public String getTag(Tag tag) {
    String value = mValues.get(tag);
    if (value == null) {
      return UNDERSCORE;
    }
    return value;
  }
public String getTag ( Tag tag ) { String value = mValues . get ( tag ) ; if ( value == null ) { return UNDERSCORE ; } return value ; }
@param tag the tag to get
@return the value of the tag