/*
* RapidMiner
*
* Copyright (C) 2001-2008 by Rapid-I and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapid-i.com
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.tools.math.container;
import java.util.Comparator;
import java.util.PriorityQueue;
/**
* This class implements a bounded priority queue which contains always the n-th smalles values.
* If a new values is added, its only added if smaller than the greatest value already in queue.
* The greatest value is then removed. The iterator does not iterate in any particular order.
* This queue will implement a reverse order in compare with the java PriorityQueue, so
* peek and poll will retrieve the greatest elements
*
* @author Sebastian Land
* @version $Id: BoundedPriorityQueue.java,v 1.3 2008/07/13 20:38:24 ingomierswa Exp $
*
* @param <E>
*/
public class BoundedPriorityQueue<E> extends PriorityQueue<E> {
private static final long serialVersionUID = 6020635755912950637L;
private int bound;
private Comparator<E> comparator;
public BoundedPriorityQueue(int bound) {
super(bound, new ReverseComparableComparator<E>());
this.comparator = new ReverseComparableComparator<E>();
this.bound = bound;
}
public BoundedPriorityQueue(int bound, Comparator<? super E> comp) {
super(bound, new ReverseComparator<E>(comp));
this.bound = bound;
this.comparator = new ReverseComparator<E>(comp);
}
public boolean offer(E e) {
if (size() == bound) {
E head = peek();
// test with Reverse(!) comparator if e is smaller: Test if greater
if (comparator.compare(e, head) > 0) {
// if smaller: remove biggest and add e
poll();
return super.offer(e);
}
} else {
return super.offer(e);
}
return false;
}
public boolean add(E e) {
return offer(e);
}
public boolean isFilled() {
return (size() == bound);
}
}