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.
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.
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, 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.
the predicate used to test elements.
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.
The
Trytype 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,
Trycan 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
Tryshown in the above example is its ability to pipeline, or chain, operations, catching exceptions along the way. TheflatMapandmapcombinators in the above example each essentially pass off either their successfully completed value, wrapped in theSuccesstype for it to be further operated upon by the next combinator in the chain, or the exception wrapped in theFailuretype usually to be simply passed on down the chain. Combinators such asrescueandrecoverare 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.
Trycomes to the Scala standard library after years of use as an integral part of Twitter's stack.2.10