PortableObjects

Introduction

Portable domain object consists of:

• domain object declaration
• transfer object declaration
• declaration and definition of specific persistent engine implementation

Domain object declaration

• write interface
  • for domain entity extend from IMutableDomainObject
  • for basic type (e.g. embedded entity) you don't need to extend, probably only from Serializable
    • don't forget to extend from Serializable if you send your objects using any serialization mechanism (like GWT-RPC)
• use "Data" suffix
• declare only business related methods

public interface ParticipantData<K> extends IMutableDomainObject<K> {
...
    static final String CUSTOMER = "customer";
    static final String CREATED = "created";
    static final String ORIENTATION = "orientation";
...
    CustomerBaseData getCustomer();
    void setCustomer(CustomerBaseData customer);

    Date getCreated();
    void setCreated(Date created);

    String getOrientation();
    void setOrientation(String orientation);
...
}

Transfer object declaration

• write class extending from domain object declaration
• use "Dto" suffix
• implement fields, getters, setters and overall logic available/runnable on all persistent engines

public class ParticipantDto implements ParticipantData<Long> {
    ...
    private Long id;
    private CustomerBaseData customer;
    private Date created;
    private String orientation;
    ...
    // and getters and setters
}

JPA domain object

• don't forget to inherit all getters you want to be present as columns
• annotate ID getter with @Id
• association mapping:
  • specify targetEntity
  • (optional) narrow the return type of the getter to the target entity class
• embedded mapping:
  • annotate with @Embedded
  • narrow the return type of the getter to the target entity class, don't use domain object declaration type (interface)

@Entity
@SequenceGenerator(name = "seqParticipant", sequenceName = "SEQ_PARTICIPANT", initialValue = 1)
@Table(name = "ou_participant")
public class JpaParticipant extends ParticipantDto {
	private static final long serialVersionUID = 3621992042068349596L;

	@Id
	@GeneratedValue(generator = "seqParticipant")
	@Override
	public Long getId() {
		return super.getId();
	}

	@OneToOne(targetEntity = JpaCustomerBase.class)
	@Override
	public CustomerBaseData getCustomer() {
		return super.getCustomer();
	}
...
}

@Entity
public class JpaCustomerBase extends CustomerBaseDto<Integer> {
    ...
	@AttributeOverride(name = JpaCompanyName.COMPANY_NAME, column = @Column(unique = true, nullable = true))
	@Embedded
	public CompanyNameData getCompany() {
		return super.getCompany();
	}
    ...
}

Hibernate specific domain object

• don't forget to adjust targetEntity on all associations to point to Hibernate specific domain objects
• don't forget to narrow embedded getter return types to Hibernate specific domain objects

@Entity
public class HibernateCustomerBase extends CustomerBaseDto {
    ...
	@AttributeOverride(name = JpaCompanyName.COMPANY_NAME, column = @Column(unique = true, nullable = true))
	@Embedded
	@Override
	public CompanyNameData getCompany() {
		return super.getCompany();
	}
    ...
}

@Embeddable
public class Address extends AddressDto {
    ...
	@ManyToOne(targetEntity = HibernateCountry.class)
	public CountryData getCountry() {
		return super.getCountry();
	}
    ...
}

Identified problems

Current Content relation:

• has different return type for //menu item// in Content (String) and in ContentDTO (MenuItem)