question: public DomainComponent addDomain ( String domain ) throws UMSException { if ( domain == null || domain . length ( ) == 0 ) { throw new IllegalArgumentException ( ) ; } if ( m_dcRoot == null ) { throw new InvalidDCRootException ( ) ; } StringTokenizer st = new StringTokenizer ( domain , "." ) ; int nDoms = st . countTokens ( ) ; String [ ] doms = new String [ nDoms ] ; int i = 0 ; while ( st . hasMoreElements ( ) ) { doms [ i ++ ] = st . nextToken ( ) ; } PersistentObject parent = UMSObject . getObject ( getSSOToken ( ) , m_dcRoot . getGuid ( ) ) ; DomainComponent dc = null ; for ( i = 0 ; i < nDoms ; i ++ ) { SearchResults results = parent . getChildren ( "dc=" + doms [ nDoms - i - 1 ] , null ) ; try { dc = ( DomainComponent ) results . assertOneEntry ( ) ; } catch ( EntryNotFoundException e ) { dc = new DomainComponent ( getSSOToken ( ) , doms [ nDoms - i - 1 ] ) ; parent . addChild ( dc ) ; } parent = UMSObject . getObject ( getSSOToken ( ) , dc . getGuid ( ) ) ; } return dc ; }
target:  Add a virtual domain into the domain component tree.