有没有比and更好/更惯用的方式来使用Maybe
JavaRx 2 中的类型?以下示例采用并尝试为他们预订随机机票。如果用户不存在,则返回空。flatMap
try/catch
Maybe<User>
Observable
fun bookRandomTicketFor(userId: UUID): Observable<Ticket> {
val agencies = travelAgents() // Observable<TravelAgency>
val user = findById(userId) // Maybe<User>
val location = locate() // Observable<GeoLocation>
return Observable
.just(user.toObservable())
.flatMap { usr ->
try {
usr.zipWith(location, { aUser, location ->
agencies
.flatMap { agency ->
agency
.search(aUser, location) // Observable<Flight>.
.toList() // Convert to List<Flight>.
.toObservable() // And to Observable<List<Flight>>.
.flatMap { flights -> // So it can be shuffled,
Observable.just( // giving a random order.
shuffle(flights as MutableList<Flight>)[0]
)
}
}.firstElement() // Now take the first randomly shuffled Flight.
}).flatMap { flight ->
book(user.toObservable(), flight.toObservable())
}
} catch (ex: Exception) {
Observable.empty<Ticket>()
}
}
.doOnSubscribe { Logger.log("Random ticket: start for $userId") }
.doOnComplete { Logger.log("Random ticket: exit for $userId") }
}
必须将 转换Maybe<User>
为 anObservable
并从 an 开始,Observable<Observable<User>>
然后我可以flatMap
和try/catch
. 只是想知道是否有更简洁的方法来做到这一点?