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Java™ Platform Standard Ed. 6 |
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java.lang.Object java.util.AbstractCollection<E> java.util.AbstractSet<E> java.util.EnumSet<E>
public abstract class EnumSet<E extends Enum<E>>
A specialized 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
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
Method Summary | ||
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static
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allOf(Class<E> elementType)
Creates an enum set containing all of the elements in the specified element type. |
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EnumSet<E> |
clone()
Returns a copy of this set. |
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static
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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. |
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static
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copyOf(Collection<E> c)
Creates an enum set initialized from the specified collection. |
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static
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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). |
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static
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noneOf(Class<E> elementType)
Creates an empty enum set with the specified element type. |
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static
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of(E e)
Creates an enum set initially containing the specified element. |
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static
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of(E first,
E... rest)
Creates an enum set initially containing the specified elements. |
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static
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of(E e1,
E e2)
Creates an enum set initially containing the specified elements. |
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static
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of(E e1,
E e2,
E e3)
Creates an enum set initially containing the specified elements. |
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static
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of(E e1,
E e2,
E e3,
E e4)
Creates an enum set initially containing the specified elements. |
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static
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of(E e1,
E e2,
E e3,
E e4,
E e5)
Creates an enum set initially containing the specified elements. |
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static
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range(E from,
E to)
Creates an enum set initially containing all of the elements in the range defined by the two specified endpoints. |
Methods inherited from class java.util.AbstractSet |
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equals, hashCode, removeAll |
Methods inherited from class java.util.AbstractCollection |
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add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, retainAll, size, toArray, toArray, toString |
Methods inherited from class java.lang.Object |
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finalize, getClass, notify, notifyAll, wait, wait, wait |
Methods inherited from interface java.util.Set |
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add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, retainAll, size, toArray, toArray |
Method Detail |
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public static <E extends Enum<E>> EnumSet<E> noneOf(Class<E> elementType)
elementType
- the class object of the element type for this enum
set
NullPointerException
- if elementType is nullpublic static <E extends Enum<E>> EnumSet<E> allOf(Class<E> elementType)
elementType
- the class object of the element type for this enum
set
NullPointerException
- if elementType is nullpublic static <E extends Enum<E>> EnumSet<E> copyOf(EnumSet<E> s)
s
- the enum set from which to initialize this enum set
NullPointerException
- 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).
c
- the collection from which to initialize this enum set
IllegalArgumentException
- if c is not an
EnumSet instance and contains no elements
NullPointerException
- if c is nullpublic static <E extends Enum<E>> EnumSet<E> complementOf(EnumSet<E> s)
s
- the enum set from whose complement to initialize this enum set
NullPointerException
- if s is nullpublic static <E extends Enum<E>> EnumSet<E> of(E e)
e
- the element that this set is to contain initially
NullPointerException
- if e is nullpublic static <E extends Enum<E>> EnumSet<E> of(E e1, E e2)
e1
- an element that this set is to contain initiallye2
- another element that this set is to contain initially
NullPointerException
- if any parameters are nullpublic static <E extends Enum<E>> EnumSet<E> of(E e1, E e2, E e3)
e1
- 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 initially
NullPointerException
- if any parameters are nullpublic static <E extends Enum<E>> EnumSet<E> of(E e1, E e2, E e3, E e4)
e1
- 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 initially
NullPointerException
- if any parameters are nullpublic static <E extends Enum<E>> EnumSet<E> of(E e1, E e2, E e3, E e4, E e5)
e1
- 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 initially
NullPointerException
- if any parameters are nullpublic static <E extends Enum<E>> EnumSet<E> of(E first, E... rest)
first
- an element that the set is to contain initiallyrest
- the remaining elements the set is to contain initially
NullPointerException
- 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)
from
- the first element in the rangeto
- the last element in the range
NullPointerException
- if first or last are
null
IllegalArgumentException
- if first.compareTo(last) > 0public EnumSet<E> clone()
clone
in class Object
Cloneable
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Java™ Platform Standard Ed. 6 |
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