Package org.apache.commons.lang3

Class EnumUtils

java.lang.Object
org.apache.commons.lang3.EnumUtils
public class EnumUtils extends Object
Utility library to provide helper methods for Java enums.

#ThreadSafe#

Since:
3.0

  • Constructor Details

    • 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 Details

    • 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:

    • 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

      @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, 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 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, not 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, 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 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.

      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 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, 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 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, not null
      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, 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 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