Software Product Line Engineering Basics - Model-Driven and Software Product Line Engineering - page 42

a given number of days, or never expire. The number of days
a password remains valid can be set in an integer attribute
associated to the inDays feature. The constraints on the
number of policies for the Expiration date are captured in
the cardinality associated with the group feature. In this
case, the Expiration date has the cardinality [1..1] , which
means that one and only one policy for the expiration date
can be selected. The feature model also takes into account
the possible requirements on the characters to be used in
a password. The constraints on characters required in a
password are specified by a group feature, Chars , with
cardinality [1..2] . This means that any actual password
policy must specify between one and two requirements on
characters ( Chars ) in a password, Upper Case and/or Lower
Case .
Such a feature model can be designed by some specific
languages but a convenient way is to use a metamodel to define
this language. This aspect is further developed and illustrated
in Chapter 3.
2.7. Application engineering
Pohl et al . define application engineering as “the process
of SPL engineering in which product line members are
built by re-using core assets and exploiting the product line
variability” [POH 05b].
D EFINITION 2.8.- Application engineering is the process of
building the products of the product line and re-using core assets
according to the production plan.
During this process, product designers use the variability
identified and the core assets created during domain
engineering to ensure the correct derivation of required
products. The application engineering process is composed
of activities for configuring individual products inside the
set of valid variation points (product configuration), and