JUnit 6.0.1 · org.junit.platform.commons.util.CollectionUtils

Access	Constructor and Description
private	CollectionUtils()

Method Summary

Modifier and Type	Method and Description
private static Optional<Method>	findIteratorMethod(Class<?> type)
private static <T extends @Nullable Object> T	firstElement(Collection<T> collection)
public static <T extends @Nullable Object> void	forEachInReverseOrder(List<T> list, Consumer<? super T> action) Call the supplied action on each element of the supplied `List` from last to first element.
public static <T extends @Nullable Object> Optional<T>	Returns: the first element of the collection; empty if the collection is empty getFirstElement(Collection<T> the collection to get the element from collection) Get the first element of the supplied collection unless it's empty.
public static <T> T	Returns: the only element of the collection getOnlyElement(Collection<T> the collection to get the element from collection) Get the only element of a collection of size 1.
public static boolean	Returns: `true` if an instance of the type can be converted into a stream isConvertibleToStream(@Nullable Class<?> the type to check; may be `null` type) Determine if an instance of the supplied type can be converted into a `Stream`.
public static Stream<?>	Returns: the resulting stream toStream(Object the object to convert into a stream; never `null` object) Convert an object of one of the following supported types into a `Stream`.
private static Stream<?>	tryConvertToStreamByReflection(Object object)

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

CollectionUtils	back to summary
private CollectionUtils()

Method Detail

findIteratorMethod	back to summary
private static Optional<Method> findIteratorMethod(Class<?> type)

firstElement	back to summary
private static <T extends @Nullable Object> T firstElement(Collection<T> collection)

forEachInReverseOrder back to summary

forEachInReverseOrder	back to summary
public static <T extends @Nullable Object> void forEachInReverseOrder(List<T> list, Consumer<? super T> action) Call the supplied action on each element of the supplied `List` from last to first element. Annotations @API status:INTERNAL since:1.9.2

public static <T extends @Nullable Object> void forEachInReverseOrder(List<T> list, Consumer<? super T> action)

Call the supplied action on each element of the supplied List from last to first element.

Annotations

@API
status:INTERNAL
since:1.9.2

getFirstElement back to summary

getFirstElement	back to summary
public static <T extends @Nullable Object> Optional<T> getFirstElement(Collection<T> collection) Get the first element of the supplied collection unless it's empty. Parameters collection:Collection<T> the collection to get the element from Returns:Optional<T> the first element of the collection; empty if the collection is empty Annotations @API status:INTERNAL since:1.11 Exceptions PreconditionViolationException: if the collection is `null` Since 1.11

public static <T extends @Nullable Object> Optional<T> getFirstElement(Collection<T> collection)

Get the first element of the supplied collection unless it's empty.

Parameters

collection:Collection<T>: the collection to get the element from

Returns:Optional<T>

the first element of the collection; empty if the collection is empty

Annotations

@API
status:INTERNAL
since:1.11

Exceptions

PreconditionViolationException:: if the collection is null

Since

1.11

getOnlyElement back to summary

getOnlyElement	back to summary
public static <T> T getOnlyElement(Collection<T> collection) Get the only element of a collection of size 1. Parameters collection:Collection<T> the collection to get the element from Returns:T the only element of the collection Exceptions PreconditionViolationException: if the collection is `null` or does not contain exactly one element

public static <T> T getOnlyElement(Collection<T> collection)

Get the only element of a collection of size 1.

Parameters

collection:Collection<T>: the collection to get the element from

Returns:T

the only element of the collection

Exceptions

PreconditionViolationException:: if the collection is null or does not contain exactly one element

isConvertibleToStream back to summary

isConvertibleToStream	back to summary
public static boolean isConvertibleToStream(@Nullable Class<?> type) Determine if an instance of the supplied type can be converted into a `Stream`. If this method returns `true`, `toStream(Object)` can successfully convert an object of the specified type into a stream. See `toStream(Object)` for supported types. Parameters type:@Nullable Class<?> the type to check; may be `null` Returns:boolean `true` if an instance of the type can be converted into a stream Annotations @API status:INTERNAL since:1.9.1 Since 1.9.1 See Also `toStream(Object)`

public static boolean isConvertibleToStream(@Nullable Class<?> type)

Determine if an instance of the supplied type can be converted into a Stream.

If this method returns true, toStream(Object) can successfully convert an object of the specified type into a stream. See toStream(Object) for supported types.

Parameters

type:@Nullable Class<?>: the type to check; may be null

Returns:boolean

true if an instance of the type can be converted into a stream

Annotations

@API
status:INTERNAL
since:1.9.1

Since

1.9.1

See Also

toStream(Object)

toStream back to summary

toStream	back to summary
public static Stream<?> toStream(Object object) Convert an object of one of the following supported types into a `Stream`. `Stream` `DoubleStream` `IntStream` `LongStream` `Collection` `Iterable` `Iterator` `Object` array primitive array any type that provides an `Iterator`-returning `iterator()` method (such as, for example, a `kotlin.sequences.Sequence`) Parameters object:Object the object to convert into a stream; never `null` Returns:Stream<?> the resulting stream Exceptions PreconditionViolationException: if the supplied object is `null` or not one of the supported types See Also `isConvertibleToStream(Class)`

public static Stream<?> toStream(Object object)

Convert an object of one of the following supported types into a Stream.

Stream
DoubleStream
IntStream
LongStream
Collection
Iterable
Iterator
Object array
primitive array
any type that provides an Iterator-returning iterator() method (such as, for example, a kotlin.sequences.Sequence)

Parameters

object:Object: the object to convert into a stream; never null

Returns:Stream<?>

the resulting stream

Exceptions

PreconditionViolationException:: if the supplied object is null or not one of the supported types

See Also

isConvertibleToStream(Class)

tryConvertToStreamByReflection	back to summary
private static Stream<?> tryConvertToStreamByReflection(Object object)

public final Class CollectionUtils

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