accept: application/json'   -H 'Content-Type: application/json'   -d 'IN_CHECK'

Error response(in case of wrong state is requested):

{
	"type": "ResponseBase",
	"success": true,
	"resultCode": 0,
	"transactionId": "492eba92-a41e-4914-99b9-572b947b02bc"
}

Get employee

curl -X 'GET'   'http://172.17.0.3:8080/v1/employee?employeeId=1'  -H 'accept: application/json'

Success response:

{
	"type": "response-employee",
	"success": true,
	"resultCode": 0,
	"transactionId": "8ec635cc-e2ca-4cbf-b7ef-3c82886c76ed",
	"returnValue": {
		"id": 1,
		"firstName": "string",
		"lastName": "string",
		"dob": "2021-12-16",
		"gender": "F",
		"passportNumber": "string",
		"status": [
			"IN_CHECK",
			"WORK_PERMIT_CHECK_STARTED",
			"SECURITY_CHECK_STARTED"
		],
		"employementTerms": {
			"id": 2,
			"jobTitle": "Backend developer",
			"jobDescription": "Job description goes here",
			"skillRequirement": "Skill requirement",
			"educationRequirement": "Education requirement goes here",
			"annualSalary": 50000.0
		}
	}
}

Error response:

{
	"type": "response-employee",
	"success": false,
	"resultCode": 404001,
	"message": "Employee not found.",
	"transactionId": "e295944d-6fb5-49ad-83da-50fd5e74a3e5"
}