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The Trove library provides high speed regular and primitive
collections for Java.
///////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2001, Eric D. Friedman All Rights Reserved.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library 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 for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
///////////////////////////////////////////////////////////////////////////////
package gnu.trove;
import java.io.*;
import java.util.Collection;
import java.util.Iterator;
import java.util.Set;
import java.util.Arrays;
import java.lang.reflect.Array;
/**
* An implementation of the Set interface that uses an
* open-addressed hash table to store its contents.
*
* Created: Sat Nov 3 10:38:17 2001
*
* @author Eric D. Friedman
* @version $Id: THashSet.java,v 1.17 2007/11/01 16:08:14 robeden Exp $
*/
public class THashSet extends TObjectHash
implements Set, Iterable, Externalizable {
static final long serialVersionUID = 1L;
/**
* Creates a new THashSet instance with the default
* capacity and load factor.
*/
public THashSet() {
super();
}
/**
* Creates a new THashSet instance with the default
* capacity and load factor.
*
* @param strategy used to compute hash codes and to compare objects.
*/
public THashSet(TObjectHashingStrategy strategy) {
super(strategy);
}
/**
* Creates a new THashSet instance with a prime
* capacity equal to or greater than initialCapacity and
* with the default load factor.
*
* @param initialCapacity an int value
*/
public THashSet(int initialCapacity) {
super(initialCapacity);
}
/**
* Creates a new THashSet instance with a prime
* capacity equal to or greater than initialCapacity and
* with the default load factor.
*
* @param initialCapacity an int value
* @param strategy used to compute hash codes and to compare objects.
*/
public THashSet(int initialCapacity, TObjectHashingStrategy strategy) {
super(initialCapacity, strategy);
}
/**
* Creates a new THashSet instance with a prime
* capacity equal to or greater than initialCapacity and
* with the specified load factor.
*
* @param initialCapacity an int value
* @param loadFactor a float value
*/
public THashSet(int initialCapacity, float loadFactor) {
super(initialCapacity, loadFactor);
}
/**
* Creates a new THashSet instance with a prime
* capacity equal to or greater than initialCapacity and
* with the specified load factor.
*
* @param initialCapacity an int value
* @param loadFactor a float value
* @param strategy used to compute hash codes and to compare objects.
*/
public THashSet(int initialCapacity, float loadFactor, TObjectHashingStrategy strategy) {
super(initialCapacity, loadFactor, strategy);
}
/**
* Creates a new THashSet instance containing the
* elements of collection.
*
* @param collection a Collection value
*/
public THashSet(Collection collection) {
this(collection.size());
addAll(collection);
}
/**
* Creates a new THashSet instance containing the
* elements of collection.
*
* @param collection a Collection value
* @param strategy used to compute hash codes and to compare objects.
*/
public THashSet(Collection collection, TObjectHashingStrategy strategy) {
this(collection.size(), strategy);
addAll(collection);
}
/**
* Inserts a value into the set.
*
* @param obj an Object value
* @return true if the set was modified by the add operation
*/
public boolean add(E obj) {
int index = insertionIndex(obj);
if (index < 0) {
return false; // already present in set, nothing to add
}
Object old = _set[index];
_set[index] = obj;
postInsertHook(old == FREE);
return true; // yes, we added something
}
public boolean equals(Object other) {
if (! (other instanceof Set)) {
return false;
}
Set that = (Set)other;
if (that.size() != this.size()) {
return false;
}
return containsAll(that);
}
public int hashCode() {
HashProcedure p = new HashProcedure();
forEach(p);
return p.getHashCode();
}
private final class HashProcedure implements TObjectProcedure {
private int h = 0;
public int getHashCode() {
return h;
}
public final boolean execute(E key) {
h += _hashingStrategy.computeHashCode(key);
return true;
}
}
/**
* Expands the set to accommodate new values.
*
* @param newCapacity an int value
*/
protected void rehash(int newCapacity) {
int oldCapacity = _set.length;
Object oldSet[] = _set;
_set = new Object[newCapacity];
Arrays.fill(_set, FREE);
for (int i = oldCapacity; i-- > 0;) {
if(oldSet[i] != FREE && oldSet[i] != REMOVED) {
E o = (E) oldSet[i];
int index = insertionIndex(o);
if (index < 0) { // everyone pays for this because some people can't RTFM
throwObjectContractViolation(_set[(-index -1)], o);
}
_set[index] = o;
}
}
}
/**
* Returns a new array containing the objects in the set.
*
* @return an Object[] value
*/
public Object[] toArray() {
Object[] result = new Object[size()];
forEach(new ToObjectArrayProcedure(result));
return result;
}
/**
* Returns a typed array of the objects in the set.
*
* @param a an Object[] value
* @return an Object[] value
*/
public T[] toArray(T[] a) {
int size = size();
if (a.length < size)
a = (T[]) Array.newInstance(a.getClass().getComponentType(), size);
forEach(new ToObjectArrayProcedure(a));
// If this collection fits in the specified array with room to
// spare (i.e., the array has more elements than this
// collection), the element in the array immediately following
// the end of the collection is set to null. This is useful in
// determining the length of this collection only if the
// caller knows that this collection does not contain any null
// elements.)
if (a.length > size) {
a[size] = null;
}
return a;
}
/**
* Empties the set.
*/
public void clear() {
super.clear();
Object[] set = _set;
for (int i = set.length; i-- > 0;) {
set[i] = FREE;
}
}
/**
* Removes obj from the set.
*
* @param obj an Object value
* @return true if the set was modified by the remove operation.
*/
public boolean remove(Object obj) {
int index = index((E) obj);
if (index >= 0) {
removeAt(index);
return true;
}
return false;
}
/**
* Creates an iterator over the values of the set. The iterator
* supports element deletion.
*
* @return an Iterator value
*/
public Iterator iterator() {
return new TObjectHashIterator(this);
}
/**
* Tests the set to determine if all of the elements in
* collection are present.
*
* @param collection a Collection value
* @return true if all elements were present in the set.
*/
public boolean containsAll(Collection collection) {
for (Iterator i = collection.iterator(); i.hasNext();) {
if (! contains(i.next())) {
return false;
}
}
return true;
}
/**
* Adds all of the elements in collection to the set.
*
* @param collection a Collection value
* @return true if the set was modified by the add all operation.
*/
public boolean addAll(Collection collection) {
boolean changed = false;
int size = collection.size();
ensureCapacity(size);
Iterator it = collection.iterator();
while (size-- > 0) {
if (add(it.next())) {
changed = true;
}
}
return changed;
}
/**
* Removes all of the elements in collection from the set.
*
* @param collection a Collection value
* @return true if the set was modified by the remove all operation.
*/
public boolean removeAll(Collection collection) {
boolean changed = false;
int size = collection.size();
Iterator it;
it = collection.iterator();
while (size-- > 0) {
if (remove(it.next())) {
changed = true;
}
}
return changed;
}
/**
* Removes any values in the set which are not contained in
* collection.
*
* @param collection a Collection value
* @return true if the set was modified by the retain all operation
*/
public boolean retainAll(Collection collection) {
boolean changed = false;
int size = size();
Iterator it;
it = iterator();
while (size-- > 0) {
if (! collection.contains(it.next())) {
it.remove();
changed = true;
}
}
return changed;
}
public void writeExternal( ObjectOutput out ) throws IOException {
// VERSION
out.writeByte( 0 );
// NUMBER OF ENTRIES
out.writeInt( _size );
// ENTRIES
SerializationProcedure writeProcedure = new SerializationProcedure( out );
if (! forEach(writeProcedure)) {
throw writeProcedure.exception;
}
}
public void readExternal( ObjectInput in )
throws IOException, ClassNotFoundException {
// VERSION
in.readByte();
// NUMBER OF ENTRIES
int size = in.readInt();
setUp( size );
// ENTRIES
while (size-- > 0) {
E val = (E) in.readObject();
add(val);
}
}
} // THashSet