diff options
Diffstat (limited to 'src')
-rw-r--r-- | src/library/scala/util/Try.scala | 87 |
1 files changed, 32 insertions, 55 deletions
diff --git a/src/library/scala/util/Try.scala b/src/library/scala/util/Try.scala index 5dc5ede1cc..a810195b9f 100644 --- a/src/library/scala/util/Try.scala +++ b/src/library/scala/util/Try.scala @@ -6,84 +6,66 @@ ** |/ ** \* */ +package scala.util -package scala.util /** - * The Try type represents a computation that may either result in an exception, - * or return a success value. It's analagous to the `Either` type. - * + * The `Try` type represents a computation that may either result in an exception, + * or return a success value. It's analagous to the `Either` type. */ sealed abstract class Try[+T] { /** - * Returns true if the Try is a Failure, false otherwise. + * Returns true if the `Try` is a `Failure`, false otherwise. */ def isFailure: Boolean /** - * Returns true if the Try is a Success, false otherwise. + * Returns true if the `Try` is a `Success`, false otherwise. */ def isSuccess: Boolean /** - * Returns the value from this Success or the given argument if this is a Failure. - */ - def getOrElse[U >: T](default: => U) = if (isSuccess) apply() else default - - /** - * Returns the value from this Success or throws the exception if this is a Failure + * Returns the value from this `Success` or the given argument if this is a `Failure`. */ - def apply(): T + def getOrElse[U >: T](default: => U) = if (isSuccess) get else default /** - * Returns the value from this Success or throws the exception if this is a Failure. - * Alias for apply() + * Returns the value from this `Success` or throws the exception if this is a `Failure`. */ - def get = apply() + def get /** * Applies the given function f if this is a Result. */ - def foreach[U](f: T => U) { onSuccess(f) } + def foreach[U](f: T => U): Unit /** - * Returns the given function applied to the value from this Success or returns this if this is a Failure. - * + * Returns the given function applied to the value from this `Success` or returns this if this is a `Failure`. */ def flatMap[U](f: T => Try[U]): Try[U] /** - * Maps the given function to the value from this Success or returns this if this is a Failure + * Maps the given function to the value from this `Success` or returns this if this is a `Failure`. */ def map[U](f: T => U): Try[U] /** - * Converts this to a Failure if the predicate is not satisfied. + * Converts this to a `Failure` if the predicate is not satisfied. */ def filter(p: T => Boolean): Try[T] /** - * Calls the exceptionHandler with the exception if this is a Failure. This is like flatMap for the exception. + * Calls the exceptionHandler with the exception if this is a `Failure`. This is like `flatMap` for the exception. */ def rescue[U >: T](rescueException: PartialFunction[Throwable, Try[U]]): Try[U] /** - * Calls the exceptionHandler with the exception if this is a Failure. This is like map for the exception. + * Calls the exceptionHandler with the exception if this is a `Failure`. This is like map for the exception. */ def handle[U >: T](rescueException: PartialFunction[Throwable, U]): Try[U] /** - * Invoked only if the computation was successful. - */ - def onSuccess[U](f: T => U): Try[T] - - /** - * Invoked only if the computation failed. - */ - def onFailure[U](rescueException: Throwable => U): Try[T] - - /** * Invoked regardless of whether the computation completed * successfully or unsuccessfully. Implemented in terms of * `respond` so that subclasses control evaluation order. Returns a @@ -93,9 +75,9 @@ sealed abstract class Try[+T] { respond { _ => f } /** - * Returns None if this is a Failure or a Some containing the value if this is a Success + * Returns `None` if this is a `Failure` or a `Some` containing the value if this is a `Success`. */ - def toOption = if (isSuccess) Some(apply()) else None + def toOption = if (isSuccess) Some(get) else None /** * Invokes the given closure when the value is available. Returns @@ -112,7 +94,7 @@ sealed abstract class Try[+T] { /** * Invokes the given transformation when the value is available, * returning the transformed value. This method is like a combination - * of flatMap and rescue. This method is typically used for more + * of `flatMap` and `rescue`. This method is typically used for more * imperative control-flow than flatMap/rescue which often exploits * the Null Object Pattern. * @@ -122,18 +104,19 @@ sealed abstract class Try[+T] { f(this) /** - * Returns the given function applied to the value from this Success or returns this if this is a Failure. - * Alias for flatMap + * Returns the given function applied to the value from this Success or returns this if this is a `Failure. + * Alias for `flatMap`. */ def andThen[U](f: T => Try[U]) = flatMap(f) /** - * Transforms a nested Try, i.e., a Try of type `Try[Try[T]]`, - * into an un-nested Try, i.e., a Try of type `Try[T]` + * Transforms a nested `Try`, i.e., a `Try` of type `Try[Try[T]]`, + * into an un-nested `Try`, i.e., a `Try` of type `Try[T]` */ def flatten[U](implicit ev: T <:< Try[U]): Try[U] } + final case class Failure[+T](e: Throwable) extends Try[T] { def isFailure = true def isSuccess = false @@ -144,16 +127,12 @@ final case class Failure[+T](e: Throwable) extends Try[T] { case e2 => Failure(e2) } } - def apply(): T = throw e + def get: T = throw e def flatMap[U](f: T => Try[U]): Try[U] = Failure[U](e) def flatten[U](implicit ev: T <:< Try[U]): Try[U] = Failure[U](e) + def foreach[U](f: T => U) {} def map[U](f: T => U): Try[U] = Failure[U](e) def filter(p: T => Boolean): Try[T] = this - def onFailure[U](rescueException: Throwable => U): Try[T] = { - rescueException(e) - this - } - def onSuccess[U](f: T => U): Try[T] = this def handle[U >: T](rescueException: PartialFunction[Throwable, U]): Try[U] = if (rescueException.isDefinedAt(e)) { Try(rescueException(e)) @@ -162,35 +141,33 @@ final case class Failure[+T](e: Throwable) extends Try[T] { } } + final case class Success[+T](r: T) extends Try[T] { def isFailure = false def isSuccess = true def rescue[U >: T](rescueException: PartialFunction[Throwable, Try[U]]): Try[U] = Success(r) - def apply() = r + def get = r def flatMap[U](f: T => Try[U]): Try[U] = try f(r) catch { case e => Failure(e) } def flatten[U](implicit ev: T <:< Try[U]): Try[U] = r + def foreach[U](f: T => U) = f(r) def map[U](f: T => U): Try[U] = Try[U](f(r)) def filter(p: T => Boolean): Try[T] = if (p(apply())) this else Failure(new NoSuchElementException("Predicate does not hold")) - def onFailure[U](rescueException: Throwable => U): Try[T] = this - def onSuccess[U](f: T => U): Try[T] = { - f(r) - this - } def handle[U >: T](rescueException: PartialFunction[Throwable, U]): Try[U] = this } -object Try { +object Try { + def apply[T](r: => T): Try[T] = { try { Success(r) } catch { case e => Failure(e) } } - -}
\ No newline at end of file + +} |