checkArgument(value == null, "recordStats does not take values");
      checkArgument(spec.recordStats == null, "recordStats already set");
      spec.recordStats = true;
    }
  }

  /** Base class for parsing times with durations */
  abstract static class DurationParser implements ValueParser {
    protected abstract void parseDuration(CacheBuilderSpec spec, long duration, TimeUnit unit);

    @Override

      checkArgument(value == null, "recordStats does not take values");
      checkArgument(spec.recordStats == null, "recordStats already set");
      spec.recordStats = true;
    }
  }

  /** Base class for parsing times with durations */
  abstract static class DurationParser implements ValueParser {
    protected abstract void parseDuration(CacheBuilderSpec spec, long duration, TimeUnit unit);

    @Override