JumboEnumSet.java revision 3758
/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package java.util;
/**
* Private implementation class for EnumSet, for "jumbo" enum types
* (i.e., those with more than 64 elements).
*
* @author Josh Bloch
* @since 1.5
* @serial exclude
*/
class JumboEnumSet<E extends Enum<E>> extends EnumSet<E> {
/**
* Bit vector representation of this set. The ith bit of the jth
* element of this array represents the presence of universe[64*j +i]
* in this set.
*/
private long elements[];
// Redundant - maintained for performance
private int size = 0;
JumboEnumSet(Class<E>elementType, Enum[] universe) {
super(elementType, universe);
elements = new long[(universe.length + 63) >>> 6];
}
void addRange(E from, E to) {
int fromIndex = from.ordinal() >>> 6;
int toIndex = to.ordinal() >>> 6;
if (fromIndex == toIndex) {
elements[fromIndex] = (-1L >>> (from.ordinal() - to.ordinal() - 1))
<< from.ordinal();
} else {
elements[fromIndex] = (-1L << from.ordinal());
for (int i = fromIndex + 1; i < toIndex; i++)
elements[i] = -1;
elements[toIndex] = -1L >>> (63 - to.ordinal());
}
size = to.ordinal() - from.ordinal() + 1;
}
void addAll() {
for (int i = 0; i < elements.length; i++)
elements[i] = -1;
elements[elements.length - 1] >>>= -universe.length;
size = universe.length;
}
void complement() {
for (int i = 0; i < elements.length; i++)
elements[i] = ~elements[i];
elements[elements.length - 1] &= (-1L >>> -universe.length);
size = universe.length - size;
}
/**
* Returns an iterator over the elements contained in this set. The
* iterator traverses the elements in their <i>natural order</i> (which is
* the order in which the enum constants are declared). The returned
* Iterator is a "weakly consistent" iterator that will never throw {@link
* ConcurrentModificationException}.
*
* @return an iterator over the elements contained in this set
*/
public Iterator<E> iterator() {
return new EnumSetIterator<>();
}
private class EnumSetIterator<E extends Enum<E>> implements Iterator<E> {
/**
* A bit vector representing the elements in the current "word"
* of the set not yet returned by this iterator.
*/
long unseen;
/**
* The index corresponding to unseen in the elements array.
*/
int unseenIndex = 0;
/**
* The bit representing the last element returned by this iterator
* but not removed, or zero if no such element exists.
*/
long lastReturned = 0;
/**
* The index corresponding to lastReturned in the elements array.
*/
int lastReturnedIndex = 0;
EnumSetIterator() {
unseen = elements[0];
}
public boolean hasNext() {
while (unseen == 0 && unseenIndex < elements.length - 1)
unseen = elements[++unseenIndex];
return unseen != 0;
}
public E next() {
if (!hasNext())
throw new NoSuchElementException();
lastReturned = unseen & -unseen;
lastReturnedIndex = unseenIndex;
unseen -= lastReturned;
return (E) universe[(lastReturnedIndex << 6)
+ Long.numberOfTrailingZeros(lastReturned)];
}
public void remove() {
if (lastReturned == 0)
throw new IllegalStateException();
final long oldElements = elements[lastReturnedIndex];
elements[lastReturnedIndex] &= ~lastReturned;
if (oldElements != elements[lastReturnedIndex]) {
size--;
}
lastReturned = 0;
}
}
/**
* Returns the number of elements in this set.
*
* @return the number of elements in this set
*/
public int size() {
return size;
}
/**
* Returns <tt>true</tt> if this set contains no elements.
*
* @return <tt>true</tt> if this set contains no elements
*/
public boolean isEmpty() {
return size == 0;
}
/**
* Returns <tt>true</tt> if this set contains the specified element.
*
* @param e element to be checked for containment in this collection
* @return <tt>true</tt> if this set contains the specified element
*/
public boolean contains(Object e) {
if (e == null)
return false;
Class eClass = e.getClass();
if (eClass != elementType && eClass.getSuperclass() != elementType)
return false;
int eOrdinal = ((Enum)e).ordinal();
return (elements[eOrdinal >>> 6] & (1L << eOrdinal)) != 0;
}
// Modification Operations
/**
* Adds the specified element to this set if it is not already present.
*
* @param e element to be added to this set
* @return <tt>true</tt> if the set changed as a result of the call
*
* @throws NullPointerException if <tt>e</tt> is null
*/
public boolean add(E e) {
typeCheck(e);
int eOrdinal = e.ordinal();
int eWordNum = eOrdinal >>> 6;
long oldElements = elements[eWordNum];
elements[eWordNum] |= (1L << eOrdinal);
boolean result = (elements[eWordNum] != oldElements);
if (result)
size++;
return result;
}
/**
* Removes the specified element from this set if it is present.
*
* @param e element to be removed from this set, if present
* @return <tt>true</tt> if the set contained the specified element
*/
public boolean remove(Object e) {
if (e == null)
return false;
Class eClass = e.getClass();
if (eClass != elementType && eClass.getSuperclass() != elementType)
return false;
int eOrdinal = ((Enum)e).ordinal();
int eWordNum = eOrdinal >>> 6;
long oldElements = elements[eWordNum];
elements[eWordNum] &= ~(1L << eOrdinal);
boolean result = (elements[eWordNum] != oldElements);
if (result)
size--;
return result;
}
// Bulk Operations
/**
* Returns <tt>true</tt> if this set contains all of the elements
* in the specified collection.
*
* @param c collection to be checked for containment in this set
* @return <tt>true</tt> if this set contains all of the elements
* in the specified collection
* @throws NullPointerException if the specified collection is null
*/
public boolean containsAll(Collection<?> c) {
if (!(c instanceof JumboEnumSet))
return super.containsAll(c);
JumboEnumSet es = (JumboEnumSet)c;
if (es.elementType != elementType)
return es.isEmpty();
for (int i = 0; i < elements.length; i++)
if ((es.elements[i] & ~elements[i]) != 0)
return false;
return true;
}
/**
* Adds all of the elements in the specified collection to this set.
*
* @param c collection whose elements are to be added to this set
* @return <tt>true</tt> if this set changed as a result of the call
* @throws NullPointerException if the specified collection or any of
* its elements are null
*/
public boolean addAll(Collection<? extends E> c) {
if (!(c instanceof JumboEnumSet))
return super.addAll(c);
JumboEnumSet es = (JumboEnumSet)c;
if (es.elementType != elementType) {
if (es.isEmpty())
return false;
else
throw new ClassCastException(
es.elementType + " != " + elementType);
}
for (int i = 0; i < elements.length; i++)
elements[i] |= es.elements[i];
return recalculateSize();
}
/**
* Removes from this set all of its elements that are contained in
* the specified collection.
*
* @param c elements to be removed from this set
* @return <tt>true</tt> if this set changed as a result of the call
* @throws NullPointerException if the specified collection is null
*/
public boolean removeAll(Collection<?> c) {
if (!(c instanceof JumboEnumSet))
return super.removeAll(c);
JumboEnumSet es = (JumboEnumSet)c;
if (es.elementType != elementType)
return false;
for (int i = 0; i < elements.length; i++)
elements[i] &= ~es.elements[i];
return recalculateSize();
}
/**
* Retains only the elements in this set that are contained in the
* specified collection.
*
* @param c elements to be retained in this set
* @return <tt>true</tt> if this set changed as a result of the call
* @throws NullPointerException if the specified collection is null
*/
public boolean retainAll(Collection<?> c) {
if (!(c instanceof JumboEnumSet))
return super.retainAll(c);
JumboEnumSet<?> es = (JumboEnumSet<?>)c;
if (es.elementType != elementType) {
boolean changed = (size != 0);
clear();
return changed;
}
for (int i = 0; i < elements.length; i++)
elements[i] &= es.elements[i];
return recalculateSize();
}
/**
* Removes all of the elements from this set.
*/
public void clear() {
Arrays.fill(elements, 0);
size = 0;
}
/**
* Compares the specified object with this set for equality. Returns
* <tt>true</tt> if the given object is also a set, the two sets have
* the same size, and every member of the given set is contained in
* this set.
*
* @param e object to be compared for equality with this set
* @return <tt>true</tt> if the specified object is equal to this set
*/
public boolean equals(Object o) {
if (!(o instanceof JumboEnumSet))
return super.equals(o);
JumboEnumSet es = (JumboEnumSet)o;
if (es.elementType != elementType)
return size == 0 && es.size == 0;
return Arrays.equals(es.elements, elements);
}
/**
* Recalculates the size of the set. Returns true if it's changed.
*/
private boolean recalculateSize() {
int oldSize = size;
size = 0;
for (long elt : elements)
size += Long.bitCount(elt);
return size != oldSize;
}
public EnumSet<E> clone() {
JumboEnumSet<E> result = (JumboEnumSet<E>) super.clone();
result.elements = result.elements.clone();
return result;
}
}