com.google.common.base

Class Enums

java.lang.Object

com.google.common.base.Enums

@GwtCompatible(emulated=true)
@Beta
public final class Enums
extends Object

Utility methods for working with Enum instances.

Since:

9.0

Author:

Steve McKay

Method Summary

Methods

Modifier and Type	Method and Description
static Field	getField(Enum<?> enumValue) Returns the Field in which enumValue is defined.
static <T extends Enum<T>> Optional<T>	getIfPresent(Class<T> enumClass, String value) Returns an optional enum constant for the given type, using Enum.valueOf(java.lang.Class<T>, java.lang.String).
static <T extends Enum<T>> Converter<String,T>	stringConverter(Class<T> enumClass) Returns a converter that converts between strings and enum values of type enumClass using Enum.valueOf(Class, String) and Enum.name().
static <T extends Enum<T>> Function<String,T>	valueOfFunction(Class<T> enumClass) Deprecated. Use stringConverter(java.lang.Class<T>) instead. Note that the string converter has slightly different behavior: it throws IllegalArgumentException if the enum constant does not exist rather than returning null. It also converts null to null rather than throwing NullPointerException. This method is scheduled for removal in Guava 18.0.

Methods inherited from class java.lang.Object

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

Method Detail

getField

@GwtIncompatible(value="reflection")
public static Field getField(Enum<?> enumValue)

Returns the Field in which enumValue is defined. For example, to get the Description annotation on the GOLF constant of enum Sport, use Enums.getField(Sport.GOLF).getAnnotation(Description.class).

Since:

12.0

valueOfFunction

@Deprecated
public static <T extends Enum<T>> Function<String,T> valueOfFunction(Class<T> enumClass)

Deprecated. Use stringConverter(java.lang.Class<T>) instead. Note that the string converter has slightly different behavior: it throws IllegalArgumentException if the enum constant does not exist rather than returning null. It also converts null to null rather than throwing NullPointerException. This method is scheduled for removal in Guava 18.0.

Returns a Function that maps an Enum name to the associated Enum constant. The Function will return null if the Enum constant does not exist.

Parameters:

enumClass - the Class of the Enum declaring the constant values

getIfPresent

public static <T extends Enum<T>> Optional<T> getIfPresent(Class<T> enumClass,
                                           String value)

Returns an optional enum constant for the given type, using Enum.valueOf(java.lang.Class<T>, java.lang.String). If the constant does not exist, Optional.absent() is returned. A common use case is for parsing user input or falling back to a default enum constant. For example, Enums.getIfPresent(Country.class, countryInput).or(Country.DEFAULT);

Since:

12.0

stringConverter

public static <T extends Enum<T>> Converter<String,T> stringConverter(Class<T> enumClass)

Returns a converter that converts between strings and enum values of type enumClass using Enum.valueOf(Class, String) and Enum.name(). The converter will throw an IllegalArgumentException if the argument is not the name of any enum constant in the specified enum.

Since:

16.0