What is State pattern?
- A behavioral design pattern that allows an object to alter its behavior when its internal state changes. The object appears to change its class, but the change is implemented as a state transition within the same object. This allows for a cleaner, more maintainable implementation of state-dependent behavior.
- A creational design pattern that is used to create objects from a common interface or base class, but with different underlying implementations depending on the specific context.
- A design pattern that focuses on managing the flow of control within an application, with the goal of improving modularity and maintainability.
- A structural design pattern that uses inheritance to compose complex objects from simple objects, with the goal of reducing coupling and increasing cohesion between the objects.
The State pattern is a behavioral design pattern that allows an object to alter its behavior when its internal state changes. The change in behavior is implemented as a state transition within the same object, rather than as a change in class. This results in a cleaner, more maintainable implementation of state-dependent behavior.
What is the difference between the Flyweight and Singleton patterns?
- None of the above
- The Flyweight and Singleton patterns are the same
- The Flyweight pattern conserves memory by sharing common data among objects, while the Singleton pattern ensures that only one instance of a class exists in the system
- The Flyweight pattern ensures that only one instance of a class exists in the system, while the Flyweight pattern conserves memory by sharing common data among objects
The Flyweight pattern conserves memory by sharing common data among objects, while the Singleton pattern ensures that only one instance of a class exists in the system
What are the entities of Service Locator pattern?
- Cache, Client, Service, Service Locator, and InitialContext
- Client, Service Locator, Service, InitialContext, and Cache
- InitialContext, Cache, Client, Service Locator, and Service
- Service, InitialContext, Service Locator, Cache, and Client
The entities of the Service Locator pattern are: Service, InitialContext, Service Locator, Cache, and Client. The Service represents the service being located. The InitialContext is responsible for performing the actual lookup of the service. The Service Locator acts as a cache, keeping track of services that have already been looked up. The Cache stores references to services that have already been looked up. The Client is the entity that requires access to the service.
What is the purpose of the Interpreter pattern?
- To create complex objects step by step, using a builder object to abstract the process of creating the object
- To define a grammatical representation for a language and provide an interpreter to deal with this grammar
- To provide a common interface for a group of related classes
- To provide a way to pass requests along a dynamic chain of receivers until one of them handles the request
The Interpreter pattern defines a grammatical representation for a language and provides an interpreter to deal with this grammar
What is an Aggregate Root in the context of Repository Pattern?
- A boundary object around a group of objects, that ensures the consistency of the data
- A special type of object that implements data access logic
- An object that is the only object that should be accessed directly, while all other objects are accessed through it
- An object that is the parent of all other objects in the aggregate and controls the consistency of all objects in the aggregate
An Aggregate Root in the context of Repository Pattern is a boundary object around a group of objects, which ensures the consistency of the data. It is the parent of all other objects in the aggregate and controls the consistency of all objects in the aggregate.
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.