In a world where data-driven applications are the norm, having an API that supports pagination and sorting is crucial. Pagination allows us to retrieve a subset of data in manageable chunks, while sorting allows us to organize the data in a desired order. When working with Java Spring REST APIs, documenting pagination and sorting can help developers understand how to consume the API effectively. In this blog post, we will explore how to document pagination and sorting using Java Spring REST Docs.

Why Document API Pagination and Sorting?

Documenting API pagination and sorting provides developers with clear instructions on how to navigate through paginated data and sort the results according to their needs. It eliminates ambiguity and reduces the chances of errors when consuming the API. Additionally, documenting these features improves the overall developer experience by providing comprehensive documentation that covers all aspects of the API.

Documenting API Pagination

To document API pagination using Java Spring REST Docs, follow these steps:

1. Add the SpringDataRestDocs dependency to your project’s build.gradle file.

implementation 'org.springframework.restdocs:spring-restdocs-webmvc'

1. Enable pagination support in your API endpoints using Spring Data’s Pageable argument.

@GetMapping("/users")
public ResponseEntity<List<User>> getUsers(Pageable pageable) {
    // Retrieve paginated users from the database
    Page<User> users = userRepository.findAll(pageable);

    // Return the response
    return ResponseEntity.ok(users.getContent());
}

1. Generate the documentation for pagination using Spring REST Docs.

@Test
public void shouldDocumentPagination() throws Exception {
    mockMvc.perform(get("/api/users")
            .param("page", "0")
            .param("size", "10"))
            .andExpect(status().isOk())
            .andDo(document("users", responseFields(
                    fieldWithPath("content").description("The list of users"))));
}

1. Build and run your tests to generate the documentation snippets. The generated snippets can then be included in your API documentation.

Documenting API Sorting

To document API sorting using Java Spring REST Docs:

1. Add the SpringDataRestDocs dependency to your project’s build.gradle file (if not already added).

implementation 'org.springframework.restdocs:spring-restdocs-webmvc'

1. Enable sorting support in your API endpoints using Spring Data’s Sort argument.

@GetMapping("/users")
public ResponseEntity<List<User>> getUsers(Sort sort) {
    // Retrieve sorted users from the database
    List<User> users = userRepository.findAll(sort);

    // Return the response
    return ResponseEntity.ok(users);
}

1. Generate the documentation for sorting using Spring REST Docs.

@Test
public void shouldDocumentSorting() throws Exception {
    mockMvc.perform(get("/api/users")
            .param("sort", "name,desc"))
            .andExpect(status().isOk())
            .andDo(document("users", responseFields(
                    fieldWithPath("content[].name").description("The name of the user").type(JsonFieldType.STRING))));
}

1. Build and run your tests to generate the documentation snippets. Include the snippets in your API documentation.

Conclusion

In this blog post, we explored how to document API pagination and sorting using Java Spring REST Docs. By documenting these features, we can provide clear instructions to developers on how to effectively consume our APIs. This improves the overall developer experience and reduces errors. Documentation is an essential part of building high-quality APIs, and by leveraging Java Spring REST Docs, we can easily generate comprehensive documentation for our pagination and sorting capabilities.