This paper presents a model driven approach for the generation of business process driven web applications within the context of ubiquitous environments. For this reason, we have taken into account that the generated Web applications can be accessed via different devices (such as PDAs), which introduce a set of constraints that are better faced at the modeling process. This proposal relies on both model-to-model and model-to-text transformation techniques to obtain the final software artifact. As a result, we have implemented an Eclipse based prototype that generates from a business process definition the adequate GUI (in terms of the device) to execute the process as well as the equivalent definition into an executable language such as WS-BPEL.
1. Introduction
Business Process specifications play an important role in enterprise application development. These specifications allow defining the interaction between different participants in order to achieve certain agreed goals. However, enterprise applications cannot be limited to be run in the computers that are located in our offices (such as desktop environments). In fact, there exist scenarios where application users are constantly moving to different locations, needing applications that (1) help them performing the tasks that they are responsible of and (2) fit into their day life working devices. As a result, the development of this sort of applications could overcome spatial and technological obstacles that exist today. Then, we should take into account how our applications are going to be displayed in different devices which usually introduce both new characteristics and limitations.
Therefore, in this work we propose a methodological approach that allows us to
obtain from a business process definition (represented in the BPMN notation [
The remainder of the paper is structured as follows. Section 2 presents briefly the
proposed MDA approach and how it is completed to overcome output device
limitations at the modeling level. Section 3 provides a general overview of the generation
process by means of an implemented tool, where both model-to-model and
model-totext transformations are applied to automate the generation process. Finally, section 4
closes the paper with some conclusions and outlines further work.
2. A MDA Approach for Building Ubiquitous Business Process
Applications
Roughly, the MDA approach proposes defining the software building process based
on a set of models. Depending on the level of abstraction, these models are dependent
or independent of technological issues. Following this approach, the OOWS approach
[
Navigational and Presentation models (NM and PM hereafter) were introduced by
Web Engineering methods in order to handle interaction aspects during the software
modeling process. However, these two models are built independently of any
technological aspects, and therefore they cannot be used to introduce specific aspects
concerned about target devices [
For this reason, we have defined, at the PSM level, a mechanism that allows us to characterize those aspects introduced by output devices (such as space limitation) and that need to be considered during the modeling process. This mechanism has been designed taking into account that some characteristics and limitations introduced by output devices are not always exclusive of one device and can be shared by several devices. In addition, these characteristics are not always orthogonal to each other, and some of them can be used to solve the limitations introduced by others. 1 Model -devices Device
-name -capabilities *
Capabilit -name 1
* -capability 0..1 * 1 * -coverage Coverage
PartialCoverage -degree FullCoverage 3. An Eclipse Based Tool for the Generation of Ubiquitous Business Process Driven Web Applications In order to materialize the presented approach, we have developed an Eclipse based tool as a proof of concept of these ideas. In particular, this tool allows us to obtain from a business process definition (1) the corresponding GUIs (specified by means of a navigational model) that are necessary to execute the process in any of the supported devices and (2) the process equivalent definition in terms of an executable language (WS-BPEL). Moreover, the Navigational Model previously generated is also transformed into the code that represents these GUI.
The definition and implementation of a set of transformations rules have empowered us to fully automate the generation process. The prototype tool has been developed within the context of the Eclipse environment. First of all, we have defined the metamodels involved in the proposal (CD, SM and NM) in EMF. The reason of having models defined in this format are that (1) we can manipulate them easily with the model instances editor provided by the framework and (2) it allows us to navigate models in order to transform them into either other models or directly into code. On the other hand, the set of transformations implemented in the prototype have been defined using two different languages. In the first place, to implement model-to-model transformations we have used the MOF 2.0 QVT Operational Mappings implementation provided by the Borland Together Architect 2006 for Eclipse. In the second place, model-to-text transformations have been implemented using the MOFScript tool, which provides an implementation of the MOFScript language, an OMG candidate proposal for MOF2Text transformation. Ubiquitous Computing capabilities can improve considerably the way Business Processes are performed. Moreover, these improvements can be applied to a wide range of scenarios, from critical aircraft maintenance operations to supply chain management. However, little research has been done in taking advantage of conceptual modeling techniques for enabling an automatic software development of Business Processes defined within a ubiquitous environment.
In this work we have presented a MDA approach for the development of ubiquitous business process driven applications. This approach allows us to obtain automatically from a business process definition both the GUIs that represent the required user interaction to support the process execution for different kind of output devices and the executable definition of the process in the WS-BPEL language. Moreover, this proposal has been reinforced with the implementation of a prototype, which allows automating the generation process by the use of metamodels and the application of model transformation technologies.
As a result of this work, we have learned that model transformations techniques allows us to generate in a systematic way technological independent system specifications in terms of an specific technology. The real challenge arises in defining and handling properly the primitives that represent the system (its domain and its execution context) at the modeling level.
As further work we have planned to extend the proposal to cover the new challenges that introduce ambient intelligence and eAccesibility and eInclusion systems within a model driven approach and how these issues are translated into our tool. 5. References