@Noncacheable

Use @Noncacheable to configure caching behavior for relationships. If used on a relationship, that relationship will not be cached, even though the parent Entity may be cached.

Annotation Elements

There are no elements for this annotation.

Usage

Each time EclipseLink retrieves the Entity, the relationship will be reloaded from the datasource. This may be useful for situations where caching of relationships is not desired or when using different EclipseLink cache types and having cached references extends the cache lifetime of related Entities using a different caching scheme. For instance Entity A references Entity B, Entity A is Full and Entity B is Weak. Without removing the caching of the relationsip the Entity B's cache effectively become Full.

Examples

Example 2-76 shows how to use @Noncacheable to create a protected cache.

@Entity
@Cache(
  isolation=CacheIsolationType.PROTECTED
)
public class Employee {
  @Id
  private long id;
  ...
  @OneToMany(mappedBy="manager")
  @Noncacheable
  private List<Employee> managedEmployees;
  ...
}

Example 2-77 shows using the <noncacheable> XML element in the eclipselink-orm.xml file.

<?xml version="1.0"?>
<entity-mappings
    xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/orm"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.eclipse.org/eclipselink/xsds/persistence/orm http://www.eclipse.org/eclipselink/xsds/eclipselink_orm_2_4.xsd"
    version="2.4">
    <entity name="Employee" class="org.acme.Employee" access="FIELD">
        <cache isolation="PROTECTED"/>
        <attributes>
            <id name= "id"/>
            <one-to-many name="managedEmployees" mapped-by="manager">
                <noncacheable/>
            </one-to-many>
        </attributes>
    </entity>
</entity-mappings

See Also

For more information, see:

• "Caching"
  http://wiki.eclipse.org/EclipseLink/UserGuide/JPA/Basic_JPA_Development/Caching

• "EclipseLink Caches" in Understanding EclipseLink

• "Scaling EclipseLink Applications in Clusters" in Solutions Guide for EclispeLink