ch.jalu.typeresolver

Class EnumUtils

java.lang.Object

ch.jalu.typeresolver.EnumUtils

public final class EnumUtils
extends Object

Utilities for enum classes.

Method Summary

Modifier and Type	Method and Description
static Optional<Class<? extends Enum<?>>>	asEnumClassIfPossible(@Nullable Class<?> clazz) Returns an optional with the class cast as enum extension, empty otherwise.
static Optional<Class<? extends Enum<?>>>	getAssociatedEnumType(@Nullable Class<?> clazz) Returns an optional with the class if it is an enum, or with the actual enum class if the given class is a synthetic class of an enum entry.
static boolean	isEnumOrEnumEntryType(@Nullable Class<?> clazz) Indicates whether the given class is an enum or a synthetic class of an enum entry.
static <E extends Enum<E>> Collector<E,?,EnumSet<E>>	toEnumSet(Class<E> enumType) Returns a collector that collects the results of a stream into an EnumSet.
static <T> Optional<T>	tryValueOf(@Nullable Class<T> clazz, @Nullable String name) Returns an optional of the enum entry with the given name if the provided class is an enum and has an entry that matches exactly the given name.
static <T> Optional<T>	tryValueOfCaseInsensitive(@Nullable Class<T> clazz, @Nullable String name) Returns an optional of the enum entry with the given name if the provided class is an enum and has an entry that matches the given name in a case-insensitive manner.

Methods inherited from class java.lang.Object

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

Method Detail

tryValueOf

public static <T> Optional<T> tryValueOf(@Nullable
                                         @Nullable Class<T> clazz,
                                         @Nullable
                                         @Nullable String name)

Returns an optional of the enum entry with the given name if the provided class is an enum and has an entry that matches exactly the given name. Otherwise, an empty optional is returned.

Type Parameters:

T - the class type

Parameters:

clazz - the class to check for enum entries, or null

name - the name to match, or null

Returns:

optional of the enum entry if the class is an enum and has an entry of the given name; empty otherwise

tryValueOfCaseInsensitive

public static <T> Optional<T> tryValueOfCaseInsensitive(@Nullable
                                                        @Nullable Class<T> clazz,
                                                        @Nullable
                                                        @Nullable String name)

Returns an optional of the enum entry with the given name if the provided class is an enum and has an entry that matches the given name in a case-insensitive manner. Otherwise, an empty optional is returned. The first found match is returned if multiple enum entries match the name.

Type Parameters:

T - the class type

Parameters:

clazz - the class to check for enum entries, or null

name - the name to match (case-insensitive), or null

Returns:

optional of the enum entry if the class is an enum and the name matched; empty otherwise

asEnumClassIfPossible

public static Optional<Class<? extends Enum<?>>> asEnumClassIfPossible(@Nullable
                                                                       @Nullable Class<?> clazz)

Returns an optional with the class cast as enum extension, empty otherwise. Convenient to check if a class is an enum and to continue working with it as such. This class only returns an optional with the given class if it represents an enum type; use getAssociatedEnumType(java.lang.Class<?>) if synthetic classes of enum entries should be converted to their enum type.

Examples:

   Class<?> class1 = TimeUnit.class;
   Class<?> class2 = String.class;

   EnumUtils.typeAsEnumClass(class1)    = Optional.of(TimeUnit.class)
   EnumUtils.typeAsEnumClass(class2)    = Optional.empty()
 

Parameters:

clazz - the class to inspect, or null

Returns:

optional with the enum type if applicable, otherwise empty optional

isEnumOrEnumEntryType

public static boolean isEnumOrEnumEntryType(@Nullable
                                            @Nullable Class<?> clazz)

Indicates whether the given class is an enum or a synthetic class of an enum entry. Synthetic classes are created when an enum entry extends the enum type anonymously.

Examples:

   Class<?> class1 = NumericShaper.Range.class;
   Class<?> class2 = NumericShaper.Range.ETHIOPIC.getClass(); // NumericShaper$Range$1.class

   EnumUtils.isEnumOrEnumEntryType(class1)    = true
   EnumUtils.isEnumOrEnumEntryType(class2)    = true
   EnumUtils.isEnumOrEnumEntryType(null)      = false
   EnumUtils.isEnumOrEnumEntryType(int.class) = false
 

Parameters:

clazz - the class to inspect, or null

Returns:

true if the class is an enum or the class of an enum entry

getAssociatedEnumType

public static Optional<Class<? extends Enum<?>>> getAssociatedEnumType(@Nullable
                                                                       @Nullable Class<?> clazz)

Returns an optional with the class if it is an enum, or with the actual enum class if the given class is a synthetic class of an enum entry.

Examples:

   Class<?> class1 = NumericShaper.Range.class;
   Class<?> class2 = NumericShaper.Range.ETHIOPIC.getClass(); // NumericShaper$Range$1.class

   EnumUtils.asEnumType(class1)    = Optional.of(NumericShaper.Range.class)
   EnumUtils.asEnumType(class2)    = Optional.of(NumericShaper.Range.class)
   EnumUtils.asEnumType(null)      = Optional.empty()
   EnumUtils.asEnumType(int.class) = Optional.empty()
 

Note: to always get the actual enum class of an enum entry, use Enum.getDeclaringClass().

Parameters:

clazz - the class to inspect, or null

Returns:

optional with the enum type if applicable, otherwise empty optional

toEnumSet

public static <E extends Enum<E>> Collector<E,?,EnumSet<E>> toEnumSet(Class<E> enumType)

Returns a collector that collects the results of a stream into an EnumSet. Convenience method for brevity.

Type Parameters:

E - the enum type

Parameters:

enumType - the class of the enum the stream consists of

Returns:

collector to EnumSet