Methodologies for Design of Service-Based Systems - Intentional Perspectives on Information Systems Engineering - page 307

Fig. 3 Business map [ 10]

Alt.
1

a

Alt.
2 3

1

b

1

c

A business map allows representing different ways of achieving an intention. An
intention can be achieved with several paths in a map from source intentions to
targets, and some sections can be mutually exclusive. A hierarchy of maps can be
defined to refine business intentions. In this way processes are modelled focusing
on intentions and there is no need to focus on “how” a goal is achieved until later
stages. Maps are associated with a method to derive intentional services from maps,
thus providing an approach which is tailored to the specific characteristics of the
service-oriented approach.

4 Designing Service Compositions

The next phase is to derive service compositions that allow the satisfaction of the
specified requirements. One of the main goals in this phase is to examine existing
services and legacy applications in order to be able to design or redesign processes
as compositions of existing services.
In the methodological guidelines of [ 8] , in the analysis phase the objective
is to identify aggregations of services in processes and to identify subprocesses
to prevent business processes to become unmanageable. Abstract processes are
considered in this phase, and a gap analysis is performed to determine which
services have to be developed, reused, or repurposed. Only in the design phase
granularity and reusability issues are taken into account, as principles for service
development. Design is strictly related to service specification, i.e. the ability of
representing functional and behavioural aspects of services, as well as policies
associated to them. Service compositions are represented with process structures,
with abstract process schemas specification, such as in abstract BPEL. Graphical
notations can be used in the design phase, such as BPMN. Policies associ-
ated to processes and services are mainly in terms of Service Level Agreements
(SLA) to specify non-functional concerns, expressed in terms of quality of service
constraints.
In synthesis, guidelines are provided to construct abstract process schemas from
requirements, taking into consideration the availability of a number of services,
possibly derived from a service registry, and annotating the processes with SLAs.