public <T> T executeTask(final GraphCallable<T> callable, final String info) {
   logFine("calling: " + info);
   return callable.call(lifecycle.graphDb());
 }
 public boolean isRunning() {
   return lifecycle != null && lifecycle.graphDb() != null;
 }
 public void executeTask(final GraphRunnable runnable, final String info) {
   logFine("starting: " + info);
   runnable.run(lifecycle.graphDb());
   logFine("finishing: " + info);
 }