Pedagogical Pattern #43
Model Transformation (MT) Pattern
(Version 1.0)
Kevin Morris Marler
Raytheon E-Systems Garland
Manager of Learning Services
Technology Transfer Center marler@onramp.net
Name:
Model Transformation Pattern
Intent:
To emphasis the relationship between models within an object oriented engineering process by creating an opportunity for students to present the UML diagrams that they develop within the context of the other diagrams.
Motivation:
Students are often taught each diagram without being taught how the diagrams relate to each other while in practice there is a high degree of correlation between the diagrams. The MT pedagogy provides an approach the emphasizes the transformations. Students are encouraged to make changes to models that they have previously developed to show that they are gaining an increased understanding of the system being designed.
Applicability:
Use the Model Transformations pattern while teaching a process that contains a series of diagrams that contain information that relate to each other within a larger context.
Structure:
Origin of the design is presented:
Customer operational concepts document, requirements lists, or customer needs assessment.
First transformation information is extracted:
Operation contexts should be extracted, if engineering is to begin with Use Case engineering. First UML model is developed:
Use Case diagrams are prepared from the transformation information and verified back to the original source of the desired system. Next set of transformation information is extracted:
From the Use Cases, system responsibilities can be extracted in preparation for finding classes. Next model is presented:
Class diagrams are prepared from the responsibilities transformation information. Interaction diagrams have proven useful in related use case engineering and class modeling engineering efforts.
Repeats the "next" steps while working through all of the UML models.
Consequences:
The MT pattern:
the degree of consistency between the drawings is increased due to understanding the information that ties the diagrams together;
students are more aware of the impact of changes, they know if the change relates to transformational information and what other diagrams need to be updated;
provides the instructor with the opportunity to discuss the management of change.
Implementation:
Issues to consider:
student teams can prepare their UML drawings on easel paper-sheets, a series of easels can be lined up across the front of the class room,
students present each diagram by discussion the transformation information
first. This allows the students to discuss changes to previous diagrams as they continue design from diagram to diagram while learning more about the system and capturing the knowledge as it is realized.
Related Patterns:
(none so far)
Example Instances:
This pattern has been used to teach:
Software Systems Engineering Object-Oriented Analysis and Design