In support of the J2EE Connector Architecture specification 1.0., IBM provides WebSphere InterChange Server Access for J2EE. With this product, you instantiate a WebSphere Access Resource Adapter (often called just an Access Resource Adapter) within your application component. This resource adapter provides J2EE application components access to WebSphere Interchange Server (ICS). InterChange Server is the component of the WebSphere business integration system that provides the ability to maintain business processes that involve multiple EISs.
The WebSphere Access Resource Adapter brings the following benefits to application components in a J2EE application:
The following situations are possible usage scenarios for Server Access for J2EE:
In an E-commerce scenario, when a customer wants to check the status on an order placed, the J2EE module (such as an EJB) responsible to fetch this information can channel the request through a WebSphere Access Resource Adapter, as follows:
If the same J2EE module needs to access a different EIS application (one also managed by InterChange Server) to retrieve another value, the module sends a request to the same Access Resource Adapter to execute a different collaboration. This collaboration passes on the request to the appropriate connector, which in turn manages the retrieval from its EIS application. In this way, IBM WebSphere InterChange Server Access for J2EE provides an integrated view of all the ICS-managed EIS applications.
The J2EE Connector Architecture specification 1.0. does not support asynchronous event processing. However, you can use a combination of WebSphere business integration system components to facilitate asynchronous communication. For example, events that an EIS application originates can be used for delivering a combination of a collaboration and the WebSphere business integration system connector for JMS. The connector for JMS can deliver messages (events) to an application component as they arrive; the application component does not have to request messages in order to receive them.
Server Access for J2EE provides support for the following standards of the J2EE Connector Architecture specification 1.0.:
A WebSphere Access Resource Adapter enables an application component to access and use IBM WebSphere Business Integration Collaborations and other services. Collaborations represent business processes, which can involve multiple EISs. The WebSphere business integration solution initiates execution of a collaboration at the request of the Access Resource Adapter. The Access Resource Adapter sends data that represents the triggering event of a collaboration to the WebSphere business integration system solution, which in turn sends it to an ICS instance. Because these solutions are external to the WebSphere business integration system, their request for collaboration execution initiates a call-triggered flow. By requesting execution of collaborations, Access Resource Adapters can send and receive information in the ICS-managed EIS.
For an application component to communicate with a WebSphere Access Resource Adapter, Server Access for J2EE implements the CCI. To communicate with an ICS-managed EIS, an application component sends a request in the form of a CCI call to an Access Resource Adapter, which communicates with ICS to initiate the request. InterChange Server handles any communication with ICS-managed EISs through execution of the collaboration.
Figure 4 shows the WebSphere business integration system implementation of the J2EE connector architecture.
Figure 4. Access to an ICS-managed EIS through Server Access for J2EE
As Figure 4 shows, communication with an ICS-managed EIS involves an application component sending a request to an Access Resource Adapter. The Access Resource Adapter communicates with ICS to initiate the request. ICS handles any communication with ICS-managed EISs by controlling execution of the collaboration. To provide this communication, the IBM WebSphere Server Access for J2EE product includes the following components:
To provide communication between the application component and the Access Resource Adapter, the application component issues calls to the CCI.
To provide communication between the Access Resource Adapter and ICS, each of these components uses WebSphere InterChange Server Access.
For an application component to communicate with a WebSphere Access Resource Adapter, Server Access for J2EE implements the CCI. To communicate with an ICS-managed EIS, an application component sends a request in the form of a CCI call to an Access Resource Adapter, which communicates with ICS to initiate the request. InterChange Server handles any communication with ICS-managed EISs through execution of the collaboration.
Table 2 provides a summary of the tasks that an application
component can request from an
Access Resource Adapter.
Table 2. Server Access for J2EE implementation of CCI
Task of the application component | CCI Interface | For more information |
---|---|---|
Manage a connection to WebSphere InterChange Server | ConnectionFactoryConnectionConnectionSpec | "Managing the connection" |
Send information to an InterChange Server-managed EIS | InteractionInteractionSpec | "Sending data to an ICS-managed EIS" |
Represent data to send to and receive from the InterChange Server-managed EIS | Record MappedRecordIndexedRecordRecordFactory | "Using records" |
Acquire metadata | ConnectionMetaDataResourceAdapterMetaData | "Obtaining metadata" |
Handle exceptions | ResourceException | "Handling exceptions" |
All interfaces listed in the CCI Interface column in Table 2 are part of the following Java package:
javax.resource.cci
All Server Access for J2EE implementations of these CCI interfaces are part of the Java package:
com.crossworlds.j2eeconnector
To communicate with an ICS-managed EIS, a J2EE component sends a request to the WebSphere Access Resource Adapter, which communicates with ICS to initiate the request. ICS handles any communication with ICS-managed EISs by controlling execution of the collaboration. To provide communication between the Access Resource Adapter and ICS, IBM provides WebSphere InterChange Server Access.
InterChange Server Access Interface is the low-level Java interface that enables external process (called access clients) to request execution of a collaboration. An Access Resource Adapter is an external process to the WebSphere business integration system and therefore uses InterChange Server Access to communicate with an instance of ICS. The Server Access Interface methods use CORBA-IIOP as the underlying transport mechanism. By isolating the calls to the Server Access Interface within an Access Resource Adapter, the application component does not have to contain ICS-specific code.
Server Access for J2EE provides implementations of the CCI interfaces that use methods of the Server Access Interface. This interface enables the Access Resource Adapter to support the application-component tasks in Table 2.. Figure 5 shows the structure of the communication between an Access Resource Adapter and ICS.
Figure 5. Access to an ICS-managed EIS
In a managed environment, the application server communicates with resource
adapters to enable application components to obtain EIS information.
For an application server to communicate with a WebSphere Access Resource
Adapter, the resource adapter implements the system-level contracts that the
J2EE Connector Architecture specification 1.0. defines. Table 3 shows the system-level contracts that IBM WebSphere
InterChange Server Access for J2EE
provides.
Table 3. System-level contracts supported by Server Access for J2EE