code: public synchronized <Solution_> boolean addProblemFactChanges(List<ProblemFactChange<Solution_>> problemFactChangeList) {
          boolean added = problemFactChangeQueue.addAll(problemFactChangeList);
          notifyAll();
          return added;
      }
docs: Concurrency note: unblocks {@link #waitForRestartSolverDecision()}.
  @param problemFactChangeList never null
  @return as specified by {@link Collection#add}