Methods Detail

• public Stream from(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()
  

  Parameters:

  Since:

  5.0.0

• public Stream from(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']
  

  Parameters:

  Since:

  5.0.0

• public List getAt(EmptyRange range)

  Returns an empty list.

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

  Parameters:

  Since:

  5.0.0

• public List getAt(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']
  

  Parameters:

  Since:

  5.0.0

• public Object getAt(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
  

  Parameters:

  Since:

  5.0.0

• public Stream plus(Iterable 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]
  

  Parameters:

  Since:

  4.0.0

• public Stream plus(Collection 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]
  

  Parameters:

  Since:

  4.0.0

• public Stream plus(Stream 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]
  

  Parameters:

  Since:

  4.0.0

• public long size()

  An alias for count. Returns the count of elements for this stream. This is a terminal operator and, depending on the underlying stream, may invoke the stream pipeline, leaving it empty after this call. Care should be taken with stream pipelines that have side effects. This method should not be called on an infinite stream.

  assert [1, 2, 3].stream().size() == 3
  

  Returns:

  the count of elements in this stream

  Since:

  5.0.0

  See Also:

  Stream#count()

• public Object[] toArray(Class 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:

  type - the array element type

  Since:

  3.0.4

• public List toList()

  Accumulates the elements of stream into a new List.

  Returns:

  a new java.util.List instance

  Since:

  2.5.0

• public Set toSet()

  Accumulates the elements of stream into a new Set.

  Returns:

  a new java.util.Set instance

  Since:

  2.5.0