future-ops
所属分类：collect
开发工具：Scala
文件大小：0KB
下载次数：0
上传日期：2020-02-25 09:36:35
上 传 者：
sh-1993
说明： 操作以简化与Future的编程，
(Operations to ease programming with Future,)
文件列表:
build.sbt (182, 2020-02-25)
src/ (0, 2020-02-25)
src/main/ (0, 2020-02-25)
src/main/scala/ (0, 2020-02-25)
src/main/scala/io/ (0, 2020-02-25)
src/main/scala/io/github/ (0, 2020-02-25)
src/main/scala/io/github/hamsters/ (0, 2020-02-25)
src/main/scala/io/github/hamsters/EmptyValueError.scala (120, 2020-02-25)
src/main/scala/io/github/hamsters/FutureOps.scala (1369, 2020-02-25)
src/test/ (0, 2020-02-25)
src/test/scala/ (0, 2020-02-25)
src/test/scala/io/ (0, 2020-02-25)
src/test/scala/io/github/ (0, 2020-02-25)
src/test/scala/io/github/hamsters/ (0, 2020-02-25)
src/test/scala/io/github/hamsters/FutureOpsSpec.scala (3056, 2020-02-25)
# FutureOps
This is a port of Hamsters FutureOps to Scala 2.13.
## Goal
Monad stacks are not easy to compose (e.g. in a for comprehension), and if you don't want to use Monad transformers you can use this Future additional methods.
## FutureOps.fromEither
```scala
import io.github.hamsters.FutureOps
FutureOps.fromEither(Right("a")) //Future("a")
FutureOps.fromEither(Left(BoomError)) //Future(BoomError)
```
## squash Future[Either[Throwable, A]] and Future[Try[A]]
You can use `squash` on a `Future[Either[Throwable, A]]` to get a `Future[A]`.
```scala
import FutureOps._
abstract class Error(message: String) extends Exception(message)
case object BoomError extends Error("Boom")
val fea: Future[Either[Error, String]] = Future(Right("a"))
val feb: Future[Either[Error, String]] = Future(Left(BoomError))
fea.squash //Future("a")
feb.squash //Future(BoomError)
```
You can also `squash` on a `Future[Try[A]]` to get a `Future[A]` in much the same way:
```scala
import FutureOps._
val fta: Future[Try[String]] = Future(Success("a"))
val ftb: Future[Try[String]] = Future(Failure(new Exception("Boom")))
fta.squash //Future("a")
ftb.squash //Future(Exception("Boom"))
```
It can also be useful to compose several `Future[Either[Throwable, _]]` without monad transformers :
```scala
def fea: Future[Either[Throwable, Int]] = Future(Right(1))
def feb(a: Int): Future[Either[Throwable, Int]] = Future(Right(a + 2))
val composedAB: Future[Int] = for {
a <- fea.squash
ab <- feb(a).squash
} yield ab
composedAB // Future("ab")
val error: Either[Throwable, Int] = Left(BoomError)
val composedABWithError: Future[Int] = for {
a <- Future.successful(error).squash
ab <- feb(a).squash
} yield ab
composedABWithError //Future(Failure(BoomError))
```
Composing several `Future[Try[_]]`s without monad transformers is also possible:
```scala
def fta: Future[Try[Int]] = Future(Success(1))
def ftb(a: Int): Future[Try[Int]] = Future(Success(a + 2))
val composedAB: Future[Int] = for {
a <- fta.squash
ab <- ftb(a).squash
} yield ab
composedAB // Future("ab")
```
## Options
Same operations can be used with options : `FutureOps.fromOption` and `squash` on `Future[Option[A]]`.
For empty options, an `EmptyValueError` will be raised.
# Install
Add this to you build.sbt :
```scala
resolvers += Resolver.bintrayRepo("loicdescotte", "Hamsters")
libraryDependencies += "io.github.scala-hamsters" %% "future-ops" % "1.0.0"
```
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