hibernate manyToMany, find object not linked

[saad bousf]

Hello,

I have two Hibernate entities with manyToMany Relation between them: Product and Category.

I want to find Product who are NOT linked with ANY Category, using DetachedCriteria.

these are my two object:

@Entity
@Table(name = Product.TABLE_NAME)
public class AbstractProduct{

    public static final String TABLE_NAME = "PRODUCT";

	@Id
	@AccessType("property")
	@GeneratedValue(generator = "system-uuid")
	@GenericGenerator(name = "system-uuid", strategy = "guid")
	@Column(name = "PRODUCT_ID")
	private String productId;

	@ManyToMany(fetch = FetchType.LAZY)
	@JoinTable(name = "PRODUCT_CATEGORY", joinColumns = @JoinColumn(name = "PRODUCT_ID"), inverseJoinColumns = @JoinColumn(name = "CATEGORY_ID"))
	private List<Category> categoryList;	

}
   

@Entity
@Table(name = Category.TABLE_NAME)
public class Category extends VersionnedEntity {

	protected static final String TABLE_NAME = "CATEGORY";

	@Id
	@AccessType("property")
	@GeneratedValue(generator = "system-uuid")
	@GenericGenerator(name = "system-uuid", strategy = "guid")
	@Column(name = "CATEGORY_ID")
	private String categoryId;

	@ManyToMany(mappedBy = "categoryList", fetch = FetchType.LAZY)
	private List<AbstractProduct> productsList;
}   

I tried the following without succes:

@Override
public List<Product> findProductWithoutCategory(
			ProductCatalog pProductCatalog) {

		DetachedCriteria vProductCriteria = DetachedCriteria
				.forClass(Product.class);

		vProductCriteria.createAlias("categoryList", "thealias");
		vProductCriteria.add(Restrictions.isNull("categoryList"));

		@SuppressWarnings("unchecked")
		List<Product> products = getHibernateTemplate().findByCriteria(
				vProductCriteria);
		return products;

}

Please, help!

[Jeanne Boyarsky]

I don't know that you can. A many-to-many relationship isn't going to match on links that don't exist. (An outer join would, but that's not what you have here). Which means what you want to know isn't in the many-to-many relationship cache in the first place.