WebSphere Business Integration Adapters: An Adapter Development and WebSphere Business Integration Solution

278 WebSphere Business Integration Adapters

17.1 Extending the event store class

To define an event store, a connector developer must derive an event-store class

from the CWConnectorEventStore class and must implement some of its

methods for the event store.An

event store is an application’s mechanism for

persistently storing events. For our adapter, we created the RMEventStore class.

Figure 17-1 The class diagram for the RMEventStore

CWConnectorEventStore

CWConnectorAgent

«uses»

RMEventStore

(com.ibm.itso.RedHouse.RM.Adapter)

-connectionPool : com.ibm.itso.RedHouse.RM.Adapter.RMConnectionPool

+fetchEvents() : void

+recoverInProgressEvents() : void

+deleteEvent(String eventID) : void

+setEventStatus(String eventID, int status) : void

+archiveEvents() : void

Chapter 17. Implementing event notification 279

The CWConnectorEventStore class is a base class to provide a Java connector

with the ability to access an event store. The application stores event records in

the event store. The connector retrieves events from the event store and

processes them for transferal to the integration broker.

17.1.1 Implementing methods to in the CWConnectoreEventStore

Table 17-1 summarizes the methods in the CWConnectorEventStore class.

Table 17-1 Member methods of the CWConnectorEventStore class

Important: All Java connectors must extend this class to access the

application’s event store. To access the application’s event store through the

Java CWConnectorEventStore class, implement the following abstract

methods in their derived event-store class:

 deleteEvent()

 fetchEvents()

 setEventStatus()

Member method Description

CWConnectorEventStore() Creates an event-store object.

archiveEvent() Archives the event in the application’s archive

store with the appropriate status.

cleanupResources() Releases resources that the poll method has

used to access the event store.

deleteEvent() Deletes the event from the application’s event

store.

fetchEvents() Retrieves a specified number of Ready-for-Poll

events from the application’s event store.

getBO() Builds a business object based on the

information for an event from the event store.

getNextEvent() Retrieves the next event object from the

eventsToProcess vector.

recoverInProgressEvents() Recovers any in-progress events in the event

store.

resubmitArchivedEvents() Copies the archived event from the

application’s archive store to the event store

and changes the event status to

READY_FOR_POLL.

280 WebSphere Business Integration Adapters

All Java connectors must extend this class to access the event store. To access

the application’s event store through the Java CWConnectorEventStore class,

implement the following abstract methods in their derived event-store class:

 deleteEvent()

 fetchEvents()

 setEventStoreStatus()

To access an archive store, implement the archiveEvent() method.

To provide the ability to recover in-progress events, implement the

recoverInProgressEvents() method.

To provide the ability to resubmit archived events for subsequent polls of the

event store, implement the resubmitArchivedEvents() method.

Example 17-1 shows the skeleton for the RMEventStore class of our custom

adapter. See Figure 17-1 on page 278 for the class diagram.

Example 17-1 The extended RMEventStore class

public class RMEventStore extends CWConnectorEventStore {

public void fetchEvents() throws StatusChangeFailedException {

}

public void recoverInProgressEvents() throws StatusChangeFailedException {

}

public void deleteEvent(String eventID) throws DeleteFailedException {

}

public void setEventStatus(String eventID, int status)

throws InvalidStatusChangeException {

}

public void archiveEvents() throws StatusChangeFailedException {

}

}

setEventStatus() Sets the status of an event in the event store.

setEventsToProcess() Sets the eventsToProcess vector with

specified events.

setTerminate() Sets the internal terminate-connector flag to

true.

updateEventStatus() Updates the event status both in the event

store and in the event.

Note: In the RMAdapter, we do not provide the ability to resubmit archived

events. As a result, we do not implement the resubmitArchiveEvents()

method.

Member method Description