/* This file is part of the db4o object database http://www.db4o.com
Copyright (C) 2004 - 2011 Versant Corporation http://www.versant.com
db4o is free software; you can redistribute it and/or modify it under
the terms of version 3 of the GNU General Public License as published
by the Free Software Foundation.
db4o 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 General Public License along
with this program. If not, see http://www.gnu.org/licenses/. */
package com.db4o.foundation;
public class NoDuplicatesQueue implements Queue4 {
private Queue4 _queue;
private Hashtable4 _seen;
public NoDuplicatesQueue(Queue4 queue) {
_queue = queue;
_seen = new Hashtable4();
}
public void add(Object obj) {
if(_seen.containsKey(obj)) {
return;
}
_queue.add(obj);
_seen.put(obj, obj);
}
public boolean hasNext() {
return _queue.hasNext();
}
public Iterator4 iterator() {
return _queue.iterator();
}
public Object next() {
return _queue.next();
}
public Object nextMatching(Predicate4 condition) {
return _queue.nextMatching(condition);
}
}