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 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