The intraday reporting service
structure generalizes the reporting idea and routes external messages to its internal services. This
aggregated relationship offers a certain level of isolation to the service??™s internal constituents.
The service-oriented design rule of thumb suggests that a message exchange between
an internal service and its corresponding consumer (typically an external service-oriented asset)
must occur through the service??™s hosting service. Thus, going back to Exhibit 12.5, the intraday
reporting service becomes the de facto isolating proxy that provides protection to internal services.
This requires that no outside consumers or services shall be given access to internal assets.
To further clarify this concept, review the formal model presentation depicted in
Exhibit 12.6. The download equity trading activity consumer maintains an implied design relationship
with the aggregated and protected equity reports atomic service by using the pass-through
granted by the intraday reporting composite service. Note that in a service-oriented design relationship
diagram we should not be concerned about the aggregated structures. Here the focus is
on the message routes and the visibility aspects of the message exchange parties. To learn about
the containment structure of services, always refer to the formal analysis proposition diagram
(discussed in Chapter 8).
Service Design Visibility Aspects 241
Intraday Reporting Service
Mutual Funds Trading
Reporting Service
Equity Trading Intraday
Reporting Service
EXHIBIT 12.
Pages:
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421