程序包 net.dongliu.commons.sequence

接口 Sequence<T>

所有超级接口:

java.util.Iterator<T>

public interface Sequence<T>
extends java.util.Iterator<T>

A sequence of elements supporting support map and reduce operations. Sequence like Stream, but comes with more convenient methods. Sequence not support parallel operations, so the implementation can be simpler.

方法概要

修饰符和类型	方法	说明
default boolean	allMatch(java.util.function.Predicate<? super T> predicate)	If all elements in this sequence meet the predicate.
default boolean	anyMatch(java.util.function.Predicate<? super T> predicate)	If any element in this sequence meet the predicate.
default java.lang.Iterable<T>	asIterable()	Return a iterable that wrap this sequence, and can iterate only once.
default java.util.stream.Stream<T>	asStream()	Return a Stream that wrap this sequence.
default java.util.Optional<T>	at(long seq)	Return the element at index, return empty Optional if this Sequence do not have enough elements.
default double	averageDouble(java.util.function.ToDoubleFunction<T> function)	Calculate the average value of values calculated by the elements.
default double	averageLong(java.util.function.ToLongFunction<T> function)	Calculate the average value of values calculated by the elements.
default Sequence<java.util.List<T>>	chunked(int size)	Buffer this sequence into a sequence of lists each not exceeding the given size.
default <R> R	collect(CollectConsumer<? super T,? extends R> collectConsumer)	Collect elements to collection.
default Sequence<T>	concat(java.util.Collection<? extends Sequence<T>> sequences)	Return a Sequence contains elements in all Sequences.
default Sequence<T>	concat(Sequence<T> sequence)	Return a Sequence contains elements in both Sequence.
default long	count()	return the count of elements
default Sequence<T>	distinct()	Return a sequence do not contains duplicated elements.
default <E> Sequence<T>	distinctBy(java.util.function.Function<? super T,E> keyMapper)	Return a sequence do not contains duplicated elements.
default Sequence<T>	drop(long size)	Drop first N elements
default Sequence<T>	dropWhile(java.util.function.Predicate<? super T> predicate)	Drop elements while all meet elements pass the predicate
default Sequence<T>	filter(java.util.function.Predicate<? super T> filter)	filter operator
default Sequence<T>	filterNonNull()	Return a Sequence only contains non-null values.
default Sequence<T>	filterOrConsume(java.util.function.Predicate<? super T> filter, java.util.function.Consumer<T> consumer)	filter operator.
default java.util.Optional<T>	find(java.util.function.Predicate<? super T> predicate)	Find and return the first element meet the predicate in Sequence.
default java.util.Optional<T>	findLast(java.util.function.Predicate<? super T> predicate)	Find and return the lat element meet the predicate in Sequence.
default java.util.Optional<T>	first()	Return the first element of Sequence.
default <R> Sequence<R>	flatMap(java.util.function.Function<? super T,? extends Sequence<R>> mapper)	flat map operator
default void	forEach(java.util.function.Consumer<? super T> consumer)	Consumer the remained element in this Sequence.
static <T> Sequence<T>	generate(java.util.function.LongFunction<T> generator)	Generate a sequence, according to current index
static <T> Sequence<T>	generate(java.util.function.Supplier<T> supplier)	Generate a sequence, from value supplier
static <T> Sequence<T>	generate(java.util.function.Supplier<T> initial, java.util.function.UnaryOperator<T> generator)	Generate a sequence, from initial value
default <K,R> java.util.Map<K,R>	groupAndCollect(java.util.function.Function<? super T,? extends K> keyMapper, java.util.function.Supplier<? extends CollectConsumer<? super T,? extends R>> collector)	Group the element by key mapper; for per single key, collect elements with this key to the result value.
default <K,R> java.util.Map<K,R>	groupAndReduce(java.util.function.Function<? super T,? extends K> keyMapper, java.util.function.Supplier<R> initial, java.util.function.BiFunction<? super R,? super T,? extends R> reducer)	Group the element by key mapper; for per single key, reduce elements with this key to the result value.
default <K,R extends java.util.Collection<T>> java.util.Map<K,R>	groupToCollection(java.util.function.Function<? super T,? extends K> keyMapper, java.util.function.Supplier<R> collectionSupplier)	Group the element by key mapper; for per single key, reduce elements with this key to the result value.
default <K> java.util.Map<K,java.util.List<T>>	groupToList(java.util.function.Function<? super T,? extends K> keyMapper)	Group the element by key mapper; for per single key, a immutable list contains all elements with this key is constructed.
boolean	hasNext()
default void	joinTo(java.lang.Appendable appendable, java.lang.CharSequence sep, java.lang.CharSequence prefix, java.lang.CharSequence suffix)	Join the elements to String out
default java.lang.String	joinToString(java.lang.CharSequence sep)	Join the elements to String
default java.lang.String	joinToString(java.lang.CharSequence sep, java.lang.CharSequence prefix, java.lang.CharSequence suffix)	Join the elements to String
default java.util.Optional<T>	last()	Return the last element of Sequence.
default <R> Sequence<R>	map(java.util.function.Function<? super T,? extends R> mapper)	map operator
default java.util.Optional<T>	max()	Get the max value by natural order comparator.
default java.util.Optional<T>	maxBy(java.util.Comparator<? super T> comparator)	Get the max value by comparator.
default java.util.Optional<T>	min()	Get the min value by natural order comparator.
default java.util.Optional<T>	minBy(java.util.Comparator<? super T> comparator)	Get the min value by comparator.
T	next()
default boolean	noneMatch(java.util.function.Predicate<? super T> predicate)	If no elements in this sequence meet the predicate.
static <T> Sequence<T>	of()	Return a empty sequence
static <T> Sequence<T>	of(java.lang.Iterable<T> iterable)	Create sequence from iterable
static <T> Sequence<T>	of(java.util.Collection<T> collection)	Create sequence from collection.
static <T> Sequence<T>	of(java.util.Iterator<T> iterator)	Create sequence from iterator
static <T> Sequence<T>	of(java.util.Optional<T> optional)	Return a empty sequence
static <T> Sequence<T>	of(java.util.stream.Stream<T> stream)	Create a new Sequence from stream.
static <T> Sequence<T>	of(T value)	Return a empty sequence
static <T> Sequence<T>	of(T... values)	Create sequence from values, or array.
default <R extends java.util.Collection<T>> PartitionResult<R>	partitionAndCollect(java.util.function.Predicate<? super T> predicate, java.util.function.Supplier<R> supplier)	Partition the elements by predicate, and then collect elements.
default <R> PartitionResult<R>	partitionAndReduce(java.util.function.Predicate<? super T> predicate, java.util.function.Supplier<R> initial, java.util.function.BiFunction<? super R,? super T,? extends R> reducer)	Partition the elements by predicate, and then do reducer for both Seq of elements.
default PartitionResult<java.util.List<T>>	partitionToList(java.util.function.Predicate<? super T> predicate)	Partition the elements by predicate, and then collect elements to immutable list.
default Sequence<T>	peek(java.util.function.Consumer<? super T> consumer)	Return a Sequence, with has a side effect when a element is take out, it is consume by specified consumer.
default <R> R	reduce(R initialValue, java.util.function.BiFunction<? super R,? super T,? extends R> reducer)	reduce operator
default void	remove()	已过时。
default Sequence<T>	sorted()	Return a sorted Sequence, Sequence element type T should implement Comparable interface.
default Sequence<T>	sortedBy(java.util.Comparator<? super T> comparator)	Return a sorted Sequence.
default double	sumDouble(java.util.function.ToDoubleFunction<T> function)	Sum the double values calculated by the elements.
default int	sumInt(java.util.function.ToIntFunction<T> function)	Sum the int values calculated by the elements.
default long	sumLong(java.util.function.ToLongFunction<T> function)	Sum the long values calculated by the elements.
default Sequence<T>	take(long size)	Only take first n elements
default Sequence<T>	takeWhile(java.util.function.Predicate<? super T> predicate)	Take elements while all meet elements pass the predicate
default java.util.ArrayList<T>	toArrayList()	reduce to array list.
default <R extends java.util.Collection<T>> R	toCollection(java.util.function.Supplier<R> collectionSupplier)	Collect elements to collection.
default <K,V> java.util.HashMap<K,V>	toHashMap(java.util.function.Function<? super T,? extends K> keyMapper, java.util.function.Function<? super T,? extends V> valueMapper)	reduce to hash map
default java.util.HashSet<T>	toHashSet()	reduce to hash set
default java.util.List<T>	toImmutableList()	reduce to immutable List.
default <K,V> java.util.Map<K,V>	toImmutableMap(java.util.function.Function<? super T,? extends K> keyMapper, java.util.function.Function<? super T,? extends V> valueMapper)	collect elements to immutable Map.
default java.util.Set<T>	toImmutableSet()	reduce to immutable Set.
default <K,V,R extends java.util.Map<K,V>> R	toMap(java.util.function.Supplier<R> mapSupplier, java.util.function.Function<? super T,? extends K> keyMapper, java.util.function.Function<? super T,? extends V> valueMapper)	collect elements to map
static <S,T> Sequence<Pair<S,T>>	zip(Sequence<@NonNull S> s1, Sequence<@NonNull T> s2)	Returns a sequence of values built from the elements of this sequence and the other sequence with the same index.

从接口继承的方法 java.util.Iterator

forEachRemaining

方法详细资料

hasNext

boolean hasNext()

指定者:

hasNext 在接口中 java.util.Iterator<T>

next

T next()

指定者:

next 在接口中 java.util.Iterator<T>

remove

@Deprecated
default void remove()

已过时。

指定者:

remove 在接口中 java.util.Iterator<T>

zip

static <S,T> Sequence<Pair<S,T>> zip(Sequence<@NonNull S> s1,
                                                 Sequence<@NonNull T> s2)

Returns a sequence of values built from the elements of this sequence and the other sequence with the same index. The resulting sequence ends as soon as the shortest input sequence ends.

of

static <T> Sequence<T> of(java.util.Iterator<T> iterator)

Create sequence from iterator

of

static <T> Sequence<T> of(java.lang.Iterable<T> iterable)

Create sequence from iterable

of

static <T> Sequence<T> of(java.util.Collection<T> collection)

Create sequence from collection. This method do not do defensive copy.

of

static <T> Sequence<T> of(java.util.stream.Stream<T> stream)

Create a new Sequence from stream. The stream is then terminated.

of

static <T> Sequence<T> of()

Return a empty sequence

类型参数:

T - the element type

of

static <T> Sequence<T> of(T value)

Return a empty sequence

类型参数:

T - the element type

of

@SafeVarargs
static <T> Sequence<T> of(T... values)

Create sequence from values, or array. This method do not do defensive copy.

of

static <T> Sequence<T> of(java.util.Optional<T> optional)

Return a empty sequence

类型参数:

T - the element type

generate

static <T> Sequence<T> generate(java.util.function.Supplier<T> supplier)

Generate a sequence, from value supplier

类型参数:

T - the value type

返回:

a sequence

generate

static <T> Sequence<T> generate(java.util.function.LongFunction<T> generator)

Generate a sequence, according to current index

类型参数:

T - the value type

返回:

a sequence

generate

static <T> Sequence<T> generate(java.util.function.Supplier<T> initial,
                                java.util.function.UnaryOperator<T> generator)

Generate a sequence, from initial value

类型参数:

T - the value type

参数:

initial - the initial value supplier

generator - generate value from previous value

返回:

a sequence

concat

default Sequence<T> concat(Sequence<T> sequence)

Return a Sequence contains elements in both Sequence.

concat

default Sequence<T> concat(java.util.Collection<? extends Sequence<T>> sequences)

Return a Sequence contains elements in all Sequences.

map

default <R> Sequence<R> map(java.util.function.Function<? super T,? extends R> mapper)

map operator

filter

default Sequence<T> filter(java.util.function.Predicate<? super T> filter)

filter operator

filterOrConsume

default Sequence<T> filterOrConsume(java.util.function.Predicate<? super T> filter,
                                    java.util.function.Consumer<T> consumer)

filter operator. If element is not accepted, call consumer for it.

flatMap

default <R> Sequence<R> flatMap(java.util.function.Function<? super T,? extends Sequence<R>> mapper)

flat map operator

distinctBy

default <E> Sequence<T> distinctBy(java.util.function.Function<? super T,E> keyMapper)

Return a sequence do not contains duplicated elements.

参数:

keyMapper - function to get a element key, to judge if elements are duplicated.

distinct

default Sequence<T> distinct()

Return a sequence do not contains duplicated elements.

filterNonNull

default Sequence<T> filterNonNull()

Return a Sequence only contains non-null values.

drop

default Sequence<T> drop(long size)

Drop first N elements

参数:

size - the elements number to drop

dropWhile

default Sequence<T> dropWhile(java.util.function.Predicate<? super T> predicate)

Drop elements while all meet elements pass the predicate

take

default Sequence<T> take(long size)

Only take first n elements

takeWhile

default Sequence<T> takeWhile(java.util.function.Predicate<? super T> predicate)

Take elements while all meet elements pass the predicate

at

default java.util.Optional<T> at(long seq)

Return the element at index, return empty Optional if this Sequence do not have enough elements. The elements in Seq should not be null.

参数:

seq - the element index, start from zero

chunked

default Sequence<java.util.List<T>> chunked(int size)

Buffer this sequence into a sequence of lists each not exceeding the given size.

参数:

size - the max size for buffer

sortedBy

default Sequence<T> sortedBy(java.util.Comparator<? super T> comparator)

Return a sorted Sequence. A comparator is needed for sort. If T is sub type of Comparable and want to use it's compare impl for sorting, Comparator.naturalOrder() can be passed in.

参数:

comparator - the comparator to sort sequence

sorted

default Sequence<T> sorted()

Return a sorted Sequence, Sequence element type T should implement Comparable interface. The elements should not be null, or NPE maybe thrown. ClassCastException may be thrown if T not sub type of Comparable

forEach

default void forEach(java.util.function.Consumer<? super T> consumer)

Consumer the remained element in this Sequence.

参数:

consumer - the consumer

peek

default Sequence<T> peek(java.util.function.Consumer<? super T> consumer)

Return a Sequence, with has a side effect when a element is take out, it is consume by specified consumer.

reduce

default <R> R reduce(R initialValue,
                     java.util.function.BiFunction<? super R,? super T,? extends R> reducer)

reduce operator

类型参数:

R - the result value type

参数:

initialValue - the initial value

reducer - the reducer

返回:

a value calculate by reducer

collect

default <R> R collect(CollectConsumer<? super T,? extends R> collectConsumer)

Collect elements to collection.

类型参数:

R - the returned Collection type

参数:

collectConsumer - to create a Collection instance

toCollection

default <R extends java.util.Collection<T>> R toCollection(java.util.function.Supplier<R> collectionSupplier)

Collect elements to collection.

类型参数:

R - the returned Collection type

参数:

collectionSupplier - to create a Collection instance

toArrayList

default java.util.ArrayList<T> toArrayList()

reduce to array list.

toImmutableList

default java.util.List<T> toImmutableList()

reduce to immutable List.

toHashSet

default java.util.HashSet<T> toHashSet()

reduce to hash set

toImmutableSet

default java.util.Set<T> toImmutableSet()

reduce to immutable Set.

toHashMap

default <K,V> java.util.HashMap<K,V> toHashMap(java.util.function.Function<? super T,? extends K> keyMapper,
                                                           java.util.function.Function<? super T,? extends V> valueMapper)

reduce to hash map

类型参数:

K - map key type

V - map value type

参数:

keyMapper - the mapper to calculate map key

valueMapper - the mapper to calculate map value

返回:

a new map

toMap

default <K,V,R extends java.util.Map<K,V>> R toMap(java.util.function.Supplier<R> mapSupplier,
                                                                     java.util.function.Function<? super T,? extends K> keyMapper,
                                                                     java.util.function.Function<? super T,? extends V> valueMapper)

collect elements to map

类型参数:

K - map key type

V - map value type

参数:

mapSupplier - to get a map instance

keyMapper - the mapper to calculate map key

valueMapper - the mapper to calculate map value

返回:

a new map

toImmutableMap

default <K,V> java.util.Map<K,V> toImmutableMap(java.util.function.Function<? super T,? extends K> keyMapper,
                                                            java.util.function.Function<? super T,? extends V> valueMapper)

collect elements to immutable Map.

groupAndReduce

default <K,R> java.util.Map<K,R> groupAndReduce(java.util.function.Function<? super T,? extends K> keyMapper,
                                                            java.util.function.Supplier<R> initial,
                                                            java.util.function.BiFunction<? super R,? super T,? extends R> reducer)

Group the element by key mapper; for per single key, reduce elements with this key to the result value.

类型参数:

K - the group key type

R - the reduce result type

参数:

keyMapper - get key from element

initial - initial value supplier for reducing

reducer - reduce function

返回:

a map contains grouped result. The is no guaranty for the map's immutability.

groupAndCollect

default <K,R> java.util.Map<K,R> groupAndCollect(java.util.function.Function<? super T,? extends K> keyMapper,
                                                             java.util.function.Supplier<? extends CollectConsumer<? super T,? extends R>> collector)

Group the element by key mapper; for per single key, collect elements with this key to the result value.

类型参数:

K - the group key type

R - the reduce result type

参数:

keyMapper - get key from element

collector - the collector supplier

返回:

a map contains grouped result. The is no guaranty for the map's immutability.

groupToCollection

default <K,R extends java.util.Collection<T>> java.util.Map<K,R> groupToCollection(java.util.function.Function<? super T,? extends K> keyMapper,
                                                                                               java.util.function.Supplier<R> collectionSupplier)

Group the element by key mapper; for per single key, reduce elements with this key to the result value.

类型参数:

K - the group key type

R - the reduce result type

参数:

keyMapper - get key from element

collectionSupplier - supplier to make a Collection instance

返回:

a map contains grouped result. The is no guaranty for the map's immutability.

groupToList

default <K> java.util.Map<K,java.util.List<T>> groupToList(java.util.function.Function<? super T,? extends K> keyMapper)

Group the element by key mapper; for per single key, a immutable list contains all elements with this key is constructed.

类型参数:

K - the group key type

参数:

keyMapper - get key from element

返回:

a map contains grouped result as immutable list. The is no guaranty for the returned map's, or the list's immutability.

partitionAndReduce

default <R> PartitionResult<R> partitionAndReduce(java.util.function.Predicate<? super T> predicate,
                                                  java.util.function.Supplier<R> initial,
                                                  java.util.function.BiFunction<? super R,? super T,? extends R> reducer)

Partition the elements by predicate, and then do reducer for both Seq of elements.

类型参数:

R - the reduce result type

参数:

predicate - predicate for partition

initial - initial value supplier for reducing

reducer - reduce function

partitionAndCollect

default <R extends java.util.Collection<T>> PartitionResult<R> partitionAndCollect(java.util.function.Predicate<? super T> predicate,
                                                                                   java.util.function.Supplier<R> supplier)

Partition the elements by predicate, and then collect elements.

类型参数:

R - the collection type

参数:

predicate - predicate for partition

supplier - collection supplier

返回:

a PartitionResult contains grouped result

partitionToList

default PartitionResult<java.util.List<T>> partitionToList(java.util.function.Predicate<? super T> predicate)

Partition the elements by predicate, and then collect elements to immutable list.

参数:

predicate - predicate for partition

返回:

a PartitionResult contains grouped result as list. The is no guaranty for the returned lists's immutability.

joinTo

default void joinTo(java.lang.Appendable appendable,
                    java.lang.CharSequence sep,
                    java.lang.CharSequence prefix,
                    java.lang.CharSequence suffix)

Join the elements to String out

参数:

appendable - the appendable to append str

sep - the separator string between elements

prefix - the prefix to prepend before all elements

suffix - the suffix to append after elements

joinToString

default java.lang.String joinToString(java.lang.CharSequence sep,
                                      java.lang.CharSequence prefix,
                                      java.lang.CharSequence suffix)

Join the elements to String

参数:

sep - the separator string between elements

prefix - the prefix to prepend before all elements

suffix - the suffix to append after elements

joinToString

default java.lang.String joinToString(java.lang.CharSequence sep)

Join the elements to String

参数:

sep - the separator string between elements

count

default long count()

return the count of elements

maxBy

default java.util.Optional<T> maxBy(java.util.Comparator<? super T> comparator)

Get the max value by comparator. If Sequence has no element, return empty Optional. If T is sub type of Comparable and want to use it's compare impl for comparing, Comparator.naturalOrder() can be passed in.

参数:

comparator - the comparator

max

default java.util.Optional<T> max()

Get the max value by natural order comparator. If Sequence has no element, return empty Optional. Elements in this Sequence should not be null. ClassCastException may be thrown if T not sub type of Comparable

minBy

default java.util.Optional<T> minBy(java.util.Comparator<? super T> comparator)

Get the min value by comparator. If Sequence has no element, return empty Optional. If T is sub type of Comparable and want to use it's compare impl for comparing, Comparator.naturalOrder() can be passed in.

参数:

comparator - the comparator

min

default java.util.Optional<T> min()

Get the min value by natural order comparator. If Sequence has no element, return empty Optional. Elements in this Sequence should not be null. ClassCastException may be thrown if T not sub type of Comparable

sumInt

default int sumInt(java.util.function.ToIntFunction<T> function)

Sum the int values calculated by the elements.

参数:

function - the function convert elements to int values

sumLong

default long sumLong(java.util.function.ToLongFunction<T> function)

Sum the long values calculated by the elements.

参数:

function - the function convert elements to long values

sumDouble

default double sumDouble(java.util.function.ToDoubleFunction<T> function)

Sum the double values calculated by the elements.

参数:

function - the function convert elements to double values

averageLong

default double averageLong(java.util.function.ToLongFunction<T> function)

Calculate the average value of values calculated by the elements.

参数:

function - the function convert elements to long values

averageDouble

default double averageDouble(java.util.function.ToDoubleFunction<T> function)

Calculate the average value of values calculated by the elements.

参数:

function - the function convert elements to double float values

first

default java.util.Optional<T> first()

Return the first element of Sequence. If sequence is empty, return empty Optional. The element in sequence should not be null.

last

default java.util.Optional<T> last()

Return the last element of Sequence. If sequence is empty, return empty Optional. The element in sequence should not be null.

find

default java.util.Optional<T> find(java.util.function.Predicate<? super T> predicate)

Find and return the first element meet the predicate in Sequence. If none is found, return empty Optional. The element in sequence should not be null.

findLast

default java.util.Optional<T> findLast(java.util.function.Predicate<? super T> predicate)

Find and return the lat element meet the predicate in Sequence. If none is found, return empty Optional. The element in sequence should not be null.

anyMatch

default boolean anyMatch(java.util.function.Predicate<? super T> predicate)

If any element in this sequence meet the predicate. This method would always return false if Sequence is empty.

allMatch

default boolean allMatch(java.util.function.Predicate<? super T> predicate)

If all elements in this sequence meet the predicate. This method would always return true if Sequence is empty.

noneMatch

default boolean noneMatch(java.util.function.Predicate<? super T> predicate)

If no elements in this sequence meet the predicate. This method would always return true if Sequence is empty.

asIterable

default java.lang.Iterable<T> asIterable()

Return a iterable that wrap this sequence, and can iterate only once.

asStream

default java.util.stream.Stream<T> asStream()

Return a Stream that wrap this sequence.