SEKE 2012 Proceedings - Knowledge Systems Institute

o
Guideline 6.4: Softgoal dependencies – typically,
the softgoal dependency in i* is a n NFR for the
intended system. Hence, a softgoal does not
represent a use case, but an NFR associated with a
specific use case or with the SPL as a whole;
After applying Step 2 to the example, we discovered that
only the “Photo Added” goal dependency can be mapped to a
use case.
Step 3 – Discovering and describing use case scenarios:
Guideline 7: After discovering the use cases, the field
“Feature” in their description (Table II) should be
filled. Also, the scenario steps to be discovered by
using the next guidelines should be annotated with the
features related to them;
o Guideline 7.1: If a task or resource dependency
originated the use case, then the “Feature” field is
filled with the name of the feature related to the
task/resource on the table of traceability (Table I);
o
o
Guideline 7.2: If a goal dependency originated the
use case, then it is necessary to analyze the
internal element to which the dependency is
connected in the SPL actor. If such element is a
task or resource, the “Feature” field is filled with
the name of the feature related to that
task/resource. If the element is a g oal, then the
“Feature” field will be filled with the name(s) of
the feature(s) related to the task(s) in which this
goal is refined .
Guideline 7.3: The steps obtained from tasks or
resources should be annotated with the name of
the related feature between brackets – [];
Guideline 8: Analyze sub-elements of task
decompositions in order to map them to m andatory
steps of the use case primary scenario;
o Guideline 8.1: If the decomposed task in analysis
satisfies a dependency that was mapped to a use
case, then the sub-elements of that decomposition
will be mapped to mandatory steps of such use
case;
o
o
Guideline 8.2: Every step obtained from task
decomposition sub-elements is identified by a
unique number without parenthesis, according to
PLUSS notation for mandatory steps;
Guideline 8.3: If a sub-element of a t ask
decomposition is a softgoal, then it is associated to
the use case as an NFR;
Guideline 9: When a means-end relationship has only
one sub-element, the sub-element’s cardinality should
be analyzed;
o Guideline 9.1: If the cardinality is [1..1], the
element will be mapped to a mandatory step.
Hence, it will be identified by a unique number
without parenthesis;
o
Guideline 9.2: If the cardinality is [0..1], the
element will be mapped to an optional step.
Hence, it will be identified by a unique number
between parenthesis, according to th e PLUSS
notation for optional steps;
Guideline 10: When a means-end relationship has more
than one sub-element, the relationship cardinality
should be analyzed;
o Guideline 10.1: If the cardinality is , the
sub-elements will be mapped to mutually
exclusive alternative steps. Therefore, they will be
identified by equal numbers without parenthesis;
o
o
o
o
Guideline 10.2: If the cardinality is , the
sub-elements will be mapped to alternative steps
where only one may be selected. Therefore, they
will be identified by equal numbers between
parenthesis;
Guideline 10.3: If the cardinality is and
n>1, the sub-elements will be mapped to
alternative steps where none or at most n can be
selected. Therefore, they will be identified by
equal numbers between parenthesis, followed by a
different letter for each alternative;
Guideline 10.4: If the cardinality is , i ≠0 and
j>1, the sub-elements will be mapped to
alternative steps where at least i and at most j can
be selected. Therefore, they will be identified by
equal numbers without parenthesis, followed by a
different letter for each alternative;
Guideline 10.5: If there is cardinality only in the
sub-elements, but not in the relationship, the subelements
will be mapped to alternative steps and
some of them may be o ptional, according to the
cardinality. Therefore, they will be identified by
equal numbers, followed by a different letter for
each alternative. However, those with [0..1]
cardinality should have their identifications
between parenthesis;
Guideline 11: The SR model should be analyzed to
discover additional information about the use cases;
o Guideline 11.1: A nalyze contribution links from
other elements (source) to softgoals (target). If the
source element is part of a use case, then the target
softgoal will be associated to this use case as a
non-functional requirement;
o
Guideline 11.2: Analyze links between elements
that generated steps to different use cases. These
links may represent that an element is a precondition
of a u se case (obtained from the other
element) or a rel ationship, such as “include” or
“extend”, between use cases (obtained from the
related elements);
Guideline 12: Analyze use cases to check if they can be
refined or generate new use cases. Each scenario step
654