Chapter7

Session 7

Dynamic Model

OOAD with UML / Session 7 / 2 of 25

Review Use Cases bring out the users of the

system Use Case Diagrams help to define the

roles of actors The services and interaction between

users is described using Use Case Diagrams

Very often these are the first diagrams to be drawn while modeling a system


Objectives Discuss state diagram Explain sequence diagram Work with collaboration diagram

and activity diagram Explain the definitions of dynamic

diagrams in UML


Message and Message Notations

Message is drawn as a line with an arrow between sender and receiver of the message. The arrowhead indicates the type of the message sent


State Diagram State diagrams are one set of diagrams which helps to

draw the dynamics of a system The state of an object at any point in time is the

condition of the object at that instant State of the object is defined by all the attributes of

the object and the links maintained by it


State and Transition The process of change in state is

called state transition Transitions are typically the result of

the invocation of an operation that causes an important change in state

An action is something, in the case of a class it is an operation, which is invoked by/on the entity being modeled


Sub-state-1 The state of an object can have

sub-states in it A sub state is a part of the

composite state Sub States can be concurrent or

sequential


Sub-state-2


Use state diagram


Sequence Diagram Illustrate interaction between

objects; that is the messages sent and received between the objects

Have two axes Vertical axis shows the time,

where as the horizontal axis shows a set of objects


General Sequence Diagram-1

Events are depicted by horizontal lines

Objects by Vertical Lines Time is depicted vertically starting

from top. This means that the events should be depicted in the order in which they occur from top to bottom.


General Sequence Diagram-2

: Customer : Interface : Vendor

Input Coin

Verify Coin

Reject Faulty Coin with Message

Send Genuine Coin

Vend Tea


Recursion

Repetition of the same activity again and again until a condition is met

While showing recursion the event arrow comes back to the same object from where it started


Use Sequence Diagram


Collaboration Diagram-1

Describes interaction between objects just like the Sequence diagram but unlike the Sequence diagram the primary focus is on events

Objects are shown using the Class icon Sequence in Collaboration diagram is

shown by numbering the messages Better for understanding all the effects

on a given object and for procedural design


Collaboration Diagram-2


Activity Diagram-1 To capture action (work) when the

operation is executing. This is the most common usage.

To describe how interactions between related objects take place

To describe a Use-Case’s performance in terms of actions and object state changes.

To capture internal process of an object To describe the functional flow of the

system in terms of objects


Activity Diagram-2


Activity Diagram-3


Activity diagram Concurrency

Concurrency paths run at the same time and then join below The split and merge are represented as solid horizontal lines


Signal-1

Sending a signal

Receiving a signal

Signals Indicate input and output events

The symbol for sending a signal is a convex pentagon. The symbol for receiving a signal is a concave pentagon.


Signal-2


Swimlanes


Use Activity Diagram


Summary State diagrams depict the dynamics of a system

State diagrams can have concurrent or sequential sub states

Sequence diagrams depict the interaction amongst objects. They might contain recursion.

Interaction between objects is shown using Collaboration Diagram

Activity Diagrams capture the activities and their results

Swimlanes simplify the activity diagram and help in understanding the distribution of activities amongst the objects

Chapter7

Technology

general sequence diagram

sequence diagram

activity diagram

collaboration diagram

case diagrams

state diagrams

diagrams

depicted