org.apache.commons.lang3

Class EnumUtils

java.lang.Object

org.apache.commons.lang3.EnumUtils

public class EnumUtils
extends java.lang.Object

Utility library to provide helper methods for Java enums.

#ThreadSafe#

Since:

3.0

Constructor Summary

Constructors

Constructor and Description
EnumUtils() This constructor is public to permit tools that require a JavaBean instance to operate.

Method Summary

Modifier and Type	Method and Description
static <E extends java.lang.Enum<E>> long	generateBitVector(java.lang.Class<E> enumClass, E... values) Creates a long bit vector representation of the given array of Enum values.
static <E extends java.lang.Enum<E>> long	generateBitVector(java.lang.Class<E> enumClass, java.lang.Iterable<? extends E> values) Creates a long bit vector representation of the given subset of an Enum.
static <E extends java.lang.Enum<E>> long[]	generateBitVectors(java.lang.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 java.lang.Enum<E>> long[]	generateBitVectors(java.lang.Class<E> enumClass, java.lang.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 java.lang.Enum<E>> E	getEnum(java.lang.Class<E> enumClass, java.lang.String enumName) Gets the enum for the class, returning null if not found.
static <E extends java.lang.Enum<E>> E	getEnum(java.lang.Class<E> enumClass, java.lang.String enumName, E defaultEnum) Gets the enum for the class, returning defaultEnum if not found.
static <E extends java.lang.Enum<E>> E	getEnumIgnoreCase(java.lang.Class<E> enumClass, java.lang.String enumName) Gets the enum for the class, returning null if not found.
static <E extends java.lang.Enum<E>> E	getEnumIgnoreCase(java.lang.Class<E> enumClass, java.lang.String enumName, E defaultEnum) Gets the enum for the class, returning defaultEnum if not found.
static <E extends java.lang.Enum<E>> java.util.List<E>	getEnumList(java.lang.Class<E> enumClass) Gets the List of enums.
static <E extends java.lang.Enum<E>> java.util.Map<java.lang.String,E>	getEnumMap(java.lang.Class<E> enumClass) Gets the Map of enums by name.
static <E extends java.lang.Enum<E>,K> java.util.Map<K,E>	getEnumMap(java.lang.Class<E> enumClass, java.util.function.Function<E,K> keyFunction) Gets the Map of enums by name.
static <E extends java.lang.Enum<E>> E	getEnumSystemProperty(java.lang.Class<E> enumClass, java.lang.String propName, E defaultEnum) Gets the enum for the class in a system property, returning defaultEnum if not found.
static <E extends java.lang.Enum<E>> E	getFirstEnumIgnoreCase(java.lang.Class<E> enumClass, java.lang.String enumName, java.util.function.Function<E,java.lang.String> stringFunction, E defaultEnum) Gets the enum for the class, returning defaultEnum if not found.
static <E extends java.lang.Enum<E>> boolean	isValidEnum(java.lang.Class<E> enumClass, java.lang.String enumName) Checks if the specified name is a valid enum for the class.
static <E extends java.lang.Enum<E>> boolean	isValidEnumIgnoreCase(java.lang.Class<E> enumClass, java.lang.String enumName) Checks if the specified name is a valid enum for the class.
static <E extends java.lang.Enum<E>> java.util.EnumSet<E>	processBitVector(java.lang.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 java.lang.Enum<E>> java.util.EnumSet<E>	processBitVectors(java.lang.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.

Methods inherited from class java.lang.Object

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

Constructor Detail

EnumUtils

public EnumUtils()

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

Method Detail

generateBitVector

@SafeVarargs
public static <E extends java.lang.Enum<E>> long generateBitVector(java.lang.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:

java.lang.NullPointerException - if enumClass or values is null

java.lang.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 java.lang.Enum<E>> long generateBitVector(java.lang.Class<E> enumClass,
                                                                   java.lang.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:

java.lang.NullPointerException - if enumClass or values is null

java.lang.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 java.lang.Enum<E>> long[] generateBitVectors(java.lang.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:

java.lang.NullPointerException - if enumClass or values is null

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

Since:

3.2

generateBitVectors

public static <E extends java.lang.Enum<E>> long[] generateBitVectors(java.lang.Class<E> enumClass,
                                                                      java.lang.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:

java.lang.NullPointerException - if enumClass or values is null

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

Since:

3.2

getEnum

public static <E extends java.lang.Enum<E>> E getEnum(java.lang.Class<E> enumClass,
                                                      java.lang.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 java.lang.Enum<E>> E getEnum(java.lang.Class<E> enumClass,
                                                      java.lang.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, not null

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 java.lang.Enum<E>> E getEnumIgnoreCase(java.lang.Class<E> enumClass,
                                                                java.lang.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, not null

enumName - the enum name, null returns null

Returns:

the enum, null if not found

Since:

3.8

getEnumIgnoreCase

public static <E extends java.lang.Enum<E>> E getEnumIgnoreCase(java.lang.Class<E> enumClass,
                                                                java.lang.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, not null

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 java.lang.Enum<E>> java.util.List<E> getEnumList(java.lang.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 java.lang.Enum<E>> java.util.Map<java.lang.String,E> getEnumMap(java.lang.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 java.lang.Enum<E>,K> java.util.Map<K,E> getEnumMap(java.lang.Class<E> enumClass,
                                                                            java.util.function.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 java.lang.Enum<E>> E getEnumSystemProperty(java.lang.Class<E> enumClass,
                                                                    java.lang.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.

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

getFirstEnumIgnoreCase

public static <E extends java.lang.Enum<E>> E getFirstEnumIgnoreCase(java.lang.Class<E> enumClass,
                                                                     java.lang.String enumName,
                                                                     java.util.function.Function<E,java.lang.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, not null

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:

the enum, default enum if not found

Since:

3.13.0

isValidEnum

public static <E extends java.lang.Enum<E>> boolean isValidEnum(java.lang.Class<E> enumClass,
                                                                java.lang.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, not null

enumName - the enum name, null returns false

Returns:

true if the enum name is valid, otherwise false

isValidEnumIgnoreCase

public static <E extends java.lang.Enum<E>> boolean isValidEnumIgnoreCase(java.lang.Class<E> enumClass,
                                                                          java.lang.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, not null

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 java.lang.Enum<E>> java.util.EnumSet<E> processBitVector(java.lang.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:

java.lang.NullPointerException - if enumClass is null

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

Since:

3.0.1

processBitVectors

public static <E extends java.lang.Enum<E>> java.util.EnumSet<E> processBitVectors(java.lang.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:

java.lang.NullPointerException - if enumClass is null

java.lang.IllegalArgumentException - if enumClass is not an enum class

Since:

3.2