5.10.1. Extending an Entity
In the application project, derive an entity class from com.haulmont.cuba.security.entity.User
and add the required attribute with the corresponding access methods:
@Entity(name = "sales$ExtUser")
@Extends(User.class)
public class ExtUser extends User {
@Column(name = "ADDRESS", length = 100)
private String address;
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
The new name of the entity should be specified in the @Entity annotation. Since the parent entity does not declare the inheritance strategy, it is assumed to be SINGLE_TABLE
by default. It means that the child entity will be stored in the same table as the parent one, and the @Table annotation is not required. Other parent entity annotations ( @NamePattern, @Listeners, etc.) are automatically applied to the child entity, but can be overridden in its class.
An important element of the new entity class is the @Extends
annotation, which takes the parent class as a parameter. It enables creating a registry of child entities and forces the platform mechanisms to use them everywhere instead of the parent ones. The registry is implemented by the ExtendedEntities
class, which is a Spring bean named cuba_ExtendedEntities
, and is also accessible via the Metadata interface.
Add a localized name of the new attribute to the com.sample.sales.entity
package:
messages.properties
ExtUser.address=Address
messages_ru.properties
ExtUser.address=Адрес
Register the new entity in the persistence.xml file of the project:
<class>com.sample.sales.entity.ExtUser</class>
Add the update script for the corresponding table to the database create and update scripts:
-- add column for "address" attribute
alter table SEC_USER add column ADDRESS varchar(100)
^
-- add discriminator column required for entity inheritance
alter table SEC_USER add column DTYPE varchar(100)
^
-- set discriminator value for existing records
update SEC_USER set DTYPE = 'sales$ExtUser' where DTYPE is null
^
In order to use new entity attributes in screens, create views for the new entity with the same names as the views of the base entity. A new view should extend the base view and define new attributes, for example:
<view class="com.sample.sales.entity.ExtUser"
name="user.browse"
extends="user.browse">
<property name="address"/>
</view>
An extended view is not required if the base one extends _local
and you add only local attributes, so in the described case this step can be omitted.