io.pravega.common.util

Class EnumHelpers

java.lang.Object

io.pravega.common.util.EnumHelpers

public final class EnumHelpers
extends java.lang.Object

General helpers on Enum types.

Constructor Summary

Constructors

Constructor and Description
EnumHelpers()

Method Summary

Modifier and Type	Method and Description
static <T extends java.lang.Enum<T>> T[]	indexById(java.lang.Class<T> enumClass, java.util.function.ToIntFunction<T> getId) Indexes the values of the given Enum by a specified Id function.

Methods inherited from class java.lang.Object

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

Constructor Detail

EnumHelpers

public EnumHelpers()

Method Detail

indexById

public static <T extends java.lang.Enum<T>> T[] indexById(java.lang.Class<T> enumClass,
                                                          java.util.function.ToIntFunction<T> getId)

Indexes the values of the given Enum by a specified Id function. This method maps getId on an integer interval from 0 to max()+1, and fills in the slots where getId returns a value. Empty slots will contain null.

Notes:

• This method will create an array of size max(getId(all-enum-values)), so it could get very large. It is not recommended for sparse Enums (in which case a Map would be better suited).
• This method has undefined behavior if getId does not return unique values. It does not check, so Enum values that have the same result from getId may not be indexed correctly.

Type Parameters:

T - Type of the enum.

Parameters:

enumClass - The Enum Class.

getId - A function that returns an Id for each enum value.

Returns:

An array of type T with Enum values indexed by the result of the getId function.