SampleService.kt

@Service
class SampleService(private val ff4j: FF4j) {

    fun callSampleService() {
        if (ff4j.isEnabled("some-feature")) {
            print("some-feature is enabled")
        }
        
        if (ff4j.isDisabled("other-feature")) {
            print("other-feature is disabled")
        }
    }
}