/*
 *  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.Collection;
import java.util.HashMap;
import java.util.Map;

import com.rapidminer.operator.learner.associations.Item;
import com.rapidminer.tools.Tools;

/**
 * This is the basic data structure for {@link FPGrowth}.
 * 
 * @author Sebastian Land
 * @version $Id: FPTree.java,v 1.4 2008/05/09 19:23:19 ingomierswa Exp $
 */
public class FPTree extends FPTreeNode {

	private Map<Item, Header> headerTable;

	public FPTree() {
		super();
		headerTable = new HashMap<Item, Header>();
		children = new HashMap<Item, FPTreeNode>();
	}

	/**
	 * This method adds a set of Items to the tree. This set of items has to be sorted after the frequency of the contained items. This method should
	 * be used to add Items of a transaction or a treepath to the tree. The frequency of the set is represented of weight, which should be 1 if items
	 * are gathered from transaction
	 * 
	 * @param itemSet
	 *            the sorted set of items
	 * @param weight
	 *            the frequency of the set of items
	 */
	public void addItemSet(Collection<Item> itemSet, int weight) {
		super.addItemSet(itemSet, headerTable, weight);
	}

	public Map<Item, Header> getHeaderTable() {
		return headerTable;
	}

	public String toString(String abs, int recursionDepth) {
		StringBuffer buffer = new StringBuffer();
		buffer.append(abs);
		buffer.append("+ ROOT");
		buffer.append(Tools.getLineSeparator());
		for (FPTreeNode node : children.values()) {
			buffer.append(node.toString(abs + "  ", recursionDepth));
		}
		return buffer.toString();
	}

	public String printHeaderTable(int recursionDepth) {
		StringBuffer buffer = new StringBuffer();
		for (Item item : headerTable.keySet()) {
			buffer.append(item.toString());
			buffer.append(" : ");
			buffer.append(headerTable.get(item).getFrequencies().getFrequency(recursionDepth));
			buffer.append(Tools.getLineSeparator());
		}
		return buffer.toString();
	}
}