What is the purpose of the Command pattern?
- To allow for loose coupling between the sender of a request and its receivers.
- To allow sending requests to objects without knowing anything about the operation being requested or the receiver of the request.
- To convert the interface of a class into another interface clients expect.
- To provide a unified interface to a set of interfaces in a subsystem.
The Command pattern is used to allow sending requests to objects without knowing anything about the operation being requested or the receiver of the request. It provides a way to queue or log requests and acts as a marshal between the sender and the receiver.
Explain difference between the Facade, Proxy, Adapter and Decorator design patterns?
- The Facade design pattern provides a simplified interface to a complex system, while the Proxy design pattern provides a placeholder for another object to control access to it. The Adapter design pattern converts the interface of a class into another interface that the client expects, and the Decorator design pattern adds behavior to an individual object, dynamically, without affecting the behavior of other objects from the same class.
- The Facade design pattern provides a unified interface to a set of interfaces in a system, while the Proxy design pattern provides a way to access an object indirectly. The Adapter design pattern adapts an object to a new interface, and the Decorator design pattern adds behavior to an individual object, dynamically, but affects the behavior of other objects from the same class.
- The Facade design pattern provides a way to access a system's functionality, while the Proxy design pattern provides a way to extend an object's functionality. The Adapter design pattern converts the interface of one class into that of another, and the Decorator design pattern adds behavior to an individual object, statically, and affects the behavior of other objects from the same class.
- The Facade design pattern provides an intermediary between two systems, while the Proxy design pattern provides a default implementation of an interface. The Adapter design pattern is used to allow two systems to work together, and the Decorator design pattern adds behavior to an object, statically, without affecting the behavior of other objects from the same class.
The Facade design pattern provides a simplified interface to a complex system, while the Proxy design pattern provides a placeholder for another object to control access to it. The Adapter design pattern converts the interface of a class into another interface that the client expects, and the Decorator design pattern adds behavior to an individual object, dynamically, without affecting the behavior of other objects from the same class.
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 purpose of the Adapter pattern?
- To allow for loose coupling between the sender of a request and its receivers.
- To convert the interface of a class into another interface clients expect.
- To create objects based on a blueprint.
- To provide a unified interface to a set of interfaces in a subsystem.
The Adapter pattern is used to convert the interface of a class into another interface clients expect, allowing classes to work together that couldn't otherwise because of incompatible interfaces.
How is Bridge pattern different from Adapter pattern?
- The Bridge pattern aims to change the interface of an object while the Adapter pattern aims to reuse an existing object.
- The Bridge pattern allows for multiple inheritance while the Adapter pattern only allows for single inheritance.
- The Bridge pattern decouples an abstraction from its implementation while the Adapter pattern modifies the interface of an existing class to a client class.
- The Bridge pattern is a structural pattern while the Adapter pattern is a behavioral pattern.
The Bridge pattern decouples an abstraction from its implementation while the Adapter pattern modifies the interface of an existing class to a client class.
Can you give any good explanation what is the difference between Proxy and Decorator?
- The main difference between the Proxy and Decorator patterns is that the Proxy pattern provides a copy of another object to control access to it, while the Decorator pattern allows encapsulating an object dynamically. Proxies are often used to control access to an object or to encapsulate it, while Decorators are used to encapsulate an object.
- The main difference between the Proxy and Decorator patterns is that the Proxy pattern provides a placeholder for another object to control access to it, while the Decorator pattern allows adding or extending behavior dynamically to an object. Proxies are often used to control access to an object or to add functionality such as caching, while Decorators are used to add or extend the behavior of an object.
- The main difference between the Proxy and Decorator patterns is that the Proxy pattern provides a replacement for another object to control access to it, while the Decorator pattern allows changing the behavior of an object dynamically. Proxies are often used to add functionality such as caching or security, while Decorators are used to modify the behavior of an object.
- The main difference between the Proxy and Decorator patterns is that the Proxy pattern provides a substitute for another object to control access to it, while the Decorator pattern allows modifying the appearance of an object dynamically. Proxies are often used to control access to an object or to change its appearance, while Decorators are used to modify the appearance of an object.
The main difference between the Proxy and Decorator patterns is that the Proxy pattern provides a placeholder for another object to control access to it, while the Decorator pattern allows adding or extending behavior dynamically to an object. Proxies are often used to control access to an object or to add functionality such as caching, while Decorators are used to add or extend the behavior of an object.
What is Gang of Four (GOF)?
- A group of four software design experts, namely Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides, who wrote a book titled "Design Patterns: Elements of Reusable Object-Oriented Software".
- A group of software design experts who provide consulting services on software design.
- A group of software developers who work together on software development projects.
- A software development company that specializes in creating design patterns.
The Gang of Four (GOF) is a group of four software design experts who wrote a seminal book on design patterns. The book, which was published in 1995, popularized the concept of design patterns and provided a common vocabulary and a standard way of thinking about software design problems. The GOF book is considered an essential reference for software developers and is widely used in the software development community.
What is the Chain of Responsibility pattern?
- The Chain of Responsibility pattern is a design pattern that allows multiple objects to handle a request one by one, until one of them handles it successfully.
- The Chain of Responsibility pattern is a design pattern that allows objects to be chained together, so that when a request is made, it can be passed from one object to the next, until it is handled.
- The Chain of Responsibility pattern is a design pattern that allows objects to be linked together, so that a request can be passed from one object to another, until it is handled.
- The Chain of Responsibility pattern is a design pattern that uses a set of objects to handle a request, without specifying the receiver.
The Chain of Responsibility pattern is a behavioral design pattern that involves passing a request sequentially through a dynamic list of objects until one of them handles it. The objects become a chain of receivers, and the request is sent from one object to another, until it is handled. This allows for a greater level of decoupling between the objects, making it easier to modify or extend the system.