SEKE 2012 Proceedings - Knowledge Systems Institute

environment. Therefore, it is possible to deal with purpose
for configuration files as functions of application. By relating
purpose for configuration files and functions of application, it
becomes possible to specify what combinations of setting item
and parameter are required for execution of application.
B. Errors of configuration files
We focus on syntax error and semantic error of configuration
files. Syntax error means that combinations of setting
item and parameter are invalid, or dependencies between
combinations are not satisfied. Semantic error means that
configuration files do not meet requirements for configuration
files. Factors of configuration file error are size and complexity
of configuration files. Therefore, it is needed to solve these
factors in order to make error-free configuration files.
III. APPROACH
We take an approach to manage variability of configuration
files. Configuration files have variability in syntax and
correspondence relations between requirements. Variability of
syntax means combinations of setting item and candidate of
parameter. Variability of correspondence relations between
requirements and configuration files means that requirements
also have variability and what combinations of setting item
and parameter are required in order to perform requirement.
Our approach consists of using a model and a consistency
checking method. We propose configuration file model which
organizes variability of configuration files. In particular, configuration
file model represents candidates of combinations of
setting item and parameter, constraints on making configuration
files, requirements, and correspondence relations between
requirements and configuration files. In order to check semantic
error, we consider that requirements and correspondence
relations between requirements and configuration files should
be organized. Consistency checking method checks consistency
between configuration file model and configuration files.
Concept of our approach is shown in Fig. 1.
use Alloy[1][4] in order to formalize and check the feature
diagram. The details of configuration model and consistency
checking method are shown in our previous work [9].
IV. CONFIGURATION FILE MODEL
A. Elements of configuration and relations
Basic elements of configuration file model are setting item,
parameter and requirement. Setting item and parameter are
specific elements of each configuration file. Requirement is
function of application. Requirement should be considered in
order to specify what combination of setting item and parameter
are described in a configuration file. Configuration file
model includes following relations between basic elements.
• Combination of setting item and parameter
This combination shows valid candidates of parameter for
each setting item.
• Dependency between specific combinations of setting
item and parameter
This dependency shows that somecombinations of setting
item and parameter may be required to describe other
combination.
• Relation between requirements
This relation shows that some requirements may be
required to perform other requirement.
• Relation between requirement and combinations of setting
item and parameter
This relation shows candidates of combinations of setting
item and parameter for execution of a requirement.
The concept of configuration file model is shown in Fig. 2.
Fig. 2.
Concept of Configuration File Model
Fig. 1.
Approach of Our Method
In order to clarify structure of configuration file model,
configuration file model is described using the feature diagram
[5] [3]. Requirements and configuration files are described by
using the feature diagram. Correspondence relations between
requirements and configuration files are described by correspondence
relations between feature diagram of requirements
and feature diagram of configuration files. In our method,
a diagram that configuration file model is described by the
feature diagram is called configuration model. Besides, we
B. Definition of Configuration File Model
The definition of configuration file model (CFM) is as
follows.
CFM =PN, PV, R, CR, Conf, Rel, RRel, Req
The explanation of CFM is as follows. PN is set of names
of setting item. PV is set of parameters. R is set of names of
requirement. CR shows that what requirements are chosen by
users or administrators for configuration file description. Conf
means PN → 2 PV , and shows candidates of combination of
setting item and parameter. Rel is subset of ( ( PN × PV )
× (PN× PV ) ), and shows relations between combinations
of setting item and parameter. RRel is subset of R × 2 R ,
and shows relations between requirements. Req means R
→ 2 (PN×PV) , and shows combinations of setting item and
parameter that corresponding to a requirement.
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