INFORMATION SYSTEM
FOR FAMILY DENTAL CARE
(FDC)
FATHIMA HAFSHA ZIYARD
ADVANCED PROGRAMMING
REG. NO: COL/E-005674
BATCH: HND-COM-100
ESOFT METRO CAMPUS
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Higher National Diploma in Computing & Systems Development /
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Name
FATHIMA HAFSHA ZIYARD
ESOFT Reg. No
COL/E-005674
Name of Group Members (If
Applicable)
Edexcel No
Module Name
Advanced Programming
Name of the Lecturer
Mr. Tharaka
Date Due
24/07/2022
Date Submitted
24/07/2022
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Advanced Programming
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Information System for Family Dental Care (FDC)
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Advanced Programming
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Unit Title
FATHIMA HAFSHA ZIYARD / COL-E 005674
Unit 20 – Advanced Programming
Assignment Number 1
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Date Received
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LO1. Examine the key components related to the object orientated programming paradigm,
analysing design pattern types.
Pass, Merit & Distinction Descripts
P1
M1
D1
M2
D2
M3
D3
LO2. Design a series of UML class diagrams
Pass, Merit & Distinction Descripts
P2
LO3. Implement code applying design patterns
Pass, Merit & Distinction Descripts
P3
LO4. Investigate scenarios with respect to design patterns
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FATHIMA HAFSHA (COL/E-005674)
Advanced Programming
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My lecturer for the Advance Programming unit is Mr. Nuhman His lecturing style is perfect. He used a
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not only encouraged us to do our best, but he also guided us to do our best.
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FATHIMA HAFSHA (COL/E-005674)
Advanced Programming
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FATHIMA HAFSHA (COL/E-005674)
Advanced Programming
5
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FATHIMA HAFSHA (COL/E-005674)
Advanced Programming
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FATHIMA HAFSHA (COL/E-005674)
Advanced Programming
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Higher National Diploma in Business
Assignment Brief
Student Name /ID Number
FATHIMA HAFSHA ZIYARD / COL/E 005674
Unit Number and Title
Unit 20 – Advance Programming
Academic Year
2018/1
2021/22
Unit Tutor
Mr. Tharaka
Assignment Title
Issue Date
Submission Date
24/07/2022
IV Name & Date
Submission format
The submission is in the form of an individual written report about. This
should be written in a concise, formal business style using single spacing
and font size 12. You are required to make use of headings, paragraphs and
subsections as appropriate, and all work must be supported with research
and referenced using the Harvard referencing system. Please also provide
an end list of references using the Harvard referencing system. Please note
that this is an activity-based assessment where your document submission
should include evidences of activities carried out and of team working. To
carry out activities given on the brief, you are required to form groups,
comprising not exceeding 15 individuals.
The recommended word count is 4,000–4,500 words for the report
excluding annexures. Note that word counts are indicative only and
you would not be penalised for exceeding the word count.
FATHIMA HAFSHA (COL/E-005674)
Advanced Programming
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Unit Learning Outcomes:
Learning Outcomes
By the end of this unit students will be able to:
LO1. Examine the key components related to the object-orientated
programming paradigm, analyzing design pattern types.
LO2. Design a series of UML class
diagrams.
LO3. Implement code applying
design patterns.
LO4 Investigate scenarios with respect to design patterns.
FATHIMA HAFSHA (COL/E-005674)
Advanced Programming
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Assignment Brief and Guidance:
BOC Software solutions is leading software company in Kandy as system analyst
you have to build an application for Family Dental Care (FDC) considering given
scenario.
Family Dental Care (FDC) is a leading up market dental surgery located in
Kandy. It provides all types of dental treatments to patients which include
extractions, nerve fillings, maxillofacial surgeries (i.e. surgeries involving jaw
bone) and sophisticated dental implants. It is visited by prominent dentists and
dental consultants with post graduate qualifications, some of whom are working
at the Faculty of Dental Science at the University of Peradeniya.
Patients consult doctors by appointment. On their first visit, patients are required
to register by entering their personal details such as name, address, national
identity card number and contact number. A small fee is charged from the patient
during registration. A separate fee is charged for each treatment given.
Doctors too must get registered at FDC by providing personal details such as
name, address, date of birth, national ID number and contact number. In addition,
consultants must provide the name of their post graduate qualification along with
the country of the University that granted it and ordinary dentists should indicate
the number of years of experience.
FDC consists of four fully equipped surgery rooms so that four patients can be
accommodated at any given time. FDC also contains a dental scan room which
can be attended by one patient at a time. The dental scan machine is operated
by one of the dentists of the FDC facility. Normally, a dentist without
appointments for a given time slot (say, between 5 PM and 6 PM) is assigned to
the machine by the manager. When that time slot finishes, another doctor who
is free will be assigned.
The staff of FDC is made up of a manager, four nurses (one for each of the
four surgery rooms) and a receptionist who handles registrations and
appointments.
An information system is required to keep track of patients, doctors,
appointments, treatments given to patients and payments. The system must
also maintain information about the staff. It has been decided to use an object
oriented approach to design and implement the system.
FATHIMA HAFSHA (COL/E-005674)
Advanced Programming
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Task 1
Examine the Object oriented concepts given below. Provide diagrams and
code snippets from suitable specific programming language to supplement
your explanations.
i)
Class
ii)
Object
iii)
Message
iv)
Encapsulation
v)
Inheritance
vi)
Polymorphism
vii)
Aggregation/composition
Task 2
Design and build the detailed UML class diagram for the Family Dental Care
system. Your solution should demonstrate all inter-class relationships namely
Association, Inheritance and Aggregation/composition. The classes should
include attributes and methods needed.
Draw the class diagram for the explained system. Including all notations and
details and ensure that the diagram has the required functionalities. Analyze
the class diagram provided above and derive code scenarios related to the
UML diagram.
Task 3
Determine and briefly discuss the range of design patterns and describe at
least one design pattern from the three available types of design pattern.
Provide suitable UML diagrams for the given patterns and analyze the
relationship between object-oriented paradigm and design patterns providing
a suitable example.
FATHIMA HAFSHA (COL/E-005674)
Advanced Programming
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Task 4
Scenario 1
FDC owns a very expensive, state of the art dental scan machine (a device far
superior to a traditional dental X-ray machine) manufactured by Toshiba,
Japan. FDC will be own just one such machine in the foreseeable future. When
modeling and implementing FDC system in software, you must ensure that
only one instance of that machine is created.
You may include suitable attributes for the machine such as serial number,
make, country of origin and cost. Implementation should allow the user to
enter details of the dental scanner and create the sole instance of that
machine.
Scenario 02
Below table provides the hierarchy of the Employees and their monthly salary in FDC.
Emp Id
Name
Position
Salary
A001
Anton
Director
1,000,000 LKR
A002
Chamod
Dentist
600,000 LKR
A003
Supuni
Dentist
600,000 LKR
A004
Madhavi
Dentist
600,000 LKR
A005
Piyal
Nurse
200,000 LKR
A006
Kamal
Nurse
200,000 LKR
A007
Kapila
Nurse
200,000 LKR
All the Nurses are working under the Dentists and Chamod(Dentist) is working under the
Supuni(Dentist) and Madhavi(Dentist) is working under the Anton(Director).
FATHIMA HAFSHA (COL/E-005674)
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Develop a system to display the details of all employees and your system should display
which employee is working under which employee clearly.
Scenario 03
Patients who need dental scans are kept in a First in First Out queue.
Assume that you have found an already developed Queue container in a
software library. It provides standard queue operations to insert and remove
data (known as enqueue and deque respectively). However, you need some
specific operations such as search() to look up a particular patient and
showAll() to list all the patients in the queue. These additional operations are
not provided by the library unit.
For each of the above scenarios:
Select and Justify the most appropriate design pattern for each of the above given
scenarios then Define and Draw class diagrams for above mentioned design patterns and
develop code for the above scenarios (except for the 3rd Scenario) using an appropriate
programming language. Critically evaluate why you selected the above design patterns
and compare your answer with the range of design patterns available.
FATHIMA HAFSHA (COL/E-005674)
Advanced Programming
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Grading Rubric
Grading Criteria
Achieved
Feedback
LO1 Examine the key components
related to the
object-orientated programming
paradigm,
analyzing design pattern types
P1 Examine the characteristics of the
object-orientated paradigm as well as the
various class relationships.
M1 Determine a design pattern from
each of the creational, structural and
behavioral pattern
types.
D1 Analyse the relationship between the
object-orientated paradigm and design
patterns.
LO2 Design a series of UML class diagrams
P2 Design and build class diagrams using
a UML tool.
M2 Define class diagrams for specific
design patterns using a UML tool.
D2 Analyse how class diagrams can be
derived from a given code scenario using
a UML tool.
LO3 Implement code applying design
patterns
P3 Build an application derived from UML
class diagrams.
M3 Develop code that implements a
design pattern for a given purpose.
D3 Evaluate the use of design patterns
for the given purpose specified in M3.
LO4 Investigate scenarios with respect to
design Patterns
FATHIMA HAFSHA (COL/E-005674)
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P4 Discuss a range of design patterns
with relevant examples of creational,
structure and behavioral pattern types.
M4 Reconcile the most appropriate
design
pattern from a range with a series of
given scenarios.
D4 Critically evaluate a range of
design patterns against the range of
given scenarios with justification of
your choices.
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Acknowledgement
First of all, I thank God for all the opportunities, trials and strength that have been showered
on me to finish writing the assignment. I experienced so much during this process and this
assignment also helped me in doing a lot of research and I came to know about so many new
things. Not only from the academic aspect but also from the aspect of professionally. First and
foremost, I would like to sincerely thank my lecturer Mr. Tharaka for the guidance, positive
encouragement and warm spirit to finish this assignment. It has been a great pleasure and
honor to have him as my lecturer. Secondly, my deepest gratitude goes to all of my family
members. It would not be possible to write this assignment without support from them. I offer
my special thanks to all my friends. May God shower the above-cited personalities with success
and honor in their life.
Yours sincerely,
Fathima Hafsha Ziyard
FATHIMA HAFSHA (COL/E-005674)
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Table of Contents
Acknowledgement............................................................................................................. 16
List of Figure .................................................................................................................... 19
List of Table ..................................................................................................................... 21
Task 1 .............................................................................................................................. 22
Examine the Object oriented concepts given below. Provide diagrams and code snippets
from suitable specific programming language to supplement your explanations. ............... 22
1.1 Object Oriented Programming (OOP) ................................................................... 22
1.1.1 Class ................................................................................................................. 24
1.1.2 Object ............................................................................................................... 27
1.1.3 Message............................................................................................................ 29
1.1.4 Encapsulation..................................................................................................... 30
1.1.5 Inheritance ........................................................................................................ 32
1.1.6 Polymorphism .................................................................................................... 33
1.1.7 Aggregation/composition..................................................................................... 35
1.2 Relationship between OOP and Design Patterns .................................................... 37
Task 2 .............................................................................................................................. 39
Design and build the detailed UML class diagram for the Family Dental Care system. Your
solution should demonstrate all inter-class relationships namely Association, Inheritance
and Aggregation/composition. The classes should include attributes and methods needed.
..................................................................................................................................... 39
2.1 UML Class Diagram............................................................................................. 39
2.1.1 Association Relationship Evaluation ................................................................... 40
2.1.2 Inheritance Relationship Evaluation .................................................................... 40
2.1.3 Aggregation Relationship Evaluation .................................................................. 41
2.1.4 Composition Relationship Evaluation ................................................................. 42
Task 3 .............................................................................................................................. 43
Determine and briefly discuss the range of design patterns and describe at least one design
pattern from the three available types of design pattern. Provide suitable UML diagrams for
the given patterns and analyze the relationship between object-oriented paradigm and
design patterns providing a suitable example .................................................................. 43
3.1 Design Patterns .................................................................................................... 43
3.1.1 Types of Design Patterns ................................................................................... 44
3.1.1.1 Creational Design Patterns .............................................................................. 44
3.1.1.2 Structural Design Patterns............................................................................... 44
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3.1.1.3 Behavioral Design Patterns ............................................................................. 45
Task 4 .............................................................................................................................. 53
Scenario 1 ..................................................................................................................... 53
FDC owns a very expensive, state of the art dental scan machine (a device far superior to
a traditional dental X-ray machine) manufactured by Toshiba, Japan. FDC will be own
just one such machine in the foreseeable future. When modeling and implementing FDC
system in software, you must ensure that only one instance of that machine is created. 53
4.1.1 Dental Scan Machine ......................................................................................... 53
Scenario 02 ................................................................................................................... 56
Below table provides the hierarchy of the Employees and their monthly salary in FDC.56
Scenario 03 ................................................................................................................... 59
Patients who need dental scans are kept in a First in First Out queue. Assume that you
have found an already developed Queue container in a software library. It provides
standard queue operations to insert and remove data (known as enqueue and deque
respectively). However, you need some specific operations such as search() to look up a
particular patient and showAll() to list all the patients in the queue. These additional
operations are not provided by the library unit ............................................................. 59
Conclusion ........................................................................................................................ 61
Self-Criticism..................................................................................................................... 62
Gantt chart ....................................................................................................................... 63
References ....................................................................................................................... 64
FATHIMA HAFSHA (COL/E-005674)
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List of Figure
Figure 1 Object Oriented Programming (OOP) .................................................................. 22
Figure 2 Class in our system.............................................................................................. 24
Figure 3 Class code for FDC system.................................................................................. 25
Figure 4 Object Denoted as Diagram ................................................................................. 27
Figure 5 Object Code Snippet ............................................................................................ 28
Figure 6 Message Passing Diagram.................................................................................... 29
Figure 7 Message Passing Code Snippet ............................................................................. 29
Figure 8 Encapsulation Diagram........................................................................................ 30
Figure 9 Implementing Encapsulation................................................................................. 31
Figure 10 Inheritance ........................................................................................................ 32
Figure 11 Inheritance Code Snippet ................................................................................... 32
Figure 12 Polymorphism .................................................................................................... 33
Figure 13 Polymorphism .................................................................................................... 33
Figure 14 overriding .......................................................................................................... 33
Figure 15 overloading ........................................................................................................ 34
Figure 16 Aggregation/composition .................................................................................... 35
Figure 17 Aggregation ....................................................................................................... 35
Figure 18 Relationship between OOP and Design Patterns - Example 01 ............................ 37
Figure 19 Relationship between OOP and Design Patterns - Example 02 ............................ 37
Figure 20 Relationship between OOP and Design Patterns - Example Output ...................... 38
Figure 21 UML Class Diagram.......................................................................................... 39
Figure 22 UML Association Relationship Evaluation .......................................................... 40
Figure 23 UML Association Inheritance Evaluation ............................................................ 40
Figure 24 UML Aggregation Relationship Evaluation ......................................................... 41
Figure 25 UML Composition Relationship Evaluation ........................................................ 42
Figure 26 Design Patterns ................................................................................................. 43
Figure 27 Singleton Class Diagram.................................................................................... 46
Figure 28 Composite Design Pattern Diagram.................................................................... 48
Figure 29 Treatment Types Implementation 01 .................................................................. 48
Figure 30 Treatment Types Implementation 02 .................................................................. 49
Figure 31 Treatment Types Implementation 03 .................................................................. 49
Figure 32 Treatment Types Implementation 04 .................................................................. 50
FATHIMA HAFSHA (COL/E-005674)
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Figure 33 Treatment Types Implementation Output............................................................ 50
Figure 34 Singleton Design Pattern Diagram...................................................................... 53
Figure 35 Singleton Applied .............................................................................................. 54
Figure 36 Scan Object ....................................................................................................... 55
Figure 37 Dental Scan Machine Implementation Output ..................................................... 55
Figure 38 Scanner Exists ................................................................................................... 55
Figure 39 Class for Employee............................................................................................ 56
Figure 40 Employees Types Implementation 01 ................................................................. 57
Figure 41 Employees Types Implementation Output .......................................................... 58
Figure 42 Employees Types Implementation 02 ................................................................. 58
Figure 43 Scanning List UML Diagram ............................................................................. 60
Figure 44 Gantt chart ........................................................................................................ 63
FATHIMA HAFSHA (COL/E-005674)
Advanced Programming
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List of Table
Table 1 Hierarchy of the Employees and their monthly salary in FDC ................................. 56
FATHIMA HAFSHA (COL/E-005674)
Advanced Programming
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Task 1
Examine the Object oriented concepts given below. Provide diagrams and
code snippets from suitable specific programming language to supplement
your explanations.
1.1 Object Oriented Programming (OOP)
Object Oriented Programming (OOP) is a programming approach that uses objects, logics, and
functions to organize designs and data. When OOP ideas are used, huge systems may be broken
down into smaller portions, making it easier for several programmers to work on the project.
This is one of the reasons why many major corporations have adopted OOP.
In the OOP idea, an object is a data field that has its own set of actions and properties. Objects
that have been created in the system can be modified in numerous places within the software.
Furthermore, these items are useful when creating larger and more sophisticated applications,
making the system more user-friendly.
When utilizing OOP, the first step for every programmer is to gather system requirements. The
requirements will subsequently be translated into system objects and functions, which will be
linked to needed system locations. This process is known as 'Data Modelling.' A 'Class' is used
to name an object, and it specifies the object data types as well as program logic. 'Method,'
which
contains
the
object
functions,
will
likewise
be
included
in
the
class
(howtodoinjava.com, 2022).
Figure 1 Object Oriented Programming (OOP)
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The majority of important software development nowadays is done with OOP. You're probably
used to dividing down enormous issues into smaller ones and tackling them in discrete code
units. You may also be familiar with functional programming, which considers code parts as
exact mathematical functions that do not impact other elements, in other words, there are no
side effects. When you get a handle on OOP, though, you'll find that it opens up a whole new
world of problem-solving possibilities. Instead of creating a program, you construct classes
with OOP. Data and functions are both contained in a class. You construct an object, which is
an instance of that class when you wish to save something in memory. As an example, you
may create a Customer class that contains customer-related data and methods. You must then
build a new Customer class object if you want your software to generate a customer in memory.
Object-oriented programming has several advantages over procedural programming:
•
OOP is faster and easier to execute
•
OOP provides a clear structure for the programs
•
OOP helps to keep the Java code DRY "Don't Repeat Yourself", and makes the code
easier to maintain, modify and debug
•
OOP makes it possible to create full reusable applications with less code and shorter
development time
Benefits of Object-Oriented Programming
Because of its adaptability, object-oriented programming is quite popular. In a programming
environment, the ability to treat code structures as objects allows programmers to freely shape
programs.
Conclusion
According to the text, OOPs are one of the most important subjects in programming
languages. In order to do programming efficiently, a programmer needs have a thorough
understanding of this notion. This article covers a wide range of topics, including the benefits
and drawbacks of OOPs, as well as other key concepts.
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1.1.1 Class
A Class in object-oriented programming is considered to be specific set of instructions, acting
as a blueprint in order to create an object. Classes are also contemplated as real-life entities
often. Classes define what an object will contain and how it will behave. Moreover, logic
sequences included in any class are known as methods (w3schools.com, 2022).
A class is a user defined blueprint or prototype from which objects are created. It represents
the set of properties or methods that are common to all objects of one type. In general, class
declarations can include these components, in order:
•
Modifiers: A class can be public or has default access (Refer this for details).
•
Class name: The name should begin with an initial letter (capitalized by convention).
•
Superclass (if any): The name of the class’s parent (superclass), if any, preceded by the
keyword extends. A class can only extend (subclass) one parent.
•
Interfaces (if any): A comma-separated list of interfaces implemented by the class, if
any, preceded by the keyword implements. A class can implement more than one
interface.
•
Body: The class body surrounded by braces, { }.
•
Constructors are used for initializing new objects. Fields are variables that provides the
state of the class and its objects, and methods are used to implement the behavior of the
class and its objects.
Figure 2 Class in our system
According to the class diagram, modifier types are directly connected to encapsulation, which
is an important aspect of Object Oriented Programming. Encapsulation, as a reminder, is a
concept that connects data to the code that manipulates it. You can avoid misuse by restricting
access. For example, ensuring that some variables can only be accessible through well-defined
ways (the normal get/set combo of methods) ensures that we won't find any unexpected values
or completely block outside access to specific variables/methods. There are three types of
FATHIMA HAFSHA (COL/E-005674)
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access modifiers: public, private, as previously stated. When no modifier is supplied, Java
offers default access control, which is comparable to protected.
•
public - the member can be accessed from anywhere
•
private - the member can only be accessed by other members within the same class
This table only applies to class members, not whole classes. Only public or without a modifier
may a non-nested class be. When a class is defined without a modifier, it can only be accessible
by code inside the same package, however when it is declared public, it may be used in any
package. The public class must be the file's sole (non-nested) class, and the file must be named
after the class.
Using visual code, a code snippet of a class written in Java is given below. The sample depicts
the construction of a basic class called 'Room'.
Figure 3 Class code for FDC system
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According to the code snippet is located in the "Room.java" file. Because we'll make the class
public so we can access it from another package, the name must match the class. The same is
true for the following courses.
Encapsulating a class is a typical procedure. This implies that we define member variables as
private and modify them via public methods. For example, we want to allow someone to update
the int ID field while simultaneously ensuring that int ID is always a positive integer. We may
conduct a check and alter the field if the provided value passes our check using the public
method. This is a set() function, and it's commonly used in conjunction with a get() method
(because we can't read private members outside of our class) or when we want to control how
and when a variable's value is read.
Also worth noting is that protected is the least commonly utilized of all the access modifiers.
If we want to, we can simply get around it. We may simply inherit the class whose protected
members we wish to access from another package and then access them through that inherited
class.
With that in mind, protected is most typically used as a recommendation that states "This
member is not supposed to be accessible by non-subclasses in a separate package," thus even
if we can easily defeat protected access control, it's not recommended.
Conclusion
Modifiers are keywords that allow us to fine-tune how our class and its members are accessed,
as well as their scope and behavior in specific scenarios. They give essential characteristics for
our classes and members. To get the most out of them, every developer should become wellversed in them.
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1.1.2 Object
An Object is known as a unique element, included with a series of properties and methods in
order to implement a specific data type, which is also meaningful. Moreover, objects can be
simply recognized as simple samplings of real-world entities in the system. An object can only
be created if there is a class in the system (mozilla.org, 2022).
•
State: It is represented by the attributes of an object. It also reflects the properties of
an object.
•
Behavior: It is represented by the methods of an object. It also reflects the response of
an object to other objects.
•
Identity: It gives a unique name to an object and enables one object to interact with
other objects.
Eventually, the below diagram clarifies the structure of classes integrated with objects;
Figure 4 Object Denoted as Diagram
Below is a code excerpt for an object called employee, which has data like as employeeID,
MOB, paydiscount, and finalamount. getPID, for example, would be one of the techniques ().
Only Methods belonging to the payment class have access to the data associated with the class
by default. By restricting access to its data, a class may assure that no other component of the
program has interfered with it. It also means that the underlying data structures of an item may
be concealed from other objects. If it is written properly, a class (and presumably a collection
of other dependent classes – classes within classes that inherit the same traits and data) may be
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re-coded and upgraded without affecting other areas of the program that need it. As long as the
public-facing interface (API) and functionality stay the same,
Figure 5 Object Code Snippet
Conclusion
The classes are as vital to Java programming as breathing is to our survival. In Java, it is the
most fundamental unit of Object-oriented programming. A single variable or function cannot
be created outside of a class. Everything in Java has to be contained within a class. The value
of classes in Java may have been appreciated by the programmer. I also went through the syntax
for constructing classes as well as objects from them. I also went through the examples and
sample codes so you can simply put them into practice according to the scenario.
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1.1.3 Message
When objects are included in a class, it is also essential to establish a connection between
multiple objects. Eventually, objects will be sending and receiving messages, when two or
more objects are communicating. While messages are passed, each object acts independently,
as an instance of calling an object to change its display value (geeksforgeeks.org, 2022).
Figure 6 Message Passing Diagram
The method for acquiring access is depicted. A patient package object should receive a message
from the class immunologist. The class immunologist creates the message, which is then
forwarded to the package message handler, who checks it for authorization. If the message is
authorized, it is transmitted to the employee message handler. The root class employee then
authorizes delegation and delivery of the communication to the patient. Depending on the
patient package, access may be permitted or refused. If access is granted, the patient sends the
message to the target program element for further processing.
Message passing is works only if there are two types of data’s like (int, string). If this function
is in the employee class, we need to create an object. This is followed by a call to the function
that brings up the data’s and pass the above function Below shown is a code snippet of a
message, using Java language, on visual code.
Figure 7 Message Passing Code Snippet
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1.1.4 Encapsulation
Encapsulation is an effective method to wrap multiple codes and their data manipulation
together, under one specific element. The major reason for this concept is to protect certain
data, without allowing an outside function to access them. For instance, variables in a class
can be set as private, so that any function from outside the current class cannot access them
(afteracademy.com, 2022).
Encapsulation is:
•
•
Figure 8 Encapsulation Diagram
Binding the data with the code that manipulates it.
It keeps the data and the code safe from external interference
Similarly, same concept of encapsulation can be applied to code. Encapsulated code should
have following characteristics:
•
Everyone knows how to access it.
•
Can be easily used regardless of implementation details.
•
There shouldn’t any side effects of the code, to the rest of the application.
The idea of encapsulation is to keep classes separated and prevent them from having tightly
coupled with each other.
In this case, the treatment class has employed the Encapsulation approach. The treatment's
details/variables have been generated using the private method, which implies that no other
classes may directly access these characteristics. The public getter and setter methods were
utilized to access these attributes of the Treatment class. If the treatment class has to be used
elsewhere, for example, if the treatment details need to be used in the payment class, an object
for the treatment class will be generated in that location, and these attributes will be accessible
using the public getter and setter procedures. The properties, however, cannot be accessed
directly. The information about the attributes has been hidden here, even though they can only
be accessible directly by the treatment class, but it can be reached to the needed locations by
utilizing the public getter and setter functions.
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Below shown is a code snippet of encapsulation, using Java language, on visual code.
Figure 9 Implementing Encapsulation
Conclusion
I showed in the previous Java code how we can use getter and setter methods to achieve
polymorphism; this way is actually rather versatile. If we want the variables to be read-only,
for example, we may remove the setter methods. Similarly, in the example above, if you wish
to make the variables write-only, you must remove the getter methods. The enclosed code is
simple to debug and allows for unit testing. In our application, you may reuse the code and add
new requirements. The implementation of the program definitions might be hidden. The user,
for example, will never be able to see what variables are stored in the program. They'll interact
with the program's getter and setter methods.
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1.1.5 Inheritance
In object-oriented programming, inheritance is the mechanism of basing an object or class upon
another object (prototype-based inheritance) or class (class-based inheritance), retaining a
similar implementation. Also defined as deriving new classes (subclasses) from existing ones
such as super class or base class and then forming them into a hierarchy of classes. In most
class-based object-oriented languages, an object created through inheritance, a "child object",
acquires all the properties and behaviors of the "parent object”, with the exception of
constructors, destructors, and overloaded operators and friend functions of the base class
(javatpoint.com, 2022).
Figure 10 Inheritance
Below shown is a code snippet of Inheritance, using Java language, on visual code
Figure 11 Inheritance Code Snippet
Conclusion
Many of the advantages and disadvantages of class-based inheritance are well understood.
Object-based inheritance has remained a little-known concept. Although it's been used in
prototype-based programming for a long time, it's less commonly used in business modeling.
We discover that object inheritance is quite effective in three cooperation patterns: actor—role,
item—specific item, and composite transaction—line item, when we examine the notion in the
context of business modeling. Object inheritance may be achieved in a class-based language
like Java by identifying the specific characteristics of object inheritance that are helpful and
carefully limiting its scope.
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1.1.6 Polymorphism
Polymorphism is considered one of the important features of Object-Oriented Programming.
Polymorphism allows us to perform a single action in different ways. In other words,
polymorphism allows you to define one interface and have multiple implementations. The word
“poly” means many and “morphs” means forms, so it means many forms (geeksforgeeks.org,
2022).
Figure 12 Polymorphism
Below shown is a code snippet of Polymorphism, using Java language, on visual code.
Figure 13 Polymorphism
Overriding is a feature that allows a subclass or child class to implement a method that is
already offered by one of its super-classes or parent classes, for as employee.
Figure 14 overriding
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When a method in a subclass has the same name, same parameters or signature and same return
type (or sub-type) as a method in its super-class, then the method in the subclass is said to
override the method in the super-class.
Figure 15 overloading
Overloading allows different methods to have the same name, but different signatures where
the signature can differ by the number of input parameters or type of input parameters or both.
Overloading is related to compile-time (or static) polymorphism.
Conclusion
Polymorphism is a strong Java method that, when applied correctly, makes a class's design
flexible and extendable, with a customizable implementation that is simple to construct. This
is such a fundamental feature of Java that you can't even start without knowing what
polymorphism is and how to use it in the language. This article attempted to provide a peek of
certain complexities that may be useful in helping you code better in Java.
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1.1.7 Aggregation/composition
The term "association" refers to a relationship that exists between two distinct classes that is
established through their Objects. One-to-one, one-to-many, many-to-one, and many-to-many
associations are all possible. An Object communicates with another object in Object-Oriented
programming to leverage the capabilities and services offered by that object. The two types of
association are composition and aggregation (geeksforgeeks.org, 2022).
Figure 16 Aggregation/composition
Code reuse is also best achieved by aggregation when there is no is-a relationship. Inheritance
should be used only if the relationship is-a is maintained throughout the lifetime of the objects
involved; otherwise, aggregation is the best choice
Below shown is a code snippet of Aggregation, using Java language, on visual code
Figure 17 Aggregation
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When we constructed the room, we don’t want to include the doctor since if the doctor wants
to connect with the rooms, we may add the manually. Is the strong connection. Not more than
a connection of composition.
Conclusion
When a job demands OOP abilities, one of the most typical topics posed in interviews is
"aggregation vs composition." You must follow the guidelines of UML diagrams if you are
requested to conduct an object-oriented design. This allows people to comprehend your code's
connections without needing to know your notation. UML may help you save a lot of time
while designing a system. This class covers the fundamentals of certain advanced OOP topics,
as well as visualizing the structure of an OOP design.
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1.2 Relationship between OOP and Design Patterns
In order to get the most out of the components and properties, Object-Oriented Patterns are
linked to design patterns. These notions, on the other hand, are typically linked in order to
minimize programming complexity and increase code reuse.
An example of how OOP and Design Patterns are combined is shown below.
Figure 18 Relationship between OOP and Design Patterns - Example 01
When you look at the singleton design pattern cord above, you'll see that it was developed
utilizing object-oriented programming methods since classes, constructors, and access
modifiers were utilized properly to maintain encapsulation.
The goal of employing this design pattern is to avoid the production of the same item several
times. As a result, the constructor must be a public function according to the object-oriented
programming style, but the design pattern changes it to a private function to prohibit object
formation.
Furthermore, the design pattern uses abstraction to make it easy for the developer or class users
to utilize this class. Because if anyone needs to utilize this pattern, all they have to do is call
the class function using the static method to obtain a class object.
Figure 19 Relationship between OOP and Design Patterns - Example 02
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"Hello World!" is the code's output, as illustrated below. This indicates that the OOP
components and design pattern have been effectively integrated.
Figure 20 Relationship between OOP and Design Patterns - Example Output
As a consequence, each object-oriented programming design pattern, such as classes, access
modifiers, objects, and numerous components, produces efficient outcomes. Finally, this
implies that design patterns and object-oriented programming principles have a close link.
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Task 2
Design and build the detailed UML class diagram for the Family Dental Care
system. Your solution should demonstrate all inter-class relationships
namely Association, Inheritance and Aggregation/composition. The classes
should include attributes and methods needed.
2.1 UML Class Diagram
Figure 21 UML Class Diagram
The UML diagram depicts the properties, actions, and attributes of the information system's
many classes. Furthermore, the graphic establishes particular links between various classes
depending on their functions. Simply said, the system will be implemented totally based on the
UML diagram for maximum efficiency.
There are eight primary classes in the diagram, which include numerous connections such as
Association, Inheritance, Aggregation, and Composition. The base functions of each class are
used to examine these connections. All of the aforementioned classes are also linked to a
suitable database for effective class record storage.
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2.1.1 Association Relationship Evaluation
In order to meet FDC's needs, the system has a number of basic association links. A basic link
between two classes is an association relationship. It means that some of the classes'
characteristics or attributes have been shared in a specified way.
An UML diagram was used to accurately depict the suitable system, which included all of the
association connection classes. Furthermore, the fact that the majority of the system's classes
are linked via association relationships is crucial.
The learner, for example, has established a link between the 'Patient Registration' and 'Patient'
courses. The association relationship is illustrated as a diagram in the UML example below.
Figure 22 UML Association Relationship Evaluation
2.1.2 Inheritance Relationship Evaluation
There are examples of inheritance connections in the system due to FDC's needs. Inheritance
connections are simply built to allow a child class to inherit properties from a parent class.
An UML diagram had been used to adequately depict the relevant system. The 'Employee'
components of a class must be configured to be inherited at first. This is due to the fact that the
dental system has four different types of doctors, all of whom have similar characteristics.
However, there are times when some employees are required to have certain credentials and
experience, but they are resolved as children classes. Dentist, Nurse, Manager, and Dental
Consultant are four offspring classes inherited from the Employee parent class.
The inheritance UML diagram sample is shown below, defining how the specific connection
is depicted as an illustration.
Figure 23 UML Association Inheritance Evaluation
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2.1.3 Aggregation Relationship Evaluation
The learner implemented the aggregate relationship between the classes 'Patient' and
'Employee.' This indicates that the existence of the Patient class is contingent on the presence
of the Employee class. However, one of these classes might exist independently of the other,
constituting the aggregation process.
Figure 24 UML Aggregation Relationship Evaluation
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2.1.4 Composition Relationship Evaluation
The learner implemented that the classes, ‘Payment and ‘Appointment are in composition
relationship. This means that the Payment class entirely depends on the Appointment class for
existence. Taking a real-time scenario, a payment for a patient cannot be processed without the
patient having an appointment, so the payment call is completely dependent.
Figure 25 UML Composition Relationship Evaluation
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Task 3
Determine and briefly discuss the range of design patterns and describe at
least one design pattern from the three available types of design pattern.
Provide suitable UML diagrams for the given patterns and analyze the
relationship between object-oriented paradigm and design patterns
providing a suitable example.
3.1 Design Patterns
Design Patterns are a set of guidelines used by programmers to solve common difficulties
during the development process. Object-oriented programmers are familiar with the idea of
design patterns. During development, design patterns are mainly employed to solve frequent
recurrent problems. A design pattern, for example, is like incomplete code that is used as a
template to solve problems (sourcemaking.com, 2022).
There are a number of elements that contribute to the formation of design patterns. Design
patterns, for example, help to accelerate development by include proven and confirmed system
elements. Most significantly, these patterns are reusable, which improves the system's quality
and accuracy. These pattern templates assist developers in avoiding reoccurring issues caused
by human mistake. In other words, if programmers become accustomed to designing patterns,
they will be more comfortable with them and make less mistakes.
In addition, there are three primary categories of design patterns.
•
Creational Patterns
•
Structural Patterns
•
Behavioral Patterns
Figure 26 Design Patterns
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3.1.1 Types of Design Patterns
3.1.1.1 Creational Design Patterns
Creational patterns are specifically implemented for program object creation purposes, in order
to develop quality and accurate objects. The major objective of these patterns is to reduce any
complications while creating objects in a program. Moreover, the concept includes the factor
of not considering object creation logics and declare them directly using operators
(gofpatterns.com, 2022).
1. Factory Pattern
Factory pattern method is used to create object templates for the program, using a ‘superclass’
which declares the main properties and behaviors, which can then be passed on to subclasses.
The subclasses decide the specific class to be initiated from the parent classes.
2. Object Pool Pattern
Object pool method is used to cache pools by sharing previous object pools, while creating new
pools. Simply, all reusable objects can be stored as pools for later use. When a programmer
needs to create a new object, the pool can be referred rather than creating from scratch.
3. Singleton Pattern
Singleton pattern is used to make classes provide single occurrence objects on implementation
and execution. For instance, the object class can be expressed as private and static method,
which encapsulates the class data.
3.1.1.2 Structural Design Patterns
Structural design patterns are implemented for a simple convenience, which is defining the
relationship between multiple entities. The patterns are executed in a manner to simplify the
task of providing relationships within a class entity.
Various methods are included while considering structural patterns, listed as follows;
1. Adapter Pattern
Adapter pattern method is implemented with major consideration of reusing code. The adapter
pattern works as a connector to integrate multiple classes together. The major concept is that,
during development, verified codes have a higher reliability, which motivates programmers to
reuse verified codes throughout the develop process.
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2. Decorator Pattern
Decorator design patterns are implemented for any additional interface design enhancements.
The decorators will also be adding additional responsibilities, with developer requirements.
Examples of decorators include sidebars or borders on the system interface. However, any
decorator function will be static and its behavior cannot be changed after execution.
3. Composite Pattern
Composite design patterns are used to define special ‘abstract’ classes. Abstract classes are
used to represent certain inheritable functions, whereas composite patterns are also used for
changing object behavior while parent functions are inherited in child class. The composite
could also occur recursively and allows to deal with objects in a uniform manner.
3.1.1.3 Behavioral Design Patterns
Behavioral design patterns are essential in identifying similar communications between
multiple class objects. Programmers analyze these communications in order to identify specific
patterns within the objects.
Various methods are included while considering behavioral patterns, listed as follows;
1. Chain of Responsibility Pattern
Chain of responsibility design patterns are used to handle object requests by wrapping elements
using abstract functions. The chain establishes a connection between objects and allows
communications. The sender object sends objects from the top of the chain, which travels
through chain process and ends at the receiver.
2. Mediator Pattern
Mediator design patterns are implemented to create reusable elements, using encapsulation
methodology between interacting objects. The mediator analyses communication between
objects and compare their object references, where the interaction passes through the mediator.
The major objective is to partition objects in order to increase reusability.
3. Observer Pattern
Observer design patterns are used to differentiate a dependent and independent functions. The
dependent function will be known as ‘observer’, while the independent function acting as
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abstract will be known as ‘subject’. So, when the properties of an independent function are
changed, they are automatically altered in the dependent functions.
Advantage of design pattern
•
They are reusable in multiple projects.
•
They provide the solutions that help to define the system architecture.
•
They capture the software engineering experiences.
•
They provide transparency to the design of an application.
•
They are well-proved and testified solutions since they have been built upon the
knowledge and experience of expert software developers.
•
Design patterns don’t guarantee an absolute solution to a problem. They provide clarity
to the system architecture and the possibility of building a better system
Singleton Design Pattern
According to The FDC's senior senirio, The Singleton Design Pattern is a Creational pattern in
which just one instance of a class is created and only one global access point to that object is
provided. Calendar is a frequent example of a class like this in Java, where you can't create an
instance of it. It also has its own getInstance() method for obtaining the object that will be
utilized.
A class that follows the singleton design pattern will have the following features,
Figure 27 Singleton Class Diagram
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1. A private static variable, holding the only instance of the class.
2. A private constructor, so it cannot be instantiated anywhere else.
3. A public static method, to return the single instance of the class.
Singleton design may be implemented in a variety of ways. I'll be going over the
implementations of today's topic.
1. Eager Instantiation
2. Lazy Instantiation
3. Thread-safe Instantiation
Conclusion
The communication between classes and objects is the core of a behavioral design pattern. The
command pattern's main goal is to encourage a larger degree of loose coupling between the
parties involved (read: classes). Coupling is the process through which two (or more) classes
interact with one another. When these classes interact, the ideal scenario is that they are not
overly reliant on one another. That's referred to as loose coupling. So, a better notion of loose
coupling would be interconnected classes that utilize each other the least. The necessity for this
pattern developed when it was necessary to send requests without knowing what you were
asking for or who the recipient was. The calling class is detached from the class that actually
executes the action in this pattern. When the client asks it, the invoker class simply contains
the callable method execute, which executes the required command.
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Composite pattern would be the appropriate design pattern to be implemented with the
treatment type’s scenario, according to the requirements. Composite patterns are used in
occasions where multiple objects are considered as a single object, which are initiated using
tree structures.
Figure 28 Composite Design Pattern Diagram
Initially, the properties to be included in the class were assigned. Moreover, list method was
used to store the sub treatments. The implemented code is shown below.
Figure 29 Treatment Types Implementation 01
The sub treatments are stored as ‘Subsidiary’ which are treatments required by the hospital to
carry out before the main treatment is done.
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Functions to add or remove patient sub treatments were also added, as shown below.
Figure 30 Treatment Types Implementation 02
Following objects are used to return functions, whereas patient treatments are also defined. Three
treatments are defined in the code, ‘Tooth Implant, Scaling and Cleaning and Antibiotic Treatment’ as
treatment subsidiaries, to be done before the main treatment is done.
Figure 31 Treatment Types Implementation 03
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The complete treatment type class code looks like.
Figure 32 Treatment Types Implementation 04
The treatment type’s code output window is shown below.
Figure 33 Treatment Types Implementation Output
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Object-oriented paradigm
Previously, structured programming techniques
were
used. Structured programming
approaches were applied, which resulted in a host of problems. In structured programming, a
top-down approach was adopted. To overcome these challenges, the object-oriented
programming approach was created. In object-oriented programming, the bottom-up technique
is utilized. It also keeps up with the increasing complexity of the world. An object-oriented
program may be described as a set of data that restricts access to code. Object-oriented
programming is a programming technique that involves the creation of a program using objects
and a set of well-defined interfaces to those objects. Because it describes how components of
a computer program must be constructed, the object-oriented programming approach is
referred to as a paradigm. It also specifies how the various components should interact with
one another (pcmag.com, 2022).
Uses of Design Patterns
Design patterns can help developers save time by providing tried-and-true development
paradigms. Effective software design necessitates taking into account challenges that may not
be apparent until later in the implementation process. For coders and architects acquainted with
the patterns, reusing design patterns helps to eliminate minor flaws that can lead to large
difficulties and improves code readability. People frequently only know how to apply specific
software design strategies to specific challenges. These methods are challenging to apply to a
larger set of issues. Design patterns are generic solutions that are described in a way that does
not necessitate specifics connected to a specific situation. Patterns also help engineers to speak
about software interactions using well-known, well-understood terms. Over time, common
design patterns may be enhanced, making them more durable than haphazard designs
(sourcemaking.com, 2022).
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Analyze the relationship between object-oriented paradigm and design patterns
In software engineering, a design pattern is a general repeatable solution to a commonly
occurring problem in software design. A design pattern isn't a finished design that can be
transformed directly into code. It is a description or template for how to solve a problem that
can be used in many different situations.
As Design Patterns are well documented and understood by software architects, designers and
developers, then their application within a specific solution will likewise be well understood.
Design Patterns give a software developer an array of tried and tested solutions to common
problems, thus reducing the technical risk to the project by not having to employ a new and
untested design.
Design Patterns are well-known ways to resolving difficulties in OOP programming. Knowing
design patterns might help you save time when deciding how to tackle a problem. Some design
patterns, such as the Visitor Pattern, allow you to perform things that would otherwise be
difficult or hard, such as adding new functionality to a collection of classes without their
knowing about it. An interface or virtual methods that each class implements would be created
using standard OOP procedures. This is in violation of the OOP open/closed paradigm. Patterns
are used frequently in the Java as well as systems, so programmers apply them without ever
learning them. The Decorator pattern is used by the majority of the classes in the Java IO
namespace. Knowing this does not make someone an expert in OOP, but it can assist in making
sense of things. Object-Oriented Programming (OOP) is a programming style or philosophy
that divides code into objects and their connections. Design Patterns provide tried-and-true
techniques of creating types/objects to tackle a certain problem in a software.
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Task 4
Scenario 1
FDC owns a very expensive, state of the art dental scan machine (a device far superior to
a traditional dental X-ray machine) manufactured by Toshiba, Japan. FDC will be own
just one such machine in the foreseeable future. When modeling and implementing FDC
system in software, you must ensure that only one instance of that machine is created.
4.1.1 Dental Scan Machine
Considering the application requirements of the dental scanning machine, singleton design
pattern would be the appropriate pattern to be implemented. Singleton pattern is used to make
classes provide single occurrence objects on implementation and execution. For instance, the
object class can be expressed as private and static method, which encapsulates the class data.
Figure 34 Singleton Design Pattern Diagram
The singleton pattern has one of the simplest architectures of all the patterns. Because it is often
necessary to give only one instance of our class, such as a single DB connection shared by
numerous instances, implementing a separate DB connection for each item would be
prohibitively costly. Similarly, instead of having several managers, an application that manages
all problems should have a single configuration manager or error manager.
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Definition
The singleton pattern is a design pattern that restricts a class's instantiation to to one object.
Because the singleton pattern contains only one instance and more instances are restricted as
the scenario requires, it is the most suited design for the scenario. Only one scanner is made,
and the other scanner cannot be inserted at that time. The code snippet below should be used
to create a new scanner, and if another scanner is added, a message stating "Scanner existing"
should be displayed.
The complete scanning machine class code is shown below.
.
Figure 35 Singleton Applied
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The real results of the added data will be shown below, along with the run code with the object
name scan.
Figure 36 Scan Object
Figure 37 Dental Scan Machine Implementation Output
The output gets messages indicating "Scanner exists" until the scanner is transmitted for the
second time, as shown in the figure below.
Figure 38 Scanner Exists
As a result, the singleton pattern used within the system performs as predicted by the scenario.
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Scenario 02
Below table provides the hierarchy of the Employees and their monthly salary in FDC.
Table 1 Hierarchy of the Employees and their monthly salary in FDC
Emp Id
A001
A002
A003
A004
A005
A006
A007
Name
Anton
Chamod
Supuni
Madhavi
Piyal
Kamal
Kapila
Position
Director
Dentist
Dentist
Dentist
Nurse
Nurse
Nurse
Salary
1,000,000 LKR
600,000 LKR
600,000 LKR
600,000 LKR
200,000 LKR
200,000 LKR
200,000 LKR
All the Nurses are working under the Dentists and Chamod(Dentist) is working under the
Supuni(Dentist) and Madhavi(Dentist) is working under the Anton(Director).
Figure 39 Class for Employee
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The complete Employee class code is shown below.
Figure 40 Employees Types Implementation 01
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Figure 42 Employees Types Implementation 02
Figure 41 Employees Types Implementation Output
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Scenario 03
Patients who need dental scans are kept in a First in First Out queue. Assume that yo u
have found an already developed Queue container in a software library. It provides
standard queue operations to insert and remove data (known as enqueue and deque
respectively). However, you need some specific operations such as search() to look up a
particular patient and showAll() to list all the patients in the queue. These additional
operations are not provided by the library unit.
The dental scans are retained in a First In First Out queue, according to the situation. Assume
the learner has discovered an existing Queue container in a software library. Enqueue() and
dequeue() are common queue procedures for adding and removing data, respectively ().
Learners will, however, require some specialized operations such as search() to look for a
specific patient and showAll() to display a list of all the patients in the queue. Such functions
are not available in the library unit. So, for this demand, the iterator designing pattern is more
appropriate since, according to the scenario, a library was provided with enqueue() and
dequeue() functions for usage with the first in first out approach. However, according to the
scenario, the serach() and view() methods should be displayed with those functions, therefore
at this point, the learner has constructed an interface using the Iterator design pattern, which
contains two functions: serach() and showAll (). The two functions in the class should be
implemented by whoever implements the interface. The learner has constructed the patient
object, which has some information that patients require. The enqueue() and dequeue()
procedures will operate on the patient object in this case. The implementations and objects that
are between the patient going to work in the PatientArea. People who utilize the PatientArea
class can use functions like enqueue(), dequeue(), search(), and ShowAll().
In the Java and.Net programming environments, the Iterator design pattern is quite popular.
This technique is used to gain a method to sequentially access the elements of a collection
object without having to know its underlying form.
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Figure 43 Scanning List UML Diagram
In the name, the learner has created an Iterator interface. The methods serach() and showAll
are part of this interface (). PatientArea is a section for patients that has been expanded from
the iterator interface. This class already contains the enqueue) (and dequeue() functions, and it
must implement the Search() and ShowAll() operations, according to the preceding description
(). Since it extends from the iterator's interface. After then, a complete patient library will be
created.
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Conclusion
Family Dental Care (FDC) designed an information system that focuses on the tasks and
operations performed by personnel and consumers. FDC offers a wide range of dental
procedures, therefore the system should be suitable for any situation.
In the beginning of the assignment, basic Object-Oriented Programming (OOP) principles are
presented with appropriate examples. The learner then began the first phase of system
implementation by gathering the dental needs and information needed to finish the system. The
student utilized DIA software to create a UML diagram from the requirements he had gathered.
The example diagram contained relationships, inheritances, characteristics, properties, and
actions. Eventually, the assignment established and explained the majority of the important
class connections. The class relationships were used to create the information system. For more
efficient development, specific design patterns were assigned throughout system construction.
This same educator was able to grasp a variety of important programming ideas at a high level,
which was beneficial for system development. The learner hopes that the existing method
satisfies all of the standards for dental treatment and is successful enough to be used on a
regular basis.
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Self-Criticism
The learner gained valuable experience in designing and developing the information system
for Family Dental Care (FDC). The student was able to pick up on a variety of sophisticated
programming techniques. The student was also able to grasp more advanced ideas in objectoriented programming. The student hopes that the system representations would be helpful.
The learner was able to discover some strengths throughout the design of the information
system for Family Dental Care (FDC), such as.
•
Effective participation and interest in each system procedure are essential.
•
Analyze the prerequisites for an efficient dental care system.
The student, on the other hand, was able to identify some of the flaws mentioned throughout
the exercise, such as.
•
There is a lack of scheduled time allocation.
•
In some jobs, there is a lack of entire focus.
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Gantt chart
Figure 44 Gantt chart
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