We need to create validators for each status. The validator will check if transition from current state is allowed or not. All validators are injected into WorkflowExecutionValidator. private List<Validator> validators WorkflowExecutionValidator will pick up an appropriate validator from a list and check if transition is allowed. Validators are implemented for each workflow execution status Validators are applied in production code

@Data
public class WorkflowExecutionValidator {
    private List<Validator> validators;

    public void validate(WorkflowExecutionStatus current, WorkflowExecutionStatus target) {
        // 1. select validator based on current status
        // 2. apply validator to check if the transition is allowed
    }
}