我正在学习scalaZ的monad IO,我无法理解catchAll和catchSome运算符是如何工作的。 我期待看到一个类似于RxJava的onError或onErrorrResumeNext的行为,但是没有抓住throwable,它只是打破了测试并抛出了NullPointerException ..
这是我的两个例子
@Test
def catchAllOperator(): Unit = {
val errorSentence: IO[Throwable, String] =
IO.point[Throwable, String](null)
.map(value => value.toUpperCase())
.catchAll(error => IO.fail(error))
println(unsafePerformIO(errorSentence))
}
和catchSome示例
@Test
def catchSomeOperator(): Unit = {
val errorFunction = new PartialFunction[Throwable /*Entry type*/ , IO[Throwable, String] /*Output type*/ ] {
override def isDefinedAt(x: Throwable): Boolean = x.isInstanceOf[NullPointerException]
override def apply(v1: Throwable): IO[Throwable, String] = IO.point("Default value")
}
val errorSentence = IO.point[Throwable, String](null)
.map(value => value.toUpperCase())
.catchSome(errorFunction)
println(unsafePerformIO(errorSentence))
}
知道我做错了吗?
此致