The visitor design pattern
•Download as PPTX, PDF•
2 likes•2,085 views
The Visitor Design Pattern allows defining a new operation over elements in an object structure without changing the classes of the elements. It puts the operations in visitor classes so new operations are easy to add. While this keeps behavior partitioned and localized, adding new element classes is difficult as it requires changes to the visitor interface and implementations. The element interface may also need powerful operations that compromise encapsulation.
Report
Share
Report
Share
Recommended
Visitor pattern
The visitor pattern represents an operation to be performed on elements of an object structure without changing the classes of the elements. It is used when there are many unrelated operations needed on the structure. In the visitor pattern, an operation is encapsulated in a visitor object that traverses the elements and performs the operation based on each element's type. This separates the operations from the element classes and makes adding new operations easier than changing each element class.
Visitor design patterns
This document discusses the visitor design pattern. The visitor pattern represents an operation to be performed on elements of an object structure without changing the classes of the elements. It is useful when adding new operations to an object structure like an abstract syntax tree that contains many node types. With the visitor pattern, each node type accepts a visitor object that contains operations specific to that node type, rather than putting operations directly in each node class. This avoids changing node classes when adding new operations and separates operation code from class code for better structure and maintenance.
Visitor Pattern
The Visitor pattern allows new operations to be added to existing object structures without modifying those structures. It separates an object structure from the operations performed on it, allowing independent extension of both. Some key aspects include:
- Visitors define a visit operation for each element type in the object structure. Concrete visitors implement the operations.
- Elements contain an accept method to accept visitor operations. Concrete elements call the appropriate visit method.
- Clients traverse the structure and pass a visitor to each element's accept method.
The pattern allows encapsulation of new operations without changing element classes, and separates unrelated operations for elements. It can apply to structures without a shared hierarchy.
Visitor design pattern
This presentation contains a specification of visitor design pattern, an example of its usage, advantage and disadvantage of it.
Behavioral Design Patterns
Behavioral Design Patterns
Foundations of Software Engineering, Ben Gurion University, Fall 2015
Observer, Mediator, State, Strategy, Iterator, Visitor
Mediator
The Mediator pattern defines an object that encapsulates how a set of classes interact, promoting loose coupling by acting as an intermediary between classes that may know nothing about each other. By consolidating all interaction in a single mediator class, dependencies between reusable classes are reduced and flexibility is improved, though this increases the complexity of the mediator itself. The mediator pattern is related to both the Observer and Facade patterns which also aim to simplify interactions between classes.
Mediator pattern
Here is one way to implement the calendar reminder application using the Mediator pattern:
1. Create a ReminderMediator class that acts as the mediator. It will coordinate the ReminderAlarm and Notification classes.
2. Create ReminderAlarm and Notification classes that act as colleagues. The alarm raises events when triggered and the notification displays and handles user input.
3. When the alarm triggers, it notifies the mediator. The mediator then tells the notification to display.
4. The notification displays and handles user input, notifying the mediator of snooze or close.
5. If snooze, the mediator sets a timer then tells the alarm to trigger again after the time span. If close
PATTERNS03 - Behavioural Design Patterns
An introduction to behavioural design patterns in object orientation. Suitable for intermediate to advanced computing students and those studying software engineering.
Recommended
Visitor pattern
The visitor pattern represents an operation to be performed on elements of an object structure without changing the classes of the elements. It is used when there are many unrelated operations needed on the structure. In the visitor pattern, an operation is encapsulated in a visitor object that traverses the elements and performs the operation based on each element's type. This separates the operations from the element classes and makes adding new operations easier than changing each element class.
Visitor design patterns
This document discusses the visitor design pattern. The visitor pattern represents an operation to be performed on elements of an object structure without changing the classes of the elements. It is useful when adding new operations to an object structure like an abstract syntax tree that contains many node types. With the visitor pattern, each node type accepts a visitor object that contains operations specific to that node type, rather than putting operations directly in each node class. This avoids changing node classes when adding new operations and separates operation code from class code for better structure and maintenance.
Visitor Pattern
The Visitor pattern allows new operations to be added to existing object structures without modifying those structures. It separates an object structure from the operations performed on it, allowing independent extension of both. Some key aspects include:
- Visitors define a visit operation for each element type in the object structure. Concrete visitors implement the operations.
- Elements contain an accept method to accept visitor operations. Concrete elements call the appropriate visit method.
- Clients traverse the structure and pass a visitor to each element's accept method.
The pattern allows encapsulation of new operations without changing element classes, and separates unrelated operations for elements. It can apply to structures without a shared hierarchy.
Visitor design pattern
This presentation contains a specification of visitor design pattern, an example of its usage, advantage and disadvantage of it.
Behavioral Design Patterns
Behavioral Design Patterns
Foundations of Software Engineering, Ben Gurion University, Fall 2015
Observer, Mediator, State, Strategy, Iterator, Visitor
Mediator
The Mediator pattern defines an object that encapsulates how a set of classes interact, promoting loose coupling by acting as an intermediary between classes that may know nothing about each other. By consolidating all interaction in a single mediator class, dependencies between reusable classes are reduced and flexibility is improved, though this increases the complexity of the mediator itself. The mediator pattern is related to both the Observer and Facade patterns which also aim to simplify interactions between classes.
Mediator pattern
Here is one way to implement the calendar reminder application using the Mediator pattern:
1. Create a ReminderMediator class that acts as the mediator. It will coordinate the ReminderAlarm and Notification classes.
2. Create ReminderAlarm and Notification classes that act as colleagues. The alarm raises events when triggered and the notification displays and handles user input.
3. When the alarm triggers, it notifies the mediator. The mediator then tells the notification to display.
4. The notification displays and handles user input, notifying the mediator of snooze or close.
5. If snooze, the mediator sets a timer then tells the alarm to trigger again after the time span. If close
PATTERNS03 - Behavioural Design Patterns
An introduction to behavioural design patterns in object orientation. Suitable for intermediate to advanced computing students and those studying software engineering.
Facade Design Pattern
Presented by,
Ms. Nandana S V
Team Lead, Sr Software Engineer, Livares Technologies
Facade design pattern
Facade is a part of Gang of Four design pattern (23 others).
As the name suggests, it means the face of the building.
The people walking past the road can only see this glass face of the building.
They do not know anything about it, the wiring, the pipes and other complexities.
It hides all the complexities of the building and displays a friendly face.
Facade design pattern
Same goes for the Facade Design Pattern. It hides the complexities of the system and provides an interface to the client from where the client can access the system.
PATTERNS04 - Structural Design Patterns
An introduction to structural design patterns in object orientation. Suitable for intermediate to advanced computing students and those studying software engineering.
Design Patterns - 01 Introduction and Decorator Pattern
This is the first presentation of multi part series on design patterns. It covers introduction to design pattern and decorator pattern.
React hooks
This document discusses React hooks and how they enhance functional components. It explains that hooks allow functional components to maintain state and lifecycle methods like class components. The key hooks discussed are useState for managing state, useEffect for side effects like data fetching, and useCallback and useMemo for optimization. Custom hooks are also covered as a way to extract reusable logic. Overall, hooks improve on class components by making code more modular, reusable and easier to test.
Bridge pattern
The Bridge pattern decouples an abstraction from its implementation so that they can vary independently. It is applicable when abstraction and implementation should be extensible by subclassing and changes in implementation should not affect clients. The structure of Bridge pattern contains Abstraction, RefinedAbstraction, Implementor and ConcreteImplementor classes. Abstraction maintains reference to Implementor and forwards requests to it. This decouples interface and implementation and improves extensibility.
Design patterns english
The document discusses design patterns and summarizes three behavioral patterns:
1. The State pattern encapsulates varying behavior for the same object based on its internal state. It uses state objects to represent different states.
2. The Strategy pattern defines a family of algorithms, puts each of them in a separate class, and makes their objects interchangeable. This allows selecting an algorithm at runtime.
3. The Visitor pattern represents an operation performed on elements of an object structure. It separates the algorithms from the structure on which they operate and allows adding new operations without changing classes.
Software Design Patterns
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.
PATTERNS02 - Creational Design Patterns
An introduction to creational design patterns in object orientation. Suitable for intermediate to advanced computing students and those studying software engineering.
Command Design Pattern
The document discusses the Command design pattern, which encapsulates requests as objects so that different requests can be parameterized, queued, logged, or made undoable. The pattern addresses the need to issue requests without knowing the operation or receiver. A command defines an interface for executing an operation, concrete commands bind a receiver to an action, and a client creates concrete commands while an invoker carries out the request.
Chain of responsibility
The Chain of Responsibility pattern avoids coupling the sender of a request to its receiver by allowing more than one object to handle the request, which is passed along a chain of handler objects until one of the objects handles it. It allows flexibility in distributing responsibilities for handling requests among objects by giving each object a reference to its successor in the chain. While this reduces coupling, there is no guarantee that a request will be handled if it falls off the end of the chain without being processed.
Java Chapter 04 - Writing Classes: part 1
This document discusses key concepts for writing classes in Java, including defining classes to represent objects with state and behavior, using access modifiers like private to promote encapsulation of instance variables, and declaring methods and constructors. It introduces the topics that will be covered in Chapter 4, such as class definitions, instance data, encapsulation, method declaration, parameter passing, and constructors.
I can see your house from here
Joint presentation with Till Adam and Marius Bugge Monsen.
The model/view framework is one of the most powerful areas of Qt4, but also one of the most complex. It is elegant in its design, but proves to be difficult to master for many who try in practice. While a lot of effort went into anticipating how developers would use and potentially mis-use this API, real world usage patterns, best practices and common errors turn out to be interestingly deviant. Marius, who was part of the original architecture team behind these classes, and Till, who has taught the concepts to varied audiences and seen a wide range of real world applications of them both in his work on KDEPIM and as a consultant at KDAB, combine their experiences in this presentation to provide a unique joint perspective.
Design pattern composite 20120413 joncash 01
The composite pattern allows objects to be composed into tree structures to represent part-whole hierarchies. It allows clients to treat individual objects and compositions uniformly. The pattern involves two class hierarchies - component and composite - where composite inherits component and contains child components. This allows clients to recursively traverse composite structures and treat individual objects and compositions uniformly. An example using a tree view in ASP.NET is provided to demonstrate how composite represents tree structures.
Bridge Pattern
The document describes the Bridge pattern which decouples an abstraction from its implementation so they can vary independently. It provides an example of a Window abstraction with different WindowImp implementations. The Window abstraction delegates implementation tasks to a WindowImp object via the GetWindowImp method and WindowSystemFactory class. This allows Window objects to work with different WindowImp subclasses without code changes.
Understanding react hooks
This document provides an overview and explanation of React Hooks. It introduces common Hooks like useState, useEffect, useReducer, and custom hooks. useState is used to add local state to functional components. useEffect is similar to component lifecycle methods and lets you perform side effects. useReducer is an alternative to useState for managing state in a single object. Custom hooks let you extract reusable logic and share it without changing components. The document also includes a FAQ addressing questions about hooks and class components.
Understanding React hooks | Walkingtree Technologies
React and its component structure
● What are Hooks?
● React Hooks and their capabilities
● Migrating Your Existing Apps to React Hooks
● Combine Existing React Hooks into New Custom Hooks
● Benefits of using React Hooks
● Best Practices
Design patterns
The Article is describe about Design Patterns. Its gives overview idea about all design patterns and its use.
Command Design Pattern
The Command pattern encapsulates a request as an object, allowing requests to be parameterized with different objects and queued or logged. A command object represents the method call and stores the method name, owner object, and parameters. A client creates a concrete command object and passes it to an invoker, which stores the command and calls its execute method, invoking the action on the receiver object. This decouples the requestor from the performer and allows invokers to be parameterized with different commands at runtime.
Lesson10 behavioral patterns
This document provides an overview of the Command design pattern. It begins by defining the Command pattern as encapsulating a request as an object, and passing it to another object (the invoker) to execute the request. It then provides examples of the key elements of the pattern - Command, ConcreteCommand, Client and Invoker. Finally, it provides step-by-step instructions for implementing the Command pattern in code using a simple example of opening and saving documents.
Lesson12 other behavioural patterns
This document discusses several software design patterns including behavioral patterns like the strategy pattern, template pattern, and iterator pattern. It provides code examples to illustrate how each pattern can be implemented in Java. The strategy pattern encapsulates algorithms and makes them interchangeable. The template pattern defines a skeleton for subclasses. The iterator pattern accesses elements of a collection without exposing its internal structure.
Applying Design Patterns in Practice
The document discusses applying design patterns in practice. It begins with a warm-up exercise identifying different design patterns like factory method, decorator, builder, strategy, and composite. It then discusses why design patterns are important for capturing expert knowledge in proven reusable solutions. The key principles behind patterns are to program to an interface, favor composition over inheritance, and encapsulate what varies. The document also discusses refactoring, smells approach to learning patterns, and various design patterns like factory method, builder, strategy, decorator, composite, and visitor in detail with examples.
More Related Content
What's hot
Facade Design Pattern
Presented by,
Ms. Nandana S V
Team Lead, Sr Software Engineer, Livares Technologies
Facade design pattern
Facade is a part of Gang of Four design pattern (23 others).
As the name suggests, it means the face of the building.
The people walking past the road can only see this glass face of the building.
They do not know anything about it, the wiring, the pipes and other complexities.
It hides all the complexities of the building and displays a friendly face.
Facade design pattern
Same goes for the Facade Design Pattern. It hides the complexities of the system and provides an interface to the client from where the client can access the system.
PATTERNS04 - Structural Design Patterns
An introduction to structural design patterns in object orientation. Suitable for intermediate to advanced computing students and those studying software engineering.
Design Patterns - 01 Introduction and Decorator Pattern
This is the first presentation of multi part series on design patterns. It covers introduction to design pattern and decorator pattern.
React hooks
This document discusses React hooks and how they enhance functional components. It explains that hooks allow functional components to maintain state and lifecycle methods like class components. The key hooks discussed are useState for managing state, useEffect for side effects like data fetching, and useCallback and useMemo for optimization. Custom hooks are also covered as a way to extract reusable logic. Overall, hooks improve on class components by making code more modular, reusable and easier to test.
Bridge pattern
The Bridge pattern decouples an abstraction from its implementation so that they can vary independently. It is applicable when abstraction and implementation should be extensible by subclassing and changes in implementation should not affect clients. The structure of Bridge pattern contains Abstraction, RefinedAbstraction, Implementor and ConcreteImplementor classes. Abstraction maintains reference to Implementor and forwards requests to it. This decouples interface and implementation and improves extensibility.
Design patterns english
The document discusses design patterns and summarizes three behavioral patterns:
1. The State pattern encapsulates varying behavior for the same object based on its internal state. It uses state objects to represent different states.
2. The Strategy pattern defines a family of algorithms, puts each of them in a separate class, and makes their objects interchangeable. This allows selecting an algorithm at runtime.
3. The Visitor pattern represents an operation performed on elements of an object structure. It separates the algorithms from the structure on which they operate and allows adding new operations without changing classes.
Software Design Patterns
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.
PATTERNS02 - Creational Design Patterns
An introduction to creational design patterns in object orientation. Suitable for intermediate to advanced computing students and those studying software engineering.
Command Design Pattern
The document discusses the Command design pattern, which encapsulates requests as objects so that different requests can be parameterized, queued, logged, or made undoable. The pattern addresses the need to issue requests without knowing the operation or receiver. A command defines an interface for executing an operation, concrete commands bind a receiver to an action, and a client creates concrete commands while an invoker carries out the request.
Chain of responsibility
The Chain of Responsibility pattern avoids coupling the sender of a request to its receiver by allowing more than one object to handle the request, which is passed along a chain of handler objects until one of the objects handles it. It allows flexibility in distributing responsibilities for handling requests among objects by giving each object a reference to its successor in the chain. While this reduces coupling, there is no guarantee that a request will be handled if it falls off the end of the chain without being processed.
Java Chapter 04 - Writing Classes: part 1
This document discusses key concepts for writing classes in Java, including defining classes to represent objects with state and behavior, using access modifiers like private to promote encapsulation of instance variables, and declaring methods and constructors. It introduces the topics that will be covered in Chapter 4, such as class definitions, instance data, encapsulation, method declaration, parameter passing, and constructors.
I can see your house from here
Joint presentation with Till Adam and Marius Bugge Monsen.
The model/view framework is one of the most powerful areas of Qt4, but also one of the most complex. It is elegant in its design, but proves to be difficult to master for many who try in practice. While a lot of effort went into anticipating how developers would use and potentially mis-use this API, real world usage patterns, best practices and common errors turn out to be interestingly deviant. Marius, who was part of the original architecture team behind these classes, and Till, who has taught the concepts to varied audiences and seen a wide range of real world applications of them both in his work on KDEPIM and as a consultant at KDAB, combine their experiences in this presentation to provide a unique joint perspective.
Design pattern composite 20120413 joncash 01
The composite pattern allows objects to be composed into tree structures to represent part-whole hierarchies. It allows clients to treat individual objects and compositions uniformly. The pattern involves two class hierarchies - component and composite - where composite inherits component and contains child components. This allows clients to recursively traverse composite structures and treat individual objects and compositions uniformly. An example using a tree view in ASP.NET is provided to demonstrate how composite represents tree structures.
Bridge Pattern
The document describes the Bridge pattern which decouples an abstraction from its implementation so they can vary independently. It provides an example of a Window abstraction with different WindowImp implementations. The Window abstraction delegates implementation tasks to a WindowImp object via the GetWindowImp method and WindowSystemFactory class. This allows Window objects to work with different WindowImp subclasses without code changes.
Understanding react hooks
This document provides an overview and explanation of React Hooks. It introduces common Hooks like useState, useEffect, useReducer, and custom hooks. useState is used to add local state to functional components. useEffect is similar to component lifecycle methods and lets you perform side effects. useReducer is an alternative to useState for managing state in a single object. Custom hooks let you extract reusable logic and share it without changing components. The document also includes a FAQ addressing questions about hooks and class components.
Understanding React hooks | Walkingtree Technologies
React and its component structure
● What are Hooks?
● React Hooks and their capabilities
● Migrating Your Existing Apps to React Hooks
● Combine Existing React Hooks into New Custom Hooks
● Benefits of using React Hooks
● Best Practices
Design patterns
The Article is describe about Design Patterns. Its gives overview idea about all design patterns and its use.
Command Design Pattern
The Command pattern encapsulates a request as an object, allowing requests to be parameterized with different objects and queued or logged. A command object represents the method call and stores the method name, owner object, and parameters. A client creates a concrete command object and passes it to an invoker, which stores the command and calls its execute method, invoking the action on the receiver object. This decouples the requestor from the performer and allows invokers to be parameterized with different commands at runtime.
Lesson10 behavioral patterns
This document provides an overview of the Command design pattern. It begins by defining the Command pattern as encapsulating a request as an object, and passing it to another object (the invoker) to execute the request. It then provides examples of the key elements of the pattern - Command, ConcreteCommand, Client and Invoker. Finally, it provides step-by-step instructions for implementing the Command pattern in code using a simple example of opening and saving documents.
Lesson12 other behavioural patterns
This document discusses several software design patterns including behavioral patterns like the strategy pattern, template pattern, and iterator pattern. It provides code examples to illustrate how each pattern can be implemented in Java. The strategy pattern encapsulates algorithms and makes them interchangeable. The template pattern defines a skeleton for subclasses. The iterator pattern accesses elements of a collection without exposing its internal structure.
What's hot (20)
Design Patterns - 01 Introduction and Decorator Pattern
Design Patterns - 01 Introduction and Decorator Pattern
Understanding React hooks | Walkingtree Technologies
Understanding React hooks | Walkingtree Technologies
Viewers also liked
Applying Design Patterns in Practice
The document discusses applying design patterns in practice. It begins with a warm-up exercise identifying different design patterns like factory method, decorator, builder, strategy, and composite. It then discusses why design patterns are important for capturing expert knowledge in proven reusable solutions. The key principles behind patterns are to program to an interface, favor composition over inheritance, and encapsulate what varies. The document also discusses refactoring, smells approach to learning patterns, and various design patterns like factory method, builder, strategy, decorator, composite, and visitor in detail with examples.
Thomas Hardy
Thomas Hardy was a Victorian author known for his novels and poetry. He was born in 1840 in Dorset, England and received some formal education but became an architect. He had a difficult marriage to his wife Emma that ended with her death in 1912, which deeply impacted him. His novels were controversial but popular, while his poetry was less appreciated during his lifetime. This analysis focuses on Hardy's poetry, including themes of loss, nature, and criticism of war. It also provides a close reading of his poem "If It's Ever Spring Again" which contrasts memories of past happiness with current feelings of lack and regret.
Thomas hardy
The document provides an overview of Thomas Hardy's life and works. It discusses his most famous novels including Far From the Madding Crowd, highlights some of the main characters in that novel like Bathsheba Everdene and Gabriel Oak, and summarizes the plot which involves relationships and marriages between the characters. The biography section notes details about Hardy's birthplace, family, education, marriages, and career as both an architect and acclaimed author.
Introduction to Thomas Hardy
CAPE Literatures in English (Unit 1) - An introduction to the poet Thomas Hardy, his life and his works.
The Role of Enterprise Integration in Digital Transformation
The document discusses how digital transformation is driving changes in enterprise integration needs, moving from centralized integration middleware towards decentralized microservices and micro-integrations. It introduces Ballerina, a new programming language from WSO2 that can be used to build independent, lightweight integration microservices visually or textually. WSO2's next generation integration platform will use Ballerina to replace the ESB and address modern integration requirements around agility, orchestration, APIs, microservices, performance and scalability.
Design Patterns
The document discusses several design patterns including Observer, State, Template Method, Memento, Command, Chain of Responsibility, Interpreter, Mediator, Iterator, Strategy, Visitor, Flyweight, and Singleton patterns. For each pattern, it provides the definition, participants, structure, intent, caveats, and examples.
Viewers also liked (7)
The Role of Enterprise Integration in Digital Transformation
The Role of Enterprise Integration in Digital Transformation
Similar to The visitor design pattern
How to implement dependency injection in c#
This slide explains the usage of dependency injection in order to write more precise code.
More Details: https://www.loginworks.com/technical-blogs/implement-dependency-injection-c/
React Development | Advanced Component Composition Patterns
React development with advanced component composition patterns. Elevate your coding expertise with proven strategies for efficient and scalable React applications
ReactJs Training in Hyderabad | ReactJS Training
ReactJs Training in Hyderabad - Visualpath is the Leading and ReactJS Training Course in Hyderabad. Avail complete job oriented ReactJs Training in Hyderabad by simply enrolling in our institute in Ameerpet. You will get the best course at an affordable cost. Call on - +91-9989971070
whatsApp: https://www.whatsapp.com/catalog/919989971070
Visit : https://www.visualpath.in/ReactJs-Training-in-Hyderabad.html
Gof design pattern
The document discusses various design patterns. It begins by explaining that design patterns represent best practices used by experienced software developers to solve common problems. It then discusses the Gang of Four (GOF) patterns, which were identified in 1994 and include creational, structural, and behavioral patterns. Creational patterns like Singleton, Factory Method, Abstract Factory, and Prototype are covered. Structural patterns like Adapter, Bridge, Composite, Decorator, Facade, Flyweight, and Proxy are also introduced. Behavioral patterns like Chain of Responsibility, Command, Interpreter, Iterator, Mediator, Memento, Observer, State, Strategy, Template Method, and Visitor are briefly mentioned as well. The document then discusses some Java Enterprise
KnockOutjs from Scratch
This document provides an overview and introduction to KnockoutJS, a JavaScript MVVM library created by Steve Sanderson. It discusses key features of KnockoutJS like observable properties, observable arrays, and bindings. Observable properties allow automatic updating of the UI when the model changes. Bindings provide a simple way to connect UI elements to the model. The document also covers how to set up a basic Knockout app with a view model, bindings, and applying bindings. Additional resources for learning KnockoutJS are provided at the end.
Design Patterns Part1
The document discusses several design patterns including Factory Method, Abstract Factory, Singleton, Bridge, Decorator, Visitor, and Interpreter. It provides an overview and definition of each pattern, describes when to apply the pattern, shows the basic structure and an example, and discusses the consequences of using the pattern. The patterns cover creational, structural, and behavioral categories and are approaches to solving common programming problems by defining core solutions that can be reused in different situations.
C# Advanced L07-Design Patterns
The document discusses several design patterns including Singleton, Factory Method, Strategy, and others. It provides descriptions of the patterns, examples of how they can be implemented in code, and discusses how some patterns like Singleton can be adapted for multi-threaded applications. It also briefly introduces the Multiton pattern, which is an extension of Singleton that allows multiple instances associated with different keys.
Porting the Legacy Application to Composite Application Guidance
This document discusses porting a legacy application to use the Model-View-ViewModel (MVVM) and Composite Application Guidance (CAL) patterns. It defines key MVVM concepts like models, views, presenters, and presentation models. It outlines advantages of CAL like modularity, reusability, and separation of concerns. It then provides a sample scenario of a legacy life insurance application and steps to refactor it to use these patterns, including creating modules, services, and using regions to host views.
React-JS.pptx
React js is a free and open-source front-end JavaScript library for building user interfaces based on UI components. It allows creating reusable UI components that can be nested to build complex applications. A React component may maintain internal state and re-render when data changes. React uses a declarative paradigm that makes code more predictable and easier to debug.
To use React, install Node packages and create a new project using create-react-app. Components let you break up the UI into reusable pieces responsible for rendering HTML. Components can be stateful class components or stateless function components. Components can be created using ES6 class syntax or function syntax and can be nested. Choosing between class and function depends on requirements like using
Facadepattern
The Facade pattern provides a simplified interface to a complex subsystem. It decouples the subsystem from clients and other subsystems. A facade class acts as an entry point to the subsystem and delegates client requests to appropriate subsystem classes. This reduces dependencies between clients and the complexities of the subsystem.
Sda 8
The document discusses several creational design patterns including Singleton, Abstract Factory, Builder, and Prototype patterns. It provides definitions and examples of how each pattern works, including ensuring a class only has one instance (Singleton), creating object factories without specifying classes (Abstract Factory), constructing complex objects step-by-step (Builder), and copying existing objects (Prototype). The document is intended for teaching software design patterns to students.
Basics of React Hooks.pptx.pdf
The session will provide the knowledge about react page life cycle and how more precise actions or operations can be performed using react hooks concepts
Unit 5
The document discusses the process of designing view layer classes in a user interface. It involves:
1) Identifying view layer objects during analysis by examining use cases and interaction diagrams.
2) Designing individual view layer objects by applying design principles like simplicity and usability testing.
3) Iteratively refining the design by getting feedback and making improvements.
Unit 5
The document discusses the process of designing view layer classes in a user interface. It involves:
1) Identifying view layer objects during analysis by examining use cases and interaction diagrams.
2) Designing individual view layer objects by applying design principles to best support the application functions and provide a usable interface.
3) Prototyping, testing usability, and refining the view layer interface through iterative design.
VIPER Architecture
The document discusses the VIPER architecture, which aims to improve testability of iOS apps by separating concerns into distinct layers. It describes the main components of VIPER - View, Interactor, Presenter, Entity, and Router. The Interactor contains business logic, the Presenter prepares data for the View, and the Router handles navigation. By separating concerns, VIPER allows for easier testing and maintenance of large iOS codebases. It advocates designing the app as independent, reusable modules that conform to the single responsibility principle.
Facade pattern
This document discusses the facade design pattern. The facade pattern provides a simplified interface to a more complex subsystem. It decouples the subsystem from the client and makes the subsystem easier to use. A facade acts as a front-facing interface that hides the underlying complexities of the subsystem and delegates client requests to appropriate subsystem classes. This reduces dependencies between subsystems and promotes loose coupling. The facade pattern is useful for layering subsystems and simplifying access to them through a single interface.
Dependency Injection або Don’t call me, I’ll call you
This document provides an overview of dependency injection using the Unity framework. It begins by explaining concepts like inversion of control and dependency injection. It then demonstrates how to implement dependency injection with Unity through examples of constructor injection, property injection, and lifetime managers. The document also compares Unity to other frameworks like StructureMap and Spring, and discusses where each framework is best applied. Overall, the document is an introduction to dependency injection principles and how to implement them using the Unity framework.
Agile cards
The document discusses Agile principles for software development and their relationships to various software design patterns. It lists 12 Agile principles focused on customer satisfaction, acceptance of changing requirements, frequent delivery of working software, collaboration between business and development teams, trust in individuals, face-to-face communication, technical excellence, self-organizing teams, regular adjustment to improve, valuing individuals over processes, working software over documentation, and responding to change over following a strict plan. It then provides brief descriptions of various design patterns related to each principle.
Encapsulation
The document discusses encapsulation in C++ and object-oriented design principles. It covers:
1) Encapsulation requires that classes have clearly defined external interfaces and hide implementation details. This reduces coupling between classes.
2) Functions and classes should minimize side effects by passing parameters as constants and returning values rather than references when possible.
3) References are generally preferable to pointers as they only provide access to an object's interface rather than its memory.
4) Constructors and destructors help classes encapsulate their own resource management by allocating resources during initialization and freeing them during destruction.
Cs 1023 lec 8 design pattern (week 2)
The document discusses design patterns, which are reusable solutions to common software design problems. It provides examples of different types of patterns, including creational (Factory Method, Abstract Factory, Builder, Prototype, Singleton), structural (Adapter, Bridge, Composite, Decorator, Facade, Flyweight, Proxy), and behavioral (Chain of Responsibility, Command, Interpreter, Iterator, Mediator, Memento, Observer, State, Strategy, Template Method, Visitor) patterns. Each pattern is defined and an example problem and solution using the pattern is described.
Similar to The visitor design pattern (20)
React Development | Advanced Component Composition Patterns
React Development | Advanced Component Composition Patterns
Porting the Legacy Application to Composite Application Guidance
Porting the Legacy Application to Composite Application Guidance
Dependency Injection або Don’t call me, I’ll call you
Dependency Injection або Don’t call me, I’ll call you
More from Samnang Chhun
Find your passion
The document discusses the importance of passion and finding what you love. It recommends trying many things to discover your passion, which could be related to your childhood dreams or ideal day. Following your passion, even if it doesn't make money, is important for true satisfaction and doing great work in life. The document also suggests sharing your passions and successes or failures with others to help the community.
Software developer career growth
The document discusses career growth as a software developer. It recommends being passionate about coding, practicing regularly, getting certified in technologies, and learning from online communities and local meetups. It also suggests considering becoming a project manager or business owner later in one's career, and continuing to learn through reading, open source contributions, automating tasks, and staying updated on new tools and domains. Mentoring others and finding a mentor are also presented as helpful for career development.
Why i love ruby than x
This document discusses why the author loves Ruby over other programming languages like Java. It provides a brief history of Ruby, describing it as an interpreted, object-oriented scripting language created in 1995. It highlights several reasons for preferring Ruby, such as its simplicity, dynamic typing, support for duck typing, reflection capabilities, ability to monkey patch, emphasis on testing, use of domain-specific languages, large library ecosystem, and focus on giving programmers freedom. The author encourages learning Ruby through tools like IRB, Try Ruby, and Ruby Learning.
12 Things Every Programmer Should Know
This presentation is about best practices, techniques, and attitudes of a professional software developer.
Peforming Code Katas
Kata is a Japanese term for choreographed patterns of movements practiced solo or in pairs to learn techniques. The document describes doing a code kata which involves practicing solving a simple programming problem for 30 minutes to an hour each day through test-driven development, experimentation and reflection to improve coding skills. It provides an example kata of creating a string calculator that can handle different delimiters and numbers on new lines through observation, scoring, and constructive criticism from peers.
Introduction To Share Vision
The document discusses encouraging a culture of sharing knowledge and experience within the Cambodian community. It mentions building strong networks between members and universities to provide student training. It also notes publishing best practices and solutions. Details are provided on existing tools and projects, including a website, forum, and mailing list used by the 34 member organization to collaborate and communicate. Past events focused on version control and web architecture.
Test Driven Development
The document discusses test-driven development (TDD) and design-driven development (DDD). It advocates for writing tests before code using short iterative development cycles. TDD helps produce clean code that fulfills requirements by making developers think about required behavior, providing documentation, and improving quality. Common objections to TDD are addressed, noting that it forces understanding of code and tests, creates reusable modular code, and drives simplicity. Guidelines for effective TDD include writing small focused tests with descriptive intentions that are independent and repeatable.
Version Control With Subversion
This document provides an overview of version control and Subversion (SVN). It defines version control as the management of changes to documents and files. It discusses why version control is needed, such as for backup, synchronization, tracking changes and owners. It then describes the basic concepts and terminology of SVN like repositories, working copies, revisions, checkouts, checkins and updates. The document also demonstrates the basic SVN workflow and architecture. It concludes with best practices for using SVN.
Layering
Layering is a common technique used by software designers to break apart complicated software systems. Each layer has a well-defined interface and dependencies with other layers, implementing one technical function like data access. The pros of layering include understandability, separation of concerns, reusability, and independent development. The cons are that layers do not encapsulate all things well and extra layers can harm performance. Layers and tiers are often used interchangeably, but tiers imply a physical separation. Common layers in information systems include the UI, application, business, services, data, and unit testing layers.
NHibernate (The ORM For .NET Platform)
This document provides an introduction to object-relational mapping (ORM) and NHibernate. It discusses ORM techniques for converting data between object-oriented programming languages and relational databases. The document then provides an overview of NHibernate, an open source ORM framework for .NET, including its basic concepts, configuration, querying capabilities, and additional reading.
More from Samnang Chhun (10)
Recently uploaded
Pengantar Penggunaan Flutter - Dart programming language1.pptx
Pengantar Penggunaan Flutter - Dart programming language1.pptx
clinical examination of hip joint (1).pdf
described clinical examination all orthopeadic conditions .
Traditional Musical Instruments of Arunachal Pradesh and Uttar Pradesh - RAYH...
Traditional Musical Instruments of Arunachal Pradesh and Uttar Pradesh
Main Java[All of the Base Concepts}.docx
This is part 1 of my Java Learning Journey. This Contains Custom methods, classes, constructors, packages, multithreading , try- catch block, finally block and more.
Advanced Java[Extra Concepts, Not Difficult].docx
This is part 2 of my Java Learning Journey. This contains Hashing, ArrayList, LinkedList, Date and Time Classes, Calendar Class and more.
Walmart Business+ and Spark Good for Nonprofits.pdf
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
BÀI TẬP BỔ TRỢ TIẾNG ANH 8 CẢ NĂM - GLOBAL SUCCESS - NĂM HỌC 2023-2024 (CÓ FI...
BÀI TẬP BỔ TRỢ TIẾNG ANH 8 CẢ NĂM - GLOBAL SUCCESS - NĂM HỌC 2023-2024 (CÓ FI...Nguyen Thanh Tu Collection
https://app.box.com/s/y977uz6bpd3af4qsebv7r9b7s21935vdHindi varnamala | hindi alphabet PPT.pdf
हिंदी वर्णमाला पीपीटी, hindi alphabet PPT presentation, hindi varnamala PPT, Hindi Varnamala pdf, हिंदी स्वर, हिंदी व्यंजन, sikhiye hindi varnmala, dr. mulla adam ali, hindi language and literature, hindi alphabet with drawing, hindi alphabet pdf, hindi varnamala for childrens, hindi language, hindi varnamala practice for kids, https://www.drmullaadamali.com
Wound healing PPT
This document provides an overview of wound healing, its functions, stages, mechanisms, factors affecting it, and complications.
A wound is a break in the integrity of the skin or tissues, which may be associated with disruption of the structure and function.
Healing is the body’s response to injury in an attempt to restore normal structure and functions.
Healing can occur in two ways: Regeneration and Repair
There are 4 phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. This document also describes the mechanism of wound healing. Factors that affect healing include infection, uncontrolled diabetes, poor nutrition, age, anemia, the presence of foreign bodies, etc.
Complications of wound healing like infection, hyperpigmentation of scar, contractures, and keloid formation.
BÀI TẬP BỔ TRỢ TIẾNG ANH LỚP 9 CẢ NĂM - GLOBAL SUCCESS - NĂM HỌC 2024-2025 - ...
BÀI TẬP BỔ TRỢ TIẾNG ANH LỚP 9 CẢ NĂM - GLOBAL SUCCESS - NĂM HỌC 2024-2025 - ...Nguyen Thanh Tu Collection
https://app.box.com/s/tacvl9ekroe9hqupdnjruiypvm9rdanePollock and Snow "DEIA in the Scholarly Landscape, Session One: Setting Expec...
Pollock and Snow "DEIA in the Scholarly Landscape, Session One: Setting Expec...National Information Standards Organization (NISO)
This presentation was provided by Steph Pollock of The American Psychological Association’s Journals Program, and Damita Snow, of The American Society of Civil Engineers (ASCE), for the initial session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session One: 'Setting Expectations: a DEIA Primer,' was held June 6, 2024.Chapter 4 - Islamic Financial Institutions in Malaysia.pptx
Chapter 4 - Islamic Financial Institutions in Malaysia.pptxMohd Adib Abd Muin, Senior Lecturer at Universiti Utara Malaysia
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
RHEOLOGY Physical pharmaceutics-II notes for B.pharm 4th sem students
Physical pharmaceutics notes for B.pharm students
Recently uploaded (20)
Pengantar Penggunaan Flutter - Dart programming language1.pptx
Pengantar Penggunaan Flutter - Dart programming language1.pptx
Traditional Musical Instruments of Arunachal Pradesh and Uttar Pradesh - RAYH...
Traditional Musical Instruments of Arunachal Pradesh and Uttar Pradesh - RAYH...
NEWSPAPERS - QUESTION 1 - REVISION POWERPOINT.pptx
NEWSPAPERS - QUESTION 1 - REVISION POWERPOINT.pptx
Walmart Business+ and Spark Good for Nonprofits.pdf
Walmart Business+ and Spark Good for Nonprofits.pdf
spot a liar (Haiqa 146).pptx Technical writhing and presentation skills
spot a liar (Haiqa 146).pptx Technical writhing and presentation skills
BÀI TẬP BỔ TRỢ TIẾNG ANH 8 CẢ NĂM - GLOBAL SUCCESS - NĂM HỌC 2023-2024 (CÓ FI...
BÀI TẬP BỔ TRỢ TIẾNG ANH 8 CẢ NĂM - GLOBAL SUCCESS - NĂM HỌC 2023-2024 (CÓ FI...
BÀI TẬP BỔ TRỢ TIẾNG ANH LỚP 9 CẢ NĂM - GLOBAL SUCCESS - NĂM HỌC 2024-2025 - ...
BÀI TẬP BỔ TRỢ TIẾNG ANH LỚP 9 CẢ NĂM - GLOBAL SUCCESS - NĂM HỌC 2024-2025 - ...
Pollock and Snow "DEIA in the Scholarly Landscape, Session One: Setting Expec...
Pollock and Snow "DEIA in the Scholarly Landscape, Session One: Setting Expec...
Chapter 4 - Islamic Financial Institutions in Malaysia.pptx
Chapter 4 - Islamic Financial Institutions in Malaysia.pptx
RHEOLOGY Physical pharmaceutics-II notes for B.pharm 4th sem students
RHEOLOGY Physical pharmaceutics-II notes for B.pharm 4th sem students
The visitor design pattern
- 1. The Visitor Design Pattern SamnangChhun Yoolk Inc.
- 2. Represent an operation to be performed on the elements of an object structure. Visitor lets you define a new operation without changing the classes of the elements on which it operates. What this? Open Closed Principle is the key The Visitor Design Pattern
- 3. Structure
- 4. Example
- 5. Consequences Benefits Adding new operations is easy Related behavior isn’t spread over the classes defining the object structure; it’s localized in a visitor. Unrelated sets of behavior are partitioned in own visitor subclasses. Liabilities Adding new ConcreteElement class is hard. Each new ConcreteElement give rise to a new abstract operation on Visitor and a corresponding implementation in every ConcreteVisitor class. The ConcreteElement interface must be powerful enough to let visitors do their job. You may be forced to provide public operations that access an element’s internal state, which may compromise its encapsulation.
- 6. Don’t forget to review all of them again and again
- 7. Thank you!