question: private void previousWindow ( Calendar startTime ) { if ( isDaily ( ) ) { startTime . add ( Calendar . DAY_OF_MONTH , - 1 ) ; } else if ( isWeekly ( ) ) { startTime . add ( Calendar . WEEK_OF_MONTH , - 1 ) ; } else if ( isMonthly ( ) ) { int month = startTime . get ( Calendar . MONTH ) ; adjustDayOfMonth ( startTime , month + - 1 ) ; } }
target:  Changes to the previous window start time.