1. Chapter 14. Activity Modeling for Transformational Systems

2. Key Takeaway Points
Activity modeling deals with the modeling of the information processing activities of an application or a system that exhibits sequencing, branching, concurrency, as well as synchronous and asynchronous behavior.
Activity modeling is useful for the modeling and design of transformational systems.

3. Activity Modeling in the Methodology Context
Use case-iteration allocation matrix
Business goals
& needs
Current situation
Accommodating
Requirements Change
Customer
feedback
Acquiring
Requirements
Iteration use cases
Domain Modeling
Preliminary requirements
Domain model
Domain model
Deriving Use Cases
from Requirements
Actor-System Interaction Modeling
Abstract & high level use cases, use case diagrams
Expanded use cases & UI design
Allocating Use Cases & Subsystems
to Iterations
Behavior Modeling &
Responsibility Assignment
Behavior models
Use case-iteration allocation matrix
Deriving Design Class
Diagram
Producing an Architecture Design
Design class diagram
Software architecture
Test Driven Development, Integration, & Deployment
(a) Planning Phase
(b) Iterative Phase – activities during each iteration
control flow
data flow
control flow & data flow

4. What Is Activity Modeling
Activity modeling focuses on modeling and design for
complex information processing activities and operations
information flows and object flows among the activities
branching according to decisions
synchronization, concurrency, forking, and joining control flows
workflow among the various departments or subsystems

5. Why Activity Modeling
Systems analysis and design need to
describe current information processing activities in the organization or existing system (modeling of the existing system) to help the development team understand the existing business
describe information processing with the proposed solution (system design)

6. A UML activity diagram is a combination of
An activity diagram models the information processing activity in the real world (analysis model) or the system (design model).
A UML activity diagram is a combination of
flowchart diagram
for decision making or branching
data flow diagram
for information processing and data flows
Petri net diagram
for various control flows
for synchronization, concurrency, forking, and joining

7. A Flowchart
decision
making
x=x+1
x<10
y=y+1
y<10

8. A Data Flow Diagram information processing activity data flow Verify
Order
Customer
Books
Customers
Generate
Requisition
to Publisher
Publishers
Book
details
Credit status
orders
Pending orders
verified
order
Order details
Publisher
Purchase
address 1 2
information
processing
activity
data flow

9. Petri Nets places, representing an abstract condition
transitions, representing an event or happing
relationship between a place and a transition,
it can only come from a place to a transition
or from a transition to a place
tokens, which can be placed in places to
indicate that the condition is true

10. A Petri Net Example You can interpret the places and a new job arrives
transitions. That
is, assigning
meanings to them.
a new job arrives
begin
process
done
job leaves
job waiting
processor available
job being
processed
job ready to go
events
condition of
system

11. Petri Net Execution
A transition is enabled if and only if each of its input places contains a token.
A transition can be fired sooner or later if it is enabled.
Firing a transition
removes a token from each of its input places AND
places a token into each of its output places t1 t2 t3 t4

12. Petri Net Marking
An initial marking is an assignment of tokens to places. t1 p2
t1 is always enabled, because it does not
have an input place. p1
firing t1 places a token in p1 t2
t2 is now enabled p3
firing t2 removes one token from
each of p1 and p2 and places one
token in p3 t3
t3 is now enabled p4
firing t3 removes one token from
p3 and places one token in p4 and p2 t4

13. Petri Net Marking “a new job arrives” is always enabled,
meaning a new job can arrive anytime.
a new job arrives
processor
available
fire “a new job arrives”
job
waiting
“begin process” is now enabled
begin
process
fire “begin process”
job being
processed
job is being processed
“process done” is now enabled
process
done
fire “process done”
job is ready to leave & processor is
available again
job ready to go
“job leaves” is now enabled
job leaves
fire “job leaves”

14. Analysis of Petri Net (p1, p2, p3, p4) (0, 1, 0, 0) p2 p1 t1
(0, 1, 0, 0) p1 t1
(1, 1, 0, 0) t2 t2 t1 p3
(1, 1, 0, 0)
(0, 0, 1, 0) t3 p4 t4

15. Petri Net Analysis Tree
A marking is presented by a list of “0” and “1”:
(n1, n2, ..., nk)
where ni = 1 if place i contains a token
The root of the tree denotes the initial marking (initial system state).
Thus, the initial marking and root of tree for the Petri net on left is:
(0, 1, 0, 0). t1 p2 p1 t2 p3 t3 p4 t4

16. Petri Net Analysis Tree
Firing a transition grows the tree with a new branch, labeled by the transition fired and the resulting new marking.
(0, 1, 0, 0)
(1, 1, 0, 0) t1 t2 t3 t4 p1 p2 p3 p4
(0, 0, 1, 0) t2 t1 t3 t4 p1 p2 p3 p4 t1 t2 t3 t4 p1 p2 p3 p4
(1, 1, 0, 0)

17. Petri Net Analysis (0, 1, 0, 0) t1 p1 p2 (w, 1, 0, 0) t2 (w, 0, 1, 0)
w denotes a
large number of tokens
because t1 can be fired
many times.
(0, 1, 0, 0) t1 p1 p2
(w, 1, 0, 0) t2 t2
(w, 0, 1, 0) p3 t3 t3
(w, 1, 0, 1) t2 t4 p4
(w, 1, 0, 0)
(w, 0, 1, 0) t4
These have occurred at a
higher level.

18. Petri Net Expressiveness
parallelism
sequencing
synchronization
exclusion

19. Activity Diagram Notions and Notations
Activity or action
Conditional branching
Control flow
Object flow
obj:Class
Forking
Joining or synchronization
Swim lane to represent info
and control flow between
departments/subsystems
Initial node, final node, and flow final node

20. Box Office Order Processing
branching condition
branching
Set Up Order
[single order]
Assign Seats
activity
[subscription]
forking to create concurrent threads
Assign Seats
Award Bonus
Debit Account
Charge Credit Card
joining to synchronize concurrent threads
merging alternating threads
Mail Package

21. Activity Diagram: Swim Lane
Customer
Sales
Accounting
Warehouse
object flow
Pack Items
Place Order
: NewOrder
Ship Order
branching
Verify Order
forking
[reject]
[ok]
Show Msg
Fill Order
: Invoice
Send Invoice
Make Payment
Process Payment
merging alternating routes
joining concurrent threads
Close Order

22. Activity Decomposition and Invocation
A complex activity can be decomposed and represented by another activity diagram.
The rake-style symbol is used to signify that the activity has a more detailed activity diagram.
<<Server>>
Database
An Activitiy
It is described by
a more detailed
activity diagram.
Another DB

23. Expansion Region
An expansion region is a subset of activities or actions that should be repeated for each element of a collection.
The repeated region may produce one or more collections.
A collection of line items
Place Order
:Order
:LineItem
Add Item to shipment
Add Cost to Invoice
:Item
:LineItemCost
Expansion region
:Shipment
:Invoice
Ship Order
Send Invoice

24. Using Activity Diagram
Modeling, analysis and design of complex information processing activities involving one or all of the following:
control flows
object flows or data flows
access to databases or data depositories
conditional branching
concurrent threads
synchronization
Work flow among multiple organizational units and/or subsystems.

25. Using Activity Diagram
Activity diagram can be used alone or used with the other diagrams.
Activity diagram can be used to model the information processing activity of a system, subsystem or component, or a method of a class.

26. Steps for Activity Modeling

27. Relation to Other Diagrams
An activity may be a use case, or suggest a use case. Therefore, activity modeling is useful for identifying use cases.
Activity diagrams are useful for showing workflows and control flows among use cases.
Activity modeling is useful for processing complex requests in a sequence diagram.
An activity may exhibit state-dependent behavior, which can be refined by state modeling.

28. Relation to Other Diagrams
A state may represent a complex process, which can be modeled by an activity diagram.
Each object sent from one activity to another should appear in the design class diagram (DCD), or the domain model.
Swim lanes may suggest object classes in the domain model, or the DCD. The activities of the swim lane identify operations for the class.
A complex activity may decompose into lower-level activities. Some of these may be operations of the class.

29. Describe the activities for doing one of the following:
Class Exercise
Describe the activities for doing one of the following:
preparing and submitting a project proposal in your organization
buying a new or used car
workflow for configuration management
Convert the description into an activity diagram.
Review the diagram and identify potential problems.

30. Applying Agile Principles
Value working software over comprehensive documentation.
Active user involvement is imperative.
A collaborative and cooperative approach between all stakeholders is essential.
Capture requirements at a high level; make them lightweight and visual.
Do barely enough activity modeling.