ARCHITECTING SOA SOLUTIONS FROM
ENTERPRISE MODELS
A Model Driven Framework to Architect SOA Solutions from Enterprise Models
Xabier Larrucea, Gorka Benguria
European Software Institute, ParqueTecnologico de Zamudio ,E-48170 Zamudio-Bizkaia, Spain
Keywords: Enterprise Models, Service Oriented Architecture, Platform Independent Model, Model Transformation.
Abstract: The improvement of the operational efficiency is an important concern in the several kinds of enterprises,
but it involves the management of a multitude of elements. To be able to cope with such as complexity
several enterprises are relaying in the use of enterprise modelling tools. This usually becomes a starting
point for business process automation initiatives towards the improvement of the organisation. However,
there is still a large gap from these enterprise models to the infrastructure systems. The current paper
presents a MDA (Model Driven Architectures) framework over eclipse platform to address this gap for SOA
(Service Oriented Architecture) based solutions and more in deep the notation and transformation aspects of
the framework. The framework provides a systematic approach for deriving SOA solutions from enterprises
models, ensuring that the information systems really implements the models developed by the business
experts and no partial interpretations from IT experts.
1 INTRODUCTION
The improvement of the operational efficiency is an
important concern in several kinds of organisations
from banking (Allen et al., 1996) to healthcare
(HayGroup, 2005). This continuous activity requires
leveraging the interaction among a multitude of
organisational elements from clients and providers,
to employees and existing IT systems. To deal with
this complexity, organisations describe their
structures using enterprise models.
The usage of enterprise models brings several
advantages when an organisation is planning to
change its actual structure to achieve a greater
efficiency. On the one hand, enterprise models
describes in a coherent and consistent way all
elements involved the operational processes of the
organisation at conceptual level. On the other hand,
these models allow users to have a common
understanding of the enterprise model from different
views. Besides, enterprise models establish the basis
for the performance analysis of the new models and
their latter automation through the intensive usage of
enterprise information systems.
Unfortunately, the automation of the enterprise
models into enterprise information systems is not a
straightforward activity: the business expert
develops the improved enterprise model, he meets
the information system expert and in somehow he
explains what he requires from the information
systems; then the information system expert
implements what he has understood.
Clearly, there is a gap between enterprise models
and their information systems implementations. This
separation and differentiation of concerns cause
mainly a loss of information, a lack of flexibility,
traceability and makes more difficult a consistency
check between the enterprise layer and the system
layer.
Moreover the introduction of new standardised
approaches such as service oriented architectures
(SOA) to implement information systems provides
many benefits (Fiorano Software, 2004). In
summary, they are allowing fast, secure, flexible and
automated relationships between enterprises. This
makes it possible to achieve higher automation
levels of the enterprise models, as this technology
allows us to automate our relationship with external
partners. The level of automation is increasing and it
becomes more necessary to resolve the gap between
the enterprise models and their information systems
implementations.
551
Larrucea X. and Benguria G. (2006).
ARCHITECTING SOA SOLUTIONS FROM ENTERPRISE MODELS - A Model Driven Framework to Architect SOA Solutions from Enterprise Models.
In Proceedings of the Eighth International Conference on Enterprise Information Systems - ISAS, pages 551-554
DOI: 10.5220/0002461605510554
Copyright
c
SciTePress
SOA implementations can be combined to
implement ICT systems. For example Web services
technology could be used with peer to peer and
agents technologies to provide new capabilities.
MDA allows the separation of concerns between the
logical solutions and the technology used avoiding
organisations to reinvent the wheel when there are
changes at conceptual or technical layer.
This paper presents a framework to bridge the
gap between enterprise layer and technical layer
from a Model Driven Architecture (MDA)
viewpoint, and the specific mechanisms that uses to
represent service architectures and to transform
those representations into a platform independent
model for service oriented architectures.
This paper is structured in three main sections.
Firstly a brief state of the art on this area is provided
emphasising the motivation and the start point of our
work and approach. The second part describes the
mechanisms to architect service oriented
architectures solutions taking into account several
important enterprise aspects to be modelled. In
addition, this section sets up the relationships
between business layer and technical layer from a
model driven point of view using model
transformations. The last section sums up our work
and outlines future directions.
2 CONTEXT AND STATE OF THE
ART
Enterprise models (EM) allow stakeholders to model
their organisations and dimensions (Vernadat, 1996)
described in terms of enterprise architectures in a
coherent and consistent way. Most of these
enterprise models are related to EM tools (GRAI
tools, Metis, MO2GO, e-MAGIM, etc) (ATHENA
DA1.1,2005)( UEML D1.1,2002). Interoperability
problems arise when those organisations aim to
achieve enterprise interoperability at a conceptual
level. Much effort is spent in European projects
(ATHENA, 2005), (INTEROP,2005) to alleviate
interoperability issues. Most of these problems are
related to the technologies and languages used.
The definition of a well defined metamodels
allows a common understanding of the elements
described. The standardisation of these metamodels
allows tools to interoperate amongst these tools. One
of these metamodels is Unified Modelling Language
(UML) (UML 2.0, 2003) and its metamodel Meta
Object Facility (MOF) (Meta Object Facility,2004).
These metamodels are standardised by the Object
Management Group (OMG). MOF allows the
specification of well defined languages like UML.
UML is a de-facto industry standard to specify and
to design software systems. UML2.0 is the major
revision of this language increasing considerably its
capabilities. One of these extended capabilities is the
specialisation of UML for specific domains through
UML profiles.
The Eclipse platform (Eclipse Modelling
Framework,2005) is an open initiative based on
plug-ins implementing an essential subset of MOF
called essential MOF (EMOF). This platform is also
used as a java development platform but our main
interest is on its capabilities to define metamodels
and to model with respect to a metamodel. For
example using the UML2.0 plug-in for the eclipse
platform, we are able to specify models that are
compliant with UML. However, this open initiative
does not provide the graphical implementation of
UML and its diagrams. Rational Software Modeller
(RSM) and Omondo are UML tools based on the
eclipse platform implementing the graphical side of
these models. RSM provides facilities to represent
profiles.
Models transformations are key pieces within
MDA allowing traceability and checking
consistency between models. The OMG MOF
Query, View and Transformation (QVT) (QVT,
2002) initiative is a language to transform and to
query models represented according to MOF
metamodels. QVT is still under standardisation
process but in the near future it will become an
OMG standard. There are two first implementations:
Atlas Transformation Language (ATL) (ATL, 2005)
and Model Transformation Framework (MTF)
(MTF,2005). Both implementations are based on
rules and they are used to transform and to query
models. MTF as well as ATL is compatible with
eclipse platform.
3 A MODEL DRIVEN
FRAMEWORK FOR
ENTERPRISE MODELS
ATHENA project has developed a metamodel and a
UML (Unified Modelling Language) profile called
POP* to represent in a common way enterprise
models. The Unified Enterprise Modelling Language
(UEML,2001) is a POP* predecessor. The main
intention of this paper is not to provide a huge
description of both metamodels and their differences
but to outline that the main difference between them
is that POP* is able to represent in its metamodel
and profile the following dimensions: process,
ICEIS 2006 - INFORMATION SYSTEMS ANALYSIS AND SPECIFICATION
552
organisation, product, decision, and infrastructure.
Therefore it increases the model interchange
capability with respect UEML amongst commercial
EM tools.
From a MDA model driven architecture point of
view POP* metamodel is one of the highest
architectural levels representing the business aspects
that an organisation wants to model. In addition
enterprises face up to interoperability issues by
adopting service oriented architectures to implement
and to publish their business functionality as
services. Within the ATHENA project a platform
independent model (PIM) metamodel is defined to
describe services and their collaborations in a
platform independent way. POP* metamodel as well
as service oriented architectures are solutions to
alleviate interoperability issues in each layer.
However they do not resolve the existing gap
between the business layer and the technical layer.
Our approach is focused on providing a
framework to derive service oriented solutions from
enterprise models and to specify a domain language
for service oriented solutions. In order to bridge the
gap between the business layer and the technical
layer a model driven transformation framework has
been defined. Figure 1 represents our approach to
bridge this gap where business layer is represented
separately from technical layer. Two plug-ins for
Rational Software Modeller related to two UML
profiles are defined in order to represent models
compliant with the above metamodels. POP* plug-in
is related to POP* UML profile, and PIM4SOA
plug-in is related to PIM for SOA UML profile. A
set of model driven transformations are also defined
to maintain the consistency between UML profiles
and their metamodels, and to transform POP*
models to PIM for SOA models.
Business Layer
Enterprise
Model
Business Layer
Enterprise
Model
Technical Layer
PIM for SOA
Technical Layer
PIM for SOA
Eclipse platform
POP*
metamodel
EMF model
PIM4SOA
metamodel
EMF model
Rational
Software
Modeler
MTF rules
POP*
plugin
PIM4SOA
plugin
Figure 1: Model driven framework for enterprise models
approach.
3.1 PIM for SOA Profile
The UML profile for SOA is based on the aspects
and dimensions defined in the PIM for SOA
metamodel and it represents graphically UML
models depicting service oriented models in a
platform independent way. Concepts as well as their
relationships are defined in the metamodel but the
profile and the plug-in maintain the same concepts
and meanings providing a graphical editor.
The PIM4SOA profile defines for each
dimension (service, process, information) a set of
UML extensions.
Service extensions: “Collaboration” represents
the definition of a service. Each service is viewed as
collaboration amongst roles. “CollaborationUse”
represents the usage of a service. “RoleBinding” is
used to relate a service use to a specific role. “Role”
represents a structural part in a specific
collaboration. “Endpoint” represents the address for
a service.
Information extensions: “Document” describes a
business document information model.
“BusinessTypeLibrary” describes the business logic
of the information aspects. “Entity” represents
elements used to describe complex types.
“TypeLibrary” defines reusable type library.
Process extensions: “Process” represents the
behaviour of a service provider. “StructuredTask” is
composed by a set of tasks. “Task” is an activity.
“Decision” is used to declare a control decision
within the process.
3.2 Model Driven Transformations
One of the most important pieces in this framework
is the development of the model driven
transformations. In this context Model
Transformation Framework (MTF,2005) is used to
describe those transformations based on rules
relating different elements of different metamodels.
At this level three different kinds of
transformations are implemented. The first one is
used to check the consistency and to transform
between UML models representing POP* models
and the POP* metamodel represented as an ecore
model. The second transformation bridges the gap
from enterprise models (POP*) to systems models
(PIM for SOA). And finally the third one transforms
and checks the consistency between UML models
representing SOA solutions and the PIM for SOA
metamodel represented as an ecore model. The
transformation language is Relation Definition
Language which file format is “.rdl”. This language
ARCHITECTING SOA SOLUTIONS FROM ENTERPRISE MODELS - A Model Driven Framework to Architect SOA
Solutions from Enterprise Models
553
defines relations between metamodel elements of
different metamodels and it reconciles the models
involved.
4 CONCLUSIONS
In this paper a MDA approach is applied to address
the gap between business models and ICT systems
implementations and to build service oriented
solutions from a platform independent point of view.
A framework based on the eclipse platform is
described. This framework contains the introduced
POP* metamodel, as a business model, the PIM for
SOA metamodel, a set of model driven
transformations and a UML profile to describe SOA.
The separation between business models and ICT
implementation models assigns flexibility to change
elements within models keeping a separation of
concerns between metamodels. The implementation
of POP* and PIM for SOA metamodels and its
model transformation in the Eclipse platform
provides a higher independence from the tools and
technologies used. The model transformations
provide a certain level of traceability between
business needs and ICT implementations. The usage
of the PIM for SOA UML profile allows users to
instantiate service oriented solutions and to
transform them as an instance of the PIM for SOA
metamodel.
In spite of these benefits this is a weak approach
if one of the involved metamodels changes
considerably. The existing models must be modified.
This task could be resolved using a model
transformation from the old metamodel to the new
one. In addition this framework is independent form
UML tools but the part concerning the PIM for SOA
plug-in for Rational Software Modeller must be
specialized for each specific UML tool.
One of the future directions is to derive from the
PIM for SOA directly BPEL and WSDL code.
Acknowledgments
This work was funded by ATHENA IP (IST-
2003-507849). We would like to thanks ATHENA
partners for they great feedback.
REFERENCES
Allen, Linda & Rai, Anoop, 1996. "Operational efficiency
in banking: An international comparison," Journal of
Banking & Finance, Elsevier, vol. 20(4), pages 655-
672
ATHENA, 2005. Advanced Technologies for
interoperability of Heterogenous Enterprise Networks
and Applications project, IST- 507849
http://www.athena-ip.org/
ATHENA DA1.1,2005. First Version of State of the Art in
Enterprise Modelling Techniques and Technologies to
Support Enterprise Interoperability.
http://www.athena-ip.org/
ATL, 2005.Atlas Transformation Language
http://www.sciences.univ-nantes.fr/lina/atl/
Eclipse Modelling Framework,2005.
http://www.eclipse.org/emf
Fiorano Software, 2004. Service Oriented Architectures
Implementation Frameworks. http://www.fiorano.com
HayGroup, 2005. “Annual Benchmarking Comparison of
Canadian Hospitals”,
http://www.haygroup.ca/services/Benchmarking%20H
ealth/2005/CIHI%202005.pdf
INTEROP, 2005. Interoperability Research for Networked
Enterprises Applications and Software project,
http://www.interop-noe.org/
Meta Object Facility,2004. Object Management Group
(OMG), Document ptc/03-10-04.
http://www.omg.org/docs/ptc/03-10-04.pdf
MTF,2005. Model Transformation Framework,
http://www.alphaworks.ibm.com/tech/mtf
QVT, 2002. "Revised submission for MOF 2.0
Query/Views/Transformations RFP (ad/2002-04-10),
Version 1.8", Object Management Group (OMG),
Document ad/04-10-04, 2004.
http://www.omg.org/docs/ad/04-10-04.pdf
UEML, 2001. Unified Enterprise Modelling Language
project, IST- 34229. http://www.ueml.org
UEML D1.1,2002. Report on the State of the art in
Enterprise Modelling
http://athena.troux.com/AKMii/WebComputas/TeamB
lob.aspx?TeamPage=/Team/Repository/Projects/Proje
ct_249/Upload/Attachments/239_30_122__UEMLD1
1.pdf
UML 2.0, 2003. Infrastructure Specification, Object
Management Group (OMG), Document ptc/03-09-15,
December 2003. http://www.omg.org/docs/ptc/03-09-
15.pdf
Vernadat,F.B. 1996. Enterprise Modeling and Integration:
Principles and Applications. Chapman and Hall
ICEIS 2006 - INFORMATION SYSTEMS ANALYSIS AND SPECIFICATION
554
