Completes this Try
with an exception wrapped in a Success
.
Completes this Try
with an exception wrapped in a Success
. The exception is either the exception that the
Try
failed with (if a Failure
) or an UnsupportedOperationException
.
Converts this to a Failure
if the predicate is not satisfied.
Returns the given function applied to the value from this Success
or returns this if this is a Failure
.
Transforms a nested Try
, ie, a Try
of type Try[Try[T]]
,
into an un-nested Try
, ie, a Try
of type Try[T]
.
Applies the given function f
if this is a Success
, otherwise returns Unit
if this is a Failure
.
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.
Returns the value from this Success
or throws the exception if this is a Failure
.
Returns true
if the Try
is a Failure
, false
otherwise.
Returns true
if the Try
is a Success
, false
otherwise.
Maps the given function to the value from this Success
or returns this if this is a Failure
.
Applies the given function f
if this is a Failure
, otherwise returns this if this is a Success
.
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.
Applies the given function f
if this is a Failure
, otherwise returns this if this is a Success
.
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.
Returns string formatted according to given format
string.
Returns string formatted according to given format
string.
Format strings are as for String.format
(@see java.lang.String.format).
Returns the value from this Success
or the given default
argument if this is a Failure
.
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.
Returns this Try
if it's a Success
or the given default
argument if this is a Failure
.
Returns None
if this is a Failure
or a Some
containing the value if this is a Success
.
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
.
The
Try
type represents a computation that may either result in an exception, or return a successfully computed value. It's similar to, but semantically different from the scala.util.Either type.Instances of
Try[T]
, are either an instance of scala.util.Success[T] or scala.util.Failure[T].For example,
Try
can be used to perform division on a user-defined input, without the need to do explicit exception-handling in all of the places that an exception might occur.Example:
An important property of
Try
shown in the above example is its ability to pipeline, or chain, operations, catching exceptions along the way. TheflatMap
andmap
combinators in the above example each essentially pass off either their successfully completed value, wrapped in theSuccess
type for it to be further operated upon by the next combinator in the chain, or the exception wrapped in theFailure
type usually to be simply passed on down the chain. Combinators such asrescue
andrecover
are designed to provide some type of default behavior in the case of failure.Note: only non-fatal exceptions are caught by the combinators on
Try
(see scala.util.control.NonFatal). Serious system errors, on the other hand, will be thrown.Note:: all Try combinators will catch exceptions and return failure unless otherwise specified in the documentation.
Try
comes to the Scala standard library after years of use as an integral part of Twitter's stack.2.10