question: public void write ( String filename ) { logger . info ( "write carrier plans" ) ; try { openFile ( filename ) ; writeXmlHead ( ) ; startCarriers ( this . writer ) ; for ( Carrier carrier : carriers ) { startCarrier ( carrier , this . writer ) ; writeVehicles ( carrier , this . writer ) ; writeShipments ( carrier , this . writer ) ; writePlans ( carrier , this . writer ) ; endCarrier ( this . writer ) ; } endCarriers ( this . writer ) ; close ( ) ; logger . info ( "done" ) ; } catch ( IOException e ) { e . printStackTrace ( ) ; logger . error ( e ) ; System . exit ( 1 ) ; } }
target:  Writes carriers and their plans into a xml-file.