Package com.github.twitch4j.util

Class EnumUtil

java.lang.Object

com.github.twitch4j.util.EnumUtil

public final class EnumUtil
extends Object

Method Summary

Modifier and Type	Method	Description
static <E extends Enum<E>> Map<String,E>	buildMapping(@NotNull E[] values)	Creates a mapping of enum values by their string representation.
static <E extends Enum<E>, K> Map<K,E>	buildMapping(@NotNull E[] values, @NotNull Function<E,K> keySelector)	Creates a mapping of enum values via an arbitrary key derivation function.
static <E extends Enum<E>, K, V> Map<K,V>	buildMapping(@NotNull E[] values, @NotNull Function<E,K> keySelector, @NotNull Function<E,V> valueMapper)	Transforms enum values to a key-value map based on the specified functions.

Methods inherited from class java.lang.Object

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

Method Details

buildMapping

public static <E extends Enum<E>,
K,
V> Map<K,V> buildMapping(@NotNull
 @NotNull E[] values,
 @NotNull
 @NotNull Function<E,K> keySelector,
 @NotNull
 @NotNull Function<E,V> valueMapper)

Transforms enum values to a key-value map based on the specified functions.

Type Parameters:

E - the type of enum

K - the type of keys

V - the type of values

Parameters:

values - the values within an enum to be transformed

keySelector - a function that derives a key associated to an enum entry

valueMapper - a function that yields a value for a given enum entry

Returns:

a Map of key-value associations from transforming the specified enum entries

API Note:

The key derivation function should not yield collisions (even though we do not throw an exception upon a duplicate key).

Implementation Requirements:

The returned map is unmodifiable. The underlying map is HashMap so that null keys (and values) are supported.

Implementation Note:

Enum#values is used instead of Class.getEnumConstants() to avoid reflection overhead.

buildMapping

public static <E extends Enum<E>,
K> Map<K,E> buildMapping(@NotNull
 @NotNull E[] values,
 @NotNull
 @NotNull Function<E,K> keySelector)

Creates a mapping of enum values via an arbitrary key derivation function.

Type Parameters:

E - the type of enum

K - the type of keys

Parameters:

values - the values within an enum to be mapped

keySelector - a function that derives a key associated to an enum value

Returns:

the mapping of enum values by the derived keys

See Also:

• buildMapping(Enum[], Function, Function)

buildMapping

public static <E extends Enum<E>> Map<String,E> buildMapping(@NotNull
 @NotNull E[] values)

Creates a mapping of enum values by their string representation.

Type Parameters:

E - the type of enum

Parameters:

values - the values within an enum to be mapped

Returns:

a mapping of Enum.toString() to the enum value itself

See Also:

• buildMapping(Enum[], Function)