Copyright ©2004 Cezary Z Janikow 1 Domain Model n Visualization of entities and relationships n In UP presented as Class Diagrams – Classes, Relationships, Attributes in the domain n Important analysis artifacts – Driven by use case – Stipulates initial design ideas in contracts – Stipulates final design in Interactions – Provides visual dictionary n Moves through different perspectives – Conceptual: from use case – Design: from Interactions – Implementation: implementation details

Copyright ©2004 Cezary Z Janikow 2 Domain Model: when n Start in Inception n Most efforts to detail in Elaboration

Copyright ©2004 Cezary Z Janikow 3 Domain Model

Copyright ©2004 Cezary Z Janikow 4 Domain Model: partial POS example (conceptual)

Copyright ©2004 Cezary Z Janikow 5 Class Diagram n Static view of the domain n Presents domain conceptual classes n And not proposed implementation or design classes

Copyright ©2004 Cezary Z Janikow 6 Conceptual Class n Symbol n Intension: definition n Extension: set of elements

Copyright ©2004 Cezary Z Janikow 7 Domain Model vs. Design Model n Same names and notation lower the representation gap

Copyright ©2004 Cezary Z Janikow 8 Domain Model vs. Data Model? n Domain Model – Concepts, entities, can be abstract – Relations – Attributes n Data Model – How data is stored into persistent storage – Pure data, in files or databases

Copyright ©2004 Cezary Z Janikow 9 Domain Model: how to create? 1. Find conceptual classes – Refine existing model and/or use patterns – Explore concepts in the Category List See Table 9.1 – Explore Noun Phrases Lexical/linguistic analysis of use cases and other text documents See pate Add associations 3. Add attributes

Copyright ©2004 Cezary Z Janikow 10 Conceptual classes in POS n Class or Attribute? – Use the 3 object properties to test – Remember design will change things if needed

Copyright ©2004 Cezary Z Janikow 11 Description Classes n Class that describes something else – Example: Item object represents physical object Description of the object is separate In the design perspective, we need to retain description even if sold out on items (and thus no item objects)

Copyright ©2004 Cezary Z Janikow 12 Rules for having Description classes – If descriptions are independent of the exietence of items – If deleting an object deletes information that may need to be maintained – If it reduces duplications or adds clarity

Copyright ©2004 Cezary Z Janikow 13 Associations n Relationships between classes – Stemming from relationships on objects Transient (for some duration that we need to investigate details of) Persistent n Derived from Analysis or the Association List (Table 9.2) n In the conceptual model, association is just a statement about the relationships – If message need to be passes, it will persist in the design model (from Interactions) Visibility and navigability will have to be established

Copyright ©2004 Cezary Z Janikow 14 Association Notations

Copyright ©2004 Cezary Z Janikow 15 Associations n Naming – Verb Phrases n Roles – Each end – Having Names for the roles of the two classe/objects (sometime this is called “roles”) Multiplicity How many objects participate Navigability How one object will find the other object to send a message

Copyright ©2004 Cezary Z Janikow 16 Multiplicity

Copyright ©2004 Cezary Z Janikow 17 Multiplicity

Copyright ©2004 Cezary Z Janikow 18 Multiple Associations n Two classes can have multiple relations

Copyright ©2004 Cezary Z Janikow 19 Conceptual Domain Model in POS

Copyright ©2004 Cezary Z Janikow 20 Attributes n Logical data value of an object n Carefully distinguish attributes from objects – Do not use to relate classes or objects Use associations instead – Use as classes if Composed of multiple elements (has attributes-states) There are operations (behavior) Has units of quantity

Copyright ©2004 Cezary Z Janikow 21 Attributes: notation

Copyright ©2004 Cezary Z Janikow 22 Multiplicity vs. derived attribute

Copyright ©2004 Cezary Z Janikow 23 Multiplicity vs. derived attribute

Copyright ©2004 Cezary Z Janikow 24 Attributes: examples

Copyright ©2004 Cezary Z Janikow 25 Attributes: examples

Copyright ©2004 Cezary Z Janikow 26 Attributes: examples of quantities

Copyright ©2004 Cezary Z Janikow 27 POS Domain Model w/attributes