Examples of repositories in Domain-Driven Design

Here are some examples of repositories in Domain-Driven Design (DDD):

• CustomerRepository: This repository would be responsible for managing customer aggregates, including their addresses, orders, and other related data.

public interface CustomerRepository {
    CustomerAggregate findById(String customerId);
    void save(CustomerAggregate customerAggregate);
    // Additional methods for searching, updating, and deleting customer aggregates
}

• ProductRepository: This repository would be responsible for managing product aggregates, including their descriptions, prices, and inventory levels.

public interface ProductRepository {
    ProductAggregate findById(String productId);
    void save(ProductAggregate productAggregate);
    // Additional methods for searching, updating, and deleting product aggregates
}

• OrderRepository: This repository would be responsible for managing order aggregates, including the customer who placed the order, the products that were ordered, and the shipping and billing information.

public interface OrderRepository {
    OrderAggregate findById(String orderId);
    void save(OrderAggregate orderAggregate);
    // Additional methods for searching, updating, and deleting order aggregates
}

• AccountRepository: This repository would be responsible for managing account aggregates, including the customer's account information, such as their name, email address, and balance.

public interface AccountRepository {
    AccountAggregate findById(String accountId);
    void save(AccountAggregate accountAggregate);
    // Additional methods for searching, updating, and deleting account aggregates
}

• PostRepository: This repository would be responsible for managing post aggregates, including the post's title, content, and author.

public interface PostRepository {
    PostAggregate findById(String postId);
    void save(PostAggregate postAggregate);
    // Additional methods for searching, updating, and deleting post aggregates
}

Repositories can be used to implement a variety of use cases, such as:

• Retrieving aggregate roots by ID: For example, a customer service application might use a CustomerRepository to retrieve a customer aggregate by their customer ID.

// Example for CustomerRepository
CustomerAggregate customer = customerRepository.findById("123");

• Storing aggregate roots: For example, an e-commerce application might use a ProductRepository to store a new product aggregate when a customer places an order.

// Example for ProductRepository
ProductAggregate newProduct = createNewProduct(); // Assume a method to create a new product aggregate
productRepository.save(newProduct);

• Searching for aggregate roots by complex criteria: For example, a social media application might use a PostRepository to search for posts that contain a specific keyword.

// Example for PostRepository
List<PostAggregate> posts = postRepository.searchByKeyword("Java");

• Deleting aggregate roots: For example, an accounting application might use an AccountRepository to delete an account aggregate when a customer closes their account.

// Example for AccountRepository
accountRepository.delete(accountId); // Assume a method to delete an account by ID

Note: The actual implementation of these repositories would depend on the specific requirements of your application and the underlying technology stack (e.g., whether you are using a relational database, a NoSQL database, etc.). Additionally, the Aggregate classes and their methods (e.g., createNewProduct(), searchByKeyword(), etc.) would need to be implemented based on the details of your domain model.

Note: Above pseudo-code snippets illustrate the basic structure of repositories. In a real-world scenario, you would likely have more sophisticated implementations and considerations.