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java.util
abstract public class: EnumSet [javadoc | source]
java.lang.Object
   java.util.AbstractCollection<E>
      java.util.AbstractSet<E>
         java.util.EnumSet

All Implemented Interfaces:
    Cloneable, java$io$Serializable, Set, Collection

Direct Known Subclasses:
    JumboEnumSet, MiniEnumSet, HugeEnumSet, RegularEnumSet

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.

Field Summary
final  Class<E> elementType    The class of all the elements of this set. 
final  Enum[] universe    All of the values comprising T. (Cached for performance.) 
Constructor:
 EnumSet(Class<E> elementType,
    Enum[] universe) 
Method from java.util.EnumSet Summary:
addAll,   addRange,   allOf,   clone,   complement,   complementOf,   copyOf,   copyOf,   noneOf,   of,   of,   of,   of,   of,   of,   range,   typeCheck,   writeReplace
Methods from java.util.AbstractSet:
equals,   hashCode,   removeAll
Methods from java.util.AbstractCollection:
add,   addAll,   clear,   contains,   containsAll,   isEmpty,   iterator,   remove,   removeAll,   retainAll,   size,   toArray,   toArray,   toString
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from java.util.EnumSet Detail:
 abstract  void addAll()
    Adds all of the elements from the appropriate enum type to this enum set, which is empty prior to the call.
 abstract  void addRange(E from,
    E to)
    Adds the specified range to this enum set, which is empty prior to the call.
 public static EnumSet<E> allOf(Class<E> elementType) 
    Creates an enum set containing all of the elements in the specified element type.
 public EnumSet<E> clone() 
    Returns a copy of this set.
 abstract  void complement()
    Complements the contents of this enum set.
 public static EnumSet<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.
 public static EnumSet<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).
 public static EnumSet<E> copyOf(Collection<E> 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).
 public static EnumSet<E> noneOf(Class<E> elementType) 
    Creates an empty enum set with the specified element type.
 public static EnumSet<E> of(E 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.
 public static EnumSet<E> of(E e1,
    E 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.
 public static EnumSet<E> of(E first,
    E 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.
 public static EnumSet<E> of(E e1,
    E e2,
    E 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.
 public static EnumSet<E> of(E e1,
    E e2,
    E e3,
    E 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.
 public static EnumSet<E> of(E e1,
    E e2,
    E e3,
    E e4,
    E 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.
 public static EnumSet<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. The returned set will contain the endpoints themselves, which may be identical but must not be out of order.
 final  void typeCheck(E e) 
    Throws an exception if e is not of the correct type for this enum set.
 Object writeReplace()