Method Detail

• public static boolean asBoolean(Optional<?> optional)

  Coerce an Optional instance to a boolean value.

   assert !Optional.empty().asBoolean()
   assert Optional.of(1234).asBoolean()
   

  Parameters:

  optional - the Optional

  Returns:

  true if a value is present, otherwise false

  Since:

  2.5.0

• <S, T> public static Optional<T> collect(Optional<S> self, @ClosureParams(FirstParam.FirstGenericType.class) Closure<T> transform)

  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()
   

  Parameters:

  self - an Optional

  transform - the closure used to transform the optional value if present

  Returns:

  an Optional containing the transformed value or empty if the optional is empty or the transform returns null

  Since:

  3.0.0

• <S, T> public static Future<T> collect(Future<S> self, @ClosureParams(FirstParam.FirstGenericType.class) Closure<T> transform)

  Returns a Future asynchronously returning a transformed result.

   import java.util.concurrent.*
   def executor = Executors.newSingleThreadExecutor()
   Future foobar = executor.submit{ "foobar" }
   Future foobarSize = foobar.collect{ it.size() }
   assert foobarSize.get() == 6
   executor.shutdown()
   

  Parameters:

  self - a Future

  transform - the closure used to transform the Future value

  Returns:

  a Future allowing the transformed value to be obtained asynchronously

  Since:

  3.0.0

• <T> public static Optional<T> filter(Optional<?> self, Class<T> type)

  Tests 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)
   

  Since:

  3.0.0

• public static OptionalInt filter(OptionalInt self, IntPredicate test)

  If a value is present in the OptionalInt, tests the value using the given predicate and returns the optional if the test returns true or else empty.

   assert !OptionalInt.empty().filter(i -> true).isPresent()
   assert  OptionalInt.of(1234).filter(i -> true).isPresent()
   assert !OptionalInt.of(1234).filter(i -> false).isPresent()
   assert  OptionalInt.of(1234).filter(i -> true).getAsInt() == 1234
   

  Since:

  3.0.0

• public static OptionalLong filter(OptionalLong self, LongPredicate test)

  If a value is present in the OptionalLong, tests the value using the given predicate and returns the optional if the test returns true or else empty.

   assert !OptionalLong.empty().filter(n -> true).isPresent()
   assert  OptionalLong.of(123L).filter(n -> true).isPresent()
   assert !OptionalLong.of(123L).filter(n -> false).isPresent()
   assert  OptionalLong.of(123L).filter(n -> true).getAsLong() == 123L
   

  Since:

  3.0.0

• public static OptionalDouble filter(OptionalDouble self, DoublePredicate test)

  If a value is present in the OptionalDouble, tests the value using the given predicate and returns the optional if the test returns true or empty otherwise.

   assert !OptionalDouble.empty().filter(n -> true).isPresent()
   assert  OptionalDouble.of(Math.PI).filter(n -> true).isPresent()
   assert !OptionalDouble.of(Math.PI).filter(n -> false).isPresent()
   assert  OptionalDouble.of(Math.PI).filter(n -> true).getAsDouble() == Math.PI
   

  Since:

  3.0.0

• @Override public void forEachRemaining(Consumer<? super T> action)

• public static int get(OptionalInt self)

  If a value is present in the OptionalInt, returns the value, otherwise throws NoSuchElementException.

   assert OptionalInt.of(1234).get() == 1234
   

  Since:

  3.0.0

• public static long get(OptionalLong self)

  If a value is present in the OptionalLong, returns the value, otherwise throws NoSuchElementException.

   assert OptionalLong.of(1234L).get() == 1234L
   

  Since:

  3.0.0

• public static double get(OptionalDouble self)

  If a value is present in the OptionalDouble, returns the value, otherwise throws NoSuchElementException.

   assert OptionalDouble.of(Math.PI).get() == Math.PI
   

  Since:

  3.0.0

• public static StringBuilder leftShift(StringBuilder self, Object value)

  Overloads the left shift operator to provide an easy way to append multiple objects as string representations to a StringBuilder.

  Parameters:

  self - a StringBuilder

  value - a value to append

  Returns:

  the StringBuilder on which this operation was invoked

  Since:

  1.5.2

• <T> public static OptionalDouble mapToDouble(Optional<T> self, ToDoubleFunction<? super T> 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.

   assert !Optional.empty().mapToDouble(x -> Math.PI).isPresent()
   assert  Optional.of('x').mapToDouble(x -> Math.PI).getAsDouble() == Math.PI
   

  Since:

  3.0.0

• <T> public static OptionalInt mapToInt(Optional<T> self, ToIntFunction<? super T> 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.

   assert !Optional.empty().mapToInt(x -> 42).isPresent()
   assert  Optional.of('x').mapToInt(x -> 42).getAsInt() == 42
   

  Since:

  3.0.0

• <T> public static OptionalLong mapToLong(Optional<T> self, ToLongFunction<? super T> 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.

   assert !Optional.empty().mapToLong(x -> 42L).isPresent()
   assert  Optional.of('x').mapToLong(x -> 42L).getAsLong() == 42L
   

  Since:

  3.0.0

• <T> public static Optional<T> mapToObj(OptionalInt self, IntFunction<? extends T> mapper)

  If a value is present in the OptionalInt, returns an Optional consisting of the result of applying the given function to the value or else empty.

   assert !OptionalInt.empty().mapToObj(x -> new Object()).isPresent()
   assert  OptionalInt.of(1234).mapToObj(x -> new Object()).isPresent()
   assert !OptionalInt.of(1234).mapToObj(x -> null).isPresent()
   assert  OptionalInt.of(1234).mapToObj(Integer::toString).get() == '1234'
   

  Since:

  3.0.0

• <T> public static Optional<T> mapToObj(OptionalLong self, LongFunction<? extends T> mapper)

  If a value is present in the OptionalLong, returns an Optional consisting of the result of applying the given function to the value or else empty.

   assert !OptionalLong.empty().mapToObj(x -> new Object()).isPresent()
   assert  OptionalLong.of(123L).mapToObj(x -> new Object()).isPresent()
   assert !OptionalLong.of(123L).mapToObj(x -> null).isPresent()
   assert  OptionalLong.of(1234L).mapToObj(Long::toString).get() == '1234'
   

  Since:

  3.0.0

• <T> public static Optional<T> mapToObj(OptionalDouble self, DoubleFunction<? extends T> mapper)

  If a value is present in the OptionalDouble, returns an Optional consisting of the result of applying the given function to the value or else empty.

   assert !OptionalDouble.empty().mapToObj(x -> new Object()).isPresent()
   assert  OptionalDouble.of(Math.PI).mapToObj(x -> new Object()).isPresent()
   assert !OptionalDouble.of(Math.PI).mapToObj(x -> null).isPresent()
   assert  OptionalDouble.of(Math.PI).mapToObj(Double::toString).get().startsWith('3.14')
   

  Since:

  3.0.0

• public static Object next(Enum self)

  Overloads the ++ operator for enums. It will invoke Groovy's default next behaviour for enums that do not have their own next method.

  Parameters:

  self - an Enum

  Returns:

  the next defined enum from the enum class

  Since:

  1.5.2

• public static String plus(StringBuilder self, String value)

  Appends a String to this StringBuilder.

  Parameters:

  self - a StringBuilder

  value - a String

  Returns:

  a String

  Since:

  1.5.2

• public static Object previous(Enum self)

  Overloads the -- operator for enums. It will invoke Groovy's default previous behaviour for enums that do not have their own previous method.

  Parameters:

  self - an Enum

  Returns:

  the previous defined enum from the enum class

  Since:

  1.5.2

• public static void putAt(StringBuilder self, IntRange range, Object value)

  Supports the range subscript operator for StringBuilder. Index values are treated as characters within the builder.

  Parameters:

  self - a StringBuilder

  range - a Range

  value - the object that's toString() will be inserted

  Since:

  1.5.2

• public static void putAt(StringBuilder self, EmptyRange range, Object value)

  Supports the range subscript operator for StringBuilder.

  Parameters:

  self - a StringBuilder

  range - a Range

  value - the object that's toString() will be inserted

  Since:

  1.5.2

• @Deprecated public static int size(StringBuilder self)

  Provides the standard Groovy size() method for StringBuilder.

  Parameters:

  self - a StringBuilder

  Returns:

  the length of the StringBuilder

  Since:

  1.5.2

  See Also:

  StringGroovyMethods.size

• <T> public static Stream<T> stream(NullObject self)

  Returns an empty sequential Stream.

   def item = null
   assert item.stream().toList() == []
   assert !item.stream().findFirst().isPresent()
   

  Since:

  3.0.0

• <T> public static Stream<T> stream(T self)

  Returns a sequential Stream containing a single element.

   def item = 'string'
   assert item.stream().toList() == ['string']
   assert item.stream().findFirst().isPresent()
   

  Since:

  3.0.0

• <T> public static Stream<T> stream(T[] self)

  Returns a sequential Stream with the specified array as its source.

  Type Parameters:

  T - The type of the array elements

  Parameters:

  self - The array, assumed to be unmodified during use

  Returns:

  a Stream for the array

  Since:

  2.5.0

• public static Stream<Integer> stream(int[] self)

  Returns a sequential Stream with the specified array as its source.

  Parameters:

  self - The array, assumed to be unmodified during use

  Returns:

  a Stream for the array

  Since:

  2.5.0

• public static Stream<Long> stream(long[] self)

  Returns a sequential Stream with the specified array as its source.

  Parameters:

  self - The array, assumed to be unmodified during use

  Returns:

  a Stream for the array

  Since:

  2.5.0

• public static Stream<Double> stream(double[] self)

  Returns a sequential Stream with the specified array as its source.

  Parameters:

  self - The array, assumed to be unmodified during use

  Returns:

  a Stream for the array

  Since:

  2.5.0

• public static Stream<Character> stream(char[] self)

  Returns a sequential Stream with the specified array as its source.

  Parameters:

  self - The array, assumed to be unmodified during use

  Returns:

  a Stream for the array

  Since:

  2.5.0

• public static Stream<Byte> stream(byte[] self)

  Returns a sequential Stream with the specified array as its source.

  Parameters:

  self - The array, assumed to be unmodified during use

  Returns:

  a Stream for the array

  Since:

  2.5.0

• public static Stream<Short> stream(short[] self)

  Returns a sequential Stream with the specified array as its source.

  Parameters:

  self - The array, assumed to be unmodified during use

  Returns:

  a Stream for the array

  Since:

  2.5.0

• public static Stream<Boolean> stream(boolean[] self)

  Returns a sequential Stream with the specified array as its source.

  Parameters:

  self - The array, assumed to be unmodified during use

  Returns:

  a Stream for the array

  Since:

  2.5.0

• public static Stream<Float> stream(float[] self)

  Returns a sequential Stream with the specified array as its source.

  Parameters:

  self - The array, assumed to be unmodified during use

  Returns:

  a Stream for the array

  Since:

  2.5.0

• <T> public static Stream<T> stream(Enumeration<T> self)

  Returns a sequential Stream with the specified element(s) as its source.

   def tokens = new StringTokenizer('one two')
   assert tokens.stream().toList() == ['one', 'two']
   

  Since:

  3.0.0

• <T> public static Stream<T> stream(Iterable<T> self)

  Returns a sequential Stream with the specified element(s) as its source.

   class Items implements Iterable {
     Iterator iterator() {
       ['one', 'two'].iterator()
     }
   }
   def items = new Items()
   assert items.stream().toList() == ['one', 'two']
   

  Since:

  3.0.0

• <T> public static Stream<T> stream(Iterator<T> self)

  Returns a sequential Stream with the specified element(s) as its source.

   [].iterator().stream().toList().isEmpty()
   ['one', 'two'].iterator().stream().toList() == ['one', 'two']
   

  Since:

  3.0.0

• <T> public static Stream<T> stream(Spliterator<T> self)

  Returns a sequential Stream with the specified element(s) as its source.

   [].spliterator().stream().toList().isEmpty()
   ['one', 'two'].spliterator().stream().toList() == ['one', 'two']
   

  Since:

  3.0.0

• <T> public static Stream<T> stream(Optional<T> self)

  If a value is present in the Optional, returns a Stream with the value as its source or else an empty stream.

  Since:

  3.0.0

• public static IntStream stream(OptionalInt self)

  If a value is present in the OptionalInt, returns an IntStream with the value as its source or else an empty stream.

  Since:

  3.0.0

• public static LongStream stream(OptionalLong self)

  If a value is present in the OptionalLong, returns a LongStream with the value as its source or else an empty stream.

  Since:

  3.0.0

• public static DoubleStream stream(OptionalDouble self)

  If a value is present in the OptionalDouble, returns a DoubleStream with the value as its source or else an empty stream.

  Since:

  3.0.0

• <T> public static T[] toArray(Stream<? extends T> self, Class<T> type)

  Returns an array containing the elements of the stream.

   import static groovy.test.GroovyAssert.shouldFail
  
   assert Arrays.equals([].stream().toArray(Object), new Object[0])
   assert Arrays.equals([].stream().toArray(String), new String[0])
   assert Arrays.equals([].stream().toArray(String[]), new String[0][])
   assert Arrays.equals(['x'].stream().toArray(Object), ['x'].toArray())
   assert Arrays.equals(['x'].stream().toArray(String), ['x'] as String[])
   assert Arrays.deepEquals([['x'] as String[]].stream().toArray(String[]), [['x'] as String[]] as String[][])
   assert Arrays.equals(['x'].stream().toArray(CharSequence), ['x'] as CharSequence[])
  
   shouldFail(ArrayStoreException) {
       ['x'].stream().toArray(Thread)
   }
  
   shouldFail(IllegalArgumentException) {
       ['x'].stream().toArray((Class) null)
   }
  
   // Stream#toArray(IntFunction) should still be used for closure literal:
   assert Arrays.equals(['x'].stream().toArray { n -> new String[n] }, ['x'] as String[])
  
   // Stream#toArray(IntFunction) should still be used for method reference:
   assert Arrays.equals(['x'].stream().toArray(String[]::new), ['x'] as String[])
   

  Parameters:

  self - the stream

  type - the array element type

  Since:

  3.0.4

• <T> public static List<T> toList(Stream<T> self)

  Accumulates the elements of stream into a new List.

  Parameters:

  self - the stream

  Type Parameters:

  T - the type of element

  Returns:

  a new java.util.List instance

  Since:

  2.5.0

• <T> public static List<T> toList(BaseStream<T, ? extends BaseStream> self)

  Accumulates the elements of stream into a new List.

  Parameters:

  self - the java.util.stream.BaseStream

  Type Parameters:

  T - the type of element

  Returns:

  a new java.util.List instance

  Since:

  2.5.0

• <T> public static Set<T> toSet(Stream<T> self)

  Accumulates the elements of stream into a new Set.

  Parameters:

  self - the stream

  Type Parameters:

  T - the type of element

  Returns:

  a new java.util.Set instance

  Since:

  2.5.0

• <T> public static Set<T> toSet(BaseStream<T, ? extends BaseStream> self)

  Accumulates the elements of stream into a new Set.

  Parameters:

  self - the java.util.stream.BaseStream

  Type Parameters:

  T - the type of element

  Returns:

  a new java.util.Set instance

  Since:

  2.5.0

• @Override public boolean tryAdvance(Consumer<? super T> action)