Programming Tutorials

Tuplizers (org.hibernate.tuple.Tuplizer) in Hibernate

By: Dorris in Hibernate Tutorials on 2011-01-01  

org.hibernate.tuple.Tuplizer and its sub-interfaces are responsible for managing a particular representation of a piece of data given that representation's org.hibernate.EntityMode. If a given piece of data is thought of as a data structure, then a tuplizer is the thing that knows how to create such a data structure, how to extract values from such a data structure and how to inject values into such a data structure. For example, for the POJO entity mode, the corresponding tuplizer knows how create the POJO through its constructor. It also knows how to access the POJO properties using the defined property accessors.

There are two (high-level) types of Tuplizers:

• org.hibernate.tuple.entity.EntityTuplizer which is responsible for managing the above mentioned contracts in regards to entities
• org.hibernate.tuple.component.ComponentTuplizer which does the same for components

Users can also plug in their own tuplizers. Perhaps you require that java.util.Map implementation other than java.util.HashMap be used while in the dynamic-map entity-mode. Or perhaps you need to define a different proxy generation strategy than the one used by default. Both would be achieved by defining a custom tuplizer implementation. Tuplizer definitions are attached to the entity or component mapping they are meant to manage. Going back to the example of our Customer entity, Example “Specify custom tuplizers in annotations” shows how to specify a custom org.hibernate.tuple.entity.EntityTuplizer using annotations while Example, “Specify custom tuplizers in hbm.xml” shows how to do the same in hbm.xml

Specify custom tuplizers in annotations

@Entity
@Tuplizer(impl = DynamicEntityTuplizer.class)
public interface Cuisine {
    @Id
    @GeneratedValue
    public Long getId();
    public void setId(Long id);

    public String getName();
    public void setName(String name);

    @Tuplizer(impl = DynamicComponentTuplizer.class)
    public Country getCountry();
    public void setCountry(Country country);
}

Specify custom tuplizers in hbm.xml

<hibernate-mapping>
<class entity-name="Customer">
<!--
Override the dynamic-map entity-mode
tuplizer for the customer entity
-->
<tuplizer entity-mode="dynamic-map"
class="CustomMapTuplizerImpl"/>
<id name="id" type="long" column="ID">
<generator class="sequence"/>
</id>
<!-- other properties -->
 ...
</class>
</hibernate-mapping>