public abstract classEnumSet<E extendsEnum<E>>extendsAbstractSet<E>implementsCloneable,Serializable
Set implementation for use with enum types. All of the elements in an enum set must come from a single enum type that is specified, explicitly or implicitly, when the set is created. Enum sets are represented internally as bit vectors. This representation is extremely compact and efficient. The space and time performance of this class should be good enough to allow its use as a high-quality, typesafe alternative to traditionalint-based "bit flags." Even bulk operations (such ascontainsAll andretainAll) should run very quickly if their argument is also an enum set.The iterator returned by theiterator method traverses the elements in theirnatural order (the order in which the enum constants are declared). The returned iterator isweakly consistent: it will never throwConcurrentModificationException and it may or may not show the effects of any modifications to the set that occur while the iteration is in progress.
Null elements are not permitted. Attempts to insert a null element will throwNullPointerException. Attempts to test for the presence of a null element or to remove one will, however, function properly.
Like most collection implementations,EnumSet is not synchronized. If multiple threads access an enum set concurrently, and at least one of the threads modifies the set, it should be synchronized externally. This is typically accomplished by synchronizing on some object that naturally encapsulates the enum set. If no such object exists, the set should be "wrapped" using theCollections.synchronizedSet(java.util.Set<T>) method. This is best done at creation time, to prevent accidental unsynchronized access:
Set<MyEnum> s = Collections.synchronizedSet(EnumSet.noneOf(MyEnum.class));
Implementation note: All basic operations execute in constant time. They are likely (though not guaranteed) to be much faster than theirHashSet counterparts. Even bulk operations execute in constant time if their argument is also an enum set.
This class is a member of the Java Collections Framework.
EnumMap| Modifier and Type | Method | Description |
|---|---|---|
static <E extendsEnum<E>> | allOf(Class<E> elementType) | Creates an enum set containing all of the elements in the specified element type. |
EnumSet<E> | clone() | Returns a copy of this set. |
static <E extendsEnum<E>> | complementOf(EnumSet<E> s) | Creates an enum set with the same element type as the specified enum set, initially containing all the elements of this type that arenot contained in the specified set. |
static <E extendsEnum<E>> | copyOf(Collection<E> c) | Creates an enum set initialized from the specified collection. |
static <E extendsEnum<E>> | copyOf(EnumSet<E> s) | Creates an enum set with the same element type as the specified enum set, initially containing the same elements (if any). |
static <E extendsEnum<E>> | noneOf(Class<E> elementType) | Creates an empty enum set with the specified element type. |
static <E extendsEnum<E>> | of(E e) | Creates an enum set initially containing the specified element. |
static <E extendsEnum<E>> | of(E first, E... rest) | Creates an enum set initially containing the specified elements. |
static <E extendsEnum<E>> | of(E e1, E e2) | Creates an enum set initially containing the specified elements. |
static <E extendsEnum<E>> | of(E e1, E e2, E e3) | Creates an enum set initially containing the specified elements. |
static <E extendsEnum<E>> | of(E e1, E e2, E e3, E e4) | Creates an enum set initially containing the specified elements. |
static <E extendsEnum<E>> | of(E e1, E e2, E e3, E e4, E e5) | Creates an enum set initially containing the specified elements. |
static <E extendsEnum<E>> | range(E from, E to) | Creates an enum set initially containing all of the elements in the range defined by the two specified endpoints. |
equals,hashCode,removeAlladd,addAll,clear,contains,containsAll,isEmpty,iterator,remove,retainAll,size,toArray,toArray,toStringadd,addAll,clear,contains,containsAll,isEmpty,iterator,remove,retainAll,size,spliterator,toArray,toArrayparallelStream,removeIf,streampublic static <E extendsEnum<E>> EnumSet<E> noneOf(Class<E> elementType)
E - The class of the elements in the setelementType - the class object of the element type for this enum setNullPointerException - ifelementType is nullpublic static <E extendsEnum<E>> EnumSet<E> allOf(Class<E> elementType)
E - The class of the elements in the setelementType - the class object of the element type for this enum setNullPointerException - ifelementType is nullpublic static <E extendsEnum<E>> EnumSet<E> copyOf(EnumSet<E> s)
E - The class of the elements in the sets - the enum set from which to initialize this enum setNullPointerException - ifs is nullpublic static <E extendsEnum<E>> EnumSet<E> copyOf(Collection<E> c)
copyOf(EnumSet). Otherwise, the specified collection must contain at least one element (in order to determine the new enum set's element type).E - The class of the elements in the collectionc - the collection from which to initialize this enum setIllegalArgumentException - ifc is not anEnumSet instance and contains no elementsNullPointerException - ifc is nullpublic static <E extendsEnum<E>> EnumSet<E> complementOf(EnumSet<E> s)
E - The class of the elements in the enum sets - the enum set from whose complement to initialize this enum setNullPointerException - ifs is nullpublic static <E extendsEnum<E>> EnumSet<E> of(E e)
E - The class of the specified element and of the sete - the element that this set is to contain initiallyNullPointerException - ife is nullpublic static <E extendsEnum<E>> EnumSet<E> of(E e1, E e2)
E - The class of the parameter elements and of the sete1 - an element that this set is to contain initiallye2 - another element that this set is to contain initiallyNullPointerException - if any parameters are nullpublic static <E extendsEnum<E>> EnumSet<E> of(E e1, E e2, E e3)
E - The class of the parameter elements and of the sete1 - an element that this set is to contain initiallye2 - another element that this set is to contain initiallye3 - another element that this set is to contain initiallyNullPointerException - if any parameters are nullpublic static <E extendsEnum<E>> EnumSet<E> of(E e1, E e2, E e3, E e4)
E - The class of the parameter elements and of the sete1 - an element that this set is to contain initiallye2 - another element that this set is to contain initiallye3 - another element that this set is to contain initiallye4 - another element that this set is to contain initiallyNullPointerException - if any parameters are nullpublic static <E extendsEnum<E>> EnumSet<E> of(E e1, E e2, E e3, E e4, E e5)
E - The class of the parameter elements and of the sete1 - an element that this set is to contain initiallye2 - another element that this set is to contain initiallye3 - another element that this set is to contain initiallye4 - another element that this set is to contain initiallye5 - another element that this set is to contain initiallyNullPointerException - if any parameters are null@SafeVarargspublic static <E extendsEnum<E>> EnumSet<E> of(E first, E... rest)
E - The class of the parameter elements and of the setfirst - an element that the set is to contain initiallyrest - the remaining elements the set is to contain initiallyNullPointerException - if any of the specified elements are null, or ifrest is nullpublic static <E extendsEnum<E>> EnumSet<E> range(E from, E to)
E - The class of the parameter elements and of the setfrom - the first element in the rangeto - the last element in the rangeNullPointerException - iffrom orto are nullIllegalArgumentException - iffrom.compareTo(to) > 0