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.
Also see:
- EnumMap
- author:
Josh
- Bloch
- since:
1.5
-
- serial:
exclude
-
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) {
this.elementType = elementType;
this.universe = 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.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) {
EnumSet< E > result = noneOf(elementType);
result.addAll();
return result;
}
Creates an enum set containing all of the elements in the specified
element type. |
public EnumSet<E> clone() {
try {
return (EnumSet< E >) super.clone();
} catch(CloneNotSupportedException e) {
throw new AssertionError(e);
}
}
Returns a copy of this set. |
abstract void complement()
Complements the contents of this enum set. |
public static EnumSet<E> complementOf(EnumSet<E> s) {
EnumSet< E > result = copyOf(s);
result.complement();
return result;
}
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) {
return s.clone();
}
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) {
if (c instanceof EnumSet) {
return ((EnumSet< E >)c).clone();
} else {
if (c.isEmpty())
throw new IllegalArgumentException("Collection is empty");
Iterator< E > i = c.iterator();
E first = i.next();
EnumSet< E > result = EnumSet.of(first);
while (i.hasNext())
result.add(i.next());
return result;
}
}
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) {
Enum[] universe = getUniverse(elementType);
if (universe == null)
throw new ClassCastException(elementType + " not an enum");
if (universe.length < = 64)
return new RegularEnumSet< >(elementType, universe);
else
return new JumboEnumSet< >(elementType, universe);
}
Creates an empty enum set with the specified element type. |
public static EnumSet<E> of(E e) {
EnumSet< E > result = noneOf(e.getDeclaringClass());
result.add(e);
return result;
}
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) {
EnumSet< E > result = noneOf(e1.getDeclaringClass());
result.add(e1);
result.add(e2);
return result;
}
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) {
EnumSet< E > result = noneOf(first.getDeclaringClass());
result.add(first);
for (E e : rest)
result.add(e);
return result;
}
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) {
EnumSet< E > result = noneOf(e1.getDeclaringClass());
result.add(e1);
result.add(e2);
result.add(e3);
return result;
}
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) {
EnumSet< E > result = noneOf(e1.getDeclaringClass());
result.add(e1);
result.add(e2);
result.add(e3);
result.add(e4);
return result;
}
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) {
EnumSet< E > result = noneOf(e1.getDeclaringClass());
result.add(e1);
result.add(e2);
result.add(e3);
result.add(e4);
result.add(e5);
return result;
}
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) {
if (from.compareTo(to) > 0)
throw new IllegalArgumentException(from + " > " + to);
EnumSet< E > result = noneOf(from.getDeclaringClass());
result.addRange(from, to);
return result;
}
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) {
Class eClass = e.getClass();
if (eClass != elementType && eClass.getSuperclass() != elementType)
throw new ClassCastException(eClass + " != " + elementType);
}
Throws an exception if e is not of the correct type for this enum set. |
Object writeReplace() {
return new SerializationProxy< >(this);
}
|