GUI_UML Tutor

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GUI_UML Tutor

• Developed and evaluated by-
• Jim Moon and Gaylor Boobyer.
• Presented by-
• Dave Farthing.

School of Computing University of Glamorgan
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Introduction

• The Unified Modelling Language (UML) is the de
  facto standard for the visual analysis and design
  of object oriented software.
• This presentation introduces a prototype software
  tutor that is under development to try to provide
  the following-
• An understanding of how UML and a software
  program relate to each other.
• A single consistent source that describes the key
  concepts of a final year UML course.
• A guide to help ensure that the UML model is
  consistent across a number of diagrams.
• NOTE- Although this tool can create partial UML
  designs it is meant as an introductory tutor.

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Challenges of UML

• A UML model is quite an abstract representation
  of a software system.
• Currently, UML provides little support for
  mapping the abstract UML representation to the
  physical software being developed.
• Burton and Bruhn (2004) found that students of
  UML find a visual approach with active
  involvement beneficial.
• The UML language is evolving quite quickly, this
  means that many information sources are based on
  subtly different language syntax.
• The synthesis of the UML techniques is a
  cognitively challenging task.
• Frosch-Wilke (2003) published a survey of ten
  university courses on UML showing that many
  students failed to understand interdependencies
  between the different UML diagrams and did not
  really know how UML helps to build good software.

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The GUI-UML Tutor

• The tutor is intended to assist a student in
  understanding how elements of UML relate to the
  actual software.
• The tutor is also intended to provide examples of
  UML techniques working in synergy.
• It has been found that many students are good at
  producing user interfaces and often enjoy doing
  so (e.g. using Visual Basic). Therefore, the
  first task in using the tutor is to create a
  simplified GUI interface.
• This is only intended as a basic introduction to
  Use Case modelling, not as an ideal method of
  always determining Use Cases.
• Storyboards are sometimes used in a similar way
  to reflect the steps taken to play out a scenario
  (Ambler 2003).

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UML

• The following example demonstrates part of the
  development for a Cashpoint (ATM).
• A Use Case symbol is simply a visual
  representation of a significant behavioural
  feature of a system.
• E.g. for a Cashpoint Log In, Log Out,
  Withdraw Cash, etc.
• A Use Case often, although not always, reflects a
  menu item in a software system.
• By creating a User Interface the students can see
  the way the scenario plays out before writing the
  Use Case.

Withdraw Cash
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Identifying Use Case initiation
The student places a menu Item on the screen and
considers whether it initiates a Use Case
If so, the student identifies the Menu item as
initiating the Log In Use Case.
The red tabs indicate that this Menu Item
initiates a Use Case.
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Playing out the Use Case scenario in the GUI
As shown earlier, inserting the Card Initiates
the Log In Use Case
Once the card has been read the Log In Screen Is
displayed
The customer enters a PIN
Then presses OK
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Once the PIN has been entered it is checked and
the relevant account is found by the software
system.
Successful log in brings up the ATM Main Screen
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Converting to UML

• Having visually identified the sequence of steps
  in a scenario the student needs to convert them
  to UML.
• The development version (1.01) now includes Use
  Case diagramming and the student creates a Use
  Case diagram.
• The ltltboundarygtgt, ltltcontrolgtgt and ltltentitygtgt
  classes design pattern is employed.
• The tool generates a ltltboundarygtgt class for each
  data entry form.
• The tool generates a ltltcontrolgtgt class for each
  menu item.
• The students are left to develop ltltentitygtgt
  classes, e.g. via lexical analysis (nouns).

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Therefore, the student creates a Use Case diagram
to match the Use Cases they have found (version
1.01).
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Use Case Narrative (Text based)
For each use case the way a scenario is played
out is then described in a Use Case narrative
Log In
Typical Use Case Narrative- Log In Assumptions
- The cash machine is operational. Pre-conditions
- The customer has a valid bank account and bank
card. Post-conditions- The customer card has
been accepted. The customer account has been
identified. The Customer is logged in. Use Case
Dialog (Specification) (for a successful log on)
- The customer inserts their card which is
checked by the software. The log in screen is
displayed and the customer enters their pin
number and selects ok. The system checks the PIN
number, finds the relevant account and the ATM
main screen is displayed.
Customer
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The Tutor Use Case Narrative
The narrative dialog provides specific tabs to
remind the student about the data to enter
(version 1.01).
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Identifying the Use Cases automatically
produces a system ltltcontrolgtgt class.
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Also, creating the Forms automatically
produces the ltltboundarygtgt classes. E.g. for the
Log In form
These classes represent the Screens of the system
E.g. Dialog Boxes The student then needs to
take data from the dialog box and store it in
the correct ltltentitygtgt class.
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Help

• General help, tutorials and context sensitive
  help are provided to assist the student as they
  progress. In this case F1 was pressed while over
  a Use Case on a Use Case Diagram.

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Results

• Version 1.0 of the tutor was employed this year
  with a group of thirty three final year software
  engineering students.
• One final year computer studies student with less
  exposure to UML also used the tutor as a guide to
  producing the documentation for his project. He
  has not been included in the following results.
• An analysis of the software engineering students
  results follows.

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Pre tutor questionnaire results

• Surprisingly, most of the final year students
  felt quite confident about developing a complete
  software design before being given this tutor

Confidence level
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Post tutor questionnaire results

• While almost all the student cohort completed the
  pre tutor questionnaire, less than 50 completed
  the more detailed post tutor questionnaire.
• The results show that almost all those students
  who had completed both questionnaires had
  generally benefited from using the tutor software.

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Post tutor questionnaire results

• Further examination of the results indicated an
  anomaly in two of the students pre and post
  questionnaires.
• These students had originally been very confident
  of their design abilities but had become less
  confident of their abilities after using the
  tutor.
• The feeling of the team is that these particular
  students had been overly confident when initially
  completing the pre tutor questionnaire. Omitting
  these results

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The Future

• The direction of development is guided by
  feedback from the students. This year the
  students responses suggested the following order
  of development
• Increased number of case studies/tutorials in the
  help system
• Use Case diagrams
• Class diagrams
• The ability to print diagrams and export models
  to Rational Rose.
• Therefore, version 1.01 is under development and,
  as you have seen, it includes Use Case
  diagramming.
• There are many other aspects of development that
  are under consideration
• Activity diagramming
• Sequence diagramming
• The use of the .NET design time architecture to
  improve the interface.

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Concluding remarks

• This presentation has introduced a prototype
  software tutor for UML.
• The key features are-
• Using a simple GUI to guide use case reasoning
• Automatic development of simple ltltboundarygtgt and
  ltltcontrolgtgt classes
• A context sensitive help system to guide the
  students
• On line tutorials.

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References

• Ambler S W, The Object Primer Agile
  Model-Driven Development with UML 2.0, Third
  Edition, Cambridge University Press (2004).
• Burton P J, Bruhn R E, Using UML to facilitate
  the teaching of object-oriented systems analysis
  and design, Journal of Computing Sciences in
  Colleges, 19, issue 3, pp 278-290, (Jan 2004)
• Frosch-Wilke D, Using UML in software
  requirements analysis -- Experiences from
  practical student project work. Proceedings of
  the Informing Science IT Education Conference,
  Informing Science Institute, Santa Rosa, CA, pp
  175-183, June, (2003).
• Hansen K M, Ratzer A V, Tool Support for
  Collaborative Teaching and Learning of
  Object-Oriented Modeling, Proceedings of the 7th
  Annual Conference on Innovation and Technology in
  Computer Science Education ITiCSE 02, Aarhus,
  Denmark, June 24-26, pp 146-150 (2002)
• Thomas L A, Ratcliffe M, Woodbury J, Jarman E,
  2002, Learning Styles and Performance in the
  Introductory Programming Sequence, Proceedings of
  the 33rd SIGCSE technical symposium on computer
  science education. Covington, KY ACM Press,
  (2002).