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/Scala 2.12 Library

Class scala.util.Failure

final case class Failure[+T](exception: Throwable) extends Try[T] with Product with Serializable

Source
Try.scala
Linear Supertypes

Instance Constructors

new Failure(exception: Throwable)

Type Members

class WithFilter extends AnyRef

We need a whole WithFilter class to honor the "doesn't create a new collection" contract even though it seems unlikely to matter much in a collection with max size 1.

Definition Classes
Try
Annotations
@deprecatedInheritance( message = ... , since = "2.12.0" )

Value Members

final def !=(arg0: Any): Boolean

Test two objects for inequality.

returns

true if !(this == that), false otherwise.

Definition Classes
AnyRef → Any

final def ##(): Int

Equivalent to x.hashCode except for boxed numeric types and null. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For null returns a hashcode where null.hashCode throws a NullPointerException.

returns

a hash value consistent with ==

Definition Classes
AnyRef → Any

def +(other: String): String

Implicit
This member is added by an implicit conversion from Failure[T] to any2stringadd[Failure[T]] performed by method any2stringadd in scala.Predef.
Definition Classes
any2stringadd

def ->[B](y: B): (Failure[T], B)

Implicit
This member is added by an implicit conversion from Failure[T] to ArrowAssoc[Failure[T]] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc
Annotations
@inline()

final def ==(arg0: Any): Boolean

The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).

returns

true if the receiver object is equivalent to the argument; false otherwise.

Definition Classes
AnyRef → Any

final def asInstanceOf[T0]: T0

Cast the receiver object to be of type T0.

Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression 1.asInstanceOf[String] will throw a ClassCastException at runtime, while the expression List(1).asInstanceOf[List[String]] will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.

returns

the receiver object.

Definition Classes
Any
Exceptions thrown

ClassCastException if the receiver object is not an instance of the erasure of type T0.

def clone(): AnyRef

Create a copy of the receiver object.

The default implementation of the clone method is platform dependent.

returns

a copy of the receiver object.

Attributes
protected[lang]
Definition Classes
AnyRef
Annotations
@throws( ... ) @native()
Note

not specified by SLS as a member of AnyRef

def collect[U](pf: PartialFunction[T, U]): Try[U]

Applies the given partial function to the value from this Success or returns this if this is a Failure.

Definition Classes
FailureTry

def ensuring(cond: (Failure[T]) ⇒ Boolean, msg: ⇒ Any): Failure[T]

Implicit
This member is added by an implicit conversion from Failure[T] to Ensuring[Failure[T]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: (Failure[T]) ⇒ Boolean): Failure[T]

Implicit
This member is added by an implicit conversion from Failure[T] to Ensuring[Failure[T]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: Boolean, msg: ⇒ Any): Failure[T]

Implicit
This member is added by an implicit conversion from Failure[T] to Ensuring[Failure[T]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

def ensuring(cond: Boolean): Failure[T]

Implicit
This member is added by an implicit conversion from Failure[T] to Ensuring[Failure[T]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring

final def eq(arg0: AnyRef): Boolean

Tests whether the argument (that) is a reference to the receiver object (this).

The eq method implements an equivalence relation on non-null instances of AnyRef, and has three additional properties:

    It is consistent: for any non-null instances x and y of type AnyRef, multiple invocations of x.eq(y) consistently returns true or consistently returns false.For any non-null instance x of type AnyRef, x.eq(null) and null.eq(x) returns false. null.eq(null) returns true.

When overriding the equals or hashCode methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).

returns

true if the argument is a reference to the receiver object; false otherwise.

Definition Classes
AnyRef

val exception: Throwable

def failed: Try[Throwable]

Inverts this Try. If this is a Failure, returns its exception wrapped in a Success. If this is a Success, returns a Failure containing an UnsupportedOperationException.

Definition Classes
FailureTry

def filter(p: (T) ⇒ Boolean): Try[T]

Converts this to a Failure if the predicate is not satisfied.

Definition Classes
FailureTry

def finalize(): Unit

Called by the garbage collector on the receiver object when there are no more references to the object.

The details of when and if the finalize method is invoked, as well as the interaction between finalize and non-local returns and exceptions, are all platform dependent.

Attributes
protected[lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
Note

not specified by SLS as a member of AnyRef

def flatMap[U](f: (T) ⇒ Try[U]): Try[U]

Returns the given function applied to the value from this Success or returns this if this is a Failure.

Definition Classes
FailureTry

def flatten[U](implicit ev: <:<[T, Try[U]]): Try[U]

Transforms a nested Try, ie, a Try of type Try[Try[T]], into an un-nested Try, ie, a Try of type Try[T].

Definition Classes
FailureTry

def fold[U](fa: (Throwable) ⇒ U, fb: (T) ⇒ U): U

Applies fa if this is a Failure or fb if this is a Success. If fb is initially applied and throws an exception, then fa is applied with this exception.

fa

the function to apply if this is a Failure

fb

the function to apply if this is a Success

returns

the results of applying the function

Definition Classes
FailureTry
Example:
    val result: Try[Throwable, Int] = Try { string.toInt }
    log(result.fold(
      ex => "Operation failed with " + ex,
      v => "Operation produced value: " + v
    ))

def foreach[U](f: (T) ⇒ U): Unit

Applies the given function f if this is a Success, otherwise returns Unit if this is a Failure.

Note: If f throws, then this method may throw an exception.

Definition Classes
FailureTry

def formatted(fmtstr: String): String

Returns string formatted according to given format string. Format strings are as for String.format (@see java.lang.String.format).

Implicit
This member is added by an implicit conversion from Failure[T] to StringFormat[Failure[T]] performed by method StringFormat in scala.Predef.
Definition Classes
StringFormat
Annotations
@inline()

def get: T

Returns the value from this Success or throws the exception if this is a Failure.

Definition Classes
FailureTry

final def getClass(): Class[_]

Returns the runtime class representation of the object.

returns

a class object corresponding to the runtime type of the receiver.

Definition Classes
AnyRef → Any
Annotations
@native()

def getOrElse[U >: T](default: ⇒ U): U

Returns the value from this Success or the given default argument if this is a Failure.

Note:: This will throw an exception if it is not a success and default throws an exception.

Definition Classes
FailureTry

def isFailure: Boolean

Returns true if the Try is a Failure, false otherwise.

Definition Classes
FailureTry

final def isInstanceOf[T0]: Boolean

Test whether the dynamic type of the receiver object is T0.

Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression 1.isInstanceOf[String] will return false, while the expression List(1).isInstanceOf[List[String]] will return true. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.

returns

true if the receiver object is an instance of erasure of type T0; false otherwise.

Definition Classes
Any

def isSuccess: Boolean

Returns true if the Try is a Success, false otherwise.

Definition Classes
FailureTry

def map[U](f: (T) ⇒ U): Try[U]

Maps the given function to the value from this Success or returns this if this is a Failure.

Definition Classes
FailureTry

final def ne(arg0: AnyRef): Boolean

Equivalent to !(this eq that).

returns

true if the argument is not a reference to the receiver object; false otherwise.

Definition Classes
AnyRef

final def notify(): Unit

Wakes up a single thread that is waiting on the receiver object's monitor.

Definition Classes
AnyRef
Annotations
@native()
Note

not specified by SLS as a member of AnyRef

final def notifyAll(): Unit

Wakes up all threads that are waiting on the receiver object's monitor.

Definition Classes
AnyRef
Annotations
@native()
Note

not specified by SLS as a member of AnyRef

def orElse[U >: T](default: ⇒ Try[U]): Try[U]

Returns this Try if it's a Success or the given default argument if this is a Failure.

Definition Classes
FailureTry

def recover[U >: T](pf: PartialFunction[Throwable, U]): Try[U]

Applies the given function f if this is a Failure, otherwise returns this if this is a Success. This is like map for the exception.

Definition Classes
FailureTry

def recoverWith[U >: T](pf: PartialFunction[Throwable, Try[U]]): Try[U]

Applies the given function f if this is a Failure, otherwise returns this if this is a Success. This is like flatMap for the exception.

Definition Classes
FailureTry

final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef

def toEither: Either[Throwable, T]

Returns Left with Throwable if this is a Failure, otherwise returns Right with Success value.

Definition Classes
FailureTry

def toOption: Option[T]

Returns None if this is a Failure or a Some containing the value if this is a Success.

Definition Classes
FailureTry

def transform[U](s: (T) ⇒ Try[U], f: (Throwable) ⇒ Try[U]): Try[U]

Completes this Try by applying the function f to this if this is of type Failure, or conversely, by applying s if this is a Success.

Definition Classes
FailureTry

final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )

final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )

final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... ) @native()

final def withFilter(p: (T) ⇒ Boolean): WithFilter

Creates a non-strict filter, which eventually converts this to a Failure if the predicate is not satisfied.

Note: unlike filter, withFilter does not create a new Try. Instead, it restricts the domain of subsequent map, flatMap, foreach, and withFilter operations.

As Try is a one-element collection, this may be a bit overkill, but it's consistent with withFilter on Option and the other collections.

p

the predicate used to test elements.

returns

an object of class WithFilter, which supports map, flatMap, foreach, and withFilter operations. All these operations apply to those elements of this Try which satisfy the predicate p.

Definition Classes
Try
Annotations
@inline()

def [B](y: B): (Failure[T], B)

Implicit
This member is added by an implicit conversion from Failure[T] to ArrowAssoc[Failure[T]] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc

© 2002-2019 EPFL, with contributions from Lightbend.
Licensed under the Apache License, Version 2.0.
https://www.scala-lang.org/api/2.12.9/scala/util/Failure.html