gistfile1.txt

class SingletonService implements Service {
    private Logger LOG = Logger.getLogger(this.getClass());
    private Node node;

    private Supplier<Group> groupSupplier;
    private Consumer<Node> nodeConsumer;

    SingletonService(Supplier<Group> groupSupplier, Consumer<Node> nodeConsumer) {
        this.groupSupplier = groupSupplier;
        this.nodeConsumer = nodeConsumer;
    }

    @Override
    public void start(StartContext context) {
        this.node = this.groupSupplier.get().getLocalMember();

        this.nodeConsumer.accept(this.node);

        LOG.infof("Singleton service is started on node '%s'.", this.node);
    }

    @Override
    public void stop(StopContext context) {
        LOG.infof("Singleton service is stopping on node '%s'.", this.node);

        this.node = null;
    }
}