final case class Failure[+T](exception: Throwable) extends Try[T] with Product with Serializable
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- Try.scala
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- by ArrowAssoc
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Type Members
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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.
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.
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 andnull
.Equivalent to
x.hashCode
except for boxed numeric types andnull
. 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. Fornull
returns a hashcode wherenull.hashCode
throws aNullPointerException
.- 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 toif (x eq null) that eq null else x.equals(that)
.The expression
x == that
is equivalent toif (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
.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 aClassCastException
at runtime, while the expressionList(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 typeT0
.
-
def
clone(): AnyRef
Create a copy of the receiver object.
-
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 aFailure
. -
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
).Tests whether the argument (
that
) is a reference to the receiver object (this
).The
eq
method implements an equivalence relation on non-null instances ofAnyRef
, and has three additional properties:- It is consistent: for any non-null instances
x
andy
of typeAnyRef
, multiple invocations ofx.eq(y)
consistently returnstrue
or consistently returnsfalse
. - For any non-null instance
x
of typeAnyRef
,x.eq(null)
andnull.eq(x)
returnsfalse
. null.eq(null)
returnstrue
.
When overriding the
equals
orhashCode
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
- It is consistent: for any non-null instances
- val exception: Throwable
-
def
failed: Try[Throwable]
Inverts this
Try
. -
def
filter(p: (T) ⇒ Boolean): Try[T]
Converts this to a
Failure
if the predicate is not satisfied. -
def
finalize(): Unit
Called by the garbage collector on the receiver object when there are no more references to the object.
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 betweenfinalize
and non-local returns and exceptions, are all platform dependent. -
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 aFailure
. -
def
flatten[U](implicit ev: <:<[T, Try[U]]): Try[U]
Transforms a nested
Try
, ie, aTry
of typeTry[Try[T]]
, into an un-nestedTry
, ie, aTry
of typeTry[T]
. -
def
fold[U](fa: (Throwable) ⇒ U, fb: (T) ⇒ U): U
Applies
fa
if this is aFailure
orfb
if this is aSuccess
.Applies
fa
if this is aFailure
orfb
if this is aSuccess
. Iffb
is initially applied and throws an exception, thenfa
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
-
def
foreach[U](f: (T) ⇒ U): Unit
Applies the given function
f
if this is aSuccess
, otherwise returnsUnit
if this is aFailure
. -
def
formatted(fmtstr: String): String
Returns string formatted according to given
format
string.Returns string formatted according to given
format
string. Format strings are as forString.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 aFailure
. -
final
def
getClass(): Class[_]
Returns the runtime class representation of the object.
-
def
getOrElse[U >: T](default: ⇒ U): U
Returns the value from this
Success
or the givendefault
argument if this is aFailure
. -
def
isFailure: Boolean
Returns
true
if theTry
is aFailure
,false
otherwise. -
final
def
isInstanceOf[T0]: Boolean
Test whether the dynamic type of the receiver object is
T0
.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 returnfalse
, while the expressionList(1).isInstanceOf[List[String]]
will returntrue
. 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 typeT0
;false
otherwise.
- Definition Classes
- Any
-
def
isSuccess: Boolean
Returns
true
if theTry
is aSuccess
,false
otherwise. -
def
map[U](f: (T) ⇒ U): Try[U]
Maps the given function to the value from this
Success
or returns this if this is aFailure
. -
final
def
ne(arg0: AnyRef): Boolean
Equivalent to
!(this eq that)
.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.
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.
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 aSuccess
or the givendefault
argument if this is aFailure
. -
def
recover[U >: T](pf: PartialFunction[Throwable, U]): Try[U]
Applies the given function
f
if this is aFailure
, otherwise returns this if this is aSuccess
. -
def
recoverWith[U >: T](pf: PartialFunction[Throwable, Try[U]]): Try[U]
Applies the given function
f
if this is aFailure
, otherwise returns this if this is aSuccess
. -
final
def
synchronized[T0](arg0: ⇒ T0): T0
- Definition Classes
- AnyRef
-
def
toEither: Either[Throwable, T]
Returns
Left
withThrowable
if this is aFailure
, otherwise returnsRight
withSuccess
value. -
def
toOption: Option[T]
Returns
None
if this is aFailure
or aSome
containing the value if this is aSuccess
. -
def
transform[U](s: (T) ⇒ Try[U], f: (Throwable) ⇒ Try[U]): Try[U]
Completes this
Try
by applying the functionf
to this if this is of typeFailure
, or conversely, by applyings
if this is aSuccess
. -
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
-
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.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
, andwithFilter
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 supportsmap
,flatMap
,foreach
, andwithFilter
operations. All these operations apply to those elements of this Try which satisfy the predicatep
.
-
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
This is the documentation for the Scala standard library.
Package structure
The scala package contains core types like
Int
,Float
,Array
orOption
which are accessible in all Scala compilation units without explicit qualification or imports.Notable packages include:
scala.collection
and its sub-packages contain Scala's collections frameworkscala.collection.immutable
- Immutable, sequential data-structures such asVector
,List
,Range
,HashMap
orHashSet
scala.collection.mutable
- Mutable, sequential data-structures such asArrayBuffer
,StringBuilder
,HashMap
orHashSet
scala.collection.concurrent
- Mutable, concurrent data-structures such asTrieMap
scala.collection.parallel.immutable
- Immutable, parallel data-structures such asParVector
,ParRange
,ParHashMap
orParHashSet
scala.collection.parallel.mutable
- Mutable, parallel data-structures such asParArray
,ParHashMap
,ParTrieMap
orParHashSet
scala.concurrent
- Primitives for concurrent programming such asFutures
andPromises
scala.io
- Input and output operationsscala.math
- Basic math functions and additional numeric types likeBigInt
andBigDecimal
scala.sys
- Interaction with other processes and the operating systemscala.util.matching
- Regular expressionsOther packages exist. See the complete list on the right.
Additional parts of the standard library are shipped as separate libraries. These include:
scala.reflect
- Scala's reflection API (scala-reflect.jar)scala.xml
- XML parsing, manipulation, and serialization (scala-xml.jar)scala.swing
- A convenient wrapper around Java's GUI framework called Swing (scala-swing.jar)scala.util.parsing
- Parser combinators (scala-parser-combinators.jar)Automatic imports
Identifiers in the scala package and the
scala.Predef
object are always in scope by default.Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example,
List
is an alias forscala.collection.immutable.List
.Other aliases refer to classes provided by the underlying platform. For example, on the JVM,
String
is an alias forjava.lang.String
.