question: public void loadYear ( int year ) { if ( eraSet . contains ( year ) ) { loadEra ( year ) ; } if ( year > eraSet . first ( ) ) { loadEra ( eraSet . floor ( year ) ) ; } if ( year < eraSet . last ( ) ) { loadEra ( eraSet . ceiling ( year ) ) ; } }
target:  If year is equal to one of the era marks, loads that era. If it is between, loads eras on both sides.