JPA DAO Guidelines

public interface IPortletType {
    /**
     * Get the unique ID of this channel type.
     * 
     * @return unique id
     */
    public int getId();

    /**
     * Get the name of this channel type
     * 
     * @return channel type name
     */
    public String getName();

    /**
     * Get a description of this channel type
     * 
     * @return channel type description
     */
    public String getDescription();

    /**
     * Get the URI of the ChannelPublishingDocument associated with this
     * channel type.  This CPD will be used to determine configuration options 
     * for channels of this type.
     * 
     * @return ChannelPublishingDocument URI
     */
    public String getCpdUri();

    
    // Setter methods
    
    /**
     * Set the description for this channel type
     * 
     * @param description
     */
    public void setDescription(String descr);

    /**
     * Set the URI of the ChannelPublishingDocument associated with this channel
     * type.  This CPD will be used to determine configuration options for 
     * channels of this type.
     * 
     * @param ChannelPublishingDocument URI
     */
    public void setCpdUri(String cpdUri);
}

@Entity
@Table(name = "UP_PORTLET_TYPE")
@SequenceGenerator(
        name="UP_PORTLET_TYPE_GEN",
        sequenceName="UP_PORTLET_TYPE_SEQ",
        allocationSize=1
    )
@TableGenerator(
        name="UP_PORTLET_TYPE_GEN",
        pkColumnValue="UP_PORTLET_TYPE",
        allocationSize=1
    )
@NaturalIdCache
@Cacheable
@Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
public class PortletTypeImpl implements Serializable, IPortletType {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(generator = "UP_PORTLET_TYPE_GEN")
    @Column(name = "TYPE_ID")
    private final int internalId;
    
    @Version
    @Column(name = "ENTITY_VERSION")
    private final long entityVersion;
    
    //Hidden reference to the child portlet definitions, used to allow cascading deletes where when a portlet type is deleted all associated definitions are also deleted
    //MUST BE LAZY FETCH, this set should never actually be populated at runtime or performance will be TERRIBLE
    @OneToMany(mappedBy = "portletType", targetEntity = PortletDefinitionImpl.class, cascade = { CascadeType.ALL }, fetch = FetchType.LAZY, orphanRemoval = true)
    private transient Set<IPortletDefinition> portletDefinitions = null;

    @NaturalId
    @Column(name = "TYPE_NAME", length = 70)
    private final String name;
    @Column(name = "TYPE_DESCR", length = 2000)
    private String descr;
    @Column(name = "TYPE_DEF_URI", length = 255, nullable = false)
    private String cpdUri;
    
    /**
     * Default constructor used by hibernate
     */
    @SuppressWarnings("unused")
    private PortletTypeImpl() {
        this.internalId = -1;
        this.entityVersion = -1;
        this.name = null;
    }
    
    public PortletTypeImpl(String name, String cpdUri) {
        this.internalId = -1;
        this.entityVersion = -1;
        this.name = name;
        this.cpdUri = cpdUri;
    }

    @Override
    public int getId() {
        return this.internalId;
    }
    @Override
    public String getName() {
        return name;
    }
    @Override
    public String getDescription() {
        return descr;
    }
    @Override
    public String getCpdUri() {
        return cpdUri;
    }
    @Override
    public void setDescription(String descr) {
        this.descr = descr;
    }
    @Override
    public void setCpdUri(String cpdUri) {
        this.cpdUri = cpdUri;
    }
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (!(obj instanceof IPortletType))
            return false;
        IPortletType other = (IPortletType) obj;
        if (this.name == null) {
            if (other.getName() != null)
                return false;
        }
        else if (!this.name.equals(other.getName()))
            return false;
        return true;
    }
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((this.name == null) ? 0 : this.name.hashCode());
        return result;
    }
    @Override
    public String toString() {
        return "PortletTypeImpl [internalId=" + this.internalId + ", name=" + this.name + ", descr=" + this.descr
                + ", cpdUri=" + this.cpdUri + "]";
    }

    @Override
    public String getDataId() {
        return Integer.toString(getId());
    }

    @Override
    public String getDataTitle() {
        return name;
    }

    @Override
    public String getDataDescription() {
        return descr;
    }
}

public interface IPortletTypeDao {
    /**
     * Creates, initializes and persists a new {@link IPortletType} based on the specified parameters
     * 
     * @param name The name of the channel type
     * @param cpdUri The URI to the CPD file used when publishing channels of this type
     * 
     * @return A newly created, initialized and persisted {@link IPortletType}
     * @throws org.springframework.dao.DataIntegrityViolationException If a IChannelType already exists for the provide arguments
     * @throws IllegalArgumentException If any of the parameters are null
     */
    public IPortletType createPortletType(String name, String cpdUri);
    
    /**
     * Persists changes to a {@link IPortletType}.
     * 
     * @param type The channel type to store the changes for
     * @throws IllegalArgumentException if type is null.
     */
    public IPortletType updatePortletType(IPortletType type);
    
    /**
     * Removes the specified {@link IPortletType} from the persistent store.
     * 
     * @param type The type to remove.
     * @throws IllegalArgumentException if type is null.
     */
    public void deletePortletType(IPortletType type);
    
    /**
     * Get a {@link IPortletType} for the specified id.
     * 
     * @param id The id to get the type for.
     * @return The channel type for the id, null if no type exists for the id.
     */
    public IPortletType getPortletType(int id);
    
    /**
     * Get a {@link IPortletType} for the specified name
     * 
     * @param name The name to get the type for.
     * @return The channel type for the name, null if no type exists for the fname.
     * @throws IllegalArgumentException if name is null.
     */
    public IPortletType getPortletType(String name);
    
    /**
     * @return A {@link List} of all persisted {@link IPortletType}s
     */
    public List<IPortletType> getPortletTypes();

}

@Repository
public class JpaPortletTypeDao extends BasePortalJpaDao implements IPortletTypeDao {
    private CriteriaQuery<PortletTypeImpl> findAllTypesQuery;
    @Override
    public void afterPropertiesSet() throws Exception {
        this.findAllTypesQuery = this.createCriteriaQuery(new Function<CriteriaBuilder, CriteriaQuery<PortletTypeImpl>>() {
            @Override
            public CriteriaQuery<PortletTypeImpl> apply(CriteriaBuilder cb) {
                final CriteriaQuery<PortletTypeImpl> criteriaQuery = cb.createQuery(PortletTypeImpl.class);
                criteriaQuery.from(PortletTypeImpl.class);
                return criteriaQuery;
            }
        });
    }
    
    
    @Override
    @PortalTransactional
    public void deletePortletType(IPortletType type) {
        Validate.notNull(type, "definition can not be null");
        
        final IPortletType persistentChanneltype;
        final EntityManager entityManager = this.getEntityManager();
        if (entityManager.contains(type)) {
            persistentChanneltype = type;
        }
        else {
            persistentChanneltype = entityManager.merge(type);
        }
        entityManager.remove(persistentChanneltype);
    }
    @Override
    @PortalTransactional
    public IPortletType createPortletType(String name, String cpdUri) {
        Validate.notEmpty(name, "name can not be null");
        Validate.notEmpty(cpdUri, "cpdUri can not be null");
        
        final PortletTypeImpl channelType = new PortletTypeImpl(name, cpdUri);
        
        this.getEntityManager().persist(channelType);
        
        return channelType;
    }
    @Override
    public IPortletType getPortletType(int id) {
        return this.getEntityManager().find(PortletTypeImpl.class, id);
    }
    @OpenEntityManager(unitName = PERSISTENCE_UNIT_NAME)
    @Override
    public IPortletType getPortletType(String name) {
        final NaturalIdQuery<PortletTypeImpl> query = this.createNaturalIdQuery(PortletTypeImpl.class);
        query.using(PortletTypeImpl_.name, name);
        return query.load();
    }
    @Override
    public List<IPortletType> getPortletTypes() {
        final TypedQuery<PortletTypeImpl> query = this.createCachedQuery(this.findAllTypesQuery);
        final List<PortletTypeImpl> portletTypes = query.getResultList();
        return new ArrayList<IPortletType>(portletTypes);
    }
    @Override
    @PortalTransactional
    public IPortletType updatePortletType(IPortletType type) {
        Validate.notNull(type, "type can not be null");
        
        this.getEntityManager().persist(type);
        
        return type;
    }
}