code: public int store(String label) {
          if (strInt.containsKey(label)) {
              return (strInt.get(label).intValue());
          } else if (!newLabelsAllowed) {
              return KEY_DUMMY_LABEL;
          } else { // store label
              Integer intKey = count++;
              strInt.put(label, intKey);
              intStr.put(intKey, label);
              return intKey.intValue();
          }
      }
docs: Adds a new label to the dictionary if it has not been added yet.
  Returns the ID of the new label in the dictionary.
  
  @param label add this label to the dictionary if it does not exist yet
  @return ID of label in the dictionary