package auction.model;import java.io.Serializable;import java.util.Date;/** * An immutable class representing a comment from users. * <p> * Comments are always made in the context of an auction, that * is, a comment has a reference to an Item. The comment has * a free text field and a rating (using a typesafe enumeration). * * @see Item * @see User * @see Rating * @author Christian Bauer */public class Comment implements Serializable, Comparable {    private Long id = null;    private int version = 0;	private Rating rating;	private String text;	private User fromUser;	private Item item;	private Date created = new Date();	/**	 * No-arg constructor for JavaBean tools	 */	public Comment() {}	/**	 * Full constructor	 *	 * @param rating	 * @param text	 * @param fromUser	 * @param item	 */	public Comment(Rating rating, String text, User fromUser, Item item) {		this.rating = rating;		this.text = text;		this.fromUser = fromUser;		this.item = item;	}	// ********************** Accessor Methods ********************** //	public Long getId() { return id; }    public int getVersion() { return version; }	public Rating getRating() { return rating; }	public String getText() { return text; }	public void setText(String text) { this.text = text; }	public User getFromUser() { return fromUser; }	public Item getItem() { return item; }	public Date getCreated() { return created; }	// ********************** Common Methods ********************** //	public boolean equals(Object o) {		if (this == o) return true;		if (!(o instanceof Comment)) return false;		final Comment comment = (Comment) o;        if (! (created.getTime() == comment.created.getTime()) ) return false;		if (!rating.equals(comment.rating)) return false;		if (text != null ? !text.equals(comment.text) : comment.text != null) return false;		return true;	}	public int hashCode() {		int result;		result = rating.hashCode();		result = 29 * result + (text != null ? text.hashCode() : 0);		result = 29 * result + created.hashCode();		return result;	}	public String toString() {		return "Comment ('" + getId() + "'), " +				"Rating: '" + getRating() + "'";	}	public int compareTo(Object o) {		if (o instanceof Comment) {            // Don't compare Date objects! Use the time in milliseconds!            return Long.valueOf(this.getCreated().getTime()).compareTo(                    Long.valueOf( ((Comment)o).getCreated().getTime())                   );		}		return 0;	}	// ********************** Business Methods ********************** //}