Configuring a JPA time-based data updater

You can configure a time-based database update using XML for a local or distributed eXtreme Scale configuration. You can also configure a local configuration programmatically.

About this task

For more information about how the Java™ Persistence API (JPA) time-based data updater works, see JPA time-based data updater.

Procedure

Create a timeBasedDBUpdate configuration.

With an XML file:

The following example shows an objectgrid.xml file that contains a timeBasedDBUpdate configuration:

JPA time-based updater - XML example
<?xml version="1.0" encoding="UTF-8"?>
<objectGridConfig xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://ibm.com/ws/objectgrid/config ../objectGrid.xsd"
 xmlns="http://ibm.com/ws/objectgrid/config">
    <objectGrids>
        <objectGrid name="changeOG" 
            entityMetadataXMLFile="userEMD.xml">
            <backingMap name="user" >
                <timeBasedDBUpdate timestampField="rowChgTs" 
                      persistenceUnitName="userderby" 
                      entityClass="com.test.UserClass"
                      mode="INVALIDATE_ONLY"
               />
            </backingMap>
        </objectGrid>
    </objectGrids>
    <backingMapPluginCollections>
</objectGridConfig>

In this example, the map "user" is configured with time-based database update. The database update mode is INVALIDATE_ONLY, and the timestamp field is rowChgTs.

When the distributed ObjectGrid "changeOG" is started in the container server, a time-based database update thread is automatically started in partition 0.

Programmatically:
If you create a local ObjectGrid, you can also create a TimeBasedDBUpdateConfig object and set it on the BackingMap instance:
```
public void setTimeBasedDBUpdateConfig(TimeBasedDBUpdateConfig dbUpdateConfig);
```
For more information about setting an object on the BackingMap instance, see BackingMap interface
Alternatively, you can annotate the timestamp field in the entity class using the com.ibm.websphere.objectgrid.jpa.dbupdate.annotation.Timestamp annotation. By configuring the value in the class, you do not have to configure the timestampField in the XML configuration.

What to do next

Start the JPA time-based data updater. See Starting the JPA time-based updater for more information.