private UntypedMetric get(Sample sample) { Identifier dim = sample.getIdentifier(); UntypedMetric v = values.get(dim); if (v == null) { // please keep inside guard, as sample.getHistogramDefinition(String) touches a volatile v = new UntypedMetric(sample.getHistogramDefinition(dim.getName())); values.put(dim, v); } return v; }