Package org.codehaus.groovy.runtime

Class StreamGroovyMethods

java.lang.Object
org.codehaus.groovy.runtime.StreamGroovyMethods
public class StreamGroovyMethods extends Object

  • Method Details

    • getAt

      public static <T> T getAt(Stream<T> self, int index)
      Returns element at index or null.

      This is a short-circuiting terminal operation. 

       import java.util.stream.Stream
 import static groovy.test.GroovyAssert.shouldFail

 Stream stream = ['foo','bar','baz'].stream()
 shouldFail(IllegalArgumentException) { stream[-1] }

 stream = ['foo','bar','baz'].stream()
 assert stream[0] == 'foo'

 stream = ['foo','bar','baz'].stream()
 assert stream[1] == 'bar'

 stream = ['foo','bar','baz'].stream()
 assert stream[2] == 'baz'

 stream = ['foo','bar','baz'].stream()
 assert stream[3] === null
      Throws:
      IllegalArgumentException - if index is negative
      Since:
      5.0.0

    • getAt

      public static <T> List<T> getAt(Stream<T> self, IntRange range)
      Returns element(s) in range or an empty list.

      This is a short-circuiting terminal operation. 

       import java.util.stream.Stream
 import static groovy.test.GroovyAssert.shouldFail

 Stream<String> stream = ['foo','bar','baz'].stream()
 shouldFail(IllegalArgumentException) { stream[-1..0] }

 stream = ['foo','bar','baz'].stream()
 shouldFail(IllegalArgumentException) { stream[0..-1] }

 stream = ['foo','bar','baz'].stream()
 assert stream[0..<1] == ['foo']

 stream = ['foo','bar','baz'].stream()
 assert stream[1..<2] == ['bar']

 stream = ['foo','bar','baz'].stream()
 assert stream[2..<3] == ['baz']

 stream = ['foo','bar','baz'].stream()
 assert stream[3..<4] == []

 stream = ['foo','bar','baz'].stream()
 assert stream[0<..2] == ['bar','baz']

 stream = ['foo','bar','baz'].stream()
 assert stream[0..99] == ['foo','bar','baz']
      Throws:
      IllegalArgumentException - for negative index or reverse range
      Since:
      5.0.0

    • getAt

      public static <T> List<T> getAt(Stream<T> self, EmptyRange range)
      Returns an empty list. 

       import java.util.stream.Stream
 Stream<String> stream = ['foo','bar','baz'].stream()
 assert stream[1..<1].isEmpty()
      Since:
      5.0.0

    • from

      public static <T> Stream<T> from(Stream<T> self, IntRange range)
      Returns a (possibly empty) stream.

      This is a short-circuiting intermediate operation. 

       import java.util.stream.Stream
 import static groovy.test.GroovyAssert.shouldFail

 Stream<String> stream = ['foo','bar','baz'].stream()
 shouldFail(IllegalArgumentException) { stream.from(-1..0) }

 stream = ['foo','bar','baz'].stream()
 shouldFail(IllegalArgumentException) { stream.from(0..-1) }

 stream = ['foo','bar','baz'].stream()
 assert stream.from(0..<1).toList() == ['foo']

 stream = ['foo','bar','baz'].stream()
 assert stream.from(1..<2).toList() == ['bar']

 stream = ['foo','bar','baz'].stream()
 assert stream.from(2..<3).toList() == ['baz']

 stream = ['foo','bar','baz'].stream()
 assert stream.from(3..<4).toList() == []

 stream = ['foo','bar','baz'].stream()
 assert stream.from(0<..2).toList() == ['bar','baz']

 stream = ['foo','bar','baz'].stream()
 assert stream.from(0<..<2).toList() == ['bar']

 stream = ['foo','bar','baz'].stream()
 assert stream.from(0..99).toList() == ['foo','bar','baz']
      Throws:
      IllegalArgumentException - for negative index or reverse range
      Since:
      5.0.0

    • from

      public static <T> Stream<T> from(Stream<T> self, EmptyRange range)
      Returns an empty stream. 

       import java.util.stream.Stream
 Stream<String> stream = ['foo','bar','baz'].stream()
 assert !stream.from(1..<1).findAny().isPresent()
      Since:
      5.0.0

    • plus

      public static <T> Stream<T> plus(Stream<? extends T> lhs, Collection<? extends T> rhs)
      Returns a lazily concatenated stream whose elements are all the elements of this stream followed by all the elements of the Collection object. 
       import java.util.stream.Stream
 assert (Stream.of(1) + [2]).toList() == [1,2]
 assert (Stream.of(1) + []).toList() == [1]
      Since:
      4.0.0

    • plus

      public static <T> Stream<T> plus(Stream<? extends T> lhs, Iterable<? extends T> rhs)
      Returns a lazily concatenated stream whose elements are all the elements of this stream followed by all the elements of the Iterable object. 
       import java.util.stream.Stream
 assert (Stream.of(1) + [2]).toList() == [1,2]
 assert (Stream.of(1) + []).toList() == [1]
      Since:
      4.0.0

    • plus

      public static <T> Stream<T> plus(Stream<? extends T> lhs, Stream<? extends T> rhs)
      Returns a lazily concatenated stream whose elements are all the elements of this stream followed by all the elements of the second stream. 
       import java.util.stream.Stream
 assert (Stream.of(1) + Stream.<Integer>empty()).toList() == [1]
 assert (Stream.of(1) + Stream.of(2)).toList() == [1,2]
 assert (Stream.of(1) + [2].stream()).toList() == [1,2]
      Since:
      4.0.0

    • stream

      public static <T> 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

    • stream

      public static <T> 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

    • stream

      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

    • stream

      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

    • stream

      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

    • stream

      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

    • stream

      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

    • stream

      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

    • stream

      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

    • stream

      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

    • stream

      public static <T> 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

    • stream

      public static <T> Stream<T> stream(Iterable<T> self)
      Returns a sequential Stream with the specified element(s) as its source. 
       class Items implements Iterable {
   Iterator<String> iterator() {
     ['one', 'two'].iterator()
   }
 }
 def items = new Items()
 assert items.stream().toList() == ['one', 'two']
      Since:
      3.0.0

    • stream

      public static <T> 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

    • stream

      public static <T> Stream<T> stream(Spliterator<T> self)
      Returns a sequential Stream with the specified element(s) as its source. 
       assert [].spliterator().stream().toList().isEmpty()
 assert ['one', 'two'].spliterator().stream().toList() == ['one', 'two']
      Since:
      3.0.0

    • stream

      public static <T> 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

    • stream

      public static <T> 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

    • stream

      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

    • stream

      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

    • stream

      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

    • intStream

      public static IntStream intStream(int[] self)
      Returns a sequential IntStream with the specified array as its source.
      Parameters:
      self - The array, assumed to be unmodified during use
      Returns:
      a Stream for the array
      Since:
      3.0.8

    • longStream

      public static LongStream longStream(long[] self)
      Returns a sequential LongStream with the specified array as its source.
      Parameters:
      self - The array, assumed to be unmodified during use
      Returns:
      a Stream for the array
      Since:
      3.0.8

    • doubleStream

      public static DoubleStream doubleStream(double[] self)
      Returns a sequential DoubleStream with the specified array as its source.
      Parameters:
      self - The array, assumed to be unmodified during use
      Returns:
      a Stream for the array
      Since:
      3.0.8

    • toArray

      public static <T> 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

    • toList

      public static <T> List<T> toList(Stream<T> self)
      Accumulates the elements of stream into a new List.
      Type Parameters:
      T - the type of element
      Parameters:
      self - the stream
      Returns:
      a new java.util.List instance
      Since:
      2.5.0

    • toList

      public static <T> List<T> toList(BaseStream<T,? extends BaseStream> self)
      Accumulates the elements of stream into a new List.
      Type Parameters:
      T - the type of element
      Parameters:
      self - the java.util.stream.BaseStream
      Returns:
      a new java.util.List instance
      Since:
      2.5.0

    • toSet

      public static <T> Set<T> toSet(Stream<T> self)
      Accumulates the elements of stream into a new Set.
      Type Parameters:
      T - the type of element
      Parameters:
      self - the stream
      Returns:
      a new java.util.Set instance
      Since:
      2.5.0

    • toSet

      public static <T> Set<T> toSet(BaseStream<T,? extends BaseStream> self)
      Accumulates the elements of stream into a new Set.
      Type Parameters:
      T - the type of element
      Parameters:
      self - the java.util.stream.BaseStream
      Returns:
      a new java.util.Set instance
      Since:
      2.5.0