question: public static MetricId build ( final String ... parts ) { if ( parts == null || parts . length == 0 ) { return MetricId . EMPTY ; } if ( parts . length == 1 ) { return new MetricId ( parts [ 0 ] , EMPTY_TAGS ) ; } return new MetricId ( key ( parts ) , EMPTY_TAGS ) ; }
target:  Build a new metric name using the specific path components.