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156 Internet of Things

machine can be understood as a machine that is capable of defining various states of an object

and these states can be controlled by internal or external events. These diagrams are used to

model the lifetime of an object.

Why Do We Use State Chart Diagrams?

The State Chart Diagrams come under the five other UML diagrams utilized to model the

dynamic nature of the system. State chart diagrams are very useful in modeling reactive systems.

A reactive system is characterized by a system that could respond to internal or external events.

These diagrams help us to explain the flow of control from one state to another. A state can be

understood as a condition under which an object can exist and it can change itself under the trig-

ger of some event. Thus, a State chart diagram could be used to portray the lifetime of an object

from its birth to death. Some people also use these diagrams for forward and reverse engineering

of a system. However, the main purpose remains the same as modeling reactive systems.

We can use a State Chart Diagram in the following:

• It can be used to portray the dynamic aspect of a system.

• It can model the lifetime of a reactive system.

• It can describe how an object transformed into different states during its lifetime.

• It can explain a state machine to portray the state of an object.

How Can We Draw a State Chart Diagram?

So far, we understood the motive of State Chart Diagram. We should also know that the

emphasis is also drawn on the state changes by some internal and external event. These states

of the objects are very important to evaluate and implement them accurately. States can be

classified as the condition of objects when a particular event takes place.

We must clarify on these three points:

• Identifying the important objects to be evaluated,

• Identifying the states, and

• Identifying the events.

The State Chart Diagrams give control to model states and also the events that are operating on

the system. When we are implementing a system, it is very crucial to know the dierent states of

an object during its lifetime, for this requirement we use State Chart Diagrams. These diagrams

are mainly utilized to analyze the object states that are influenced by the events. Together this

analysis of the objects is very helpful in order to understand the behavior of the system.

Component Diagrams

Component diagrams are a bit dierent from the other UML diagrams in terms of behavior

and nature. They are very helpful in breaking down the actual system under development into

dierent high levels of functionality. Each component in the system has one clear goal and

only interacts with other essential elements. Component diagrams are utilized to portray the

physical attributes of a system. In these physical attributes, we include elements such as librar-

ies, executable, files, and documents. These diagrams are utilized to envision the organization

and relationships between components in a system. We can also use such diagrams to create

executable systems.

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Chapter 6 Essential Elements for Designing IoT Architecture 157

Card Reader

ATM Network

ATM

ATM Transaction

Cash Dispenser

Card validator

Customer Console

Bank

DataBase

Account Information

Client Deskto

pClient Desktop Transaction

Why Do We Use Component Diagrams?

Component diagrams do not explain the functionality of the system, instead they help us to

explain the components used to create such functionalities. These components could be

packages, libraries, files etc. These diagrams can also be explained as a fixed implementation

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