org.apache.commons.lang3

Class EnumUtils

java.lang.Object

org.apache.commons.lang3.EnumUtils

public class EnumUtils
extends Object

Provides methods for Java enums.

#ThreadSafe#

Since:

3.0

Constructor Summary

Constructors

Constructor and Description
EnumUtils() Deprecated. TODO Make private in 4.0.

Method Summary

Modifier and Type	Method and Description
static <E extends Enum<E>> long	generateBitVector(Class<E> enumClass, E... values) Creates a long bit vector representation of the given array of Enum values.
static <E extends Enum<E>> long	generateBitVector(Class<E> enumClass, Iterable<? extends E> values) Creates a long bit vector representation of the given subset of an Enum.
static <E extends Enum<E>> long[]	generateBitVectors(Class<E> enumClass, E... values) Creates a bit vector representation of the given subset of an Enum using as many longs as needed.
static <E extends Enum<E>> long[]	generateBitVectors(Class<E> enumClass, Iterable<? extends E> values) Creates a bit vector representation of the given subset of an Enum using as many longs as needed.
static <E extends Enum<E>> E	getEnum(Class<E> enumClass, String enumName) Gets the enum for the class, returning null if not found.
static <E extends Enum<E>> E	getEnum(Class<E> enumClass, String enumName, E defaultEnum) Gets the enum for the class, returning defaultEnum if not found.
static <E extends Enum<E>> E	getEnumIgnoreCase(Class<E> enumClass, String enumName) Gets the enum for the class, returning null if not found.
static <E extends Enum<E>> E	getEnumIgnoreCase(Class<E> enumClass, String enumName, E defaultEnum) Gets the enum for the class, returning defaultEnum if not found.
static <E extends Enum<E>> List<E>	getEnumList(Class<E> enumClass) Gets the List of enums.
static <E extends Enum<E>> Map<String,E>	getEnumMap(Class<E> enumClass) Gets the Map of enums by name.
static <E extends Enum<E>,K> Map<K,E>	getEnumMap(Class<E> enumClass, Function<E,K> keyFunction) Gets the Map of enums by name.
static <E extends Enum<E>> E	getEnumSystemProperty(Class<E> enumClass, String propName, E defaultEnum) Gets the enum for the class in a system property, returning defaultEnum if not found.
static <E extends Enum<E>> E	getFirstEnum(Class<E> enumClass, int value, ToIntFunction<E> toIntFunction, E defaultEnum) Gets the enum for the class and value, returning defaultEnum if not found.
static <E extends Enum<E>> E	getFirstEnumIgnoreCase(Class<E> enumClass, String enumName, Function<E,String> stringFunction, E defaultEnum) Gets the enum for the class, returning defaultEnum if not found.
static <E extends Enum<E>> boolean	isValidEnum(Class<E> enumClass, String enumName) Checks if the specified name is a valid enum for the class.
static <E extends Enum<E>> boolean	isValidEnumIgnoreCase(Class<E> enumClass, String enumName) Checks if the specified name is a valid enum for the class.
static <E extends Enum<E>> EnumSet<E>	processBitVector(Class<E> enumClass, long value) Convert a long value created by generateBitVector(java.lang.Class<E>, E...) into the set of enum values that it represents.
static <E extends Enum<E>> EnumSet<E>	processBitVectors(Class<E> enumClass, long... values) Convert a long[] created by generateBitVectors(java.lang.Class<E>, E...) into the set of enum values that it represents.
static <T> Stream<T>	stream(Class<T> clazz) Returns a sequential ordered stream whose elements are the given class' enum values.

Methods inherited from class java.lang.Object

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

Constructor Detail

EnumUtils

@Deprecated
public EnumUtils()

Deprecated. TODO Make private in 4.0.

This constructor is public to permit tools that require a JavaBean instance to operate.

Method Detail

generateBitVector

@SafeVarargs
public static <E extends Enum<E>> long generateBitVector(Class<E> enumClass,
                                                                      E... values)

Creates a long bit vector representation of the given array of Enum values.

This generates a value that is usable by processBitVector(java.lang.Class<E>, long).

Do not use this method if you have more than 64 values in your Enum, as this would create a value greater than a long can hold.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum we are working with, not null.

values - the values we want to convert, not null.

Returns:

a long whose value provides a binary representation of the given set of enum values.

Throws:

NullPointerException - if enumClass or values is null.

IllegalArgumentException - if enumClass is not an enum class or has more than 64 values.

Since:

3.0.1

See Also:

generateBitVectors(Class, Iterable)

generateBitVector

public static <E extends Enum<E>> long generateBitVector(Class<E> enumClass,
                                                         Iterable<? extends E> values)

Creates a long bit vector representation of the given subset of an Enum.

This generates a value that is usable by processBitVector(java.lang.Class<E>, long).

Do not use this method if you have more than 64 values in your Enum, as this would create a value greater than a long can hold.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum we are working with, not null.

values - the values we want to convert, not null, neither containing null.

Returns:

a long whose value provides a binary representation of the given set of enum values.

Throws:

NullPointerException - if enumClass or values is null.

IllegalArgumentException - if enumClass is not an enum class or has more than 64 values, or if any values null.

Since:

3.0.1

See Also:

generateBitVectors(Class, Iterable)

generateBitVectors

@SafeVarargs
public static <E extends Enum<E>> long[] generateBitVectors(Class<E> enumClass,
                                                                         E... values)

Creates a bit vector representation of the given subset of an Enum using as many longs as needed.

This generates a value that is usable by processBitVectors(java.lang.Class<E>, long...).

Use this method if you have more than 64 values in your Enum.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum we are working with, not null.

values - the values we want to convert, not null, neither containing null.

Returns:

a long[] whose values provide a binary representation of the given set of enum values with the least significant digits rightmost.

Throws:

NullPointerException - if enumClass or values is null.

IllegalArgumentException - if enumClass is not an enum class, or if any values null.

Since:

3.2

generateBitVectors

public static <E extends Enum<E>> long[] generateBitVectors(Class<E> enumClass,
                                                            Iterable<? extends E> values)

Creates a bit vector representation of the given subset of an Enum using as many longs as needed.

This generates a value that is usable by processBitVectors(java.lang.Class<E>, long...).

Use this method if you have more than 64 values in your Enum.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum we are working with, not null.

values - the values we want to convert, not null, neither containing null.

Returns:

a long[] whose values provide a binary representation of the given set of enum values with the least significant digits rightmost.

Throws:

NullPointerException - if enumClass or values is null.

IllegalArgumentException - if enumClass is not an enum class, or if any values null.

Since:

3.2

getEnum

public static <E extends Enum<E>> E getEnum(Class<E> enumClass,
                                            String enumName)

Gets the enum for the class, returning null if not found.

This method differs from Enum.valueOf(java.lang.Class<T>, java.lang.String) in that it does not throw an exception for an invalid enum name.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum to query, not null.

enumName - the enum name, null returns null.

Returns:

the enum, null if not found.

getEnum

public static <E extends Enum<E>> E getEnum(Class<E> enumClass,
                                            String enumName,
                                            E defaultEnum)

Gets the enum for the class, returning defaultEnum if not found.

This method differs from Enum.valueOf(java.lang.Class<T>, java.lang.String) in that it does not throw an exception for an invalid enum name.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum to query, null returns default enum.

enumName - the enum name, null returns default enum.

defaultEnum - the default enum.

Returns:

the enum, default enum if not found.

Since:

3.10

getEnumIgnoreCase

public static <E extends Enum<E>> E getEnumIgnoreCase(Class<E> enumClass,
                                                      String enumName)

Gets the enum for the class, returning null if not found.

This method differs from Enum.valueOf(java.lang.Class<T>, java.lang.String) in that it does not throw an exception for an invalid enum name and performs case insensitive matching of the name.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum to query, may be null.

enumName - the enum name, null returns null.

Returns:

the enum, null if not found.

Since:

3.8

getEnumIgnoreCase

public static <E extends Enum<E>> E getEnumIgnoreCase(Class<E> enumClass,
                                                      String enumName,
                                                      E defaultEnum)

Gets the enum for the class, returning defaultEnum if not found.

This method differs from Enum.valueOf(java.lang.Class<T>, java.lang.String) in that it does not throw an exception for an invalid enum name and performs case insensitive matching of the name.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum to query, null returns default enum.

enumName - the enum name, null returns default enum.

defaultEnum - the default enum.

Returns:

the enum, default enum if not found.

Since:

3.10

getEnumList

public static <E extends Enum<E>> List<E> getEnumList(Class<E> enumClass)

Gets the List of enums.

This method is useful when you need a list of enums rather than an array.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum to query, not null.

Returns:

the modifiable list of enums, never null.

getEnumMap

public static <E extends Enum<E>> Map<String,E> getEnumMap(Class<E> enumClass)

Gets the Map of enums by name.

This method is useful when you need a map of enums by name.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum to query, not null.

Returns:

the modifiable map of enum names to enums, never null.

getEnumMap

public static <E extends Enum<E>,K> Map<K,E> getEnumMap(Class<E> enumClass,
                                                        Function<E,K> keyFunction)

Gets the Map of enums by name.

This method is useful when you need a map of enums by name.

Type Parameters:

E - the type of enumeration.

K - the type of the map key.

Parameters:

enumClass - the class of the enum to query, not null.

keyFunction - the function to query for the key, not null.

Returns:

the modifiable map of enums, never null.

Since:

3.13.0

getEnumSystemProperty

public static <E extends Enum<E>> E getEnumSystemProperty(Class<E> enumClass,
                                                          String propName,
                                                          E defaultEnum)

Gets the enum for the class in a system property, returning defaultEnum if not found.

This method differs from Enum.valueOf(java.lang.Class<T>, java.lang.String) in that it does not throw an exception for an invalid enum name.

If a SecurityException is caught, the return value is null.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum to query, not null.

propName - the system property key for the enum name, null returns default enum.

defaultEnum - the default enum.

Returns:

the enum, default enum if not found.

Since:

3.13.0

getFirstEnum

public static <E extends Enum<E>> E getFirstEnum(Class<E> enumClass,
                                                 int value,
                                                 ToIntFunction<E> toIntFunction,
                                                 E defaultEnum)

Gets the enum for the class and value, returning defaultEnum if not found.

This method differs from Enum.valueOf(java.lang.Class<T>, java.lang.String) in that it does not throw an exception for an invalid enum name and performs case insensitive matching of the name.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum to query, not null.

value - the enum name, null returns default enum.

toIntFunction - the function that gets an int for an enum for comparison to value.

defaultEnum - the default enum.

Returns:

an enum, default enum if not found.

Since:

3.18.0

getFirstEnumIgnoreCase

public static <E extends Enum<E>> E getFirstEnumIgnoreCase(Class<E> enumClass,
                                                           String enumName,
                                                           Function<E,String> stringFunction,
                                                           E defaultEnum)

Gets the enum for the class, returning defaultEnum if not found.

This method differs from Enum.valueOf(java.lang.Class<T>, java.lang.String) in that it does not throw an exception for an invalid enum name and performs case insensitive matching of the name.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum to query, null returns default enum.

enumName - the enum name, null returns default enum.

stringFunction - the function that gets the string for an enum for comparison to enumName.

defaultEnum - the default enum.

Returns:

an enum, default enum if not found.

Since:

3.13.0

isValidEnum

public static <E extends Enum<E>> boolean isValidEnum(Class<E> enumClass,
                                                      String enumName)

Checks if the specified name is a valid enum for the class.

This method differs from Enum.valueOf(java.lang.Class<T>, java.lang.String) in that it checks if the name is a valid enum without needing to catch the exception.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum to query, null returns false.

enumName - the enum name, null returns false.

Returns:

true if the enum name is valid, otherwise false.

isValidEnumIgnoreCase

public static <E extends Enum<E>> boolean isValidEnumIgnoreCase(Class<E> enumClass,
                                                                String enumName)

Checks if the specified name is a valid enum for the class.

This method differs from Enum.valueOf(java.lang.Class<T>, java.lang.String) in that it checks if the name is a valid enum without needing to catch the exception and performs case insensitive matching of the name.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum to query, null returns false.

enumName - the enum name, null returns false.

Returns:

true if the enum name is valid, otherwise false.

Since:

3.8

processBitVector

public static <E extends Enum<E>> EnumSet<E> processBitVector(Class<E> enumClass,
                                                              long value)

Convert a long value created by generateBitVector(java.lang.Class<E>, E...) into the set of enum values that it represents.

If you store this value, beware any changes to the enum that would affect ordinal values.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum we are working with, not null.

value - the long value representation of a set of enum values.

Returns:

a set of enum values.

Throws:

NullPointerException - if enumClass is null.

IllegalArgumentException - if enumClass is not an enum class or has more than 64 values.

Since:

3.0.1

processBitVectors

public static <E extends Enum<E>> EnumSet<E> processBitVectors(Class<E> enumClass,
                                                               long... values)

Convert a long[] created by generateBitVectors(java.lang.Class<E>, E...) into the set of enum values that it represents.

If you store this value, beware any changes to the enum that would affect ordinal values.

Type Parameters:

E - the type of the enumeration.

Parameters:

enumClass - the class of the enum we are working with, not null.

values - the long[] bearing the representation of a set of enum values, the least significant digits rightmost, not null.

Returns:

a set of enum values.

Throws:

NullPointerException - if enumClass is null.

IllegalArgumentException - if enumClass is not an enum class.

Since:

3.2

stream

public static <T> Stream<T> stream(Class<T> clazz)

Returns a sequential ordered stream whose elements are the given class' enum values.

Type Parameters:

T - the type of stream elements.

Parameters:

clazz - the class containing the enum values, may be null.

Returns:

the new stream, empty of clazz is null.

Since:

3.18.0

See Also:

Class.getEnumConstants()