Replaced Enum for Result with sealed class

kanch231004 · Aug 20, 2021 · 09914d2 · 09914d2
1 parent 40d1539
commit 09914d2
Show file tree

Hide file tree

Showing 3 changed files with 20 additions and 29 deletions.
diff --git a/app/src/main/java/com/kanchanpal/newsfeed/api/BaseDataSource.kt b/app/src/main/java/com/kanchanpal/newsfeed/api/BaseDataSource.kt
@@ -15,7 +15,7 @@ abstract class BaseDataSource {
             val response = call()
             if (response.isSuccessful) {
                 val body = response.body()
-                if (body != null) return Result.success(body)
+                if (body != null) return Result.Success(body)
             }
             return error(" ${response.code()} ${response.message()}")
         } catch (e: Exception) {
@@ -28,7 +28,7 @@ abstract class BaseDataSource {
         /** We can deserialize error model (in case we get error msg from server)
          * and pass the message */
         Timber.e(message)
-        return Result.error("Network call has failed for a following reason: $message")
+        return Result.Error("Network call has failed for a following reason: $message")
     }
 }
 
diff --git a/app/src/main/java/com/kanchanpal/newsfeed/data/Result.kt b/app/src/main/java/com/kanchanpal/newsfeed/data/Result.kt
@@ -6,19 +6,8 @@ package com.kanchanpal.newsfeed.data
  * Result is usually created by the Repository classes where they return
  * `LiveData<Result<T>>` to pass back the latest data to the UI with its fetch status.
  */
-data class Result<out T>(val status: Status, val data: T?, val message: String?) {
-    enum class Status {
-        SUCCESS, ERROR, LOADING
-    }
-    companion object {
-        fun <T> success(data: T): Result<T> {
-            return Result(Status.SUCCESS, data, null)
-        }
-        fun <T> error(message: String, data: T? = null): Result<T> {
-            return Result(Status.ERROR, data, message)
-        }
-        fun <T> loading(data: T? = null): Result<T> {
-            return Result(Status.LOADING, data, null)
-        }
-    }
+
+sealed class Result<out T> {
+    data class Success<out T>(val data : T) : Result<T>()
+    data class Error<out T>(val message: String? = "Unknown error", val data: T? = null): Result<T>()
 }
diff --git a/app/src/main/java/com/kanchanpal/newsfeed/data/newsSet/NewsPageDataSource.kt b/app/src/main/java/com/kanchanpal/newsfeed/data/newsSet/NewsPageDataSource.kt
@@ -26,14 +26,14 @@ class NewsPageDataSource @Inject constructor(
         callback: LoadInitialCallback<Int, NewsListModel>
     ) {
         networkState.postValue(NetworkState.LOADING)
-        fetchData(1, params.requestedLoadSize) {
+        fetchData(page = 1, pageSize = params.requestedLoadSize) {
             callback.onResult(it, null, 2)
         }
     }
     override fun loadAfter(params: LoadParams<Int>, callback: LoadCallback<Int, NewsListModel>) {
         networkState.postValue(NetworkState.LOADING)
         val page = params.key
-        fetchData(page, params.requestedLoadSize) {
+        fetchData(page = page, pageSize = params.requestedLoadSize) {
             callback.onResult(it, page + 1)
         }
     }
@@ -47,15 +47,17 @@ class NewsPageDataSource @Inject constructor(
 
     private fun fetchData(page: Int, pageSize: Int, callback: (List<NewsListModel>) -> Unit) {
         coroutineScope.launch(getJobErrorHandler()) {
-            val response = remoteDataSource.fetchNewsList(apiKey, page, pageSize)
-            if (response.status == Result.Status.SUCCESS) {
-                val results = response.data?.articles ?: emptyList()
-                newsDao.insertAll(results)
-                callback(results)
-                networkState.postValue(NetworkState.LOADED)
-            } else if (response.status == Result.Status.ERROR) {
-                networkState.postValue(NetworkState.error(response.message ?: "Unknown error"))
-                postError(response.message ?: "Unknown error")
+            when (val response = remoteDataSource.fetchNewsList(apiKey, page, pageSize)) {
+                is Result.Error -> {
+                    networkState.postValue(NetworkState.error(response.message ?: "Unknown error"))
+                    postError(response.message)
+                }
+                is Result.Success -> {
+                    val results = response.data.articles
+                    newsDao.insertAll(results)
+                    callback(results)
+                    networkState.postValue(NetworkState.LOADED)
+                }
             }
         }
     }
@@ -64,7 +66,7 @@ class NewsPageDataSource @Inject constructor(
         postError(e.message ?: e.toString())
     }
 
-    private fun postError(message: String) {
+    private fun postError(message: String?) {
         Timber.e("An error happened: $message")
     }
 }