public abstract class java.util
EnumSet<E>


Hide details Login
Java SE 6
  
Extends: AbstractCollection > AbstractSet
Implements: Cloneable, Serializable

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 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.
version1.15, 07/10/06
since1.5
serialexclude
See also java.util.EnumMap


Methods
public static EnumSet<E> allOf(Class elementType)
Creates an enum set containing all of the elements in the specified element type.
elementTypethe class object of the element type for this enum set
ThrowsNullPointerException: if elementType is null
public EnumSet clone()
Returns a copy of this set.
returna copy of this set
public static EnumSet<E> complementOf(EnumSet 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.
sthe enum set from whose complement to initialize this enum set
ThrowsNullPointerException: if s is null
public static EnumSet<E> copyOf(EnumSet s)
Creates an enum set with the same element type as the specified enum set, initially containing the same elements (if any).
sthe enum set from which to initialize this enum set
ThrowsNullPointerException: if s is null
public static EnumSet<E> copyOf(Collection c)
Creates an enum set initialized from the specified collection. If the specified collection is an EnumSet instance, this static factory method behaves identically to #copyOf(EnumSet). Otherwise, the specified collection must contain at least one element (in order to determine the new enum set's element type).
cthe collection from which to initialize this enum set
ThrowsIllegalArgumentException: if c is not an EnumSet instance and contains no elements
ThrowsNullPointerException: if c is null
public static EnumSet<E> noneOf(Class elementType)
Creates an empty enum set with the specified element type.
elementTypethe class object of the element type for this enum set
ThrowsNullPointerException: if elementType is null
public static EnumSet<E> of(Enum e)
Creates an enum set initially containing the specified element. Overloadings of this method exist to initialize an enum set with one through five elements. A sixth overloading is provided that uses the varargs feature. This overloading may be used to create an enum set initially containing an arbitrary number of elements, but is likely to run slower than the overloadings that do not use varargs.
ethe element that this set is to contain initially
ThrowsNullPointerException: if e is null
returnan enum set initially containing the specified element
public static EnumSet<E> of(Enum e1, Enum e2)
Creates an enum set initially containing the specified elements. Overloadings of this method exist to initialize an enum set with one through five elements. A sixth overloading is provided that uses the varargs feature. This overloading may be used to create an enum set initially containing an arbitrary number of elements, but is likely to run slower than the overloadings that do not use varargs.
e1an element that this set is to contain initially
e2another element that this set is to contain initially
ThrowsNullPointerException: if any parameters are null
returnan enum set initially containing the specified elements
public static EnumSet<E> of(Enum e1, Enum e2, Enum e3)
Creates an enum set initially containing the specified elements. Overloadings of this method exist to initialize an enum set with one through five elements. A sixth overloading is provided that uses the varargs feature. This overloading may be used to create an enum set initially containing an arbitrary number of elements, but is likely to run slower than the overloadings that do not use varargs.
e1an element that this set is to contain initially
e2another element that this set is to contain initially
e3another element that this set is to contain initially
ThrowsNullPointerException: if any parameters are null
returnan enum set initially containing the specified elements
public static EnumSet<E> of(Enum e1, Enum e2, Enum e3, Enum e4)
Creates an enum set initially containing the specified elements. Overloadings of this method exist to initialize an enum set with one through five elements. A sixth overloading is provided that uses the varargs feature. This overloading may be used to create an enum set initially containing an arbitrary number of elements, but is likely to run slower than the overloadings that do not use varargs.
e1an element that this set is to contain initially
e2another element that this set is to contain initially
e3another element that this set is to contain initially
e4another element that this set is to contain initially
ThrowsNullPointerException: if any parameters are null
returnan enum set initially containing the specified elements
public static EnumSet<E> of(Enum e1, Enum e2, Enum e3, Enum e4, Enum e5)
Creates an enum set initially containing the specified elements. Overloadings of this method exist to initialize an enum set with one through five elements. A sixth overloading is provided that uses the varargs feature. This overloading may be used to create an enum set initially containing an arbitrary number of elements, but is likely to run slower than the overloadings that do not use varargs.
e1an element that this set is to contain initially
e2another element that this set is to contain initially
e3another element that this set is to contain initially
e4another element that this set is to contain initially
e5another element that this set is to contain initially
ThrowsNullPointerException: if any parameters are null
returnan enum set initially containing the specified elements
public static EnumSet<E> of(Enum first, Enum[] rest)
Creates an enum set initially containing the specified elements. This factory, whose parameter list uses the varargs feature, may be used to create an enum set initially containing an arbitrary number of elements, but it is likely to run slower than the overloadings that do not use varargs.
firstan element that the set is to contain initially
restthe remaining elements the set is to contain initially
ThrowsNullPointerException: if any of the specified elements are null, or if rest is null
returnan enum set initially containing the specified elements
public static EnumSet<E> range(Enum from, Enum to)
Creates an enum set initially containing all of the elements in the range defined by the two specified endpoints. The returned set will contain the endpoints themselves, which may be identical but must not be out of order.
fromthe first element in the range
tothe last element in the range
ThrowsNullPointerException: if first or last are null
ThrowsIllegalArgumentException: if first.compareTo(last) > 0
returnan enum set initially containing all of the elements in the range defined by the two specified endpoints
About DocWeb · Bundles · Export · Export AllTop 10 · Statistics · Login
About Sun · Contact · Privacy · Terms of Use · Trademarks
Java SE 6
· Copyright © 1994-2009 Sun Microsystems, Inc.
All rights reserved. Use is subject to license terms