Chapter 2. Architecture 15
This level of integration is typically where the application layer integrates directly
with a back-end system. An application in this context could be a Swing-based
J2SE application running on a desktop or a Web-based application running in a
Web application server. It can be argued that the application is using a
component. For example, it could use a managed or non-managed J2C
connector component. In this case, why then does the level 1 line in Figure 2-1
on page 13 not connect to the component layer? With a level 1 integration style,
the component (be it a CCF or J2C component) is part of the application, either
explicitly or implicitly. An application could use a component for its back-end
integration requirements, but that component is part of the application.
Table 2-2 lists the benefits and drawbacks of EIS integration at level 1.
Table 2-2 Benefits and drawbacks of EIS integration at level 1
Level 2, application to J2C component and service
This level of back-end integration is where an application starts to use a J2C
component that has been exposed as a service that is using Web services
technology. An example of such a level of integration is where you expose your
back-end transactions as services, using J2C connectors. (See Chapter 3:
Building CICS ECI enterprise services in the IBM Redbook Exploring
WebSphere Studio Application Developer Integration Edition V5, SG24-6200 for
detailed step-by-step instructions on how to create a service from a J2C
connector.)
Benefits Drawbacks
The development team can extend or
re-factor the implementation requirements
(for example, by compressing records
over the WAN).
Implementation is open to everyone in the
team.
There is direct control over security
aspects.
There are few incentives to formalize
interfaces.
Component reuse across channels is
implemented by copy and paste.
Reuse of enterprise business processes
across channels is difficult to achieve.
There is a strong possibility that different
channels are implemented to different
back-end integration frameworks.
16 Managing Information Access to an EIS Using J2EE and Services Oriented Architecture
Any application can invoke the J2C service using its generated proxies and
stubs. With a back-end integration at level 2, the focus is on exposing EIS
integration components as services, using Web services technology in a
service-based architecture. With a level 2 EIS integration, the EIS component
and service is not part of the application or business process.
Table 2-3 lists the benefits and drawbacks of EIS integration at level 2.
Table 2-3 Benefits and drawbacks of EIS at integration level 2
Level 3, application to EIS system process
The next level of back-end integration is where an application invokes a business
process, or rather a system process, to handle its back-end integration.
Figure 2-2 on page 17 illustrates a more detailed view of this level of EIS
integration.
Benefits Drawbacks
There is a separation of provider and
consumer.
Services that are remote to consumers
can impact service level agreements.
The implementation is hidden from the
consumer.
There is versioning and testing across
multiple channels.
Interfaces must be formalized. Services that are a direct reflection of an
existing interface may not be sufficiently
abstracted away from the implementation
to provide any real notion of loose
coupling.
You can reuse services across channels,
not components by copy and paste.
It can require a high level of understanding
of the implementation for service
consumer to correctly use the service.
It enables loose coupling, at least in a
platform dependency sense.
The granularity of the existing interface
may not match the new requirements.
Taxonomy and semantic issues must be
resolved.
Chapter 2. Architecture 17
Figure 2-2 EIS integration level 3
The architecture discussion for the following paragraphs is focussed level 3 of
EIS integration.
The key difference between level 3 and the previously discussed levels is that
the EIS service or a J2C service are not called directly or explicitly by any
application. Using this level of EIS integration, any application (or any enterprise
business process) integrates with a back-end system using a system process
that is itself exposed as an service. This system process, referred to as the EIS
system process in this discussion, contains all of the back-end system
integration rules (including logging, exception handling, routing, transformation,
configuration management, versioning, and so on) that usually are implemented
and maintained by an application.
As with an integration level 2, the EIS system process is not part of the
application. It is a business process that is exposed with Web-services
technologies using a service-based architecture style.
Illustrates business processes that are exposed as services
PresentationApplication
Presentation
Process
PresentationEIS
Presentation
Components
Logical Architecture Layers
Critical Business Processes
System Business Processes (EIS)
Presentation
Presentation
JDBC
MQ
SAP
JCA
CICS
IMS
MQ
EIS Adapters
EIS
EIS Connectors
CICS IMS
SAPDatabase
18 Managing Information Access to an EIS Using J2EE and Services Oriented Architecture
The EIS system process can be implemented using BPEL and Business Process
Choreographer. (See 2.3, “Key technologies” on page 58 for discussion on BPEL
and Business Process Choreographer.)
Notice that Figure 2-2 on page 17 illustrates some components, such as the EIS
component and the EIS connector components. More detail on the architecture
of EIS system process and the EIS components is discussed in 2.2, “Architecture
discussion and best practices” on page 19.
Figure 2-3 further illustrates this level of EIS integration.
Figure 2-3 EIS integration level 3, view of processes and components
In Figure 2-3, notice that with an EIS integration of level 3 that an application’s
business processes integrate with a back-end system using the EIS integration
system process. illustrates a typical business process that implements the Get
Company List use case. It must integrate with a back-end system to get a list of
companies, and then given certain criteria, it must get the detail for a specific
company.
Critical Business Processes (Company List)
System Process (EIS Integration)
Invoke EIS System BP
EIS Component Partner Link
EIS Connectors
JCA
CICS
IMS
MQ
EIS Adapters
MQ
CICS
SAP
etc.
JDBC
EIS
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