/**
* Copyright (C) 2001-2017 by RapidMiner and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapidminer.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.ArrayList;
import java.util.List;
/**
* A frequency stack based on a list implementation.
*
* @author Sebastian Land
*/
public class ListFrequencyStack implements FrequencyStack {
private List<Integer> list;
public ListFrequencyStack() {
list = new ArrayList<Integer>();
}
@Override
public int getFrequency(int height) {
if (height >= list.size()) {
return 0;
} else {
return list.get(height);
}
}
@Override
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.remove(stackHeight);
list.add(newValue);
} else if (stackHeight == list.size()) {
list.add(value);
}
}
@Override
public void popFrequency(int height) {
if (height <= list.size() - 1) {
list.remove(height);
}
}
}