Scala链接条件映射-`ifDefined`方法

Question

有没有更简洁的方法来有条件地映射一个值，如：

val userName: Option[String] = Some("Bob")
val address: Option[String] = Some("Planet Earth")

val dbQuery = new Query()

val afterUserName = 
  userName.map(u => dbQuery.copy(userName = u))
    .getOrElse(dbQuery)

val modifiedQuery = 
  address.map(a => afterUserName.copy(address = a))
    .getOrElse(afterUserName)

我希望有ifDefined一种适用于所有类型的方法，如下例所示。这将删除.getOrElse(...)呼叫。

dbQuery
  .ifDefined(userName)((d, u) => d.copy(userName = u)
  .ifDefined(address)((d, a) => d.copy(address = a)

Answer 1

以下内容可能会更短

dbQuery.copy(
  userName  = userName.getOrElse(dbQuery.userName),
  address = address.getOrElse(dbQuery.address)
)