com.aol.cyclops.streams

Class StreamUtils

java.lang.Object

com.aol.cyclops.streams.StreamUtils

public class StreamUtils
extends java.lang.Object

Constructor Summary

Constructors

Constructor and Description
StreamUtils()

Method Summary

Modifier and Type	Method and Description
static <T,A,R> java.util.List<R>	collect(java.util.stream.Stream<T> stream, java.lang.Iterable<java.util.stream.Collector> collectors) Apply multiple Collectors, simultaneously to a Stream
static <T,A,R> java.util.List<R>	collect(java.util.stream.Stream<T> stream, java.util.stream.Stream<java.util.stream.Collector> collectors) Apply multiple Collectors, simultaneously to a Stream
static <T> java.util.List	collect(java.util.stream.Stream<T> stream, Streamable<java.util.stream.Collector> collectors) Apply multiple Collectors, simultaneously to a Stream
static <U> java.util.stream.Stream<U>	concat(java.lang.Object o, java.util.stream.Stream<U> stream) Concat an Object and a Stream If the Object is a Stream, Streamable or Iterable will be converted (or left) in Stream form and concatonated Otherwise a new Stream.of(o) is created
static <U> java.util.stream.Stream<U>	cycle(int times, Streamable<U> s) Create a Stream that infiniteable cycles the provided Streamable
static <U> java.util.stream.Stream<U>	cycle(java.util.stream.Stream<U> s) Create a new Stream that infiniteable cycles the provided Stream
static <U> java.util.stream.Stream<U>	cycle(Streamable<U> s) Create a Stream that infiniteable cycles the provided Streamable
static <T> HeadAndTail<T>	headAndTail(java.util.stream.Stream<T> stream)
static <T> java.util.Optional<HeadAndTail<T>>	headAndTailOptional(java.util.stream.Stream<T> stream)
static <U> java.util.stream.Stream<U>	limitUntil(java.util.stream.Stream<U> stream, java.util.function.Predicate<? super U> predicate) Take elements from a Stream until the predicate holds
static <U> java.util.stream.Stream<U>	limitWhile(java.util.stream.Stream<U> stream, java.util.function.Predicate<? super U> predicate) Take elements from a stream while the predicates hold
static <R> java.util.List<R>	reduce(java.util.stream.Stream<R> stream, java.lang.Iterable<Monoid<R>> reducers) Simultanously reduce a stream with multiple reducers
static <R> java.util.List<R>	reduce(java.util.stream.Stream<R> stream, java.util.stream.Stream<Monoid<R>> reducers) Simultanously reduce a stream with multiple reducers
static <U> java.util.stream.Stream<U>	reverse(java.util.stream.Stream<U> stream) Reverse a Stream
static <U> java.util.stream.Stream<U>	reversedStream(java.util.List<U> list) Create a reversed Stream from a List
static <U> java.util.stream.Stream<U>	skipUntil(java.util.stream.Stream<U> stream, java.util.function.Predicate<? super U> predicate) skip elements in Stream until Predicate holds true
static <U> java.util.stream.Stream<U>	skipWhile(java.util.stream.Stream<U> stream, java.util.function.Predicate<? super U> predicate) skip elements in a Stream while Predicate holds true
static <U> java.util.stream.Stream<U>	stream(java.lang.Iterable<U> it) Create a stream from an iterable
static <U> java.util.stream.Stream<U>	stream(java.util.Iterator<U> it) Create a stream from an iterator
static <K,V> java.util.stream.Stream<java.util.Map.Entry<K,V>>	stream(java.util.Map<K,V> it) Create a stream from a map

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

StreamUtils

public StreamUtils()

Method Detail

headAndTail

public static final <T> HeadAndTail<T> headAndTail(java.util.stream.Stream<T> stream)

Returns:

headAndTailOptional

public static final <T> java.util.Optional<HeadAndTail<T>> headAndTailOptional(java.util.stream.Stream<T> stream)

skipUntil

public static <U> java.util.stream.Stream<U> skipUntil(java.util.stream.Stream<U> stream,
                                                       java.util.function.Predicate<? super U> predicate)

skip elements in Stream until Predicate holds true

   StreamUtils.skipUntil(Stream.of(4,3,6,7),i->i==6).collect(Collectors.toList())
  // [6,7]
  

Parameters:

stream - Stream to skip elements from

predicate - to apply

Returns:

Stream with elements skipped

skipWhile

public static <U> java.util.stream.Stream<U> skipWhile(java.util.stream.Stream<U> stream,
                                                       java.util.function.Predicate<? super U> predicate)

skip elements in a Stream while Predicate holds true

 
   StreamUtils.skipWhile(Stream.of(4,3,6,7).sorted(),i->i<6).collect(Collectors.toList())
  // [6,7]
  

Parameters:

stream -

predicate -

Returns:

limitWhile

public static <U> java.util.stream.Stream<U> limitWhile(java.util.stream.Stream<U> stream,
                                                        java.util.function.Predicate<? super U> predicate)

Take elements from a stream while the predicates hold

  StreamUtils.limitWhile(Stream.of(4,3,6,7).sorted(),i->i<6).collect(Collectors.toList());
 //[4,3]
 
 

Parameters:

stream -

predicate -

Returns:

limitUntil

public static <U> java.util.stream.Stream<U> limitUntil(java.util.stream.Stream<U> stream,
                                                        java.util.function.Predicate<? super U> predicate)

Take elements from a Stream until the predicate holds

  StreamUtils.limitUntil(Stream.of(4,3,6,7),i->i==6).collect(Collectors.toList());
 //[4,3]
 
 

Parameters:

stream -

predicate -

Returns:

reverse

public static <U> java.util.stream.Stream<U> reverse(java.util.stream.Stream<U> stream)

Reverse a Stream

Parameters:

stream - Stream to reverse

Returns:

Reversed stream

reversedStream

public static <U> java.util.stream.Stream<U> reversedStream(java.util.List<U> list)

Create a reversed Stream from a List

Parameters:

list - List to create a reversed Stream from

Returns:

Reversed Stream

cycle

public static <U> java.util.stream.Stream<U> cycle(java.util.stream.Stream<U> s)

Create a new Stream that infiniteable cycles the provided Stream

Parameters:

s - Stream to cycle

Returns:

New cycling stream

cycle

public static <U> java.util.stream.Stream<U> cycle(Streamable<U> s)

Create a Stream that infiniteable cycles the provided Streamable

Parameters:

s - Streamable to cycle

Returns:

New cycling stream

cycle

public static <U> java.util.stream.Stream<U> cycle(int times,
                                                   Streamable<U> s)

Create a Stream that infiniteable cycles the provided Streamable

Parameters:

s - Streamable to cycle

Returns:

New cycling stream

stream

public static <U> java.util.stream.Stream<U> stream(java.lang.Iterable<U> it)

Create a stream from an iterable

Parameters:

it - Iterable to convert to a Stream

Returns:

Stream from iterable

stream

public static <U> java.util.stream.Stream<U> stream(java.util.Iterator<U> it)

Create a stream from an iterator

Parameters:

it - Iterator to convert to a Stream

Returns:

Stream from iterator

concat

public static <U> java.util.stream.Stream<U> concat(java.lang.Object o,
                                                    java.util.stream.Stream<U> stream)

Concat an Object and a Stream If the Object is a Stream, Streamable or Iterable will be converted (or left) in Stream form and concatonated Otherwise a new Stream.of(o) is created

Parameters:

o - Object to concat

stream - Stream to concat

Returns:

Concatonated Stream

stream

public static <K,V> java.util.stream.Stream<java.util.Map.Entry<K,V>> stream(java.util.Map<K,V> it)

Create a stream from a map

Parameters:

it - Iterator to convert to a Stream

Returns:

Stream from a map

reduce

public static <R> java.util.List<R> reduce(java.util.stream.Stream<R> stream,
                                           java.lang.Iterable<Monoid<R>> reducers)

Simultanously reduce a stream with multiple reducers

 
  Monoid<Integer> sum = Monoid.of(0,(a,b)->a+b);
		Monoid<Integer> mult = Monoid.of(1,(a,b)->a*b);
		val result = StreamUtils.reduce(Stream.of(1,2,3,4),Arrays.asList(sum,mult));
				
		 
		assertThat(result,equalTo(Arrays.asList(10,24)));
		

Parameters:

stream - Stream to reduce

reducers - Reducers to reduce Stream

Returns:

Reduced Stream values as List entries

reduce

public static <R> java.util.List<R> reduce(java.util.stream.Stream<R> stream,
                                           java.util.stream.Stream<Monoid<R>> reducers)

Simultanously reduce a stream with multiple reducers

Parameters:

stream - Stream to reduce

reducers - Reducers to reduce Stream

Returns:

Reduced Stream values as List entries

collect

public static <T,A,R> java.util.List<R> collect(java.util.stream.Stream<T> stream,
                                                java.util.stream.Stream<java.util.stream.Collector> collectors)

Apply multiple Collectors, simultaneously to a Stream

Parameters:

stream - Stream to collect

collectors - Collectors to apply

Returns:

Result as a list

collect

public static <T,A,R> java.util.List<R> collect(java.util.stream.Stream<T> stream,
                                                java.lang.Iterable<java.util.stream.Collector> collectors)

Apply multiple Collectors, simultaneously to a Stream

Parameters:

stream - Stream to collect

collectors - Collectors to apply

Returns:

Result as a list

collect

public static <T> java.util.List collect(java.util.stream.Stream<T> stream,
                                         Streamable<java.util.stream.Collector> collectors)

Apply multiple Collectors, simultaneously to a Stream

Parameters:

stream - Stream to collect

collectors - Collectors to apply

Returns:

Result as a list