001/*
002 *                    BioJava development code
003 *
004 * This code may be freely distributed and modified under the
005 * terms of the GNU Lesser General Public Licence.  This should
006 * be distributed with the code.  If you do not have a copy,
007 * see:
008 *
009 *      http://www.gnu.org/copyleft/lesser.html
010 *
011 * Copyright for this code is held jointly by the individual
012 * authors.  These should be listed in @author doc comments.
013 *
014 * For more information on the BioJava project and its aims,
015 * or to join the biojava-l mailing list, visit the home page
016 * at:
017 *
018 *      http://www.biojava.org/
019 *
020 */
021
022
023package org.biojava.bio.dp;
024
025import java.io.Serializable;
026
027/**
028 * This is a small and ugly class for storing a transition. It is hash-code-able,
029 * and has a sensible equality operator.
030 *
031 * @author Matthew Pocock
032 */
033public class Transition implements Serializable {
034  public State from;
035  public State to;
036  
037  /**
038   * Two transitions are equal if they have the same from and to states.
039   */
040  public boolean equals(Object o)
041  throws ClassCastException {
042    Transition t = (Transition) o;
043    return from == t.from && to == t.to;
044  }
045  
046  /**
047   * The hash code is from.hashCode() ^ to.hashCode()
048   */
049  public int hashCode() {
050    return from.hashCode() ^ to.hashCode();
051  }
052  
053  public Transition(State from, State to) {
054    this.from = from;
055    this.to = to;
056  }
057}