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)
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;

    @NaturalId
    @Column(name = "TYPE_NAME", length = 70, nullable = false)
    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.name = null;
    }
    
    PortletTypeImpl(String name, String cpdUri) {
        this.internalId = -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 object) {
        if (object == this) {
            return true;
        }
        if (!(object instanceof IPortletType)) {
            return false;
        }
        IPortletType rhs = (IPortletType) object;
        return new EqualsBuilder()
            .append(this.name, rhs.getName())
            .isEquals();
    }

    @Override
    public int hashCode() {
        return new HashCodeBuilder(-1497407419, 1799845985)
            .append(this.name)
            .toHashCode();
    }

    @Override
    public String toString() {
        return new ToStringBuilder(this, ToStringStyle.SHORT_PREFIX_STYLE)
            .append("name", this.name)
            .append("cpdUri", this.cpdUri)
            .toString();
    }
}

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 BaseJpaDao implements IPortletTypeDao {
 private CriteriaQuery<PortletTypeImpl> findAllTypesQuery;
 private CriteriaQuery<PortletTypeImpl> findTypeByNameQuery;
 private ParameterExpression<String> nameParameter;
 private EntityManager entityManager;
 @PersistenceContext(unitName = "uPortalPersistence")
 public final void setEntityManager(EntityManager entityManager) {
 this.entityManager = entityManager;
 }
 
 @Override
 protected EntityManager getEntityManager() {
 return this.entityManager;
 }
 @Override
 public void afterPropertiesSet() throws Exception {
 this.nameParameter = this.createParameterExpression(String.class, "name");
 
 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;
 }
 });
 
 
 this.findTypeByNameQuery = this.createCriteriaQuery(new Function<CriteriaBuilder, CriteriaQuery<PortletTypeImpl>>() {
 @Override
 public CriteriaQuery<PortletTypeImpl> apply(CriteriaBuilder cb) {
 final CriteriaQuery<PortletTypeImpl> criteriaQuery = cb.createQuery(PortletTypeImpl.class);
 final Root<PortletTypeImpl> typeRoot = criteriaQuery.from(PortletTypeImpl.class);
 criteriaQuery.select(typeRoot);
 criteriaQuery.where(
 cb.equal(typeRoot.get(PortletTypeImpl_.name), nameParameter)
 );
 
 return criteriaQuery;
 }
 });
 }
 
 @Override
 @Transactional
 public void deletePortletType(IPortletType type) {
 Validate.notNull(type, "definition can not be null");
 
 final IPortletType persistentChanneltype;
 if (this.entityManager.contains(type)) {
 persistentChanneltype = type;
 }
 else {
 persistentChanneltype = this.entityManager.merge(type);
 }
 this.entityManager.remove(persistentChanneltype);
 }
 @Override
 @Transactional
 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.entityManager.persist(channelType);
 
 return channelType;
 }
 @Override
 public IPortletType getPortletType(int id) {
 return this.entityManager.find(PortletTypeImpl.class, id);
 }
 @Override
 public IPortletType getPortletType(String name) {
 final TypedQuery<PortletTypeImpl> query = this.createCachedQuery(this.findTypeByNameQuery);
 query.setParameter(this.nameParameter, name);
 
 final List<PortletTypeImpl> channelTypes = query.getResultList();
 return DataAccessUtils.uniqueResult(channelTypes);
 }
 @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
 @Transactional
 public IPortletType updatePortletType(IPortletType type) {
 Validate.notNull(type, "type can not be null");
 
 this.entityManager.persist(type);
 
 return type;
 }
}