oracle.toplink.descriptors
Class ChangedFieldsLockingPolicy

java.lang.Object
oracle.toplink.descriptors.FieldsLockingPolicy
oracle.toplink.descriptors.ChangedFieldsLockingPolicy

All Implemented Interfaces:

java.lang.Cloneable, oracle.toplink.internal.descriptors.OptimisticLockingPolicy, java.io.Serializable

public class ChangedFieldsLockingPolicy

extends FieldsLockingPolicy

Purpose: An implementation of the OptimisticLockingPolicy interface. This policy compares only the changed fields in the WHERE clause when doing an update. If any field has been changed, an optimistic locking exception will be thrown. A delete will only compare the primary key.

NOTE: This policy can only be used inside a unit of work.

Since:

TopLink 2.1

See Also:

Serialized Form

Constructor Summary

ChangedFieldsLockingPolicy()
PUBLIC: Create a new changed fields locking policy.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ChangedFieldsLockingPolicy

public ChangedFieldsLockingPolicy()

PUBLIC: Create a new changed fields locking policy. This locking policy is based on locking on all changed fields by comparing with their previous values to detect field-level collisions. Note: the unit of work must be used for all updates when using field locking. Without a unit of work, there is no way for TopLink to know what the original values were without the back up clone in the unit of work.