Class StreamUtils

java.lang.Object

org.aksw.commons.collections.utils.StreamUtils

public class StreamUtils
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	StreamUtils.IteratorOverEnumerable<T,R,E>

Constructor Summary

Constructors

Constructor	Description
StreamUtils()

Method Summary

Modifier and Type	Method	Description
static <T> Stream<T>	appendAction(Stream<? extends T> stream, Runnable runnable)	Creates a new stream which upon reaching its end performs and action.
static <T> T	expectOneItem(Stream<T> stream)
static <T> T	expectZeroOrOneItems(Stream<T> stream)
static <T,R,E> Stream<T>	fromEnumerableResource(Callable<R> resourceSupplier, ThrowingFunction<? super R, E> toEnumerable, ThrowingFunction<? super E, T> nextRecord, BiPredicate<T, ? super E> hasEnded, ThrowingBiConsumer<? super R, ? super E> closer)	Creates a stream over a resource via an enumerable.
static <T> Iterable<T>	iterable(Stream<T> stream)	Create a single-use Iterable from a stream.
static <T> Stream<List<T>>	mapToBatch(Stream<T> stream, int batchSize)	Note we could implement another version where each batch's List is lazy loaded from the stream - but this would probably require complete consumption of each batch in order
static <T> Stream<T>	println(Stream<T> in)
static <S,X> Stream<X>	stream(BiConsumer<S, Consumer<X>> fn, S baseSolution)
static <T> Stream<Map.Entry<T,T>>	streamToPairs(Stream<T> stream)
static <T> Stream<T>	viaList(Stream<T> in, Consumer<List<T>> consumer)

Methods inherited from class Object

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

Constructor Details

StreamUtils

public StreamUtils()

Method Details

iterable

public static <T> Iterable<T> iterable(Stream<T> stream)

Create a single-use Iterable from a stream. Allows for easier use of Streams in for-loops:

  Stream<T> stream = ...;
  for (T item : StreamUtils.iterableOf(stream)) {
  }

Type Parameters:

T -

Parameters:

stream -

Returns:

expectOneItem

public static <T> T expectOneItem(Stream<T> stream)

expectZeroOrOneItems

public static <T> T expectZeroOrOneItems(Stream<T> stream)

streamToPairs

public static <T> Stream<Map.Entry<T,T>> streamToPairs(Stream<T> stream)

mapToBatch

public static <T> Stream<List<T>> mapToBatch(Stream<T> stream,
 int batchSize)

Note we could implement another version where each batch's List is lazy loaded from the stream - but this would probably require complete consumption of each batch in order

Parameters:

stream -

batchSize -

Returns:

appendAction

public static <T> Stream<T> appendAction(Stream<? extends T> stream,
 Runnable runnable)

Creates a new stream which upon reaching its end performs and action. It concatenates the original stream with one having a single item that is filtered out again. The action is run as- part of the filter.

Parameters:

stream -

runnable -

Returns:

stream

public static <S,X> Stream<X> stream(BiConsumer<S, Consumer<X>> fn,
 S baseSolution)

fromEnumerableResource

public static <T,R,E> Stream<T> fromEnumerableResource(Callable<R> resourceSupplier,
 ThrowingFunction<? super R, E> toEnumerable,
 ThrowingFunction<? super E, T> nextRecord,
 BiPredicate<T, ? super E> hasEnded,
 ThrowingBiConsumer<? super R, ? super E> closer)

Creates a stream over a resource via an enumerable. The resource is initialized lazily once the first item is read from the stream. The returned stream should be used in a try-with-resources block in order to close the underlying resource.

Type Parameters:

T - The record type (e.g. an array of Strings)

R - The resource type (e.g. a java.sql.Connection)

E - An enumerable (e.g. a java.sql.ResultSet)

Parameters:

resourceSupplier -

toEnumerable -

nextRecord -

closer -

Returns:

viaList

public static <T> Stream<T> viaList(Stream<T> in,
 Consumer<List<T>> consumer)

println

public static <T> Stream<T> println(Stream<T> in)