Package org.apache.sis.internal.stream

Class PaginedStream<T>

java.lang.Object

org.apache.sis.internal.stream.BaseStreamWrapper<T,Stream<T>>

org.apache.sis.internal.stream.StreamWrapper<T>

org.apache.sis.internal.stream.PaginedStream<T>

Type Parameters:

T - the type of objects contained in the stream, as specified in Stream interface.

All Implemented Interfaces:

AutoCloseable, BaseStream<T,Stream<T>>, Stream<T>

public final class PaginedStream<T>
extends StreamWrapper<T>

A stream on which skip and limit operations are delegated to a root stream. This is useful when the root stream is capable of some optimizations, for example using SQL. The redirection stops as soon as an operation may change the elements order or filtering.

Since:

1.1

Version:

1.1

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.stream.Stream

Stream.Builder<T extends Object>

Field Summary

Fields

Modifier and Type	Field	Description
private Stream<?>	root	The root stream on which to delegate skip and limit operations.

Fields inherited from class org.apache.sis.internal.stream.StreamWrapper

source

Fields inherited from class org.apache.sis.internal.stream.BaseStreamWrapper

toClose

Constructor Summary

Constructors

Constructor	Description
PaginedStream(Stream<T> source, Stream<?> root)	Creates a new mapped stream.

Method Summary

Modifier and Type	Method	Description
long	count()	Returns the number of elements in this stream.
Stream<T>	distinct()	Returns a stream with distinct elements of this stream.
Stream<T>	filter(Predicate<? super T> predicate)	Returns a stream with elements of this stream that match the given predicate.
Stream<T>	limit(long maxSize)	Truncates this stream to the given number of elements.
DoubleStream	mapToDouble(ToDoubleFunction<? super T> mapper)	Returns a stream with results of applying the given function to the elements of this stream.
Stream<T>	skip(long n)	Discards the specified number of elements.
Stream<T>	sorted()	Returns a stream with elements of this stream sorted in natural order.
Stream<T>	sorted(Comparator<? super T> comparator)	Returns a stream with elements of this stream sorted using the given comparator.
Stream<T>	unordered()	Returns an equivalent stream that is unordered.

Methods inherited from class org.apache.sis.internal.stream.StreamWrapper

allMatch, anyMatch, collect, collect, delegate, findAny, findFirst, flatMap, flatMapToDouble, flatMapToInt, flatMapToLong, forEach, forEachOrdered, iterator, map, mapToInt, mapToLong, max, min, noneMatch, onClose, parallel, peek, reduce, reduce, reduce, sequential, source, spliterator, toArray, toArray

Methods inherited from class org.apache.sis.internal.stream.BaseStreamWrapper

close, inactive, isParallel

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.stream.BaseStream

close, isParallel

Field Details

root

private Stream<?> root

The root stream on which to delegate skip and limit operations.

Constructor Details

PaginedStream

public PaginedStream(Stream<T> source,
 Stream<?> root)

Creates a new mapped stream.

Parameters:

source - the stream to wrap.

root - the stream on which to delegate skip and limit operations.

Method Details

skip

public Stream<T> skip(long n)

Discards the specified number of elements. This method delegates the operation to the root stream.

Specified by:

skip in interface Stream<T>

Overrides:

skip in class StreamWrapper<T>

Parameters:

n - number of elements to skip.

Returns:

this.

limit

public Stream<T> limit(long maxSize)

Truncates this stream to the given number of elements. This method delegates the operation to the root stream.

Specified by:

limit in interface Stream<T>

Overrides:

limit in class StreamWrapper<T>

Parameters:

maxSize - number of elements to keep.

Returns:

this.

count

public long count()

Returns the number of elements in this stream. This method delegates the operation to the root stream.

Specified by:

count in interface Stream<T>

Overrides:

count in class StreamWrapper<T>

Returns:

number of elements in this stream.

mapToDouble

public DoubleStream mapToDouble(ToDoubleFunction<? super T> mapper)

Returns a stream with results of applying the given function to the elements of this stream.

Specified by:

mapToDouble in interface Stream<T>

Overrides:

mapToDouble in class StreamWrapper<T>

Parameters:

mapper - function to apply to each element.

Returns:

the new stream.

distinct

public Stream<T> distinct()

Description copied from class: StreamWrapper

Returns a stream with distinct elements of this stream.

Specified by:

distinct in interface Stream<T>

Overrides:

distinct in class StreamWrapper<T>

unordered

public Stream<T> unordered()

Description copied from class: StreamWrapper

Returns an equivalent stream that is unordered.

Specified by:

unordered in interface BaseStream<T,Stream<T>>

Overrides:

unordered in class StreamWrapper<T>

sorted

public Stream<T> sorted()

Description copied from class: StreamWrapper

Returns a stream with elements of this stream sorted in natural order.

Specified by:

sorted in interface Stream<T>

Overrides:

sorted in class StreamWrapper<T>

sorted

public Stream<T> sorted(Comparator<? super T> comparator)

Description copied from class: StreamWrapper

Returns a stream with elements of this stream sorted using the given comparator.

Specified by:

sorted in interface Stream<T>

Overrides:

sorted in class StreamWrapper<T>

filter

public Stream<T> filter(Predicate<? super T> predicate)

Description copied from class: StreamWrapper

Returns a stream with elements of this stream that match the given predicate.

Specified by:

filter in interface Stream<T>

Overrides:

filter in class StreamWrapper<T>