Introduction to UML
(Unified modeling
Language)
By Sandhya Satyarthi
UML(Unified Modeling Language)
• A diagrammatic way of showing the
relationships among classes
• This will help our understanding of the
definitions of our collections and the usage
of our collections in applications
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What is the use of UML?
• Basically, UML has been used as a general-purpose
modeling language in the field of software
engineering. However, it has now found its way into
the documentation of several business
processes or workflows.
• For example, activity diagrams, a type of UML
diagram, can be used as a replacement for
flowcharts. They provide both a more standardized
way of modeling workflows as well as a wider range
of features to improve readability and efficacy.
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UML Diagrams
• Unified Modeling Language (UML) is a
standard notation for object-oriented
design
• Used to model object-oriented designs
• Shows overall design of a solution
• Shows class specifications
• Shows how classes interact with each other
• Diagrams use specific icons and notations
• It is language independent
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• UML is a way of visualizing a software program
using a collection of diagrams. The notation has
evolved from the work of Grady Booch, James
Rumbaugh, Ivar Jacobson, and the Rational
Software Corporation to be used for objectoriented design, but it has since been extended
to cover a wider variety of software engineering
projects.
• Today, UML is accepted by the Object
Management Group (OMG) as the standard for
modeling software development.
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Types of UML Diagrams
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The current UML standards call for 13 different types of diagrams:
These diagrams are organized into two distinct groups:
Structural diagrams
Behavioral or interaction diagrams
Structural UML diagrams
 Class diagram
 Package diagram
 Object diagram
 Component diagram
 Composite structure diagram
 Deployment diagram
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• Behavioral UML diagrams
Activity diagram
Sequence diagram
Use case diagram
State diagram
Communication diagram
Interaction overview diagram
Timing diagram
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UML Class Diagram
• A class is represented in a UML
diagram by a rectangle divided into 3
sections:
• name of the class
• attributes of the class (i.e. the data fields
of the class, including variables and
constants)
• operations of the class (essentially
equivalent to a Java method or a C++
function)
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Features of UML Class Diagrams
• Class diagrams are the main building block of
any object-oriented solution. It shows the
classes in a system, attributes, and
operations of each class and the relationship
between each class
• Attributes and operations may be left
incomplete, and completed as design is
developed
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Example of Class diagram
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Package Diagram
• As the name suggests, a package diagram shows the
dependencies between different packages in a system.
• We use Package Diagrams to depict how packages and their
elements have been organized.
• A package diagram simply shows us the dependencies
between different packages and internal composition of
packages.
• Packages help us to organise UML diagrams into meaningful
groups and make the diagram easy to understand.
• They are primarily used to organise class and use case
diagrams.
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Object Diagram
• Object is an instance of a class in a particular moment in runtime
that can have its own state and data values.
• An Object Diagram can be referred to as a screenshot of the
instances in a system and the relationship that exists between
them.
• Since object diagrams depict behaviour when objects have been
instantiated, we are able to study the behaviour of the system at a
particular instant.
• An object diagram is similar to a class diagram except it shows the
instances of classes in the system. We depict actual classifiers
and their relationships making the use of class diagrams.
• On the other hand, an Object Diagram represents specific
instances of classes and relationships between them at a point of
time.
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Component Diagram
• It is use to show the structural relationships between the
components of the system.
• Component is a physical and replaceable part of system and
models physical things.
• It does not describe the functionality of the system but it
describes the components used to make those functionalities.
• The purpose of the component diagram can be summarized as
−
 Visualize the components of a system.
 Construct executables by using forward and reverse
engineering.
 Describe the organization and relationships of the components.
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• It does not describe the functionality of the system
but it describes the components used to make those
functionalities.
• Component diagrams illustrate the pieces of
software, embedded controllers, etc., that will make
up a system.
• Use to show the static view of component and their
relationship.
• Node is component (set of classes with well defined
interface)
• Edge is relationship between the components.
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Deployment Diagram
• Deployment diagrams model the physical architecture of
a system.
• Deployment diagrams show the relationships between
the software and hardware components in the system
and the physical distribution of the processing.
• Deployment diagrams consist of nodes and their
relationships
• Component diagrams and deployment diagrams are
closely related.
• Component diagrams are used to describe the
components and deployment diagrams shows how they
are deployed in hardware.
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• The purpose of deployment diagrams can be described as −
 Visualize the hardware topology of a system.
 Describe the hardware components used to deploy software
components.
 Describe the runtime processing nodes.
Basic elements by focusing on them we draw the deployment
diagram:
• Nodes
• Relationships among nodes
• They model physical hardware elements and the communication
paths between them
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Composite-structure Diagram
• We use composite structure diagrams to represent the internal
structure of a class and its interaction points with other parts of
the system.
• A composite structure diagram represents relationship between
parts and their configuration which determine how the classifier
(class, a component, or a deployment node) behaves.
• They represent internal structure of a structured classifier
making the use of parts, ports, and connectors.
• We can also model collaborations using composite structure
diagrams. They are similar to class diagrams except they
represent individual parts in detail as compared to the entire
class.
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Activity Diagram
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Activity diagrams are typically used for business process modeling, for
modeling the logic captured by a single use case or usage scenario, or
for modeling the detailed logic of a business rule.
•
Although UML activity diagrams could potentially model the internal
logic of a complex operation it would be far better to simply rewrite the
operation so that it is simple enough that you don’t require an activity
diagram.
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In many ways UML activity diagrams are the object-oriented equivalent
of flow charts and data flow diagrams (dfds) from structured
development
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Let’s start by describing the basic notation :
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Initial node. The filled in circle is the starting point of the diagram. An
initialnode isn’t required although it does make it significantly easier to
read the diagram.
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Activity final node. The filled circle with a border is the ending point.
Anactivity diagram can have zero or more activity final nodes.
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Activity. The rounded rectangles represent activities that occur. An activity
maybe physical, such as Inspect Forms, or electronic, such as Display
Create StudentScreen.
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Flow/edge. The arrows on the diagram. Although there is a subtle
differencebetween flows and edges,never a practical purpose for the
difference although.
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Use Case Diagram
According to the UML specification a use case diagram is “a diagram that
shows the relationships among actors and use cases within a system.”
Use case diagrams are often used to:
• Provide an overview of all or part of the usage requirements for a
system or organization in the form of an essential model or a business
model
• Communicate the scope of a development project
• Model your analysis of your usage requirements in the form of a
system use case model
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Use case diagram components
• To answer the question, "What is a use case diagram?" you need
to first understand its building blocks. Common components
include:
• Actors: The users that interact with a system. An actor can be a
person, an organization, or an outside system that interacts with
your application or system. They must be external objects that
produce or consume data.
• System: A specific sequence of actions and interactions between
actors and the system. A system may also be referred to as a
scenario.
• Goals: The end result of most use cases. A successful diagram
should describe the activities and variants used to reach the goal
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Interaction Diagrams
An interaction diagram depicts the
messages between objects or classes in
a program. It shows collaborations
between objects.
The UML includes two types of interaction
diagrams –
 sequence diagrams
 collaboration diagrams
Sequence Diagrams
• Describe the flow of messages, events,
actions between objects.
• Show concurrent processes and
activations
• Show time sequences that are not easily
depicted in other diagrams
• Typically used during analysis and design
to document and understand the logical
flow of your system
• Emphasize on time ordering.
Sequence Diagram Elements:
1.Object:
• Sequence diagram is made up of collection of objects.
• The objects interact with each other by sending and
receiving messages.
2. LifeLine:
• Lifeline represents the existence of an object over a
period of time.
• Mostly the objects in the interaction diagram will be in
existence for the duration of an interaction
• Objects are aligned at top of sequence diagram with
their lifeline from top to bottom.
3. Activation Bar:
• It is called as focus of control.
• It shows the period of time during which an object is
performing an action.
• Top of rectangle in aligned with start of action and the bottom
is aligned with the completion and can be marked by written
message.
4. Messages:
• The interaction between objects can be done by using
message .
• The message flow in sequence diagram specify by using an
arrow. And the flow of message is in any direction from left to
right or right to left.
Example of sequence diagram
Collaboration Diagrams
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A collaboration diagram is a network model of
the messages between interacting objects
and classes.
The collaboration diagram will indicate the
objects participating in the collaboration, and
The sequence of messages
{message(parameters), sender, receiver}
exchanged to achieve the task involved.
There is a UML convention for numbering the
messages to show the sequence in which they
occur.
Collaboration Diagrams
• Collaboration diagrams are also relatively
easy to draw.
• They show the relationship between objects
and the order of messages passed between
them.
• The objects are listed as icons and arrows
indicate the messages being passed
between them.
• The numbers next to the messages are
called sequence numbers.
Collaboration Diagram
Elements
• There are three primary elements of a
collaboration diagram:
• Objects
• Links
• Messages
Example of Collaboration
Diagram
Example of Collaboration Diagram
State-Chart Diagrams
• They define different states of an object during its
lifetime and these states are changed by events.
• State-chart diagrams are useful to model the reactive
systems.
• Reactive systems can be defined as a system that
responds to external or internal events.
• State-chart diagram describes the flow of control from
one state to another state.
• States are defined as a condition in which an object
exists and it changes when some event is triggered
• State Chart Diagrams provide a way to model the
various states in which an object can exist.
• Process that occur while an object is in certain state
are called actions.
Basic components of a state-chart diagram
• Initial state – We use a black filled circle represent the initial state
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of a System or a class.
Transition – We use a solid arrow to represent the transition or
change of control from one state to another. The arrow is label
with the event which causes the change in state.
State – We use a rounded rectangle to represent a state. A state
represents the conditions or circumstances of an object of a class
at an instant of time.
Fork –We use the fork notation to represent a state splitting into
two or more concurrent states.
Join –We use the join notation when two or more states
concurrently converge into one on the occurrence of an event or
events
Self transition- We use a solid arrow pointing back to the state
itself to represent a self transition. when the state of the object
does not change upon the occurrence of an event.
A STATE CHART DIAGRAM FOR
RESERVATION OF TICKETS & DISPLAY OF CONFIRMATION FORM.
THANK
YOU!!
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