/**
 * 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.example;

import java.util.Iterator;


/**
 * Iterates over either only the regular attribute, only the special attributes, or over all all
 * attributes.
 * 
 * @author Ingo Mierswa
 */
public class AttributeIterator implements Iterator<Attribute> {

	private Iterator<AttributeRole> parent;

	private int type = Attributes.REGULAR;

	private Attribute current = null;

	private boolean hasNextInvoked = false;

	private AttributeRole currentRole = null;

	public AttributeIterator(Iterator<AttributeRole> parent, int type) {
		this.parent = parent;
		this.type = type;
	}

	@Override
	public boolean hasNext() {
		this.hasNextInvoked = true;
		if (!parent.hasNext() && currentRole == null) {
			current = null;
			return false;
		} else {
			AttributeRole role;
			if (currentRole == null) {
				role = parent.next();
			} else {
				role = currentRole;
			}
			switch (type) {
				case Attributes.REGULAR:
					if (!role.isSpecial()) {
						current = role.getAttribute();
						currentRole = role;
						return true;
					} else {
						return hasNext();
					}
				case Attributes.SPECIAL:
					if (role.isSpecial()) {
						current = role.getAttribute();
						currentRole = role;
						return true;
					} else {
						return hasNext();
					}
				case Attributes.ALL:
					current = role.getAttribute();
					currentRole = role;
					return true;
				default:
					current = null;
					return false;
			}
		}
	}

	@Override
	public Attribute next() {
		if (!this.hasNextInvoked) {
			hasNext();
		}
		this.hasNextInvoked = false;
		this.currentRole = null;
		return current;
	}

	@Override
	public void remove() {
		parent.remove();
		this.currentRole = null;
		this.hasNextInvoked = false;
	}
}