Information Technology Reference
In-Depth Information
the conformance points declared in the specification. This body of informa-
tion is called the implementation extra information for testing, or IXIT. The
technology specification gives a proforma stating minimum requirements for
the information the implementer must include in the IXIT. This information
is then used to interpret the observations a tester can make in terms of the
vocabulary and concepts defined in the other viewpoints. For example, it al-
lows valid interactions to be recognized, so that their appropriateness can be
checked against some specified object behaviour (see chapter 8).
Proformas indicating the information that an implementer is required to
include when producing the IXIT can be attached to any technology object
or interface; figure 6.3 shows an example of the association of requirements
for this additional information with two technology objects. Another exam-
ple might involve the technology specification saying that the implementer
is required to state the precise version number of any mandatory platform
components provided, such as the EJB environment in an application server.
«TV_IXIT»
The implementer shall indicate in the IXIT the character coding to be
used in realizing these objects.
«TV_Object»
Business Object
«TV_IXIT»
The implementer shall state in the IXIT:
− the maximum number of users that can be supported;
− how internationalization is supported and managed;
− the predicted mean time between failures (MTBF) for the system.
«TV_Object»
OperatingSystem
FIGURE 6.3: Some requirements for elements in the IXIT.
6.2.4 Implementation
The technology viewpoint defines an implementation as the result of a
process that instantiates a specification, the validity of which can be subject
to test. These processes not only cover development, but also other activ-
ities related to the system deployment, configuration and evolution. They
include, for instance, configuration guides, deployment plans, change manage-
ment plans, criteria for the selection of technology and of service providers,
maintenance processes, and so on. In UML4ODP, these processes are ex-
pressed using activity diagrams stereotyped
«
TV Implementation
»
.
Figure 6.4 shows an example for the selection of a technology object. It
assumes that the owner and operator of a system need to add some functional-
ity; they perform a search for components that meets their needs and, if they
already have the elements of a suitable solution, they select and deploy them.
However, if nothing suitable is available, they specify their requirements as a
supply request and issue it to a subcontractor who will implement the com-
