What is a pattern?
- A recurring solution to a common problem in a specific context. Patterns can be used in many different fields, including software development, architecture, and design.
- A sequence of actions or behaviors that are repeated in a particular situation.
- A set of coding conventions that must be followed when developing software to ensure consistency and readability.
- A specific arrangement or design that is repeated in a work of art or architecture.
A pattern is a general, reusable solution to a commonly occurring problem in a specific context. In software development, patterns are often used to solve design problems and improve the quality and maintainability of code.
Describe what is the Event Sourcing Pattern
- A database pattern that tracks changes to data over time.
- A design pattern that stores the history of an object's state changes.
- A pattern used to store events in a database.
- An architectural pattern that saves every state change of an application as an event.
Event Sourcing is a way of modeling the state changes of an application as a sequence of events, allowing us to persist these events as they occur. The events are stored in an event store, and can be used to reconstruct the state of the application at any point in time.
What is the purpose of the Template pattern?
- To create complex objects step by step, using a builder object to abstract the process of creating the object
- To define the basic steps of an algorithm and allow subclasses to provide concrete implementations for these steps
- 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
The Template pattern defines the basic steps of an algorithm and allows subclasses to provide concrete implementations for these steps
What is the difference between the Factory and Abstract Factory patterns?
- None of the above
- The Factory and Abstract Factory patterns are the same
- The Factory pattern creates objects of a single class, while the Abstract Factory pattern creates objects of several classes
- The Factory pattern creates objects of several classes, while the Abstract Factory pattern creates objects of a single class
The Factory pattern creates objects of a single class, while the Abstract Factory pattern creates objects of several classes
What is Data Access Object (DAO) pattern?
- A design pattern to handle communication between objects
- A design pattern to handle the database connections
- A design pattern to manage complex state transitions
- A design pattern to provide a unified interface to a set of interfaces
The DAO pattern provides a unified interface to a set of data sources. It separates the data persistence mechanism from the business logic, allowing the data to be accessed and modified easily and efficiently.
What is the difference between the Singleton and Prototype patterns?
- The Singleton pattern allows multiple instances to be created from a single prototype object, while the Prototype pattern ensures that a class has only one instance and provides a global point of access to that instance.
- The Singleton pattern ensures that a class has multiple instances, while the Prototype pattern allows only one instance to be created from a single prototype object.
- The Singleton pattern ensures that a class has only one instance and provides a global point of access to that instance, while the Prototype pattern allows multiple instances to be created from a single prototype object.
- The Singleton pattern ensures that a class has only one instance, while the Prototype pattern ensures that a class has multiple instances with unique characteristics.
The Singleton pattern ensures that a class has only one instance and provides a global point of access to that instance, while the Prototype pattern allows multiple instances to be created from a single prototype object.
What is the purpose of the Chain of Responsibility pattern?
- To create complex objects step by step, using a builder object to abstract the process of creating the object
- 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
- To provide a way to pass requests along a dynamic chain of receivers until one of them handles the request
The Chain of Responsibility pattern provides a way to pass requests along a dynamic chain of receivers until one of them handles the request
What is Chain of Responsibility pattern?
- A design pattern that allows objects to represent or act on behalf of other objects, providing a level of indirection between the client and the target object
- A design pattern that creates objects by cloning existing objects, rather than creating new instances from scratch
- A design pattern that passes a request through a chain of objects, allowing the objects in the chain to either handle the request or pass it on to the next object in the chain
- A design pattern that provides a simplified interface to a complex system, allowing the client to interact with the system through a single, unified interface
Chain of Responsibility pattern is a design pattern that passes a request through a chain of objects, allowing the objects in the chain to either handle the request or pass it on to the next object in the chain. The pattern involves creating a chain of objects, where each object has a reference to the next object in the chain. This pattern can be useful in situations where you want to decouple the sender of a request from its receiver, allowing multiple objects to handle the request in a modular manner.
What is Mediator pattern?
- A design pattern that allows the client to traverse a collection of objects, without exposing the underlying representation of the collection
- A design pattern that converts a request into a standalone object, allowing the client to parametrize objects with different requests, queue a request, or log requests
- A design pattern that provides a simplified interface to a complex system, allowing the client to interact with the system through a single, unified interface
- A design pattern that uses a central authority to manage communication between components, reducing the coupling between components and allowing for more flexible and modular system design
Mediator pattern is a design pattern that uses a central authority to manage communication between components, reducing the coupling between components and allowing for more flexible and modular system design. In the Mediator pattern, the Mediator class acts as a centralized authority that manages communication between different components, and ensures that the components are decoupled from one another. This pattern can be useful in situations where you want to reduce the coupling between components, and promote a more flexible and modular system design.
What is the Observer design pattern used for?
- To define a one-to-many dependency between objects so that changes to one object result in changes to many other objects.
- To encapsulate operations in an object and pass them as messages.
- To ensure that a class has only one instance and provide a global point of access to that instance.
- To provide a way to dynamically instantiate objects of a specified class.
The Observer design pattern is used to define a one-to-many dependency between objects so that changes to one object result in changes to many other objects. This can be useful in situations where it is important to keep multiple objects in sync with each other.