code: protected Long addLongValue(Object name, long inc) {
      Long val = this.longCounters.get(name);
      Long retv = null;
      if (val == null) {
        retv = new Long(inc);
      } else {
        retv = new Long(val.longValue() + inc);
      }
      this.longCounters.put(name, retv);
      return retv;
    }
docs: Increment the given counter by the given incremental value If the counter
  does not exist, one is created with value 0.
  
  @param name
  the counter name
  @param inc
  the incremental value
  @return the updated value.