Last updated on 2024年9月13日

How do you design value objects to avoid duplication and inconsistency?

由人工智能和领英社区提供技术支持

Value objects are one of the building blocks of domain-driven design, a software development approach that focuses on the core business logic and concepts of a system. Value objects are immutable and represent a specific aspect of the domain, such as a date, a currency, or an address. They are defined by their attributes and behavior, not by their identity or relationship to other objects. In this article, you will learn how to design value objects to avoid duplication and inconsistency in your technical architecture.

此文章中的业界达人

由社区从 3 条内容中精选。了解更多

Nadeem Malik

Enterprise Architect - providing enterprise-wide insights, promoting standardization, reducing costs, mitigating risk…

1 Why use value objects?

Value objects can help you simplify and clarify your domain model, by encapsulating related data and logic in a single unit. They can also improve the performance and reliability of your system, by reducing the need for database queries, validations, and conversions. Value objects can also enable better communication and collaboration between developers and domain experts, by using a common and expressive language.

添加您的观点

Nadeem Malik

Enterprise Architect - providing enterprise-wide insights, promoting standardization, reducing costs, mitigating risk, increasing agility, realizing strategies, and driving innovation.
举报内容
Value objects simplify domain models & boost performance. They're like Lego blocks for your architecture - reusable, well-defined pieces that snap together neatly. Plus, they help techies & biz folks speak the same language. Win-win!

已翻译

赞

2 How to identify value objects?

To identify value objects, you need to analyze your domain and look for concepts that are immutable, equal by value, cohesive, and reusable. For instance, in an e-commerce domain, you might identify value objects such as Product, Price, OrderItem, and ShippingAddress. These concepts should not change their state or attributes after creation and can be compared based on their attributes instead of their identity or reference. Additionally, they should have a clear and consistent purpose and responsibility as well as be shareable and usable in different contexts.

添加您的观点

Nadeem Malik

Enterprise Architect - providing enterprise-wide insights, promoting standardization, reducing costs, mitigating risk, increasing agility, realizing strategies, and driving innovation.
举报内容
Look for immutable concepts equal by value, not identity. It's kinda like spotting constellations - you're connecting related attributes into meaningful patterns. Think Product, Price, Address. They shouldn't change after creation & should make sense across contexts.

已翻译

赞

3 How to design value objects?

In order to design value objects, one must adhere to certain best practices and principles. This includes using descriptive and meaningful names based on the domain terminology and vocabulary, defining the attributes and methods of the objects based on their properties and behavior in the domain, implementing equality and hashcode methods for comparison in collections and maps, making the objects immutable by using final fields, constructors, and getters, validating input and output with preconditions, postconditions, and invariants, and using factory methods or builders for complex or variable creation logic. This will help ensure that the value objects are always in a valid and consistent state.

添加您的观点

Nadeem Malik

Enterprise Architect - providing enterprise-wide insights, promoting standardization, reducing costs, mitigating risk, increasing agility, realizing strategies, and driving innovation.
举报内容
Use domain lingo, make 'em immutable, & validate inputs. It's sorta like crafting the perfect recipe - you need the right ingredients (attributes), clear instructions (methods), & quality checks (validation). Oh, and don't forget to make 'em comparable!

已翻译

赞

4 How to avoid duplication and inconsistency?

One of the challenges of using value objects is avoiding duplication and inconsistency in your technical architecture. Duplication can happen when multiple copies of the same value object exist in different layers or components, while inconsistency can occur when different versions of the same value object exist in different contexts or domains. To prevent this, you should employ strategies such as establishing a single source of truth for your value objects by defining them in a common and accessible module or library, using domain events to communicate changes in your value objects by publishing and subscribing to events that contain the updated value objects, and using value object adapters or mappers to translate or transform your value objects if they need to be used in different formats or protocols. This will allow you to reuse, synchronize, propagate, adapt, and integrate your value objects with external systems or services.

添加您的观点

5 How to test value objects?

Testing value objects is an essential part of ensuring the quality and functionality of your technical architecture. You can verify their correctness, completeness, and consistency by using unit tests to check the behavior and logic of your value objects. Assertions, mocks, and stubs should be used to test the constructors, methods, equality, hashcode, validation, and immutability of your value objects. Additionally, integration tests should be used to check the interaction and integration of your value objects. Test doubles, fixtures, and scenarios should be used to test the creation, usage, communication, and persistence of your value objects in different layers and components of your system. Lastly, property-based tests should be used to check the properties and invariants of your value objects. Generators, shrinkers, and checkers should be used to test the validity, consistency, and equivalence of your value objects under different inputs and outputs.

添加您的观点

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?

添加您的观点

Technical Architecture

+ 关注

给文章评分

我们借助人工智能创建了此文章。您认为这篇文章怎么样？

很棒不太好

举报此文章

查看全部

How do you design value objects to avoid duplication and inconsistency?

1

2

3

4

5

6

1 Why use value objects?

2 How to identify value objects?

3 How to design value objects?

4 How to avoid duplication and inconsistency?

5 How to test value objects?

6 Here’s what else to consider

Technical Architecture

给文章评分

感谢您的反馈

更多Technical Architecture相关文章

更多相关阅读内容