Understanding the Descriptor API

The descriptor API can be used to define, or amend TopLink descriptors through Java code. The descriptor API classes are mainly in the oracle.toplink.descriptors package. These include the following classes:

• ClassDescriptor (abstract generic descriptor API)

• RelationalDescriptor (relational project-specific API)

• DescriptorEventManager (event API)

• DescriptorQueryManager (query API)

• InheritancePolicy

• InterfacePolicy

• ReturningPolicy

• Locking policies (various optimistic locking policies)

For object-relational, EIS, and XML projects, descriptor classes are in the oracle.toplink.objectrelational, oracle.toplink.eis, and oracle.toplink.ox packages, respectively.

This section describes the important descriptor classes in the Oracle TopLink Foundation Library, including:

• Descriptor Inheritance Hierarchy

Descriptor Inheritance Hierarchy

Example 26-5 illustrates the descriptor types that derive from class oracle.toplink.descriptors.ClassDescriptor.

Example 26-5 Descriptor Inheritance Hierarchy

class oracle.toplink.descriptors.ClassDescriptor
    class oracle.toplink.descriptors.RelationalDescriptor
        class oracle.toplink.objectrelational.ObjectRelationalDescriptor
    class oracle.toplink.eis.EISDescriptor
    class oracle.toplink.ox.XMLDescriptor