question: public ViaHeader createViaHeader ( String host , int port , String transport , String branch ) throws ParseException , InvalidArgumentException { if ( host == null || transport == null ) throw new NullPointerException ( "null arg" ) ; Via via = new Via ( ) ; if ( branch != null ) via . setBranch ( branch ) ; if ( host . indexOf ( ':' ) >= 0 && host . indexOf ( '[' ) < 0 ) { if ( stripAddressScopeZones ) { int zoneStart = host . indexOf ( '%' ) ; if ( zoneStart != - 1 ) host = host . substring ( 0 , zoneStart ) ; } host = '[' + host + ']' ; } via . setHost ( host ) ; via . setPort ( port ) ; via . setTransport ( transport ) ; return via ; }
target:  Creates a new ViaHeader based on the newly supplied uri and branch values.