Object Oriented Analysis and Design unit 3

1. OOAD-3
By: Jitendra Singh Rathore
Lect., IT
TCT, Bhopal

2. OMT(Object Modeling
Technique)
 It is a methodology that combines the views of
a modeling system.
 Three types of model used.
 (1) Object Model
 (2) Dynamic Model
 (3) Functional Model

3. Object Model
 It represents static, structured, data aspect of the
system.
 Structure of a system contains following information-
• Their Identity
• Their Relationship to other objects
• Their Attribute.
• Their Operations.
 Object model provides the essential Framework into
which Dynamic and Functional model can be placed.
 It is represent (Graphically) by Object Diagram

4. Dynamic Model
 It represents the-
 Temporal
 Behavioral and,
 Control aspects of the system.

5. Functional Model
 It represents the Transformational (Functions)
aspects of the system.
 Describe those aspect of the system concerned
with Transformation of values.
 It concerned with following-
1. Functions
2. Mapping
3. Constraints and
4. Functional Dependency
 Represented by – DFD, CFD

6. Dynamic Model
 Describes the aspect of a system concerned
with Time and Sequencing of Operations-
1. Events that mark changes.
2. Sequence of Events.
3. State that defines the context for event and
4. The organization of events and states.
 It is represented by the a State Diagram.

7. Dynamic Model…………
Summary
 The dynamic model shows the time-dependent
behavior of the system and the objects in it.
 Begin dynamic analysis by looking for event,
externally visible stimuli and responses.
 The dynamic model is important for interactive
systems, but insignificant for purely static data
repository, such as database.

8. Dynamic Model……
State &
Events
 State
The attribute values and link held by an object are
called its state.
 Events-
An individual stimulus from one object to another
as called an event. OR
 An event is something that happens at a point in
time.
ex. User depress left button of a mouse.
 Overtime, the object stimulate each other,
resulting in a series of changes to their states.

9. Dynamic Model……
Events
 Concurrent Event- Two events that are casually
unrelated are said to be con current events.
 Points to Ponder:
1. In a modeling system, we don’t try to establish
an ordering between concurrent events, because
they can occur in any order.
2. An event is a one way function transmission of
information from one object to another. It is not
like a subroutine/function that returns a value.
3. Every event is a unique occurrence, but we
group into event class, & give each event class a
name to initialize a common structure and
behavior.

10. Dynamic Model……
Events
 For Exp.(Event class and attribute)
1. airplane flight depart (airline, flight no, city)
2. Mouse button pressed (button, location)
3. Input string enterd (text)
4. Phone receiver lifted
5. Digit dialed (digit)
6. Engine speed enters danger zone

11. Dynamic Modeling…..
State Diagram
 The pattern of events, state and state transitions
for a given class can be abstracted and
represented as state diagram.
1. A state diagram is network of states and events.
2. The state diagram, one state diagram for each
class with important dynamic behavior and
shows the pattern of activity for an entire system.
3. Each state machine executes concurrently and
can change state independently
4. The state diagram for the various classes
combine into a single dynamic model via shared
events.

12. Dynamic Modeling…..
 The following steps are performed in constructing a
dynamic model
1. Prepare scenarios of typical interaction
sequences
2. Identify events between objects
3. Prepare an event trace for each scenario
4. Build a state diagram
5. Match events between objects to verify
consistency

13. Dynamic Modeling…..
Scenerios & Event
Traces
 Sequence of events that occur during one
particular execution of a system.
 The scope of scenarios can vary-
1. It may include all events in the system.
2. Or, it may include only those events
impinging on or generated by certain objects
into the system.
3. Or, it can be a historical records.

14. Dynamic Modeling…..
Scenerios & Event
Traces
 Example:
1. Caller lift reciever.
2. Dial tone begins.
3. Caller dial digit(5)
4. Dial tone ends
5. Caller dial digit(5)
6. Caller dial digit(4)
Etc.

15. Dynamic Modeling…..
Scenerios & Event
Traces

16. Example -
ATM

17. State Diagram
Dialing a
number