70 Patterns: Serial Process Flows for Intra- and Inter-enterprise
Application pattern next. If the Extended Enterprise Business pattern is not
appropriate for your development efforts, review the Business patterns to
determine which pattern best addresses your e-business needs.
4.3 Application patterns
We present the Extended Enterprise Application patterns in order of increasing
flexibility and sophistication. As the Application patterns build on each other, their
capabilities and reliance on middleware increase, and they require less
application development effort. Select the following Application pattern that best
fits your requirements:
Exposed Direct Connection Application pattern: Message/Call
Connection variations
Exposed Broker Application pattern: Router variation
Exposed Serial Process Application pattern: Also known as Managed
Public Processes
The diagram conventions shown in Figure 4-2 are used to describe these
successful approaches in the following Application patterns.
Figure 4-2 Application pattern diagram conventions
Note: The Exposed Parallel Process Application pattern is another possibility,
but it is not currently being observed in the Extended Enterprise domain. It is
expected to appear at some later stage.
Transient data
Work in progress
Cached committed
data
Staged data
(data replication flow)
Application node containing
existing code with no need
for modification for this project
or that cannot be changed.
Read/write data
Read only data
Application node
containing new or modified
code for this project.
A set of applications whose
characteristics are unspecified.
Only the means with which
to interact with them is specified.
A small solid circle indicates the initiating node.
A single arrow indicates that a response is not needed.
Double arrows indicate that a response is needed.
Chapter 4. Extended Enterprise pattern 71
Business and IT drivers
Table 4-3 and Table 4-4 summarize the business and IT drivers for the Extended
Enterprise Application patterns and their variations.
Table 4-3 Business drivers
Business drivers
Exposed Direct Connection
Message variation
Exposed Direct Connection
Call variation
Exposed Broker Router
variation
Exposed Broker
Exposed Serial Process
Exposed Serial Workflow
variation
Improve organizational efficiency üüüüüü
Reduce the latency of business events üüüüüü
Support a structured exchange with business partners üüüüüü
Support real-time one-way “message” flows to partner
processes
üüüüü
Support real-time request/reply “message” flows to partner
processes
üüüüü
Support dynamic routing of “message” between partners to
one of many target applications
üüüü
Support dynamic distribution of “message” between partners
to multiple target applications
üüü
Support automated coordination of business process flow
between partners
üü
Support human interaction and intervention within the
process flow between partners
ü
72 Patterns: Serial Process Flows for Intra- and Inter-enterprise
Table 4-4 IT drivers
QoS concerns
The following QoS concerns are of particular importance when working in the
Extended Enterprise domain.
Availability
High availability can be a particularly significant issue in the inter-enterprise
integration domain. It is important that you use careful availability management to
provide acceptable levels of customer service or, in some cases, to meet
contractual obligations regarding the availability of the application service being
provided.
IT drivers
Exposed Direct Connection
Message variation
Exposed Direct Connection
Call variation
Exposed Broker
Router variation
Exposed Broker
Exposed Serial Process
Exposed Serial Workflow
variation
Minimize total cost of ownership (TCO) üüüü
Leverage existing skills üüüüüü
Leverage the legacy investment üüüüüü
Enable back-end application integration üüüüüü
Minimize application complexity üüüüüü
Minimize enterprise complexity üüüü
Improve maintainability üüüü
Improve flexibility by externalizing process logic from
application logic
üü
Support long running transactions ü
Important: This profile is intended as a rough preliminary guide to QoS
concerns that differentiate this domain, suitable for high-level architectural
design. This is not a substitute for thorough analysis at a later design stage.

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