Repository Pattern components

Components.kt

// A wrapper for handling failing requests
sealed class Result<T> {

    data class Success<T>(val value: T) : Result<T>()

    data class Failure<T>(val throwable: Throwable) : Result<T>()

}

// A DataSource for the SharedPreferences
interface ProductPreferences {

    fun isFavourite(id: String?): Boolean

}

// A DataSource for the Remote DB
interface ProductApiService {

    fun getProducts(): Single<Result<List<NetworkProduct>>>

    fun getWishlist(productIds: List<String>): Single<Result<List<NetworkProduct>>>
    
}

// A cluster of DTOs to be mapped into a Product
data class DataProduct(
    val networkProduct: NetworkProduct,
    val isFavourite: Boolean
)