1. Evolving KobrA to support SPL for
WebGIS development
Juan Manuel Moreno Rivera Elena Navarro Carlos E. Cuesta
JuanManuel.Moreno@uclm.es Elena.Navarro@uclm.es carlos.cuesta@urjc.es
VADER 2011, Hersonissos, Crete, Greece – 17-21 October
VADER 2011, Hersonissos, Crete, Greece – 17-
21 October

2. Overview
 Introduction
 WebGIS Domain
 Related Work
 KobrA in a nutshell
 Evolved KobrA containment tree
 Case Study
 Conclusions and Future Work
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

3. Introduction
 WebGIS development is more complex everyday
 Component-based development
 New emerging technologies: grid, cloud, smart phones,
participatory web …
 New users require new and more complex functionality
 Open GIS community: the supply chain
 Development and maintenance of own developed
components
 Adoption and maintenance of third party components
 Common architecture along all portfolio products
 There is an exhausting situation for SME
 Reuse is critical: SPL approaches (KobrA)
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

4. Overview
 Introduction
 WebGIS Domain
 Related Work
 KobrA in a nutshell
 Evolved KobrA containment tree
 Case Study
 Conclusions and Future Work
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

5. The WebGIS Domain (I)
 WebGIS widely used by internet users
 Core elements in WebGIS:
 Spatial Data Base
 Map server
 Map viewer
 Extra components in WebGIS
 Edition tools
 Reports and analyzing tools
 GeoProcessing features
 Mobile Devices support
 …
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

6. The WebGIS Domain (II)
 Integration of own and third party components
 Open GIS community alive and growing
 More components to be considered
 Wide variety of development approaches and
documentation
 Open standards for data communication
 Cloning emerges
 Non efficient management of the common architecture
 Difficult to track, maintain and update deployed systems
 Hard to develop test benchmarks for final systems
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

7. Overview
 Introduction
 WebGIS Domain
 Related Work
 KobrA in a nutshell
 Evolved KobrA containment tree
 Case Study
 Conclusions and Future Work
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

8. Related Work: GeoStack
 Development based on a common framework or the
combination of a group of core components
 Family of products based on a common architecture
with limited differences between their functionalities
 Problems:
 (i) Strongly linked to the technology their components
have been developed for
 (II) Variability constrained to a reduced group of final
features already considered by core components
 (III) The cloning phenomenon arises due to the lack of
traceability
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

9. Related Work:
Software Product Lines (SPL)
 Two main branches of SPL approaches
 Feature-based
 More mature
 FODA settled down the bases in the 90’s
 Component-based
 Components are the basic unit as in WebGIS
 KobrA and CoPaM
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

10. Related Work:
Variability Notations
 SPL approaches provide notation for variability
management
 There are also specific notations to improve them:
 Common Variability Language (CVL)
 Eclipse CVL plug-in
 Focused on feature diagrams
 Orthogonal Variation Model (OVM)
 VarMod Editor
 Focused on improving the testing and formal
validations of models
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

11. Overview
 Introduction
 WebGIS Domain
 Related Work
 KobrA in a nutshell
 Evolved KobrA containment tree
 Case Study
 Conclusions and Future Work
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

12. KobrA in a Nutshell (I)
 Model-driven and Component-based approach for SPL
 Any element of the system can be modelled as a component
 UML: modelling language
 KobrA Models systems hierarchy based on tree structures
 Containment tree: relations between components at development time
 Composition tree: runtime instance of the system
 Based on two main processes:
 Specification: how a component interacts with the external world
(External API)
 Realization: how a component performs its specification
 WebGIS development is based on these two main concepts
 Each Open GIS component offers an external API to be connected with
other components / systems
 Then, each component implements the functionality according to its API
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

13. KobrA in a nutshell:
Domain Engineering
Containment Tree
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

14. KobrA in a nutshell:
Application Engineering
 Solving variability in each
node of the containment tree
 Flattening process: logical
components from containment
tree are mapped into physical
ones
 Translation process: transform
physical components into
source code
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

15. KobrA in a nutshell:
Pros and Cons from [12]
 KobrA Cons:
 There is no supporting tool to KobrA
 Strong focus on design for reuse
 Lack of model transformation facilities
 KobrA Pros:
 Components are the basic unit for development
 Internal configuration + external API
 Compliant with WebGIS component-based development
 Based on an adaptation of UML
 Updated to UML 2.0
 Many available UML tools
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

16. Overview
 Introduction
 WebGIS Domain
 Related Work
 KobrA in a nutshell
 Evolved KobrA containment tree
 Case Study
 Conclusions and Future Works
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

17. Evolved KobrA
Containment Tree (I)
 KobrA is a general purpose approach
 It needs to be customized to WebGIS domain
 Variability is modelled locally in each node of the system
 Application Engineers need to go along the containment tree, node by
node, to resolve variability
 The global view of the system is lost while deciding what functionalities
are necessary
 The global interaction and dependencies of components are only
modelled in the containment tree
 Decision models are text-based models
 They are a list of questions about variability and indications of what to
make on the model to resolve variability
 Decisions are not taken based on visual models but text models, which is
not very helpful during application engineering
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

18. Evolved KobrA
Containment Tree (II)
 In WebGIS variability emerges at components interaction level
 Which functionality needs to be included is strongly linked to
which component is chosen to implement it
 When working with third party components getting into the
node of this component in the containment tree is not
necessary
 For application engineers it should be a black box with its interface
 Just in some cases it is necessary to get into the black box to customize
its implementation. Most of the times it is plugged-in as it is.
 Commonly, the first step when implementing a new system is
choosing which components are going to be included based
on user requirements
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

19. Evolved KobrA
Containment Tree (III)
 Where do we want to improve KobrA SPL framework?
 1) Work to be done during creation, maintenance and update of SPL
framework can be reduced
 2) It is necessary to manage not only which features should be included
or not, but also which specific component should be used for
implementation
 3) To facilitate application engineering tasks by making more agile the
flatting and translation process of KobrA
 Adding OVM notation into containment tree
 It makes profit of the global overview
 Excludes relation is added (not considered in KobrA)
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

20. Overview
 Introduction
 WebGIS Domain
 Related Work
 KobrA in a nutshell
 Evolved KobrA containment tree
 Case Study
 Conclusions and Future Work
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

21. Case Study: SIGTel
 SIGTel is a SME with work experience on WebGIS development
 Family of products:
 Tools for inventories of trees, lights or management tasks of cities
 Monitoring land use, forest and urban regions
 Exploitation of Water balance and water flow models
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

22. Case Study: SIGTel
 SIGTel is a SME with work experience on WebGIS development
 Family of products:
 Tools for inventories of trees, lights or maintenance tasks in cities
 Monitoring land use, forest and urban regions
 Exploitation of Water balance and water flow models
 A common architecture for all of them
 Nowadays SIGTel development is based on GeoStack (OpenLayers,
Mapserver and PostGIS)
 Open source GIS community plays the role of supply chain
 Open GIS components are assembled together with own components
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

23. Case Study
 SIGTEL SPL according to KobrA
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

24. Case Study
 SIGTEL SPL according to our proposal
 Variability management included in the
containment tree
 Global overview of the system is not lost when
solving variability
 Components election is included at this stage
linked with user requirements that guide
variability solving
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

25. Case Study
 SIGTEL SPL according to our proposal
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

26. Case Study
 SIGTEL SPL according to our proposal:
 Variability management included in the containment tree
 Global overview of the system is not lost while resolving
variability at components level
 Components selection:
 Included at this stage
 Linked to user requirements that guide the variability
resolution
 A reduced containment tree is used to apply KobrA
 Reducing time needed for resolving variability at the
feature level
 The selection of available features is constrained by the
components selection performed in a previous step
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

27. Case Study
 SIGTEL SPL: Resolution of variability according to
KobrA
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

28. Overview
 Introduction
 WebGIS Domain
 Related Works
 KobrA in a nutshell
 Evolved KobrA containment tree
 Case Study
 Conclusions and Future Work
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

29. Conclusions
 OVM can help to improve variability in SIGTel SPL
 Containment tree: a more usable tool for application
engineers
 The number of models is reduced along the process
 Text-based decision models are partially replace by
graphical elements
 Flattening process is resolved at the same time that
variability
 Maintenance and update of variability is simplified
 KobrA variability management has been customized
to WebGIS development
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

30. Future Work
 Present: Improving Tool support
 Next step: Model-to-text transformation
 M2T from Eclipse is the project to follow
 Future Challenge: Improve the interaction with
Open GIS components
 How can we incorporate new functionality into our SPL
component adaptation?
 How can we give feedback to community and publish our
improvements / modifications on these kind of
components?
 These two tasks are very time consuming for our SPL
maintenance
VADER 2011, Hersonissos, Crete, Greece – 17-21 October

31. Evolving KobrA to support SPL for
WebGIS development
Juan Manuel Moreno Rivera Elena Navarro Carlos E. Cuesta
JuanManuel.Moreno@uclm.es Elena.Navarro@uclm.es carlos.cuesta@urjc.es
VADER 2011, Hersonissos, Crete, Greece – 17-21 October
VADER 2011, Hersonissos, Crete, Greece – 17-
21 October