package org.hibernate.auction.model;import java.io.Serializable;import java.util.*;/** * The CaveatEmptor Category can have child categories and each has Items. * <p> * Categories can be nested, this is expressed as a bidirectional one-to-many * relationship that references parent and child categories. Each Category * can have many Items (and an Item can be in many categories). This is a * true many-to-many relationship. * <p> * The optional class <tt>CategorizedItem</tt> can be used if additional * information has to be kept about the link between a Category and an * Item. The collection of <tt>items</tt> will then be mapped as a * collection of dependent objects in the mapping for <tt>Category</tt>. * * @see Item * @see CategorizedItem * @author Christian Bauer <christian@hibernate.org> */public class Category implements Serializable, Comparable {	private Long id = null;	private int version;	private String name;	private Category parentCategory;	private Set childCategories = new HashSet();	private Set categorizedItems = new HashSet();	private Date created = new Date();	/**	 * No-arg constructor for JavaBean tools.	 */	public Category() {}	/**	 * Full constructor.	 */	public Category(String name, Category parentCategory, Set childCategories, Set categorizedItems) {		this.name = name;		this.parentCategory = parentCategory;		this.childCategories = childCategories;		this.categorizedItems = categorizedItems;	}	/**	 * Simple constructor.	 */	public Category(String name) {		this.name = name;	}	// ********************** Accessor Methods ********************** //	public Long getId() { return id; }    public void setId(Long id) { this.id = id; }	public String getName() { return name; }	public void setName(String name) { this.name = name; }	public Category getParentCategory() { return parentCategory; }	public void setParentCategory(Category parentCategory) { this.parentCategory = parentCategory; }	public Set getChildCategories() { return childCategories; }	public void addChildCategory(Category category) {		if (category == null)			throw new IllegalArgumentException("Can't add a null Category as child.");		// Remove from old parent category		if (category.getParentCategory() != null)			category.getParentCategory().getChildCategories()										 .remove(category);		// Set parent in child		category.setParentCategory(this);		// Set child in parent		this.getChildCategories().add(category);	}	public Set getCategorizedItems() { return categorizedItems; }	public void addCategorizedItem(CategorizedItem catItem) {		if (catItem == null)			throw new IllegalArgumentException("Can't add a null CategorizedItem.");		this.getCategorizedItems().add(catItem);	}	public Date getCreated() { return created; }	// ********************** Common Methods ********************** //	public boolean equals(Object o) {		if (this == o) return true;		if (!(o instanceof Category)) return false;		final Category category = (Category) o;		if (created != null ? !created.equals(category.created) : category.created != null) return false;		if (name != null ? !name.equals(category.name) : category.name != null) return false;		return true;	}	public int hashCode() {		int result;		result = (name != null ? name.hashCode() : 0);		result = 29 * result + (created != null ? created.hashCode() : 0);		return result;	}	public String toString() {		return  "Category ('" + getId() + "'), " +				"Name: '" + getName() + "'";	}	public int compareTo(Object o) {		if (o instanceof Category) {			return this.getName().compareTo( ((Category)o).getName() );		}		return 0;	}	// ********************** Business Methods ********************** //    public String getFullName() {        Category category = this;        String fullName = "";        while (category != null) {            fullName = category.getName() + ": " + fullName;            category = category.getParentCategory();        }        return fullName;    }    public int getDepth() {        Category category = getParentCategory();        int depth = 0;        while (category != null) {            depth++;            category = category.getParentCategory();        }        return depth;    }}