question: @ Override public void visit ( Mapping m , int line , int col , int nextLine , int nextCol ) throws IOException { if ( previousLine != line ) { previousColumn = 0 ; } if ( line != nextLine || col != nextCol ) { if ( line < maxLine ) { if ( previousLine == line ) { out . append ( ',' ) ; } writeEntry ( m , col ) ; previousLine = line ; previousColumn = col ; } else { Preconditions . checkState ( m == null ) ; } } for ( int i = line ; i <= nextLine && i < maxLine ; i ++ ) { if ( i == nextLine ) { break ; } closeLine ( false ) ; openLine ( false ) ; } }
target:  As each segment is visited write out the appropriate line mapping.