/**
 * Portions Copyright 2006 DFKI GmbH.
 * Portions Copyright 2001 Sun Microsystems, Inc.
 * Portions Copyright 1999-2001 Language Technologies Institute, 
 * Carnegie Mellon University.
 * All Rights Reserved.  Use is subject to license terms.
 * 
 * Permission is hereby granted, free of charge, to use and distribute
 * this software and its documentation without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of this work, and to
 * permit persons to whom this work is furnished to do so, subject to
 * the following conditions:
 * 
 * 1. The code must retain the above copyright notice, this list of
 *    conditions and the following disclaimer.
 * 2. Any modifications must be clearly marked as such.
 * 3. Original authors' names are not deleted.
 * 4. The authors' names are not used to endorse or promote products
 *    derived from this software without specific prior written
 *    permission.
 *
 * DFKI GMBH AND THE CONTRIBUTORS TO THIS WORK DISCLAIM ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL DFKI GMBH NOR THE
 * CONTRIBUTORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
 * THIS SOFTWARE.
 */
package marytts.unitselection.select.viterbi;

/**
 * Describes a Viterbi path.
 */
public class ViterbiPath implements Comparable<ViterbiPath> {
	final double score;
	final ViterbiCandidate candidate;
	final ViterbiPath previous;
	ViterbiPath next = null;

	public ViterbiPath(ViterbiCandidate candidate, ViterbiPath previousPath, double score) {
		this.candidate = candidate;
		this.previous = previousPath;
		this.score = score;
	}

	/**
	 * Get the score of this path
	 * 
	 * @return the score
	 */
	public double getScore() {
		return score;
	}

	/**
	 * Get the candidate of this path. Each path leads to exactly one candidate.
	 * 
	 * @return the candidate
	 */
	public ViterbiCandidate getCandidate() {
		return candidate;
	}

	/**
	 * Get the next path
	 * 
	 * @return the next path
	 */
	public ViterbiPath getNext() {
		return next;
	}

	/**
	 * Set the next path
	 * 
	 * @param next
	 *            the next path
	 */
	public void setNext(ViterbiPath next) {
		this.next = next;
	}

	/**
	 * Get the previous path
	 * 
	 * @return the previous path
	 */
	public ViterbiPath getPrevious() {
		return previous;
	}

	/**
	 * Converts this object to a string.
	 *
	 * @return the string form of this object
	 */
	public String toString() {
		return "ViterbiPath score " + score + " leads to candidate unit " + candidate.getUnit();
	}

	/**
	 * Compare two viterbi paths such that the one with the lower score is considered smaller.
	 */
	public int compareTo(ViterbiPath o) {
		return Double.compare(score, o.score);
	}
}