What is the purpose of the Facade pattern?
- To allow multiple objects to communicate with each other
- To create a reusable object-oriented design
- To provide a common interface for a group of related classes
- To provide a simplified interface to a complex system, hiding the complexity of the system behind a single interface and making it easier to use
The Facade pattern provides a simplified interface to a complex system, hiding the complexity of the system behind a single interface and making it easier to use
What is relationship between Repository and Unit of Work?
- The Repository and Unit of Work patterns are interchangeable, as they both provide similar functionality and can be used interchangeably in a project.
- The Repository and Unit of Work patterns are not related, as they are completely separate design patterns with different purposes.
- The Repository and Unit of Work patterns are related, as the Unit of Work is responsible for managing the persistence of data changes, while the Repository provides an abstraction over the data access layer. The Repository can use the Unit of Work to persist changes to the data.
- The Repository and Unit of Work patterns are the same, as they are both used to manage the persistence of data changes.
The Repository and Unit of Work patterns are related, as the Unit of Work is responsible for managing the persistence of data changes, while the Repository provides an abstraction over the data access layer. The Repository can use the Unit of Work to persist changes to the data.
What is Design Patterns and why anyone should use them?
- A collection of best practices for software development that are specific to a certain programming language or framework.
- A pre-written solution to common software problems that can be adapted to fit the specific needs of a project. Design patterns provide a common vocabulary and shared understanding among team members, allowing for more efficient and maintainable code.
- A set of coding conventions that must be followed when developing software to ensure consistency and readability.
- A set of guidelines for designing user interfaces in a way that is aesthetically pleasing and easy to use.
Design Patterns are reusable solutions to common problems that arise in software development. They provide a standardized way of approaching these problems, which can improve the efficiency, maintainability, and understandability of the code.
What is Observer pattern?
- A design pattern in which an object, called the composite, is composed of one-to-many other objects, in a tree-like structure, allowing the client to interact with individual objects and compositions of objects uniformly
- A design pattern in which an object, called the decorator, adds or overrides behavior of an existing object, dynamically
- A design pattern in which an object, called the proxy, acts as an intermediary between a client and a target object, forwarding requests from the client to the target object and vice versa
- A design pattern in which an object, called the subject, maintains a list of its dependents and notifies them automatically of any changes to its state
The Observer pattern is a design pattern in which an object, called the subject, maintains a list of its dependents and notifies them automatically of any changes to its state. The Observer pattern is used to implement a publish/subscribe mechanism, allowing the subject to be decoupled from its dependents, and allowing multiple dependents to be notified of changes to the subject's state. The Observer pattern is used to implement event-driven systems.
What are the differences between a static class and a singleton class?
- A singleton class can be extended, while a static class cannot be extended
- A singleton class can have multiple instances, while a static class can only have one instance
- A static class can be extended, while a singleton class cannot be extended
- A static class can have multiple instances, while a singleton class can only have one instance
A static class can have multiple instances, while a singleton class can only have one instance. A static class is a class that is declared as static and can only access static variables and methods. A singleton class is a class that ensures that only one instance of the class exists in the JVM.
Give an example where Interpreter pattern is used?
- Interpreter pattern is used in compilers, where expressions in a programming language need to be parsed and evaluated
- Interpreter pattern is used in database management systems, where SQL queries need to be interpreted and executed
- Interpreter pattern is used in game engines, where game rules need to be interpreted and executed
- Interpreter pattern is used in web applications, where user requests need to be interpreted and processed
One example of where Interpreter pattern is used is in compilers, where expressions in a programming language need to be parsed and evaluated. The Interpreter pattern can be used to evaluate the syntax and semantics of a programming language, and generate code or perform other actions based on the results of the evaluation.
What is the Command and Query Responsibility Segregation (CQRS) Pattern?
- A pattern in which read and write operations are separated into separate models.
- A pattern that helps to avoid race conditions and deadlocks in multithreaded applications.
- A pattern used to implement inter-process communication.
- A pattern used to improve database performance by caching results in memory.
CQRS is a pattern that separates the responsibilities of querying data (read) from modifying data (write) into separate models, improving scalability and maintainability of the application.
What is Null Object pattern?
- A design pattern in which a special object, called the null object, is used to represent the absence of a value, avoiding the need for explicit checks for null values
- A design pattern in which an object, called the context, holds a reference to an instance of one of several possible concrete state objects, each of which represents a distinct state of the context and implements a common state interface
- A design pattern in which an object, called the decorator, adds or overrides behavior of an existing object, dynamically
- A design pattern in which an object, called the prototype, is used as a template to create new objects, without specifying their concrete classes
The Null Object pattern is a design pattern in which a special object, called the null object, is used to represent the absence of a value, avoiding the need for explicit checks for null values. The Null Object pattern is used to provide a default implementation of an interface, reducing the amount of error-prone null checks in the code. The Null Object pattern can also be used to simplify the code and reduce coupling by eliminating the need for explicit checks for null values.
What is the difference between the Decorator and Flyweight patterns?
- The Decorator pattern is used to dynamically add or override behavior of an object, while the Flyweight pattern is used to reduce the number of objects created by sharing objects that are costly to create.
- The Decorator pattern is used to dynamically add or override behavior of an object, while the Flyweight pattern is used to share objects that are costly to create.
- The Decorator pattern is used to reduce the number of objects created by sharing objects that are costly to create, while the Flyweight pattern is used to dynamically add or override behavior of an object.
- The Decorator pattern is used to share objects that are costly to create, while the Flyweight pattern is used to dynamically add or override behavior of an object.
The Decorator pattern is used to dynamically add or override behavior of an object, while the Flyweight pattern is used to share objects that are costly to create.
What is the purpose of the Decorator design pattern?
- To attach additional responsibilities to an object dynamically.
- To create objects that are interchangeable with their base classes.
- To ensure that a class has only one instance and provide a global point of access to that instance.
- To manage the flow of control between objects in a complex system.
The Decorator design pattern is used to attach additional responsibilities to an object dynamically. This allows for greater flexibility and modularity in the design of a system, as well as the ability to add or remove responsibilities as needed.