YouTube Link: https://youtu.be/C_oPLDaSy-8
**Java, J2EE & SOA Certification Training - https://www.edureka.co/java-j2ee-training-course **
This Edureka PPT on "design patterns in java" will provide you with detailed knowledge about Java Design Patterns and along with it, This PPT will also cover some real-time examples of some important Design Patterns in Java, in order to provide you with a deep understanding about their functionality. This PPT will cover the following topics:
Why do we need Design Patterns?
What are Design Patterns?
Structure of a Design Pattern
Types of Design Patterns
Creational Design Pattern
Structural Design Pattern
Behavioural Design Pattern
JEE Design Pattern
Overview of design patterns
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JAVA design patterns and Basic OOp conceptsRahul Malhotra
This Presentation is about java design patterns. I have covered some OOPs concepts as well: Polymorphism, Interface, Inheritance, abstraction etc. And the Main Topic Covers: Factory Design Patterns,Observer Design Patterns,Proxy Design Patterns,Adapter Design Patterns,MVC Design Patterns etc
YouTube Link: https://youtu.be/C_oPLDaSy-8
**Java, J2EE & SOA Certification Training - https://www.edureka.co/java-j2ee-training-course **
This Edureka PPT on "design patterns in java" will provide you with detailed knowledge about Java Design Patterns and along with it, This PPT will also cover some real-time examples of some important Design Patterns in Java, in order to provide you with a deep understanding about their functionality. This PPT will cover the following topics:
Why do we need Design Patterns?
What are Design Patterns?
Structure of a Design Pattern
Types of Design Patterns
Creational Design Pattern
Structural Design Pattern
Behavioural Design Pattern
JEE Design Pattern
Overview of design patterns
Follow us to never miss an update in the future.
YouTube: https://www.youtube.com/user/edurekaIN
Instagram: https://www.instagram.com/edureka_learning/
Facebook: https://www.facebook.com/edurekaIN/
Twitter: https://twitter.com/edurekain
LinkedIn: https://www.linkedin.com/company/edureka
Castbox: https://castbox.fm/networks/505?country=in
JAVA design patterns and Basic OOp conceptsRahul Malhotra
This Presentation is about java design patterns. I have covered some OOPs concepts as well: Polymorphism, Interface, Inheritance, abstraction etc. And the Main Topic Covers: Factory Design Patterns,Observer Design Patterns,Proxy Design Patterns,Adapter Design Patterns,MVC Design Patterns etc
Patterns and Anti-patterns
How to learn design patterns?
Categories of GoF patterns
The Fundamental theorem of software engineering
Real-world problems and how design patterns solve them with GoF structural patterns
Design patterns are known as best practices that the programmer can use to solve common problems when designing an application or system.
Singelton Design Pattern
Factory Design Pattern
Builder Design Pattern
Strategy Design Pattern
Iterator Design Pattern
Observer Design Pattern
Prototype Design Pattern
Command Design Pattern
Decorator Pattern
Proxy Pattern
Adapter Pattern
what is design pattern?
what is design pattern in java?
what are the classification of design pattern?
why design pattern is important?
how we can implement any design pattern?
example of design pattern.
Design patterns are optimized, reusable solutions to the programming problems that we encounter every day. A design pattern is not a class or a library that we can simply plug into our system; it's much more than that. It is a template that has to be implemented in the correct situation. It's not language-specific either. A good design pattern should be implementable in most—if not all—languages, depending on the capabilities of the language. Most importantly, any design pattern can be a double-edged sword— if implemented in the wrong place, it can be disastrous and create many problems for you. However, implemented in the right place, at the right time, it can be your savior.
It's my report based on design pattern whosever want to learn how to create application using java with design patterns with less complexity they can see that
The modern view on implementation of classic design patterns in JavaMikalai Alimenkou
Almost every developer heard about design patterns. They was introduced long time ago to solve particular set of repeating problems in systems of different complexity level and size. But there is an opinion that many design patters just filled holes in the OOP languages of that time. Java as one of them has transformed and improved significantly in the last 10 years. So may be we could review design patterns implementation in modern Java world? Some of them are now may be easily replaced with language idioms, some others may be covered with existing libraries and frameworks. I'm sure you know some design patterns that are dead now or became anti-patterns in their initial implementation. Lets make this fun and useful review together!
Patterns and Anti-patterns
How to learn design patterns?
Categories of GoF patterns
The Fundamental theorem of software engineering
Real-world problems and how design patterns solve them with GoF structural patterns
Design patterns are known as best practices that the programmer can use to solve common problems when designing an application or system.
Singelton Design Pattern
Factory Design Pattern
Builder Design Pattern
Strategy Design Pattern
Iterator Design Pattern
Observer Design Pattern
Prototype Design Pattern
Command Design Pattern
Decorator Pattern
Proxy Pattern
Adapter Pattern
what is design pattern?
what is design pattern in java?
what are the classification of design pattern?
why design pattern is important?
how we can implement any design pattern?
example of design pattern.
Design patterns are optimized, reusable solutions to the programming problems that we encounter every day. A design pattern is not a class or a library that we can simply plug into our system; it's much more than that. It is a template that has to be implemented in the correct situation. It's not language-specific either. A good design pattern should be implementable in most—if not all—languages, depending on the capabilities of the language. Most importantly, any design pattern can be a double-edged sword— if implemented in the wrong place, it can be disastrous and create many problems for you. However, implemented in the right place, at the right time, it can be your savior.
It's my report based on design pattern whosever want to learn how to create application using java with design patterns with less complexity they can see that
The modern view on implementation of classic design patterns in JavaMikalai Alimenkou
Almost every developer heard about design patterns. They was introduced long time ago to solve particular set of repeating problems in systems of different complexity level and size. But there is an opinion that many design patters just filled holes in the OOP languages of that time. Java as one of them has transformed and improved significantly in the last 10 years. So may be we could review design patterns implementation in modern Java world? Some of them are now may be easily replaced with language idioms, some others may be covered with existing libraries and frameworks. I'm sure you know some design patterns that are dead now or became anti-patterns in their initial implementation. Lets make this fun and useful review together!
Introduction to the Spring Framework:
Generar description
IoC container
Dependency Injection
Beans scope and lifecycle
Autowiring
XML and annotation based configuration
Additional features
Have an upcoming technical interview for a junior front-end developer position at a company that uses AngularJS? Here are 29 AngularJS interview questions for you to practice with!
Why Design Patterns Are Important In Software EngineeringProtelo, Inc.
In software engineering, a design pattern is a general repeatable solution to a commonly occurring problem in software design. A design pattern is not 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. Learn how design patterns quickly solve common classes of problems and streamline communication between developers.
Agile and Modeling / MDE : friends or foes? (Agile Tour Nantes 2010)Jordi Cabot
n the talk I explore the relationships between software modeling and agile practices. For many agilists, the perception is that modeling is a useless activity that should not be part of the core agile practices. But, Is this really the case? Can agile benefit from modeling? Can modeling benefit from agile? Can modeling help companies understand the human and social aspects of agile methods and improve their chances of success when adopting them?
Boost Your Base Bootcamp - [Online & Offline] In BanglaStack Learner
Boost Your Base Bootcamp
Stack School:
https://courses.stackschool.co/courses/boost-your-base-bootcamp
"Boost Your Base Bootcamp[ Online + Offline ]", In this long course we will introduce you to C Programming Language, Java, Data Structures and Algorithms, Design Patterns and Problem Solving. At the end of the Bootcamp, you will find yourself in a place where you can engage yourself in any field of the IT world.
50+ Weeks, 100+ Classes - A Long Journey to Become A Programmer
অবজেক্ট অরিয়েন্টেড প্রোগ্রামিং, ডাটা স্ট্রাকচারস এবং অ্যালগোরিদম
আইটি জগতে নিজেকে যোগ্য করে গড়ে তোলার জন্য আপনার দরকার প্রোগ্রামিং এবং কম্পিউটার সাইন্সের দক্ষতা। এই দীর্ঘ কোর্সে আমরা আপনাকে সি প্রোগ্রামিং ল্যাংগুয়েজ, জাভা, ডাটা স্ট্রাকচার এবং অ্যালগোরিদম, ডিজাইন প্যাটার্ন এবং প্রব্লেম সল্ভিং এর সাথে পরিচয় করাবো। হাতে কলমে শেখানোর সাথে সাথে ইন্ডিভিজুয়াল এবং গ্রুপ প্রোজেক্টের মাধ্যমে আপনাকে দক্ষ করে গোড়ে তোলার চেষ্টা করা হবে এই সুবিশাল কোর্সে। এই কোর্স শেষে আপনি নিজেকে এমন একটি জায়গায় আবিষ্কার করবেন যেখান থেকে আপনি আইটি জগতের যেকোনো ফিল্ডে নিজেকে জড়িত করতে পারবেন। আপনার প্রোগ্রামিং এর ভিত্তি তৈরির কাজ করবে এই বুটক্যাম্পটি।
Part C Developing Your Design SolutionThe Production Cycle.docxsmile790243
Part C Developing Your Design
Solution
The Production Cycle
Within the four stages of the design workflow there are two distinct parts.
The first three stages, as presented in Part B of this book, were described
as ‘The Hidden Thinking’ stages, as they are concerned with undertaking
the crucial behind-the-scenes preparatory work. You may have completed
them in terms of working through the book’s contents, but in visualisation
projects they will continue to command your attention, even if that is
reduced to a background concern.
You have now reached the second distinct part of the workflow which
involves developing your design solution. This stage follows a production
cycle, commencing with rationalising design ideas and moving through to
the development of a final solution.
The term cycle is appropriate to describe this stage as there are many loops
of iteration as you evolve rapidly between conceptual, practical and
technical thinking. The inevitability of this iterative cycle is, in large part,
again due to the nature of this pursuit being more about optimisation rather
than an expectation of achieving that elusive notion of perfection. Trade-
offs, compromises, and restrictions are omnipresent as you juggle ambition
and necessary pragmatism.
How you undertake this stage will differ considerably depending on the
nature of your task. The creation of a relatively simple, single chart to be
slotted into a report probably will not require the same rigour of a formal
production cycle that the development of a vast interactive visualisation to
be used by the public would demand. This is merely an outline of the most
you will need to do – you should edit, adapt and participate the steps to fit
with your context.
There are several discrete steps involved in this production cycle:
Conceiving ideas across the five layers of visualisation design.
Wireframing and storyboarding designs.
Developing prototypes or mock-up versions.
219
Testing.
Refining and completing.
Launching the solution.
Naturally, the specific approach for developing your design solution (from
prototyping through to launching) will vary hugely, depending particularly
on your skills and resources: it might be an Excel chart, or a Tableau
dashboard, an infographic created using Adobe Illustrator, or a web-based
interactive built with the D3.js library. As I have explained in the book’s
introduction, I’m not going to attempt to cover the myriad ways of
implementing a solution; that would be impossible to achieve as each task
and tool would require different instructions.
For the scope of this book, I am focusing on taking you through the first
two steps of this cycle – conceiving ideas and wireframing/storyboarding.
There are parallels here with the distinctions between architecture (design)
and engineering (execution) – I’m effectively chaperoning you through to
the conclusion of your design thinking.
To fulfil this, Part C presents a detailed breakdown of the many design
.
UX STRAT Online 2021 Presentation by Adilakshmi Veerubhotla, IBMUX STRAT
These slides are for the following session presented at the UX STRAT Online 2021 Conference:
"Design Tools to Get the Most from AI"
Adilakshmi Veerubhotla
IBM: UX Architect
Design Patterns : The Ultimate Blueprint for SoftwareEdureka!
Object Oriented Programming is one of the biggest evolution ever happened to the software industry. Lots of languages started implementing OOP concepts thinking it would add lot of value and will improve the adaptability of the languages. While the OOP provides the concepts, programming languages still lack the essence that is needed for better software design. Design patterns fill the gap by providing solution templates for commonly occurring design problems. As any other software entity, Design Patterns is an evolving subject and it has reached its extreme maturity now by covering most of the design problems that the current software industry is facing. Practicing design patterns has helped the success ratio of software projects these days immensely. Design patterns have become a magic wand in the hands of successful software programmers and architects.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
Slack (or Teams) Automation for Bonterra Impact Management (fka Social Soluti...Jeffrey Haguewood
Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
Interested in deploying notification automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
👨🏫 Andras Palfi, Senior Product Manager, UiPath
👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
Generating a custom Ruby SDK for your web service or Rails API using Smithyg2nightmarescribd
Have you ever wanted a Ruby client API to communicate with your web service? Smithy is a protocol-agnostic language for defining services and SDKs. Smithy Ruby is an implementation of Smithy that generates a Ruby SDK using a Smithy model. In this talk, we will explore Smithy and Smithy Ruby to learn how to generate custom feature-rich SDKs that can communicate with any web service, such as a Rails JSON API.
Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
In today's fast-changing business world, Companies that adapt and embrace new ideas often need help to keep up with the competition. However, fostering a culture of innovation takes much work. It takes vision, leadership and willingness to take risks in the right proportion. Sachin Dev Duggal, co-founder of Builder.ai, has perfected the art of this balance, creating a company culture where creativity and growth are nurtured at each stage.
Smart TV Buyer Insights Survey 2024 by 91mobiles.pdf91mobiles
91mobiles recently conducted a Smart TV Buyer Insights Survey in which we asked over 3,000 respondents about the TV they own, aspects they look at on a new TV, and their TV buying preferences.
Smart TV Buyer Insights Survey 2024 by 91mobiles.pdf
Java Design Pattern Interview Questions
1. Java Design Pattern Interview Questions What is the design pattern?If a problem occurs over and over again, a solution to that problem has been used effectively. That solution is described as a pattern. The design patterns are language-independent strategies for solving common object-oriented design problems. When you make a design, you should know the names of some common solutions. Learning design patterns is good for people to communicate each other effectively. In fact, you may have been familiar with some design patterns, you may not use well-known names to describe them. SUN suggests GOF (Gang Of Four--four pioneer guys who wrote a book named
Design Patterns
- Elements of Reusable Object-Oriented Software), so we use that book as our guide to describe solutions. Please make you be familiar with these terms and learn how other people solve the code problems. Do I have to use the design pattern?If you want to be a professional Java developer, you should know at least some popular solutions to coding problems. Such solutions have been proved efficient and effective by the experienced developers. These solutions are described as so-called design patterns. Learning design patterns speeds up your experience accumulation in OOA/OOD. Once you grasped them, you would be benefit from them for all your life and jump up yourselves to be a master of designing and developing. Furthermore, you will be able to use these terms to communicate with your fellows or assessors more effectively. Many programmers with many years experience don't know design patterns, but as an Object-Oriented programmer, you have to know them well, especially for new Java programmers. Actually, when you solved a coding problem, you have used a design pattern. You may not use a popular name to describe it or may not choose an effective way to better intellectually control over what you built. Learning how the experienced developers to solve the coding problems and trying to use them in your project are a best way to earn your experience and certification. Remember that learning the design patterns will really change how you design your code; not only will you be smarter but will you sound a lot smarter, too. How many design patterns?Many. A site says at least 250 existing patterns are used in OO world, including Spaghetti which refers to poor coding habits. The 23 design patterns by GOF are well known, and more are to be discovered on the way. Note that the design patterns are not idioms or algorithms or components.What is the relationship among these patterns?Generally, to build a system, you may need many patterns to fit together. Different designer may use different patterns to solve the same problem. Usually: Some patterns naturally fit togetherOne pattern may lead to anotherSome patterns are similar and alternativePatterns are discoverable and documentablePatterns are not methods or frameworkPatterns give you hint to solve a problem effectively Software Architecture Interview Questions Part 1 - Design Pattern Interview Questions (B) What are design patterns?(A) Can you explain factory pattern?(I) Can you explain abstract factory pattern?(I)Can you explain builder pattern?(I) Can you explain prototype pattern?(A) Can you explain shallow copy and deep copy in prototype patterns?(B) Can you explain singleton pattern?(A) Can you explain command patterns?Other Interview question PDF's Introduction Hi friends , Please do not think you get an architecture position by reading interview questions. But yes there should be some kind of reference which will help you quickly revise what are the definition. Just by reading these answers you get to a position where you are aware of the fundamentals. But if you have not really worked you will surely fail with scenario based questions. So use this as a quick revision rather than a shot cut. To give you a practical understanding i have put all these design patterns in a video format and uploaded on http://www.questpond.com/FreeDesign1.htm . You can visit http://www.questpond.com and download the complete architecture interview questions PDF which covers SOA , UML , Design patterns , Togaf , OOPs etc. I am trying to get familiar with the egghead cafe editor so i am uploading questions one by one. Please cope up with me. (B) What are design patterns? Design patterns are documented tried and tested solutions for recurring problems in a given context. So basically you have a problem context and the proposed solution for the same. Design patterns existed in some or other form right from the inception stage of software development. Let’s say if you want to implement a sorting algorithm the first thing comes to mind is bubble sort. So the problem is sorting and solution is bubble sort. Same holds true for design patterns. (I) Which are the three main categories of design patterns? There are three basic classifications of patterns Creational, Structural, and Behavioral patterns. Creational Patterns • Abstract Factory:- Creates an instance of several families of classes • Builder: - Separates object construction from its representation • Factory Method:- Creates an instance of several derived classes • Prototype:- A fully initialized instance to be copied or cloned • Singleton:- A class in which only a single instance can exist Note: - The best way to remember Creational pattern is by ABFPS (Abraham Became First President of States).Structural Patterns • Adapter:-Match interfaces of different classes. • Bridge:-Separates an object’s abstraction from its implementation. • Composite:-A tree structure of simple and composite objects. • Decorator:-Add responsibilities to objects dynamically. • Façade:-A single class that represents an entire subsystem.• Flyweight:-A fine-grained instance used for efficient sharing. • Proxy:-An object representing another object. Note : To remember structural pattern best is (ABCDFFP)Behavioral Patterns • Mediator:-Defines simplified communication between classes.• Memento:-Capture and restore an object's internal state. • Interpreter:- A way to include language elements in a program.• Iterator:-Sequentially access the elements of a collection. • Chain of Resp: - A way of passing a request between a chain of objects.• Command:-Encapsulate a command request as an object. • State:-Alter an object's behavior when its state changes. • Strategy:-Encapsulates an algorithm inside a class. • Observer: - A way of notifying change to a number of classes. • Template Method:-Defer the exact steps of an algorithm to a subclass. • Visitor:-Defines a new operation to a class without change. Note: - Just remember Music....... 2 MICS On TV (MMIICCSSOTV).Note :- In the further section we will be covering all the above design patterns in a more detail manner. (A) Can you explain factory pattern? Factory pattern is one of the types of creational patterns. You can make out from the name factory itself it’s meant to construct and create something. In software architecture world factory pattern is meant to centralize creation of objects. Below is a code snippet of a client which has different types of invoices. These invoices are created depending on the invoice type specified by the client. There are two issues with the code below:- First we have lots of ‘new’ keyword scattered in the client. In other ways the client is loaded with lot of object creational activities which can make the client logic very complicated.Second issue is that the client needs to be aware of all types of invoices. So if we are adding one more invoice class type called as ‘InvoiceWithFooter’ we need to reference the new class in the client and recompile the client also. Figure: - Different types of invoice Taking these issues as our base we will now look in to how factory pattern can help us solve the same. Below figure ‘Factory Pattern’ shows two concrete classes ‘ClsInvoiceWithHeader’ and ‘ClsInvoiceWithOutHeader’. The first issue was that these classes are in direct contact with client which leads to lot of ‘new’ keyword scattered in the client code. This is removed by introducing a new class ‘ClsFactoryInvoice’ which does all the creation of objects. The second issue was that the client code is aware of both the concrete classes i.e. ‘ClsInvoiceWithHeader’ and ‘ClsInvoiceWithOutHeader’. This leads to recompiling of the client code when we add new invoice types. For instance if we add ‘ClsInvoiceWithFooter’ client code needs to be changed and recompiled accordingly. To remove this issue we have introduced a common interface ‘IInvoice’. Both the concrete classes ‘ClsInvoiceWithHeader’ and ‘ClsInvoiceWithOutHeader’ inherit and implement the ‘IInvoice’ interface. The client references only the ‘IInvoice’ interface which results in zero connection between client and the concrete classes ( ‘ClsInvoiceWithHeader’ and ‘ClsInvoiceWithOutHeader’). So now if we add new concrete invoice class we do not need to change any thing at the client side. In one line the creation of objects is taken care by ‘ClsFactoryInvoice’ and the client disconnection from the concrete classes is taken care by ‘IInvoice’ interface. Figure: - Factory pattern Below are the code snippets of how actually factory pattern can be implemented in C#. In order to avoid recompiling the client we have introduced the invoice interface ‘IInvoice’. Both the concrete classes ‘ClsInvoiceWithOutHeaders’ and ‘ClsInvoiceWithHeader’ inherit and implement the ‘IInvoice’ interface. Figure :- Interface and concrete classes We have also introduced an extra class ‘ClsFactoryInvoice’ with a function ‘getInvoice()’ which will generate objects of both the invoices depending on ‘intInvoiceType’ value. In short we have centralized the logic of object creation in the ‘ClsFactoryInvoice’. The client calls the ‘getInvoice’ function to generate the invoice classes. One of the most important points to be noted is that client only refers to ‘IInvoice’ type and the factory class ‘ClsFactoryInvoice’ also gives the same type of reference. This helps the client to be complete detached from the concrete classes, so now when we add new classes and invoice types we do not need to recompile the client. Figure: - Factory class which generates objects Note :- The above example is given in C# . Even if you are from some other technology you can still map the concept accordingly. You can get source code from the CD in ‘FactoryPattern’ folder. (I) Can you explain abstract factory pattern? Abstract factory expands on the basic factory pattern. Abstract factory helps us to unite similar factory pattern classes in to one unified interface. So basically all the common factory patterns now inherit from a common abstract factory class which unifies them in a common class. All other things related to factory pattern remain same as discussed in the previous question.A factory class helps us to centralize the creation of classes and types. Abstract factory helps us to bring uniformity between related factory patterns which leads more simplified interface for the client. Figure: - Abstract factory unifies related factory patterns Now that we know the basic lets try to understand the details of how abstract factory patterns are actually implemented. As said previously we have the factory pattern classes (factory1 and factory2) tied up to a common abstract factory (AbstractFactory Interface) via inheritance. Factory classes stand on the top of concrete classes which are again derived from common interface. For instance in figure ‘Implementation of abstract factory’ both the concrete classes ‘product1’ and ‘product2’ inherits from one interface i.e. ‘common’. The client who wants to use the concrete class will only interact with the abstract factory and the common interface from which the concrete classes inherit. Figure: - Implementation of abstract factory Now let’s have a look at how we can practically implement abstract factory in actual code. We have scenario where we have UI creational activities for textboxes and buttons through their own centralized factory classes ‘ClsFactoryButton’ and ‘ClsFactoryText’. Both these classes inherit from common interface ‘InterfaceRender’. Both the factories ‘ClsFactoryButton’ and ‘ClsFactoryText’ inherits from the common factory ‘ClsAbstractFactory’. Figure ‘Example for AbstractFactory’ shows how these classes are arranged and the client code for the same. One of the important points to be noted about the client code is that it does not interact with the concrete classes. For object creation it uses the abstract factory ( ClsAbstractFactory ) and for calling the concrete class implementation it calls the methods via the interface ‘InterfaceRender’. So the ‘ClsAbstractFactory’ class provides a common interface for both factories ‘ClsFactoryButton’ and ‘ClsFactoryText’. Figure: - Example for abstract factory Note: - We have provided a code sample in C# in the ‘AbstractFactory’ folder. People who are from different technology can compare easily the implementation in their own language. We will just run through the sample code for abstract factory. Below code snippet ‘Abstract factory and factory code snippet’ shows how the factory pattern classes inherit from abstract factory. Figure: - Abstract factory and factory code snippet Figure ‘Common Interface for concrete classes’ how the concrete classes inherits from a common interface ‘InterFaceRender’ which enforces the method ‘render’ in all the concrete classes. Figure: - Common interface for concrete classes The final thing is the client code which uses the interface ‘InterfaceRender’ and abstract factory ‘ClsAbstractFactory’ to call and create the objects. One of the important points about the code is that it is completely isolated from the concrete classes. Due to this any changes in concrete classes like adding and removing concrete classes does not need client level changes. Figure: - Client, interface and abstract factory (I)Can you explain builder pattern? Builder falls under the type of creational pattern category. Builder pattern helps us to separate the construction of a complex object from its representation so that the same construction process can create different representations. Builder pattern is useful when the construction of the object is very complex. The main objective is to separate the construction of objects and their representations. If we are able to separate the construction and representation, we can then get many representations from the same construction. Figure: - Builder concept To understand what we mean by construction and representation lets take the example of the below ‘Tea preparation’ sequence.You can see from the figure ‘Tea preparation’ from the same preparation steps we can get three representation of tea’s (i.e. Tea with out sugar, tea with sugar / milk and tea with out milk). Figure: - Tea preparation Now let’s take a real time example in software world to see how builder can separate the complex creation and its representation. Consider we have application where we need the same report to be displayed in either ‘PDF’ or ‘EXCEL’ format. Figure ‘Request a report’ shows the series of steps to achieve the same. Depending on report type a new report is created, report type is set, headers and footers of the report are set and finally we get the report for display. Figure: - Request a report Now let’s take a different view of the problem as shown in figure ‘Different View’. The same flow defined in ‘Request a report’ is now analyzed in representations and common construction. The construction process is same for both the types of reports but they result in different representations. Figure: - Different View We will take the same report problem and try to solve the same using builder patterns. There are three main parts when you want to implement builder patterns.• Builder: - Builder is responsible for defining the construction process for individual parts. Builder has those individual processes to initialize and configure the product.• Director: - Director takes those individual processes from the builder and defines the sequence to build the product.• Product: - Product is the final object which is produced from the builder and director coordination.First let’s have a look at the builder class hierarchy. We have a abstract class called as ‘ReportBuilder’ from which custom builders like ‘ReportPDF’ builder and ‘ReportEXCEL’ builder will be built. Figure: - Builder class hierarchy Figure ‘Builder classes in actual code’ shows the methods of the classes. To generate report we need to first Create a new report, set the report type (to EXCEL or PDF) , set report headers , set the report footers and finally get the report. We have defined two custom builders one for ‘PDF’ (ReportPDF) and other for ‘EXCEL’ (ReportExcel). These two custom builders define there own process according to the report type. Figure: - Builder classes in actual code Now let’s understand how director will work. Class ‘clsDirector’ takes the builder and calls the individual method process in a sequential manner. So director is like a driver who takes all the individual processes and calls them in sequential manner to generate the final product, which is the report in this case. Figure ‘Director in action’ shows how the method ‘MakeReport’ calls the individual process to generate the report product by PDF or EXCEL. Figure: - Director in action The third component in the builder is the product which is nothing but the report class in this case. Figure: - The report class Now let’s take a top view of the builder project. Figure ‘Client,builder,director and product’ shows how they work to achieve the builder pattern. Client creates the object of the director class and passes the appropriate builder to initialize the product. Depending on the builder the product is initialized/created and finally sent to the client. Figure: - Client, builder, director and product The output is something like this. We can see two report types displayed with their headers according to the builder. Figure: - Final output of builder Note :- In CD we have provided the above code in C# in ‘BuilderPattern’ folder. (I) Can you explain prototype pattern? Prototype pattern falls in the section of creational pattern. It gives us a way to create new objects from the existing instance of the object. In one sentence we clone the existing object with its data. By cloning any changes to the cloned object does not affect the original object value. If you are thinking by just setting objects we can get a clone then you have mistaken it. By setting one object to other object we set the reference of object BYREF. So changing the new object also changed the original object. To understand the BYREF fundamental more clearly consider the figure ‘BYREF’ below. Following is the sequence of the below code:-• In the first step we have created the first object i.e. obj1 from class1.• In the second step we have created the second object i.e. obj2 from class1.• In the third step we set the values of the old object i.e. obj1 to ‘old value’.• In the fourth step we set the obj1 to obj2.• In the fifth step we change the obj2 value.• Now we display both the values and we have found that both the objects have the new value. Figure :- BYREf The conclusion of the above example is that objects when set to other objects are set BYREF. So changing new object values also changes the old object value.There are many instances when we want the new copy object changes should not affect the old object. The answer to this is prototype patterns.Lets look how we can achieve the same using C#. In the below figure ‘Prototype in action’ we have the customer class ‘ClsCustomer’ which needs to be cloned. This can be achieved in C# my using the ‘MemberWiseClone’ method. In JAVA we have the ‘Clone’ method to achieve the same. In the same code we have also shown the client code. We have created two objects of the customer class ‘obj1’ and ‘obj2’. Any changes to ‘obj2’ will not affect ‘obj1’ as it’s a complete cloned copy. Figure: - Prototype in action Note :- You can get the above sample in the CD in ‘Prototype’ folder. In C# we use the ‘MemberWiseClone’ function while in JAVA we have the ‘Clone’ function to achieve the same. (A) Can you explain shallow copy and deep copy in prototype patterns? There are two types of cloning for prototype patterns. One is the shallow cloning which you have just read in the first question. In shallow copy only that object is cloned, any objects containing in that object is not cloned. For instance consider the figure ‘Deep cloning in action’ we have a customer class and we have an address class aggregated inside the customer class. ‘MemberWiseClone’ will only clone the customer class ‘ClsCustomer’ but not the ‘ClsAddress’ class. So we added the ‘MemberWiseClone’ function in the address class also. Now when we call the ‘getClone’ function we call the parent cloning function and also the child cloning function, which leads to cloning of the complete object. When the parent objects are cloned with their containing objects it’s called as deep cloning and when only the parent is clones its termed as shallow cloning. Figure: - Deep cloning in action (B) Can you explain singleton pattern? There are situations in a project where we want only one instance of the object to be created and shared between the clients. No client can create an instance of the object from outside. There is only one instance of the class which is shared across the clients. Below are the steps to make a singleton pattern:-1) Define the constructor as private.2) Define the instances and methods as static.Below is a code snippet of a singleton in C#. We have defined the constructor as private, defined all the instance and methods using the static keyword as shown in the below code snippet figure ‘Singleton in action’. The static keyword ensures that you only one instance of the object is created and you can all the methods of the class with out creating the object. As we have made the constructor private, we need to call the class directly. Figure: - Singleton in action Note :- In JAVA to create singleton classes we use the STATIC keyword , so its same as in C#. You can get a sample C# code for singleton in the ‘singleton’ folder. (A) Can you explain command patterns? Command pattern allows a request to exist as an object. Ok let’s understand what it means. Consider the figure ‘Menu and Commands’ we have different actions depending on which menu is clicked. So depending on which menu is clicked we have passed a string which will have the action text in the action string. Depending on the action string we will execute the action. The bad thing about the code is it has lot of ‘IF’ condition which makes the coding more cryptic. Figure: - Menu and Commands Command pattern moves the above action in to objects. These objects when executed actually execute the command. As said previously every command is an object. We first prepare individual classes for every action i.e. exit, open, file and print. Al l the above actions are wrapped in to classes like Exit action is wrapped in ‘clsExecuteExit’ , open action is wrapped in ‘clsExecuteOpen’, print action is wrapped in ‘clsExecutePrint’ and so on. All these classes are inherited from a common interface ‘IExecute’. Figure: - Objects and Command Using all the action classes we can now make the invoker. The main work of invoker is to map the action with the classes which have the action. So we have added all the actions in one collection i.e. the arraylist. We have exposed a method ‘getCommand’ which takes a string and gives back the abstract object ‘IExecute’. The client code is now neat and clean. All the ‘IF’ conditions are now moved to the ‘clsInvoker’ class. Figure: - Invoker and the clean client (I)Can you explain builder pattern? Builder falls under the type of creational pattern category. Builder pattern helps us to separate the construction of a complex object from its representation so that the same construction process can create different representations. Builder pattern is useful when the construction of the object is very complex. The main objective is to separate the construction of objects and their representations. If we are able to separate the construction and representation, we can then get many representations from the same construction. Figure: - Builder concept To understand what we mean by construction and representation lets take the example of the below ‘Tea preparation’ sequence. You can see from the figure ‘Tea preparation’ from the same preparation steps we can get three representation of tea’s (i.e. Tea with out sugar, tea with sugar / milk and tea with out milk). Figure: - Tea preparation Now let’s take a real time example in software world to see how builder can separate the complex creation and its representation. Consider we have application where we need the same report to be displayed in either ‘PDF’ or ‘EXCEL’ format. Figure ‘Request a report’ shows the series of steps to achieve the same. Depending on report type a new report is created, report type is set, headers and footers of the report are set and finally we get the report for display. Figure: - Request a report Now let’s take a different view of the problem as shown in figure ‘Different View’. The same flow defined in ‘Request a report’ is now analyzed in representations and common construction. The construction process is same for both the types of reports but they result in different representations. Figure: - Different View We will take the same report problem and try to solve the same using builder patterns. There are three main parts when you want to implement builder patterns. Builder: - Builder is responsible for defining the construction process for individual parts. Builder has those individual processes to initialize and configure the product. Director: - Director takes those individual processes from the builder and defines the sequence to build the product. Product: - Product is the final object which is produced from the builder and director coordination. First let’s have a look at the builder class hierarchy. We have a abstract class called as ‘ReportBuilder’ from which custom builders like ‘ReportPDF’ builder and ‘ReportEXCEL’ builder will be built. Figure: - Builder class hierarchy Figure ‘Builder classes in actual code’ shows the methods of the classes. To generate report we need to first Create a new report, set the report type (to EXCEL or PDF) , set report headers , set the report footers and finally get the report. We have defined two custom builders one for ‘PDF’ (ReportPDF) and other for ‘EXCEL’ (ReportExcel). These two custom builders define there own process according to the report type. Figure: - Builder classes in actual code Now let’s understand how director will work. Class ‘clsDirector’ takes the builder and calls the individual method process in a sequential manner. So director is like a driver who takes all the individual processes and calls them in sequential manner to generate the final product, which is the report in this case. Figure ‘Director in action’ shows how the method ‘MakeReport’ calls the individual process to generate the report product by PDF or EXCEL. Figure: - Director in action The third component in the builder is the product which is nothing but the report class in this case. Figure: - The report class Now let’s take a top view of the builder project. Figure ‘Client,builder,director and product’ shows how they work to achieve the builder pattern. Client creates the object of the director class and passes the appropriate builder to initialize the product. Depending on the builder the product is initialized/created and finally sent to the client.Figure: - Client, builder, director and productThe output is something like this. We can see two report types displayed with their headers according to the builder.Figure: - Final output of builder (I) Can you explain prototype pattern? Prototype pattern falls in the section of creational pattern. It gives us a way to create new objects from the existing instance of the object. In one sentence we clone the existing object with its data. By cloning any changes to the cloned object does not affect the original object value. If you are thinking by just setting objects we can get a clone then you have mistaken it. By setting one object to other object we set the reference of object BYREF. So changing the new object also changed the original object. To understand the BYREF fundamental more clearly consider the figure ‘BYREF’ below. Following is the sequence of the below code:- In the first step we have created the first object i.e. obj1 from class1. In the second step we have created the second object i.e. obj2 from class1. In the third step we set the values of the old object i.e. obj1 to ‘old value’. In the fourth step we set the obj1 to obj2. In the fifth step we change the obj2 value. Now we display both the values and we have found that both the objects have the new value. Figure :- BYREf The conclusion of the above example is that objects when set to other objects are set BYREF. So changing new object values also changes the old object value. There are many instances when we want the new copy object changes should not affect the old object. The answer to this is prototype patterns. Lets look how we can achieve the same using C#. In the below figure ‘Prototype in action’ we have the customer class ‘ClsCustomer’ which needs to be cloned. This can be achieved in C# my using the ‘MemberWiseClone’ method. In JAVA we have the ‘Clone’ method to achieve the same. In the same code we have also shown the client code. We have created two objects of the customer class ‘obj1’ and ‘obj2’. Any changes to ‘obj2’ will not affect ‘obj1’ as it’s a complete cloned copy. Figure: - Prototype in action Note :- You can get the above sample in the CD in ‘Prototype’ folder. In C# we use the ‘MemberWiseClone’ function while in JAVA we have the ‘Clone’ function to achieve the same. (A) Can you explain shallow copy and deep copy in prototype patterns? There are two types of cloning for prototype patterns. One is the shallow cloning which you have just read in the first question. In shallow copy only that object is cloned, any objects containing in that object is not cloned. For instance consider the figure ‘Deep cloning in action’ we have a customer class and we have an address class aggregated inside the customer class. ‘MemberWiseClone’ will only clone the customer class ‘ClsCustomer’ but not the ‘ClsAddress’ class. So we added the ‘MemberWiseClone’ function in the address class also. Now when we call the ‘getClone’ function we call the parent cloning function and also the child cloning function, which leads to cloning of the complete object. When the parent objects are cloned with their containing objects it’s called as deep cloning and when only the parent is clones its termed as shallow cloning.Figure: - Deep cloning in action(B) Can you explain singleton pattern?There are situations in a project where we want only one instance of the object to be created and shared between the clients. No client can create an instance of the object from outside. There is only one instance of the class which is shared across the clients. Below are the steps to make a singleton pattern:- Define the constructor as private. Define the instances and methods as static.Below is a code snippet of a singleton in C#. We have defined the constructor as private, defined all the instance and methods using the static keyword as shown in the below code snippet figure ‘Singleton in action’. The static keyword ensures that you only one instance of the object is created and you can all the methods of the class with out creating the object. As we have made the constructor private, we need to call the class directly. Figure: - Singleton in action Note :- In JAVA to create singleton classes we use the STATIC keyword , so its same as in C#. You can get a sample C# code for singleton in the ‘singleton’ folder.