question: public static < E , R > R ifelse ( Optional < E > condition , Function < E , R > trueMap , R falseValue ) { if ( condition . isPresent ( ) ) { return trueMap . apply ( condition . get ( ) ) ; } else { return falseValue ; } }
target:  If the condition is present, the true-function will be called with its value and the result will be returned. Else the false-value will be returned.