Advanced Domain Modeling

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Advanced Domain Modeling

• Architecting for Agility with Color Models
• David J. Anderson
• Program Manager, Microsoft
• dander_at_microsoft.com

Based on the work of Peter Coad, Stephen R.
Palmer and others
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Objectives

• Peter Coad and Patterns
• A brief history of how color modeling came about
• Archetypes and the Domain Neutral Components
• Modeling for Agility
• Loose coupling and Law of Demeter
• Advances in Color Modeling since 1999
• The role of ltltrolegtgts
• Getting the blues
• Whole-part relationships
• Patterns of color communicate architecture smells
• Enterprise components from color models

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History - 1992
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History - 1995
Object Models Strategies, Patterns
Applications, 1st ed., Coad, Mayfield North,
Yourdon Press, Prentice Hall, 1995
5
History Spring 1997

• Moment or Interval a generalization of the idea
  of a transaction e.g.
• Warranty Period
• Period of Employment
• Loan Approval Request
• Funds Disbursement

still referred to as Transaction in, Object
Models Strategies, Patterns Applications, 2nd
ed., Coad, Mayfield North, Yourdon Press,
Prentice Hall, 1997
6
History September 1997
Color instantly communicates the pattern of class
relationships to the viewer
If the colors are not configured in the correct
pattern then there are strong clues that the
model could be improved!
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Dec 1998 Archetypes
Philip Bradley argues for Archetypes not
stereotypes.
a model from which all things of the same kind
more or less follow
rather than
a conventional, formulaic, over-simplified
conception, opinion or image
And that, all business flows should or ought to
be basically the same.
Data Model Patterns - Conventions of
Thought, David Hay, Dorset House, 1996
The Universal Data Model
Phil Bradley was Development Manager Persistence
Layer, PowerLender Project, United Overseas Bank,
Singapore 1997 - 1999
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History January 1999
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Architecture Board
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Component Map
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Archived Iteration
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Definition of an Agile Model

• Elegant
• Enough to get the job done and no more
• Extensible
• Loosely coupled
• Robust and resilient to change
• Communicates clearly

In anything at all, perfection is finally
attained not when there is no longer anything to
add, but when there is no longer anything to take
away
Antoine de Saint Exupery
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Behavior of Colors
assessPerformance() salesMadeInPeriod()
averageSalesOverPeriod() assessAccuray() assessSpe
ed() isActive() isSuspended()
totalValue() isComplete() isUrgent()
_findByIdNumber() _findByName() isOfType() getVal
ue() assessAcrossRoles() listRolesPlayedBy()
totalUnitsAvailable() totalUnitsManufactured() ass
essRoleAllowed()
Courtesy Stephen R. Palmer

• Instances of Archetypes share similar attributes
• Instances of Archetypes share similar methods

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Where do ltltRolegtgts come from?
OK!
Better!
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Naming Conventions for Roles

• When no domain specific term for a ltltrolegtgt
  exists use the template
• PersonPlaceThing In Moment-Interval
• Or, GreenInPink e.g.
• ItemInSale

Note the actual aggregating ltltMoment-Intervalgtgt
is used for naming rather than the ltltMI-Detailgtgt
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Roles and Inheritance
Courtesy Stephen R. Palmer
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Inherit from a Role superclass
Courtesy Stephen R. Palmer
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Manage roles with a description
Courtesy Stephen R. Palmer
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Subsequent Roles
Courtesy Stephen R. Palmer
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Moment-Intervals get the Blues

• Missing from the original DNC in 1999
• Pink Classes can have Descriptions just like
  Greens

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Whole-Part Relationships
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Color Differences Can Be OK
(A) This model has a whole-part color conflict
but it is not wrong. It is simply less flexible
and more coupled
(B) This model resolves the color conflict and is
more loosely coupled but requires 2 more classes
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Just Plain Wrong

• Some color combinations in Whole-Part
  relationships should immediately raise the red
  flag for the modeling team
• As a general rule, question all aggregation and
  composition where color changes across the
  association

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Subsequent Blues

• Description classes can have object inheritance
  relationships with subsequent descriptions
• Generally, there will only be one green class in
  the chain. Greens may aggregate or collect other
  greens but object inheritance should be
  yellow-green, green-blue or blue-blue

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Class or Object Inheritance
Courtesy Stephen R. Palmer
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Simple Corporate Structure Example
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Types of Blues

• Blue Catalog Descriptions, but also Enumerations
  and encapsulated (plug-in) Business Rules
• Each rule can have its own interface plug-in
  point and implementors can be hooked in at runtime

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Putting It All Together
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Law of Demeter
A different view of the DNC showing the dynamic
dependencies between classes. Classes only hold
dependencies to their immediate neighbors The DNC
is very loosely coupled
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LoD Compliant Sequence Diagram
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Wrong not LoD Compliant
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Possible Component Boundaries
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DNC as Component Model
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Business Workflow Example
Component Boundary
A sequence of ltlt Moment-Intervals gtgt can be
packaged together as a component
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Re-usable Enterprise Components
Pinks and yellows are re-usable across multiple
greens the core Enterprise Components
Greens and blues are re-usable across discrete
Enterprise Applications modeled as sequences of
pinks
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Two more possible schemes
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One-way Dependency
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Resolving 2-way Dependencies
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More 2-way Dependencies
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Summary Color Modeling

• Easily learned - Easily taught
• But yet, a craft - perfected over time
• DNC is reliable and repeatable
• - a basic pattern even novice modelers can follow
• Archetypes easily identified from requirements
  documents
• Eliminates class discovery problems
• Leads to elegant, robust, extensible, agile
  models
• Take-away modeling rather than addition
• Typically an order-of-magnitude speed improvement
  for class diagrams over traditional verb-noun
  approach
• Only one pattern to learn!

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Questions?
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Contact Details
David J. Anderson Program Manager,
Microsoft dander_at_microsoft.com http//www.agileman
agement.net/
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References
Object Models Strategies, Patterns
Applications, 2nd ed., Coad, Mayfield North,
Yourdon Press, Prentice Hall, 1997 Java Modeling
in Color with UML Enterprise Components and
Process, Coad, Lefebvre, De Luca, Prentice Hall,
1999 Data Model Patterns Conventions of
Thought, David Hay, Dorset House, 1996 The Coad
Letter 68 - The Domain Neutral Component,
Stephen R. Palmer, 2002 http//www.thecoadletter.c
om/article/0,1410,29697,00.html The Coad Letter
71 From Association to DNC, Stephen R. Palmer,
2002 http//www.thecoadletter.com/article/0,1410,2
9683,00.html The Coad Letter 74 Historic
Values, Stephen R. Palmer, 2002 http//www.thecoad
letter.com/article/0,1410,29680,00.html The Coad
Letter 76 Modeling User Roles, Stephen R.
Palmer, 2002 http//www.thecoadletter.com/article/
0,1410,29678,00.html The Coad Letter 77 Object
Models to DNC, Stephen R. Palmer,
2002 http//www.thecoadletter.com/article/0,1410,2
9677,00.html The Coad Letter 79 The Example
Teaches, Stephen R. Palmer, 2002 http//www.thecoa
dletter.com/article/0,1410,29675,00.html The Coad
Letter 82 Description Class Archetype, Stephen
R. Palmer, 2002 http//www.thecoadletter.com/artic
le/0,1410,29672,00.html The Coad Letter 87
Good Ideas Behind Color Modeling, Stephen R.
Palmer, 2002 http//www.thecoadletter.com/article/
0,1410,29667,00.html The Coad Letter 103 Party
Time, Stephen R. Palmer, 2002 http//www.thecoadle
tter.com/article/0,1410,29661,00.html The Coad
Letter 107 Party Time Modeling Legal IDs,
Stephen R. Palmer, 2003 http//www.thecoadletter.c
om/article/0,1410,29605,00.html