Object-oriented design is a popular and powerful approach to software development, but it also comes with some challenges. How can you design objects that are easy to reuse and extend, without compromising readability, maintainability, and performance? In this article, we will explore some best practices and principles that can help you achieve this goal.
One of the key benefits of object-oriented design is that it allows you to group related behavior and data into coherent units, called objects. This can improve modularity, cohesion, and abstraction, as well as reduce coupling and complexity. However, to make the most of this benefit, you need to ensure that your objects have a clear and consistent interface, and that they hide their internal details from other objects. This is known as encapsulation, and it can help you reuse and extend your objects without breaking or affecting other parts of the system.
To design objects for maximum reuse and extensibility, focus on clear separation of concerns, encapsulation, and adherence to SOLID principles. Use abstraction to generalize functionality, allowing for easy extension. Implement interfaces to define contracts between components, promoting interchangeable parts. Favor composition over inheritance for flexibility. Lastly, document thoroughly and maintain a modular structure to facilitate easy modifications and reuse across different contexts
Um exemplo incrível de encapsulamento é o da entrega de pizza: - O cliente n?o tem ideia de quais os funcionários, os utensílios e os passos para fazer a pizza, sabe apenas qual a pizzaria e o sabor que quer pedir; - O entregador n?o tem pega a carteira do cliente, tirar dela o dinheiro necessário e depois a devolve. Se sua classe sabe toda a implementa??o da classe que está chamando, ou se ela acessa algo que n?o deveria em outra classe, há uma falha de encapsulamento.
Single Responsibility: Each class should have one purpose. Open/Closed: Objects should be open for extension but closed for modification. Liskov Substitution: Objects should be replaceable with instances of their subtypes without altering the correctness of the program. Interface Segregation: Many client-specific interfaces are better than one general-purpose interface. Hide the details that are likely to change, exposing only stable interfaces.
Investing effort in crafting an object model to articulate behaviors and inter-object relationships yields substantial benefits. These models serve as blueprints for delineating business processes and defining service interfaces, promoting clarity and efficiency in system design. By encapsulating complex logic and promoting reusable components, modeling streamlines development while enhancing maintainability.
Encapsulamento é um conceito fundamental no design orientado a objetos, destacando-se por promover a organiza??o de dados e comportamentos em objetos, otimizando assim a modularidade, coes?o e abstra??o do software. Esse princípio visa a cria??o de objetos com interfaces claras e consistentes, mantendo os detalhes internos privados e inacessíveis por outros objetos. Tal abordagem n?o apenas facilita a manuten??o e extens?o do código, ao permitir modifica??es internas sem impactar o sistema como um todo, mas também contribui para a redu??o do acoplamento e da complexidade, elevando a reusabilidade dos componentes de software.
Inheritance is a powerful mechanism that allows you to create new classes based on existing ones, inheriting their attributes and methods. This can help you avoid code duplication and promote reuse. However, inheritance also has some drawbacks, such as creating tight coupling between classes, violating encapsulation, and introducing fragility and complexity. A common alternative to inheritance is composition, which means creating new classes by combining existing ones, using their interfaces rather than their implementation. Composition can help you achieve more flexibility, modularity, and extensibility, as well as follow the principle of favoring interfaces over implementation.
Break down functionalities into smaller, well-defined objects where each Object should do specifically related functionality. Instead of relying solely on inheritance for new functionalities, use composition. This allows objects to be composed of other objects, promoting reuse and flexibility.
"Use composition instead of inheritance" is the main principle of object-oriented design applying it for code reuse and polymorphic behavior. Composition is an approach to making a new functionality by combining objects that are defined through behaviors via interfaces, instead of through classes or parents. This methodology minimizes dependencies and enhance modularity, which results in more maintainable and flexible systems. Through composition, it's possible to substitute or add new objects without changing the existing system's architecture. Delegation can come together with composition to reinforce the delegation of tasks among objects. Then, the software becomes easier to use and grow with time, and it keeps the unity of the parts.
Composi??o significa classes que tem outras classes como membro/atributo. é t?o mais fácil de explicar do que heran?a quanto é mais fácil de implementar do que heran?a.
O princípio de favorecer a composi??o sobre a heran?a em programa??o orientada a objetos ajuda a criar sistemas mais flexíveis e fáceis de manter. A heran?a, apesar de facilitar a reutiliza??o de código, pode causar problemas como acoplamento rígido e complexidade elevada, tornando o código mais difícil de modificar. A composi??o, por outro lado, permite combinar objetos de diferentes classes, promovendo intera??es baseadas em interfaces, o que reduz dependências diretas e aumenta a modularidade. Essa abordagem melhora a extensibilidade do sistema e alinha-se com boas práticas de design, como a separa??o de preocupa??es e a programa??o para interfaces, n?o para implementa??es.
Design patterns are reusable solutions to common problems that arise in software design. They are not ready-made code, but rather guidelines and best practices that can help you structure your code, solve specific challenges, and communicate your design intent. Design patterns can help you reuse and extend your objects by providing proven and tested solutions that are easy to understand and apply. However, you should not use design patterns blindly or excessively, as they can also introduce unnecessary complexity or overhead. You should always consider the context, the problem, and the trade-offs before applying a design pattern.
O maior objetivo das boas práticas é reduzir a complexidade do código, n?o aumentá-la. Use Design Patterns apenas se for reduzir a complexidade do código e n?o o contrário.
Os padr?es de design promovem a reutiliza??o de solu??es arquiteturais, melhorando a manutenibilidade e a extensibilidade do software. Eles oferecem estratégias testadas e aprovadas para problemas como cria??o de objetos, composi??o de classes e comunica??o entre objetos. Contudo, é crucial usar esses padr?es de maneira ponderada. Aplicá-los sem considerar as necessidades específicas do projeto ou usá-los em excesso pode levar a uma complexidade desnecessária, tornando o sistema mais difícil de entender e manter.
They incorporate a list of recipes for resolving persistent design perils that help save and reuse materials in architectures. Through the use of these patterns, the developers are able to create solutions that are not only easy to update but also increase the system's readability. The Strategy pattern will encapsulate algorithms into separate classes that may be switched at any runtime to favor flexibility. The Decorator pattern allows the possibility of attaching new responsibilities to objects while their internal structure remains immutable. Using well designed design patterns, developers are also able to work smart, not hard. It makes sense to use patterns with caution as they can lead to lack of clarity in design if used too much.
Le principal modèle de conception (design pattern) est le MVC (Modèle Vue Contr?leur) ou ses dérivés : MVC 1, MVC 2, HMVC, MVP, MVVM, avec un framework. Ce framework me permet de mettre en place une architecture pour mon application, et d'utiliser des outils inclus sans réinventer le code. Les autres design pattern sont uniquement utilisés si la complexité de l'application l'exige.
SOLID is an acronym that stands for five principles of object-oriented design that can help you create objects that are easy to reuse and extend. These include single responsibility, open/closed, Liskov substitution, interface segregation, and dependency inversion. Single responsibility means that each object should have one and only one reason to change. Open/closed means objects should be open for extension but closed for modification. Liskov substitution requires that objects of a subclass should be able to replace objects of a superclass without breaking the system. Interface segregation ensures objects should not be forced to depend on interfaces they do not use. Lastly, dependency inversion means objects should depend on abstractions rather than concrete implementations. If you follow these principles, you can create objects that are cohesive, loosely coupled, modular, and adaptable.
SRP: Results in every class having a single goal thereby simplifies the code and update of the code can be done conveniently with little or no widespread effect. OCP: Defines the concept of classes as a construct that allows extension without modification. LSP: Ensures that subclasses can be plugged instead of their parent classes with maintaining the program's correctness, thus reliable polymorphism is provided. ISP: Specify that clients should not opt for techniques that are not going to be used. Thin interfaces that meet specific client requirements should be used. DIP: Encourages developers to prefer abstractions over concrete implementation, making high-level components insensitive to low-level details to improve modularity.
Os princípios SOLID s?o um conjunto fundamental de diretrizes no design orientado a objetos, desenvolvidos para promover um software mais robusto, escalável e manutenível. Seguir esses princípios ajuda a criar sistemas que s?o mais fáceis de entender, reutilizar, estender e modificar.
design objects that are open for extension but closed for modification. This means new functionalities can be added through inheritance or composition without modifying existing code.
No matter how carefully you design your objects, you will inevitably encounter situations where you need to change or improve them. This is where refactoring and testing come in handy. Refactoring is the process of improving the design of your code without changing its functionality, while testing is the process of verifying that your code works as expected and meets the requirements. Refactoring and testing can help you reuse and extend your objects by ensuring that they are clean, readable, maintainable, and reliable. You should refactor and test your code regularly, using tools and techniques such as code analysis, unit testing, integration testing, and code reviews.
To ensure modularity, defining clear interfaces and minimizing coupling between modules is crucial. Each module's purpose should be singular and explicit. For instance, in a HelloWorld class with a sayHello method, altering parameters or modifying the method's definition can jeopardize its modularity. Data structures like Queues and Topics across various implementations (e.g., Apache, IBM, TIBCO, Cloud), where core interface methods like create/send/receive/delete Queue remain consistent over time. Users can easily understand and utilize these modules despite additional features or options. Consistent interfaces results user familiarity and simplify the integration of new functionalities without disrupting existing code.
Refatore para incluir testes e teste para facilitar a refatora??o. No mundo ágil, refatorar é necessário diariamente, e os testes facilitam infinitamente a refatora??o, em especial do código que está em produ??o.
A prática de refatora??o e teste no desenvolvimento de software é essencial para manter a qualidade, a eficiência e a adaptabilidade do código ao longo do tempo. A refatora??o é o processo de reestruturar o código existente, alterando sua estrutura interna sem modificar seu comportamento externo, com o objetivo de torná-lo mais claro, eficiente e fácil de entender, ao mesmo tempo em que facilita a manuten??o e a expans?o futuras. Já o teste é fundamental para garantir a confiabilidade do software, permitindo que desenvolvedores verifiquem se o código atende aos requisitos especificados e funciona conforme esperado em diferentes cenários.
Refactoring and testing are key practices when developing objects which are meant to be re-used and extended easily. Periodic refactoring assembles code's internal structure in a way that makes it easier to comprehend, less expensive to modify, and more suitable for future needs, while not modifying its external behavior. While on the other hand testing enables you to validate that the refactored code still behaves the way it was intended. A full automation test suite facilitate developers to do refactoring with confidence, which in term create a virtuous cycle where cleaner code lead to fewer defects and easy implementation of new features.
Je metterrai plut?t dans l'ordre : Tester puis refactoriser le code pour le rendre plus souple, plus clair et éventuellement plus optimisé. La difficulté étant d'avoir suffisamment de tests non-passants pour fiabiliser le code, et de trouver un équilibre entre souplesse, clarté et optimisation.
Minimize dependencies as much as possible, Objects should depend on abstractions, not concrete implementations. This allows for easier substitution of components. Writing good and clear documentation helps developers understand how to use and extend your objects.
Choosing the right abstractions is more important than anything else. Too often people will here that they need to think more in terms of abstractions and the other OO design principles, and will try and abstract behaviour in a way that doesn’t actually apply to the problem domain. Getting a handle on that domain first goes a long way towards the initial software design.
When testing try to treat class as Black box, focus on business value and not on current implementation, think what your class is really doing and not how it is written. Try to m?k? test as implementation agnostic as possible
Un bon code doit se passer de commentaire. Le code est souvent modifié alors que le commentaire reste. Le bloc de documentation au-dessus de chaque classe et méthode, lui reste utile. Il est auto-généré par les outils de développement modernes ; Et il est possible de l'extraire dans une documentation technique à l'attention des autres développeurs qui n'ont pas accès au code source.