org.graalvm.util

Class CollectionsUtil

java.lang.Object

org.graalvm.util.CollectionsUtil

public final class CollectionsUtil
extends Object

This class contains utility methods for commonly used functional patterns for collections.

Method Summary

Modifier and Type	Method and Description
static <T> boolean	allMatch(Iterable<T> inputs, Predicate<T> predicate) Returns whether all elements in inputs match predicate.
static <T> boolean	allMatch(T[] inputs, Predicate<T> predicate) Returns whether all elements in inputs match predicate.
static <T> boolean	anyMatch(Iterable<T> inputs, Predicate<T> predicate) Returns whether any elements in inputs match predicate.
static <T> boolean	anyMatch(T[] inputs, Predicate<T> predicate) Returns whether any elements in inputs match predicate.
static <T> Iterable<T>	concat(Iterable<T> a, Iterable<T> b) Concatenates two iterables into a single iterable.
static <T> Iterable<T>	concat(List<Iterable<T>> iterables) Concatenates multiple iterables into a single iterable.
static <T,R> R[]	filterAndMapToArray(T[] inputs, Predicate<? super T> predicate, Function<? super T,? extends R> mapper, IntFunction<R[]> arrayGenerator) Filters inputs with predicate, applies mapper and adds them in the array provided by arrayGenerator.
static <T> List<T>	filterToList(List<T> inputs, Predicate<? super T> predicate) Returns a new list consisting of the elements in inputs that match predicate.
static <T> List<T>	filterToList(List<T> inputs, Predicate<? super T> predicate, Supplier<List<T>> listGenerator) Appends elements of inputs that match predicate to the list generated by listGenerator.
static <T,R> String	mapAndJoin(Iterable<T> inputs, Function<? super T,? extends R> mapper, String delimiter) Applies mapper on the elements in inputs, and joins them together separated by delimiter.
static <T,R> String	mapAndJoin(Iterable<T> inputs, Function<? super T,? extends R> mapper, String delimiter, String prefix) Applies mapper on the elements in inputs, and joins them together separated by delimiter and starting with prefix.
static <T,R> String	mapAndJoin(Iterable<T> inputs, Function<? super T,? extends R> mapper, String delimiter, String prefix, String suffix) Applies mapper on the elements in inputs, and joins them together separated by delimiter and starting with prefix and ending with suffix.
static <T,R> String	mapAndJoin(T[] inputs, Function<? super T,? extends R> mapper, String delimiter) Applies mapper on the elements in inputs, and joins them together separated by delimiter.
static <T,R> String	mapAndJoin(T[] inputs, Function<? super T,? extends R> mapper, String delimiter, String prefix) Applies mapper on the elements in inputs, and joins them together separated by delimiter and starting with prefix.
static <T,R> String	mapAndJoin(T[] inputs, Function<? super T,? extends R> mapper, String delimiter, String prefix, String suffix) Applies mapper on the elements in inputs, and joins them together separated by delimiter and starting with prefix and ending with suffix.
static <T,R> R[]	mapToArray(Collection<T> inputs, Function<? super T,? extends R> mapper, IntFunction<R[]> arrayGenerator) Applies mapper on the elements in inputs and adds them in the array provided by arrayGenerator.
static <T,R> R[]	mapToArray(T[] inputs, Function<? super T,? extends R> mapper, IntFunction<R[]> arrayGenerator) Applies mapper on the elements in inputs and adds them in the array provided by arrayGenerator.

Methods inherited from class java.lang.Object

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

Method Detail

concat

public static <T> Iterable<T> concat(Iterable<T> a,
                                     Iterable<T> b)

Concatenates two iterables into a single iterable. The iterator exposed by the returned iterable does not support Iterator.remove() even if the input iterables do.

Throws:

NullPointerException - if a or b is null

concat

public static <T> Iterable<T> concat(List<Iterable<T>> iterables)

Concatenates multiple iterables into a single iterable. The iterator exposed by the returned iterable does not support Iterator.remove() even if the input iterables do.

Throws:

NullPointerException - if iterables or any of its elements are null

allMatch

public static <T> boolean allMatch(T[] inputs,
                                   Predicate<T> predicate)

Returns whether all elements in inputs match predicate. May not evaluate predicate on all elements if not necessary for determining the result. If inputs is empty then true is returned and predicate is not evaluated.

Returns:

true if either all elements in inputs match predicate or inputs is empty, otherwise false.

allMatch

public static <T> boolean allMatch(Iterable<T> inputs,
                                   Predicate<T> predicate)

Returns whether all elements in inputs match predicate. May not evaluate predicate on all elements if not necessary for determining the result. If inputs is empty then true is returned and predicate is not evaluated.

Returns:

true if either all elements in inputs match predicate or inputs is empty, otherwise false.

anyMatch

public static <T> boolean anyMatch(T[] inputs,
                                   Predicate<T> predicate)

Returns whether any elements in inputs match predicate. May not evaluate predicate on all elements if not necessary for determining the result. If inputs is empty then false is returned and predicate is not evaluated.

Returns:

true if any elements in inputs match predicate, otherwise false.

anyMatch

public static <T> boolean anyMatch(Iterable<T> inputs,
                                   Predicate<T> predicate)

Returns whether any elements in inputs match predicate. May not evaluate predicate on all elements if not necessary for determining the result. If inputs is empty then false is returned and predicate is not evaluated.

Returns:

true if any elements in inputs match predicate, otherwise false.

filterToList

public static <T> List<T> filterToList(List<T> inputs,
                                       Predicate<? super T> predicate)

Returns a new list consisting of the elements in inputs that match predicate.

Returns:

the new list.

filterToList

public static <T> List<T> filterToList(List<T> inputs,
                                       Predicate<? super T> predicate,
                                       Supplier<List<T>> listGenerator)

Appends elements of inputs that match predicate to the list generated by listGenerator.

Returns:

the list generated by listGenerator.

filterAndMapToArray

public static <T,R> R[] filterAndMapToArray(T[] inputs,
                                            Predicate<? super T> predicate,
                                            Function<? super T,? extends R> mapper,
                                            IntFunction<R[]> arrayGenerator)

Filters inputs with predicate, applies mapper and adds them in the array provided by arrayGenerator.

Returns:

the array provided by arrayGenerator.

mapToArray

public static <T,R> R[] mapToArray(T[] inputs,
                                   Function<? super T,? extends R> mapper,
                                   IntFunction<R[]> arrayGenerator)

Applies mapper on the elements in inputs and adds them in the array provided by arrayGenerator.

Returns:

the array provided by arrayGenerator.

mapToArray

public static <T,R> R[] mapToArray(Collection<T> inputs,
                                   Function<? super T,? extends R> mapper,
                                   IntFunction<R[]> arrayGenerator)

Applies mapper on the elements in inputs and adds them in the array provided by arrayGenerator.

Returns:

the array provided by arrayGenerator.

mapAndJoin

public static <T,R> String mapAndJoin(T[] inputs,
                                      Function<? super T,? extends R> mapper,
                                      String delimiter)

Applies mapper on the elements in inputs, and joins them together separated by delimiter.

Returns:

a new String that is composed from inputs.

mapAndJoin

public static <T,R> String mapAndJoin(T[] inputs,
                                      Function<? super T,? extends R> mapper,
                                      String delimiter,
                                      String prefix)

Applies mapper on the elements in inputs, and joins them together separated by delimiter and starting with prefix.

Returns:

a new String that is composed from inputs.

mapAndJoin

public static <T,R> String mapAndJoin(T[] inputs,
                                      Function<? super T,? extends R> mapper,
                                      String delimiter,
                                      String prefix,
                                      String suffix)

Applies mapper on the elements in inputs, and joins them together separated by delimiter and starting with prefix and ending with suffix.

Returns:

a new String that is composed from inputs.

mapAndJoin

public static <T,R> String mapAndJoin(Iterable<T> inputs,
                                      Function<? super T,? extends R> mapper,
                                      String delimiter)

Applies mapper on the elements in inputs, and joins them together separated by delimiter.

Returns:

a new String that is composed from inputs.

mapAndJoin

public static <T,R> String mapAndJoin(Iterable<T> inputs,
                                      Function<? super T,? extends R> mapper,
                                      String delimiter,
                                      String prefix)

Applies mapper on the elements in inputs, and joins them together separated by delimiter and starting with prefix.

Returns:

a new String that is composed from inputs.

mapAndJoin

public static <T,R> String mapAndJoin(Iterable<T> inputs,
                                      Function<? super T,? extends R> mapper,
                                      String delimiter,
                                      String prefix,
                                      String suffix)

Applies mapper on the elements in inputs, and joins them together separated by delimiter and starting with prefix and ending with suffix.

Returns:

a new String that is composed from inputs.