a lightweight mdd process applied in small projects
TRANSCRIPT
A Lightweight MDD Process Applied in Small Projects
Gabor Guta, PhD
Motivation
Generative approaches become popular like model driven development (MDD), domain specific languages (DSL), etc.
Several success stories about applying these techniques in large
Process frameworks and methods for full scale application of them
Lot of software developed by small teams using Agile methods
There is no or little help of its application in small!
What is MDD?
Generating software from a model– Advantage: saving time/effort on implementing
repetitive tasks by working on model level
The most well known approaches are the followings:
OMG's MDA
Microsoft's Software Factories
What is MDD? (cont'd)
The artifacts generating transformations are often called templates
Domain & intermediate models can be described with meta-models
Differences
What is the domain model (real life / implementation)?
How can the domain meta-model be represented?
What kind of notation do we use to communicate the domain model?
How are the transformations defined? Do we allow to edit the intermediate models or
the generated artifacts?
Further differences
How does MDD affect the development process? Are we able to reverse the transformation
(propagate changes of the generated artifacts back to the original model)?
How can intermediate models be merged if the original generated model was modified and a different one was generated after the domain model was changed?
What are the quality implications of the MDD? How does it modify the test and review procedures? What kind of additional problem can be expected?
Important Issues of the Lightweight MDD
Most of the risks should be mitigated No immature technology allowed Fall back to the traditional development method
The approach should not delay the schedule in general
It should have immediate business advantage
The approach should be cost sensitive No high cost MDA tool set, No extensive training
Important Issues of the Lightweight MDD (cont'd)
The domain-model should be kept as simple as possible and the generated code should be human-readable and modifiable.
The results should be reusable in other projects.
Our Minimalistic Approach
Creating the simplest solution
Using the simplest tool-set
Explicitly support the partial approach We just model and generate parts where it pays off Keeping track of which requirement applied in the
model is relatively cheap
Project Experience
An enterprise web application for a specific domain developed
Microsoft’s ASP.NET technology and an MS-SQL back-end were used (conforming to architectural guidelines of the multi-layer enterprise ASP.NET applications
Readable source code and complete developer documentation
The project team experienced with traditional iterative development method (containing elements from current Agile methodologies)
Teams
The agile development team Members were: developers, a software architect Responsible for: hand crafted software
The business analyst team Members were: managers Responsible for: requirements and the domain models
The model driven development team Members were: an MDD expert, developers Responsible for: MDD environment, the templates
Artifacts
An MDD vision A code generation tool A domain test model An MDD environment (domain metamodel, a
domain test model, and a code generation tool). Hand crafted software Released software A software requirement specification (or
requirements)
Activities
Domain model extraction In: requirements Out: initial domain model, MDD vision
The MDD environment setup In: MDD vision, initial domain model Out: code generation tool, initial version of the domain
meta-model, domain test model
Domain modeling Refine: domain model
The MDD environment development Refine: MDD environment
Activities (cont'd)
Template development Refine: templates Steps: the required functionality is implemented in a software
prototype; the implementation is extracted and to edited into the
templates; finally, the they are tested with the help of the domain
test model.
Code generation In: templates and domain model Out: generated artifacts
Activities (cont'd)
Integration In: generated artifacts, hand-crafted software Out: released software
Development Requirements Refinement Architectural prototyping Design Development
The Template Development Activity
The most complex and critical activity of the process
It becomes dominant activity of the MDD team after the MDD environment is stabilized
During an iteration several features are implemented iteratively in the frame of this activity
The Template Development Activity (cont'd)
A feature is implemented as an extension of the generated artifacts (designed, coded and tested)
The implemented feature is extracted from the source code and inserted into the templates
The artifacts re-generated with the new templates Tested with the test-cases of original
implementation
The first iteration is sightly different, because no prior generated artifacts available at that time.
Conclusion
Our model driven development method has been applied successfully
Our "experiment" has two results our process can be used successfully in an averages
small-mid sized project project can be realized with standard data format (XML,
JSON, or YAML) and template engines (XSLT, Jinja2, etc.), i.e. no need for special MDA/DSL tool chain
Our process can be also used as preparatory step before the introduction of a heavyweight process