public abstract class EnumSet<E extends Enum<E>> extends AbstractSet<E> implements Cloneable, 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 traditional int-based "bit flags." Even bulk
operations (such as containsAll and retainAll) should
run very quickly if their argument is also an enum set.
The iterator returned by the iterator method traverses the
elements in their natural order (the order in which the enum
constants are declared). The returned iterator is weakly
consistent: it will never throw ConcurrentModificationException
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 throw NullPointerException. 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 the Collections.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 their
HashSet 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 and Description |
|---|---|
static <E extends Enum<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 extends Enum<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 are
not contained in the specified set.
|
static <E extends Enum<E>> |
copyOf(Collection<E> c)
Creates an enum set initialized from the specified collection.
|
static <E extends Enum<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 extends Enum<E>> |
noneOf(Class<E> elementType)
Creates an empty enum set with the specified element type.
|
static <E extends Enum<E>> |
of(E e)
Creates an enum set initially containing the specified element.
|
static <E extends Enum<E>> |
of(E first,
E... rest)
Creates an enum set initially containing the specified elements.
|
static <E extends Enum<E>> |
of(E e1,
E e2)
Creates an enum set initially containing the specified elements.
|
static <E extends Enum<E>> |
of(E e1,
E e2,
E e3)
Creates an enum set initially containing the specified elements.
|
static <E extends Enum<E>> |
of(E e1,
E e2,
E e3,
E e4)
Creates an enum set initially containing the specified elements.
|
static <E extends Enum<E>> |
of(E e1,
E e2,
E e3,
E e4,
E e5)
Creates an enum set initially containing the specified elements.
|
static <E extends Enum<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, toStringfinalize, getClass, notify, notifyAll, wait, wait, waitadd, addAll, clear, contains, containsAll, isEmpty, iterator, remove, retainAll, size, spliterator, toArray, toArrayparallelStream, removeIf, streampublic static <E extends Enum<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 - if elementType is nullpublic static <E extends Enum<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 - if elementType is nullpublic static <E extends Enum<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 - if s is nullpublic static <E extends Enum<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 - if c is not an
EnumSet instance and contains no elementsNullPointerException - if c is nullpublic static <E extends Enum<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 - if s is nullpublic static <E extends Enum<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 - if e is nullpublic static <E extends Enum<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 extends Enum<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 extends Enum<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 extends Enum<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@SafeVarargs public static <E extends Enum<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 if rest is nullpublic static <E extends Enum<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 - if from or to are nullIllegalArgumentException - if from.compareTo(to) > 0 Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
Copyright © 1993, 2022, Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.