question: public static Set < Long > readSetOfLongs ( DataInput in ) throws IOException { int size = in . readInt ( ) ; if ( size < 0 ) { return null ; } else { Set result = new HashSet ( size ) ; boolean longIDs = in . readBoolean ( ) ; for ( int i = 0 ; i < size ; i ++ ) { long l = longIDs ? in . readLong ( ) : in . readInt ( ) ; result . add ( Long . valueOf ( l ) ) ; } return result ; } }
target:  read a set of Long objects 