public void createRuns(PerfTestRunner runner, PerfTestStep firstStep, int numberOfRuns) {
   runs = new HashMap<String, PerfTestRun>();
   for (int i = 0; i < numberOfRuns; i++) {
     String runId = idGenerator.getNextId();
     runs.put(runId, new PerfTestRun(runner, runId, firstStep));
   }
   runs = Collections.unmodifiableMap(runs);
 }
 protected void ensureHasId(DbEntity dbEntity) {
   if (dbEntity.getId() == null) {
     String nextId = idGenerator.getNextId();
     dbEntity.setId(nextId);
   }
 }