Dynamic Forms with Camunda and Spring StateMachine

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In modern workflow automation, handling dynamic forms is a crucial requirement. Enterprises need a flexible way to render and process forms based on user input and business logic. Camunda BPM and Spring StateMachine together provide a robust solution for orchestrating complex workflows with dynamic form handling.

This article explores how to implement dynamic forms using Camunda for process automation and Spring StateMachine for managing state transitions, complete with coding examples.

1. Understanding Camunda and Spring StateMachine

1.1 What is Camunda?

Camunda is a lightweight BPM (Business Process Management) engine that enables workflow and decision automation. It supports BPMN, DMN, and CMMN standards and integrates seamlessly with Java applications.

1.2 What is Spring StateMachine?

Spring StateMachine is a framework for implementing finite-state machines (FSM) in Spring applications. It provides state transition capabilities that can be integrated into business workflows.

Combining Camunda and Spring StateMachine allows us to:

  • Dynamically control form rendering based on workflow states.
  • Maintain process flow integrity with well-defined state transitions.
  • Provide flexibility to adapt to business changes without modifying the core logic.

2. Setting Up the Project

2.1 Dependencies

Add the following dependencies to your pom.xml for Camunda and Spring StateMachine:

<dependencies>
    <!-- Camunda BPM dependencies -->
    <dependency>
        <groupId>org.camunda.bpm.springboot</groupId>
        <artifactId>camunda-bpm-spring-boot-starter-webapp</artifactId>
        <version>7.18.0</version>
    </dependency>
    
    <!-- Spring StateMachine dependencies -->
    <dependency>
        <groupId>org.springframework.statemachine</groupId>
        <artifactId>spring-statemachine-core</artifactId>
        <version>3.2.0</version>
    </dependency>
</dependencies>

2.2 Configuring Camunda

Define a BPMN model for handling a dynamic form:

<bpmn:process id="dynamicFormProcess" name="Dynamic Form Handling" isExecutable="true">
    <bpmn:startEvent id="start" name="Start" />
    <bpmn:userTask id="formTask" name="Fill Form" camunda:formKey="dynamic-form" />
    <bpmn:endEvent id="end" name="End" />
</bpmn:process>

The camunda:formKey="dynamic-form" indicates that the form is dynamically rendered.

2.3 Configuring Spring StateMachine

Define a state machine with states representing form processing:

@Configuration
@EnableStateMachine
public class FormStateMachineConfig extends StateMachineConfigurerAdapter<String, String> {

    @Override
    public void configure(StateMachineStateConfigurer<String, String> states) throws Exception {
        states
            .withStates()
            .initial("FORM_START")
            .state("FORM_IN_PROGRESS")
            .end("FORM_COMPLETED");
    }

    @Override
    public void configure(StateMachineTransitionConfigurer<String, String> transitions) throws Exception {
        transitions
            .withExternal()
            .source("FORM_START").target("FORM_IN_PROGRESS").event("START_FORM")
            .and()
            .withExternal()
            .source("FORM_IN_PROGRESS").target("FORM_COMPLETED").event("SUBMIT_FORM");
    }
}

This configuration defines three states:

  • FORM_START: The form process starts.
  • FORM_IN_PROGRESS: The user is filling out the form.
  • FORM_COMPLETED: The form is submitted.

3. Implementing Dynamic Form Handling

3.1 Form Controller

A REST controller that serves the dynamic form:

@RestController
@RequestMapping("/form")
public class FormController {
    
    @Autowired
    private StateMachine<String, String> stateMachine;
    
    @PostMapping("/start")
    public ResponseEntity<String> startFormProcess() {
        stateMachine.sendEvent("START_FORM");
        return ResponseEntity.ok("Form process started. State: " + stateMachine.getState().getId());
    }

    @PostMapping("/submit")
    public ResponseEntity<String> submitForm(@RequestBody Map<String, String> formData) {
        // Process form data
        stateMachine.sendEvent("SUBMIT_FORM");
        return ResponseEntity.ok("Form submitted successfully. State: " + stateMachine.getState().getId());
    }
}

3.2 Camunda Form Rendering

Use Camunda’s form renderer to dynamically generate forms based on state transitions:

<form action="/form/submit" method="post">
    <label>Name:</label>
    <input type="text" name="name" required />
    <label>Email:</label>
    <input type="email" name="email" required />
    <button type="submit">Submit</button>
</form>

4. Running and Testing the Application

4.1 Starting the Application

Run the Spring Boot application:

mvn spring-boot:run

4.2 Testing the API

  1. Start the form process: 
    curl -X POST http://localhost:8080/form/start
  2. Submit the form: 
    curl -X POST -H "Content-Type: application/json" -d '{"name":"John Doe", "email":"john@example.com"}' http://localhost:8080/form/submit

These API calls should transition the form through its defined states.

Conclusion

By integrating Camunda BPM and Spring StateMachine, we can create highly flexible and dynamic workflows that adapt to user interactions. This approach allows businesses to dynamically render forms, enforce structured process transitions, and maintain overall workflow consistency.

This combination is particularly beneficial in scenarios where:

  • User inputs determine the next steps in a workflow.
  • Multiple form versions exist for different business cases.
  • Adaptive workflows need to be maintained with minimal development effort.

Additionally, Camunda provides a powerful BPMN engine, allowing businesses to visually model complex workflows, while Spring StateMachine ensures structured state transitions without introducing unnecessary complexity. Together, they empower developers to build scalable, maintainable, and automated form processing systems.

By leveraging these technologies, organizations can:

  • Enhance efficiency by reducing manual workflow handling.
  • Improve user experience with adaptive and context-driven forms.
  • Increase maintainability with a well-structured and modular approach.

Ultimately, this integration paves the way for intelligent workflow automation, making processes more dynamic and resilient to changes. Future enhancements could involve integrating AI-powered decision-making to further streamline user interactions and decision processes.

By continuously refining and optimizing this architecture, businesses can stay ahead in workflow automation and digital transformation.