Return type | Name and parameters |
---|---|
boolean
|
asBoolean()
Coerce an Optional instance to a boolean value.
|
Optional
|
collect(Closure transform)
If the optional contains a value, returns an optional containing the transformed value obtained using the transform closure
or otherwise an empty optional.
|
Optional
|
filter(Class type)
Tests given value against specified type and changes generics of result. |
OptionalDouble
|
mapToDouble(ToDoubleFunction mapper)
If a value is present in the OptionalDouble , returns an OptionalDouble
consisting of the result of applying the given function to the value or else empty.
|
OptionalInt
|
mapToInt(ToIntFunction mapper)
If a value is present in the OptionalInt , returns an OptionalInt
consisting of the result of applying the given function to the value or else empty.
|
OptionalLong
|
mapToLong(ToLongFunction mapper)
If a value is present in the OptionalLong , returns an OptionalLong
consisting of the result of applying the given function to the value or else empty.
|
Optional
|
orOptional(Supplier supplier)
Provides similar functionality to JDK9 or on JDK8.
|
Stream
|
stream()
If a value is present in the Optional, returns a Stream with the value as its source or else an empty stream. |
addShutdownHook
, any
, any
, asBoolean
, asType
, collect
, collect
, collect
, dump
, each
, eachMatch
, eachMatch
, eachWithIndex
, every
, every
, find
, find
, findAll
, findAll
, findIndexOf
, findIndexOf
, findIndexValues
, findIndexValues
, findLastIndexOf
, findLastIndexOf
, findResult
, findResult
, findResult
, findResult
, getAt
, getMetaClass
, getMetaPropertyValues
, getProperties
, grep
, grep
, hasProperty
, identity
, inject
, inject
, inspect
, invokeMethod
, is
, isCase
, isNotCase
, iterator
, metaClass
, print
, print
, printf
, printf
, println
, println
, println
, putAt
, respondsTo
, respondsTo
, setMetaClass
, split
, sprintf
, sprintf
, stream
, tap
, toString
, use
, use
, use
, with
, with
, withCloseable
, withStream
, withTraits
Coerce an Optional
instance to a boolean
value.
assert !Optional.empty().asBoolean() assert Optional.of(1234).asBoolean()
true
if a value is present, otherwise false
If the optional contains a value, returns an optional containing the transformed value obtained using the transform
closure
or otherwise an empty optional.
assert Optional.of("foobar").collect{ it.size() }.get() == 6 assert !Optional.empty().collect{ it.size() }.isPresent()
transform
- the closure used to transform the optional value if presentTests given value against specified type and changes generics of result.
This is equivalent to: self.filter(it -> it instanceof Type).map(it -> (Type) it)
assert !Optional.empty().filter(Number).isPresent() assert !Optional.of('x').filter(Number).isPresent() assert Optional.of(1234).filter(Number).isPresent() assert Optional.of(1234).filter(Number).get().equals(1234)
If a value is present in the OptionalDouble
, returns an OptionalDouble
consisting of the result of applying the given function to the value or else empty.
assert !Optional.empty().mapToDouble(x -> Math.PI).isPresent() assert Optional.of('x').mapToDouble(x -> Math.PI).getAsDouble() == Math.PI
If a value is present in the OptionalInt
, returns an OptionalInt
consisting of the result of applying the given function to the value or else empty.
assert !Optional.empty().mapToInt(x -> 42).isPresent() assert Optional.of('x').mapToInt(x -> 42).getAsInt() == 42
If a value is present in the OptionalLong
, returns an OptionalLong
consisting of the result of applying the given function to the value or else empty.
assert !Optional.empty().mapToLong(x -> 42L).isPresent() assert Optional.of('x').mapToLong(x -> 42L).getAsLong() == 42L
Provides similar functionality to JDK9 or
on JDK8.
def x = Optional.empty() def y = Optional.of('y') assert y.orOptional(() -> Optional.of('z')).get() == 'y' assert x.orOptional(() -> Optional.of('z')).get() == 'z'
If a value is present in the Optional, returns a Stream with the value as its source or else an empty stream.