Package com.complexible.common.base

Class Streams

java.lang.Object

com.complexible.common.base.Streams

public final class Streams
extends Object

Utility for streams

Since:

4.0

Version:

4.0

Author:

Michael Grove

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	Streams.CheckedBiConsumer<U,T>
static interface	Streams.CheckedBiFunction<In1,In2,Out>
static interface	Streams.CheckedConsumer<T>
static interface	Streams.CheckedFunction<In,Out>
static interface	Streams.CheckedPredicate<T>
static interface	Streams.CheckedRunnable
static interface	Streams.CheckedSupplier<Out>
static final class	Streams.UncheckedException	Exception indicating that Checked* threw an exception and the default handler was used

Field Summary

Fields

Modifier and Type	Field	Description
static final boolean	NOT_PARALLEL
static final boolean	PARALLEL
static final long	UNKNOWN_SIZE

Constructor Summary

Constructors

Constructor	Description
Streams()

Method Summary

Modifier and Type	Method	Description
static <Input, Output> Output	applyTerminalAndClose(Stream<Input> theStream, Function<Stream<Input>,Output> theFinisher)	Apply the given terminal operation to the stream returning the result and close the stream.
static <T> Stream<T>	concat(Stream<T> theStream, Stream<T> theOtherStream, Stream<T>... theMoreStreams)
static <T> Predicate<? super T>	distinctByKey(Function<? super T,Object> theKey)	A simple stateful predicate for filtering out stream elements which agree on their key values.
static <K, V> Collector<Map.Entry<K,V>,?,HashMap<K,V>>	entriesToMap()
static <T> CloseableIterator<T>	flatIterator(Stream<Stream<T>> theStream)
static <T> Stream<T>	flatten(Stream<Stream<T>> theStream)
static <T, E extends Throwable> void	forEachChecked(Stream<T> theStream, Streams.CheckedConsumer<T> theConsumer)
static <T> Function<Optional<T>,Stream<T>>	optional()	Returns a function that will collapse a Stream of optionals into a Stream of the references they hold.
static <T> Stream<T>	stream(Iterable<T> theIterable)	Return a new Stream from the given Iterable
static <T> Stream<T>	stream(Iterator<? extends T> theIter)
static <T> Stream<T>	stream(Iterator<? extends T> theIter, long theSize)
static <In1, In2, Out> BiFunction<In1,In2,Out>	unchecked(Streams.CheckedBiFunction<In1,In2,Out> theBiFunction)
static <In1, In2, Out> BiFunction<In1,In2,Out>	unchecked(Streams.CheckedBiFunction<In1,In2,Out> theBiFunction, Consumer<Throwable> theHandler)
static <In, Out> Function<In,Out>	unchecked(Streams.CheckedFunction<In,Out> theFunction)
static <In, Out> Function<In,Out>	unchecked(Streams.CheckedFunction<In,Out> theFunction, Consumer<Throwable> theHandler)
static <U, T> BiConsumer<U,T>	uncheckedConsumer(Streams.CheckedBiConsumer<U,T> theConsumer)
static <U, T> BiConsumer<U,T>	uncheckedConsumer(Streams.CheckedBiConsumer<U,T> theConsumer, Consumer<Throwable> theHandler)
static <T> Consumer<T>	uncheckedConsumer(Streams.CheckedConsumer<T> theConsumer)
static <T> Consumer<T>	uncheckedConsumer(Streams.CheckedConsumer<T> theConsumer, Consumer<Throwable> theHandler)
static <In> Predicate<In>	uncheckedPredicate(Streams.CheckedPredicate<In> thePredicate)
static <In> Predicate<In>	uncheckedPredicate(Streams.CheckedPredicate<In> thePredicate, Consumer<Throwable> theHandler)

Methods inherited from class java.lang.Object

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

Field Details

NOT_PARALLEL

public static final boolean NOT_PARALLEL

See Also:

• Constant Field Values

PARALLEL

public static final boolean PARALLEL

See Also:

• Constant Field Values

UNKNOWN_SIZE

public static final long UNKNOWN_SIZE

See Also:

• Constant Field Values

Constructor Details

Streams

public Streams()

Method Details

optional

public static <T> Function<Optional<T>,Stream<T>> optional()

Returns a function that will collapse a Stream of optionals into a Stream of the references they hold. To be used with Stream.flatMap(Function).

Type Parameters:

T - the optional's type

Returns:

a Function which unrolls optionals

stream

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

Return a new Stream from the given Iterable

Parameters:

theIterable - the iterable

Returns:

a stream over the iterable

stream

public static <T> Stream<T> stream(Iterator<? extends T> theIter)

stream

public static <T> Stream<T> stream(Iterator<? extends T> theIter,
 long theSize)

concat

@SafeVarargs
public static <T> Stream<T> concat(Stream<T> theStream,
 Stream<T> theOtherStream,
 Stream<T>... theMoreStreams)

applyTerminalAndClose

public static <Input,
Output> Output applyTerminalAndClose(Stream<Input> theStream,
 Function<Stream<Input>,Output> theFinisher)

Apply the given terminal operation to the stream returning the result and close the stream.

Parameters:

theStream - the stream

theFinisher - the function which will apply the terminal operation and return the result

Returns:

the result of the terminal operation.

forEachChecked

public static <T,
E extends Throwable> void forEachChecked(Stream<T> theStream,
 Streams.CheckedConsumer<T> theConsumer)
                                                    throws E

Throws:

E

unchecked

public static <In,
Out> Function<In,Out> unchecked(Streams.CheckedFunction<In,Out> theFunction)

unchecked

public static <In,
Out> Function<In,Out> unchecked(Streams.CheckedFunction<In,Out> theFunction,
 Consumer<Throwable> theHandler)

unchecked

public static <In1,
In2,
Out>
BiFunction<In1,In2,Out> unchecked(Streams.CheckedBiFunction<In1,In2,Out> theBiFunction)

unchecked

public static <In1,
In2,
Out>
BiFunction<In1,In2,Out> unchecked(Streams.CheckedBiFunction<In1,In2,Out> theBiFunction,
 Consumer<Throwable> theHandler)

uncheckedPredicate

public static <In> Predicate<In> uncheckedPredicate(Streams.CheckedPredicate<In> thePredicate)

uncheckedPredicate

public static <In> Predicate<In> uncheckedPredicate(Streams.CheckedPredicate<In> thePredicate,
 Consumer<Throwable> theHandler)

uncheckedConsumer

public static <T> Consumer<T> uncheckedConsumer(Streams.CheckedConsumer<T> theConsumer)

uncheckedConsumer

public static <U,
T> BiConsumer<U,T> uncheckedConsumer(Streams.CheckedBiConsumer<U,T> theConsumer)

uncheckedConsumer

public static <U,
T> BiConsumer<U,T> uncheckedConsumer(Streams.CheckedBiConsumer<U,T> theConsumer,
 Consumer<Throwable> theHandler)

uncheckedConsumer

public static <T> Consumer<T> uncheckedConsumer(Streams.CheckedConsumer<T> theConsumer,
 Consumer<Throwable> theHandler)

flatIterator

public static <T> CloseableIterator<T> flatIterator(Stream<Stream<T>> theStream)

flatten

public static <T> Stream<T> flatten(Stream<Stream<T>> theStream)

distinctByKey

public static <T> Predicate<? super T> distinctByKey(Function<? super T,Object> theKey)

A simple stateful predicate for filtering out stream elements which agree on their key values. TODO let the outer code create more optimized distinct filters e.g. for value types.

entriesToMap

public static <K,
V>
Collector<Map.Entry<K,V>,?,HashMap<K,V>> entriesToMap()