/*
* Copyright (C) 2003-2009 eXo Platform SAS.
*
* This 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 software 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.chromattic.common.collection;
import java.util.Set;
import java.util.Map;
import java.util.HashMap;
import java.util.AbstractSet;
import java.util.Iterator;
import java.util.HashSet;
/**
* @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
* @version $Revision$
*/
public class SetMap<K, V> {
/** . */
private final Map<K, SetImpl> map = new HashMap<K, SetImpl>();
public Set<V> peek(K key) {
if (key == null) {
throw new NullPointerException();
}
return map.get(key);
}
public Set<V> get(K key) {
if (key == null) {
throw new NullPointerException();
}
Set<V> set = map.get(key);
if (set == null) {
set = new SetImpl(key);
}
return set;
}
public Set<K> keySet() {
return map.keySet();
}
private class SetImpl extends AbstractSet<V> {
/** . */
private final K key;
/** . */
private HashSet<V> set;
/** . */
private boolean added;
private SetImpl(K key) {
this.key = key;
this.set = new HashSet<V>();
this.added = false;
}
@Override
public boolean add(V e) {
if (!added) {
if (map.containsKey(key)) {
throw new IllegalStateException();
} else {
map.put(key, this);
added = true;
}
}
return set.add(e);
}
public Iterator<V> iterator() {
return new Iterator<V>() {
final Iterator<V> iterator = set.iterator();
public boolean hasNext() {
return iterator.hasNext();
}
public V next() {
return iterator.next();
}
public void remove() {
iterator.remove();
if (set.size() == 0) {
if (map.containsKey(key)) {
map.remove(key);
} else {
throw new IllegalStateException();
}
}
}
};
}
public int size() {
return set.size();
}
}
@Override
public String toString() {
return map.toString();
}
}