=Paper= {{Paper |id=None |storemode=property |title=A Generative Approach for Creating Stakeholder-specific Enterprise Architecture Views |pdfUrl=https://ceur-ws.org/Vol-592/PaperDemo09.pdf |volume=Vol-592 |dblpUrl=https://dblp.org/rec/conf/caise/BucklMS10b }} ==A Generative Approach for Creating Stakeholder-specific Enterprise Architecture Views== https://ceur-ws.org/Vol-592/PaperDemo09.pdf

A Generative Approach for Creating
Stakeholder-specific Enterprise Architecture
Views

Sabine Buckl, Florian Matthes, and Christian M. Schweda

Technische Universität München, Institute for Informatics,
Boltzmannstr. 3, 85748 Garching, Germany
{sabine.buckl,matthes,schweda}@in.tum.de
http://www.systemcartography.info

Abstract. Understanding the architectures of complex system, e.g. en-
terprises, is greatly facilitated by using graphical views thereof. These
views result from the application of an underlying viewpoint to a com-
prehensive architectural description. The viewpoint thereby describes,
which architectural concepts should be visualized in which way. The
creation of views that consistently represent the enterprise architecture
(EA) from a specific viewpoint, is a challenge of ongoing interest in EA
management. In this paper, we present a technique that can be used to
create views consistent to arbitrary architecture viewpoints and show,
how this technique is realized in a prototypic tool. Central constituents
of the tool are a model providing the graphical primitives for describing
visualizations (called visualization model ) and a model-to-model trans-
formation reifying an architectural viewpoint.

Key words: model transformation, viewpoints, views, EA management

1 Motivation
A major task of enterprise architecture (EA) management is to provide trans-
parency concerning the overall architecture, i.e. a common goal of EA manage-
ment is to foster the communication between the different stakeholders with busi-
ness and/or IT background [1]. Commonly, visualizations (views) are regarded
as important means to facilitate communication between the stakeholders from
business and IT. In order to be useful these visualizations should not be arbitrary
”drawings” of the architecture, but should correspond to selected architecture
viewpoints 1 on dedicated parts of the overall architecture (cf. [4, 9]). What up to
this points reads quite similar to the challenge of architecture visualization in the
context of software engineering, shows at the second look some subtle complexi-
ties. In contrast to the situation in software engineering, where widely-accepted
conceptualizations of software systems, e.g. via ”classes”, ”components”, and
”interfaces”, exist, the field of EA management is lacking such well-defined and
1
The term viewpoint is used in this context according to it’s definition in [7].
2 Sabine Buckl, Florian Matthes, and Christian M. Schweda

grounded terminology. This might be ascribed to the novelty of the field, but
quite a few researchers [1, 4] give a different explanation and challenge the idea
that a ”one-size-fits-it-all” conceptualization of EAs exists. These researchers in
contrast expect the EA conceptualization to be organization-specific, such that
every enterprise has its specific EA information model that incorporates only
the information necessary for the dedicated EA management approach. Comple-
menting the variety of information models, different organizations also employ
different visualization standards, i.e. use viewpoints differing in respect to the
used symbols as well as to the employed rules underlying the layout. Against
the aforementioned background of largely differing information models and vi-
sualization principles, it becomes clear that the creation of a consistent EA view
(for an example see Figure 1) is no simple task.

Munich Hamburg Garching London
POS System Product Shipment POS System Monetary Customer
Online Shop (100) Human Resources (Germany/Munich) System (Germany) (Germany/ Inventory Control Transactions Complaint System
System (700) (1600) (400) Hamburg) (1620) System (200) System (Great (1900)
Britain) (350)

Monetary Worktime Customer
Management Fleet Management Price Tag Printing Data Warehouse POS System Satisfaction
Transactions Business Traveling System (Germany/ (Great Britain)
System (Germany) System (1000) (Germany/Munich) System (900) (800) Analysis System
(1800) Hamburg) (1720) (1650) (2000)
(300)

Price Tag Printing Document Worktime Supplier Price Tag Printing
Accounting System (Germany/ Management Management Relationship System (Great
MIS (1300) (Germany/ Management
System (500) Munich) (1700) System (1100) Britain) (1750)
Hamburg) (1820) System (1200)

Financial Customer Worktime
Costing System Campaign Relationship Management
Planning System Management Management (Great Britain)
(600) System (1500)
(1400) System (2100) (1850)

Legend
Map Symbols Visualization Rules
A Location A A
„A“ hosts „B (1)“ and „C (2)“
B (1)
B (1) Business Application B with Id 1
C (2)
nesting

Fig. 1. Exemplary architectural view

A technique suitable for generating views consistent with underlying view-
points based on arbitrary EA information models has to address different chal-
lenges. Matthes et al. give in [10] a detailed list of these challenges, of which we
– due to reasons of brevity – only provide a summary:

Coupling of information and visualization meaning that a link should be
maintained relating graphical elements in the visualization with the under-
lying architectural elements. The tool’s mechanisms, thereby account for
visualization correctness. If the graphical elements were in contrast decou-
pled from the underlying data, the views would degenerate to mere drawings,
which need to be manually maintained if the underlying information changes.
Flexibility of information schema meaning that architectural models con-
forming to an arbitrary schema should be accessible to the tool. This reflects
the fact that the information on the EA is gathered according to the specific
demands of an organization.
Adaptability of viewpoint meaning that an enterprise architect should be
able to adapt the viewpoint to its specific needs. For example, the architect
Generating Enterprise Architecture Views 3

should be able to adapt the colors according to the corporate identity of the
enterprise. Adaptability thereby reflects the fact that visualizations, as mean
of communication, heavily rely on stakeholder acceptance.
Composition and modularization of viewpoints meaning that an enter-
prise architect should be able to define viewpoint modules, i.e. reusable parts
for creating visualizations. Thereby, especially the widely-used mechanism
of layering visualizations is accounted for.

In Section 2 we outline a technique suitable for addressing the aforementioned
requirements. The technique is based on the technology of model-to-model trans-
formations, which is applied to connect information models on the one hand with
a model of visual concepts, namely the visualization model, on the other hand.
Complementing the description of the technique, we describe the prototypical
realization thereof in a tool. Related tools as well as related techniques from
nearby fields are presented in Section 3. Section 4 concludes the article with a
critical reflection of the presented approach and an outlook on future work.

2 Generating visualizations via model transformation

Model transformation approaches in the context of generating visualizations can
be used to maintain the strict separation between information and visualization,
while also ensuring consistency between both concepts. The model transforma-
tion, called syca transformation in our approach, links different types of models,
namely the model of the information to be visualized – the semantic model – and
the model describing the visualization – the symbolic model. The transformation
is thereby described relying on concepts of the models’ respective meta mod-
els. These are the information model describing the concepts used for modeling
information and the visualization model defining the graphical concepts for de-
scribing visualizations. Figure 2 illustrates the basic constituents of the approach
and further introduces the concept of the transformation meta model, which pro-
vides the basis for specifying syca transformations, as well as the concept of a
common meta model for both information and visualization model.
Different analyses of the information models used in EA management have
been undertaken, e.g. by Buckl in [3], leading to the finding that the majority
of currently used models follows the paradigm of object orientation. While the
information models of many approaches do not explicitly account for the under-
lying meta-model, the analysis of Buckl further showed that mostly only core
concepts of object-oriented modeling, e.g. classes, properties, and associations
are used. This advocates for the utilization of a simplistic common meta-model
with the OMG’s Meta Object Facility (MOF) [11], more precisely the essential
part thereof (EMOF) being a prominent candidate. The EMOF provides the
meta-model of choice for the technique presented in this paper, especially as an
implementation of the modeling facility is ready at hand as part of the Eclipse
Modeling Framework (EMF). This framework was chosen, as its metamodel,
the ECore-metamodel, can be considered to be very similar to the EMOF-
4 Sabine Buckl, Florian Matthes, and Christian M. Schweda

metamodel2 . Additionally, the EMF provides serialization and editing related
functionalities, as well as an active user and developer community.

Common
conforms to conforms to
Meta Model

is applicable on

Transformation
Meta Model
Information Visualization
Model Model
conforms to
conforms to conforms to
Syca
Transformation
Semantic Model Symbolic Model

Fig. 2. Basic idea of the model transformation approach

2.1 Semantic model and information model – the left side
The information model sets up the language for describing the modeling subject,
i.e. it introduces the core concepts, which are used to create a model of the sub-
ject’s reality. In the context of EA management, the information model contains
concepts like business processes, locations, etc., which are represented irrespec-
tive a visualization. Instance data documented in accordance to the information
model is part of the semantic model, which contains so called information ob-
jects. In this sense, the information model (for an example see Figure 3) acts a
meta-model for the semantic model, cf. Figure 4.

Fig. 4. Cutout of the semantic model
Fig. 3. Information model

2.2 Symbolic model and visualization model – the right side
The visualization model contains elements, which represent graphical concepts,
namely map symbols, e.g. ”rectangle”, or visualization rules, such as ”nesting”.
These rules do not represent visible concepts, but they exert distinct demands on
the positioning, size, or overall appearance of the symbol instances. For example,
instances of the ”nesting” rule demand that ”inner” map symbol instances are
grouped into the ”outer” map symbol. Figure 5 introduces the map symbol
2
Only minor differences concerning naming and the usage of references exist.
Generating Enterprise Architecture Views 5

and visualization rule that are needed for the exemplary visualization. Figure 6
displays the symbolic model describing that rectangles representing business
applications are nested in the rectangle representing the hosting location.

Fig. 5. Visualization model Fig. 6. Cutout of the symbolic model

The syca transformation creates a symbolic model based on the correspond-
ing semantic model, while the map symbol instances in the symbolic model
are not yet supplied with absolute positions. These positions are in a second
step calculated by a layouter, which is capable to interpret the visualization
rule instances and to compute appropriate positioning and sizing. Sketching the
mathematical formalism incorporated in the layouter, we give examples of the
layouting constraints that apply on the rectangle instance3 :

munich.x - munich.width/2 < onlineShop.x - onlineShop.width/2
munich.x + munich.width/2 > onlineShop.x + onlineShop.width/2
munich.y - munich.height/2 < onlineShop.y - onlineShop.height/2
munich.y + munich.height/2 Y onlineShop.y + onlineShop.height/2

2.3 The syca transformation and its meta model – the middle

The syca transformation establishes the link between the data and its visualiza-
tion and thereby enable the automatic generation of corresponding architectural
views. Different types of model-to-model transformation languages may be used
to implement the syca transformation.
The transformer component of the tool interprets the transformation rules
and generates a symbolic model from the corresponding semantic model. Over
the last years, we have successfully applied different model-to-model transfor-
mation languages for defining architectural viewpoints in an executable manner.
Wiegelmann showed in [13] that the Atlas Transformation Language (ATL) [2]
can be used to describe the necessary transformations. With ATL, architectural
viewpoints can be defined in a highly declarative manner, although especially
the appropriate instantiation of visualization rules becomes fairly complex, e.g.
when matrix-like views should be created. Example ATL-like code generating
the architectural visualization from Figure 1 is given below.
3
According to the visualization model of Ernst et al. [6], the symbols’ x and y-
coordinates are anchored at the symbols’ centers.
6 Sabine Buckl, Florian Matthes, and Christian M. Schweda

rule OrgUnit2Rectangle {
from infoObject : Semantic.OrganizationalUnit
to symbol : Symbolic.Rectangle (text = infoObject.name)
)

rule BusinessApp2Rectangle {
from infoObject : Semantic.BusinessApplication
to
symbol : Symbolic.Rectangle (text = infoObject.name),
rule : Symbolic.Nesting (
inner = symbol,
outer = transforming (infoObject.hostedAt)
)
)

Complementing the model-to-model transformation languages, we further
applied java to realize the syca transformations. Java-based transformations do
– due to the maximum expressiveness – not run into the difficulties that the
declarative model transformation languages have to deal with, but are even less
intuitively to develop. Targeting an increased level of usability by rising the level
of abstraction, Ramacher designed in [12] a java-based introspective framework
consisting of highly-reusable transformation primitives that can be composed to
syca transformations. First practical applications of this framework are still to
be undertaken, but the first experiences are very promising.

3 Related approaches and tools

Domokos and Varro present in [5] an approach to ensure consistency between
data and the corresponding visualization. The approach provides ”open visual-
ization framework applicable to metamodel based modeling languages”, which is
further developed towards executability. With no dedicated visualization model,
the approach aims at transforming arbitrary information models to arbitrary
visual languages, e.g. SVG, as far as both (information and visualization) can
be described with XML. Consequently, the generation of a visualization in fact
is an XSLT-based transformation between two XML-documents. In this respect,
the approach does not reach a high level of abstraction, but calls for very ba-
sic transformation procedures. Further, the article does not encompass a visual
language suitable for expressing the aspects of relative positioning, as the appli-
cation concerns petri-nets and their representation as nodes-and-edges.
Kruse et al. present in [8] a component-oriented tool for supporting EA man-
agement. Central to their approach is a strong ’componentization’ in the way,
that different types of viewpoints are implemented as different components of the
tool. Each viewpoint in this respect brings along a dedicated information model,
that describes the information necessary for creating the corresponding visual-
ization. A company willing to use the corresponding tool for visualizing their EA
Generating Enterprise Architecture Views 7

or parts thereof, selects the appropriate visualization components and supplies
a model-to-model transformation transforming parts of the organization-specific
EA information model to the information model associated with a specific view-
point. Put in other words, the approach of Kruse transforms and projects in-
stances of one information model to instances of a different information model,
which conversely is directly fed into a layout and visualization mechanism.
Multiple commercial tools provide support for EA management. Matthes et
al. analyzed in [10] nine prominent of these tools, coming to the result that most
of the tools fall for two types of visualization-related problems. On the one hand,
the process- or methodology-driven tools bring along a fixed EA information
model that underlies a set of predefined viewpoints. Visualizations corresponding
to these viewpoints can mostly be generated automatically, and may use a rich
visual language, including relative positioning of symbols to convey information.
On the other hand, metamodel-driven tools can flexibly adapt their information
model to the specific needs of the using organization, but are mostly limited to
visualizations of the nodes-and-edges type. More complex visualizations, using
e.g. relative positioning, have to be programmed in these tools utilizing scripting
languages with no visualization- and layout-specific concepts.

4 Critical reflection and outlook
This article presented a technique to create visualizations (views) from arbitrary
EA descriptions. The generated views thereby are consistent with a previously
defined viewpoint and are created using a model-to-model transformation. Com-
plementing the presented technique also a prototypic tool implementing the tech-
nique was described. This tool has been used in different practice cases in the past
and showed the applicability of the technique on various different organization-
specific EA information models. Different languages were utilized to realize the
model-to-model transformation, namely the basic programming language java
(cf. [12]) as well as the model transformation language ATL (cf. [13]). While
both languages were sufficient to generate visualizations, they provide a rather
low level of abstraction, when it comes to describing architectural viewpoints.
More precisely, the complexity of the model transformations expressed in these
languages is often beyond the level, that an enterprise architect can cope with.
Increasing the level of abstraction in defining viewpoints and thereby fa-
cilitating the creation of end-user defined viewpoints are the challenges to be
addressed next. Two different strategies to achieve this can be pursued:
– Rise the level of abstraction in the visualization model, i.e. replace the fine
grained visualization rules with more coarse ones. As an example, one could
think of a cluster -rule for visualizations like the one in Figure 1.
– Rise the level of abstraction in the transformation language, i.e. provide
domain specific concepts for specifying a syca transformation going beyond
basic query model - and transform model -concepts.
While both ideas may be useful to achieve the goals, especially the latter one
seems more appealing. In consequent continuation of the prefabrics of Ramacher
8 Sabine Buckl, Florian Matthes, and Christian M. Schweda

(cf. [12]), a tailored transformation language could allow to stay with the basic
visualization model concepts that have a clear and unambiguous semantics.

Acknowledgements
The development of the herein presented technique and prototypic tool is sup-
ported and partially funded by Siemens IT Solutions and Services (SIS).

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