/*
* 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.operator.learner.associations.fpgrowth;
import java.util.LinkedList;
/**
* A frequency stack based on a list implementation.
*
* @author Sebastian Land
* @version $Id: ListFrequencyStack.java,v 1.3 2008/05/09 19:23:19 ingomierswa Exp $
*/
public class ListFrequencyStack implements FrequencyStack {
private LinkedList<Integer> list;
public ListFrequencyStack() {
list = new LinkedList<Integer>();
}
public int getFrequency(int height) {
if (height >= list.size()) {
return 0;
} else if (height == list.size() - 1) {
return list.getLast();
} else {
return list.get(height);
}
}
public void increaseFrequency(int stackHeight, int value) {
if (stackHeight == list.size() - 1) {
// int newValue = value + list.pollLast(); // IM: pollLast only
// available in JDK 6
int newValue = value + list.removeLast();
list.addLast(newValue);
} else if (stackHeight == list.size()) {
list.addLast(value);
}
}
public void popFrequency(int height) {
if (height == list.size() - 1) {
// list.pollLast(); // IM: pollLast only available in JDK 6
list.removeLast();
} else if (height < list.size() - 1) {
list.remove(height);
}
}
}