PaginatedResponse

This API allows the pagination of backend responses, making data retrieval easier for clients.
It leverages the kotlinx serialization library to efficiently serialize data and enable flexible communication between client and server

Usage

In this example will be shown a backend based on Spring Boot and a Compose Multiplatform client application which retrieves the data using a Requester

Backend side

Creating the entity class

This class will be used by the backend to store the data related to the Dummy class, but will be used also to return the paginated data

@Entity
public class Dummy extends EquinoxItem  {

    @Column
    private final String name;

    public Dummy(String id, String name) {
        super(id);
        this.name = name;
    }

    public String getName() {
        return name;
    }

}

Creating the service

This is just an example of a possible service implementation, take a closer look just to the getDummies method

@Service
public class DummyService  {

    @Autowired
    private final DummiesRepository dummiesRepository;

    public DummyService(DummiesRepository dummiesRepository) {
        this.dummiesRepository = dummiesRepository;
    }

    public PaginatedResponse<Dummy> getDummies(int page, int pageSize) {

        // count the total values
        long total = dummiesRepository.count();

        // create the pageable to use in the query
        Pageable pageable = PageRequest.of(page, pageSize);

        // a query example
        List<Dummy> dummies = dummiesRepository.getDummies(pageable);

        // return the paginated data
        return new PaginatedResponse<>(
                dummies,
                page, // if not specified default is 0
                pageSize, // if not specified default is 10
                total
        );

    }

}

The data retrieved from the database will be directly paginated for the requested list of Dummy, making it ready to be read by the client through the same API

Client side

kotlinx-serialization implementation

To automatically serialize and then retrieve the data from the API, you have to implement the kotlinx-serialization library and the related plugin as follows:

Plugin

plugins {
    kotlin("plugin.serialization") version "latest-version"
}

Library

repositories {
    mavenCentral()
}

dependencies {
    implementation "org.jetbrains.kotlinx:kotlinx-serialization-json:latest-version"
}

Check out the official repository to find more information or the latest version available

Creating the data class

This class will be used by the client to use the information retrieved from the backend

@Serializable // required annotation
data class Dummy(
    val id: String,
    val name: String
)

Usage

Using, for example, a Requester instance we can request and then retrieve the paginated response of our Dummy class as follows:

fun dummyRequest() {
    viewModelScope.launch {
        requester.sendPaginatedRequest(
            request = {
                getDummies(
                    page = page, // if not specified default is 0
                    page = pageSize, // if not specified default is 10
                )
            },
            serialiazer = Dummy.serializer(), // required
            onSuccess = { page ->
                // use the serialized page from the response
                println(page.data) // list of paged Dummy
            },
            onFailure = {
                // handle a failed request
            },
            onConnectionError = {
                // handle a connection error
            }
        )
    }
}