Enum Class Collector.Characteristics

java.lang.Object

java.lang.Enum<Collector.Characteristics>

java.util.stream.Collector.Characteristics

All Implemented Interfaces:: Serializable, Comparable<Collector.Characteristics>, Constable

Enclosing interface:: Collector<T,A,R>

public static enum Collector.Characteristics extends Enum<Collector.Characteristics>

Characteristics indicating properties of a Collector, which can be used to optimize reduction implementations.

Since:: 1.8

Nested Class Summary

Nested classes/interfaces declared in class Enum

Enum.EnumDesc<E>

Modifier and Type	Class	Description
`static final class`	`Enum.EnumDesc<E extends Enum<E>>`	A nominal descriptor for an `enum` constant.

Enum Constant Summary

Enum Constant	Description
`CONCURRENT`	Indicates that this collector is concurrent, meaning that the result container can support the accumulator function being called concurrently with the same result container from multiple threads.
`IDENTITY_FINISH`	Indicates that the finisher function is the identity function and can be elided.
`UNORDERED`	Indicates that the collection operation does not commit to preserving the encounter order of input elements.

Method Summary

Modifier and Type	Method	Description
`static Collector.Characteristics`	`valueOf(String name)`	Returns the enum constant of this class with the specified name.
`static Collector.Characteristics[]`	`values()`	Returns an array containing the constants of this enum class, in the order they are declared.

Methods declared in class Enum

clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Modifier and Type	Method	Description
`protected final Object`	`clone()`	Throws CloneNotSupportedException.
`final int`	`compareTo(Collector.Characteristics o)`	Compares this enum with the specified object for order.
`final Optional<Enum.EnumDesc<Collector.Characteristics>>`	`describeConstable()`	Returns an enum descriptor `EnumDesc` for this instance, if one can be constructed, or an empty `Optional` if one cannot be.
`final boolean`	`equals(Object other)`	Returns true if the specified object is equal to this enum constant.
`protected final void`	`finalize()`	Deprecated, for removal: This API element is subject to removal in a future version. Finalization has been deprecated for removal.
`final Class<Collector.Characteristics>`	`getDeclaringClass()`	Returns the Class object corresponding to this enum constant's enum type.
`final int`	`hashCode()`	Returns a hash code for this enum constant.
`final String`	`name()`	Returns the name of this enum constant, exactly as declared in its enum declaration.
`final int`	`ordinal()`	Returns the ordinal of this enumeration constant (its position in its enum declaration, where the initial constant is assigned an ordinal of zero).
`String`	`toString()`	Returns the name of this enum constant, as contained in the declaration.
`static <T extends Enum<T>> T`	`valueOf(Class<T> enumClass, String name)`	Returns the enum constant of the specified enum class with the specified name.

Methods declared in class Object

getClass, notify, notifyAll, wait, wait, wait

Modifier and Type	Method	Description
`final Class<?>`	`getClass()`	Returns the runtime class of this `Object`.
`final void`	`notify()`	Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()`	Wakes up all threads that are waiting on this object's monitor.
`final void`	`wait()`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
`final void`	`wait(long timeoutMillis)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis, int nanos)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Enum Constant Details

CONCURRENT

public static final Collector.Characteristics CONCURRENT

Indicates that this collector is concurrent, meaning that the result container can support the accumulator function being called concurrently with the same result container from multiple threads.

If a CONCURRENT collector is not also UNORDERED, then it should only be evaluated concurrently if applied to an unordered data source.

UNORDERED

public static final Collector.Characteristics UNORDERED

Indicates that the collection operation does not commit to preserving the encounter order of input elements. (This might be true if the result container has no intrinsic order, such as a Set.)

IDENTITY_FINISH

public static final Collector.Characteristics IDENTITY_FINISH

Indicates that the finisher function is the identity function and can be elided. If set, it must be the case that an unchecked cast from A to R will succeed.

Method Details

values

public static Collector.Characteristics[] values()

Returns an array containing the constants of this enum class, in the order they are declared.

Returns:: an array containing the constants of this enum class, in the order they are declared

valueOf

public static Collector.Characteristics valueOf(String name)

Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)

Parameters:: name - the name of the enum constant to be returned.
Returns:: the enum constant with the specified name
Throws:: IllegalArgumentException - if this enum class has no constant with the specified name; NullPointerException - if the argument is null

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