Information Technology Reference
In-Depth Information
A.6
Correspondences
We need to specify not only the viewpoints, but also how the elements
in the individual viewpoints relate to each other. The PhoneMob system
specification defines six pairwise correspondences between the viewpoints (see
figure A.1). There is not room here to describe the detailed contents of all
these packages; instead, we will focus on how correspondences are identified
and expressed.
Chapter 7 explained that the UML4ODP standard provides checklists for
identifying the correspondences that should be specified for a system. Some
of them are mandatory for any ODP system specification, such as the ones
that link the computational and engineering objects. Others depend on the
system being specified. Examples of these optional correspondences are the
ones that link enterprise and computational objects, or enterprise interactions
with computational interfaces. Not every enterprise object or interaction has
a corresponding element in the computational viewpoint. The Paper Docu-
ment enterprise object type, for example, has no corresponding computational
element.
In general, we can identify two kinds of correspondences between viewpoint
elements, according to the type of relationship between them. In the first
place, we have the correspondences between viewpoint elements that represent
the same entity, such as a handset, from different perspectives.
Figure A.15 shows the representation of Handset objects in the enterprise,
information and computational viewpoints, each one focusing on different as-
pects, giving rise to slight variations. It also shows the correspondences be-
tween them. Note that a handset is an object in the enterprise and information
viewpoints, and a data type in the computational viewpoint. As a result, there
is no representation for it in the engineering and technology viewpoints.
«dataType»
Part
+id : PartId
+serialNo : String
+status : PartStatus
+manufacturer : CompanyId
Part
«CorrespondenceLink»
+serialNo : String
+status : PartStatus
«CorrespondenceLink»
«CorrespondenceLink»
Handset
«dataType»
Handset
Handset
+isLoan : Boolean
«CorrespondenceLink»
LoanHandset
UserHandset
«CorrespondenceLink»
+IMEI : String
«CorrespondenceLink»
User Handset
Loan Handset
«CorrespondenceLink»
ENTERPRISE
INFORMATION
COMPUTATION
FIGURE A.15: Correspondences between different views of the same entity.
 
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