Add support for TypedTasks (#8)

* Add TypedTask<T>

* Fix onIdle to be an extension function of TypedTask

* Update README

Author: Adrián García

README.md

@@ -80,11 +80,17 @@ Each ``Store`` exposes a custom `StoreCallback` though the method `observe` or a
 If you make use of the RxJava methods, you can make use of the `SubscriptionTracker` interface to keep track of the `Disposables` used on your activities and fragments.
 
 ### Tasks
-A Task is a basic object to represent an ongoing process. They should be used in the state of our `Store` to represent ongoing processes that must be represented in the UI.
+A `Task` is a basic object to represent an ongoing process. They should be used in the state of our `Store` to represent ongoing processes that must be represented in the UI.
 
+You can also use `TypedTask` to save metadata related the current task. 
+
+**IMPORTANT: Do not use TypedTask to hold values that must survive multiple task executions. Save them as a variable in the state instead.**
+
+
+### Example
 Given the example Stores and Actions explained before, the workflow will be:
 
-- View dispatch `LoginAction`.
+- View dispatches `LoginAction`.
 - Store changes his `LoginTask` status to running and call though his SessionController which will do all the async work to log in the given user.
 - View shows an Spinner when `LoginTask` is in running state.
 - The async call ends and `LoginCompleteAction` is dispatched on UI, sending a null `User` and an error state `Task` if the async work failed or a success `Task` and an `User`.
@@ -201,7 +207,7 @@ dependencies {
 You'll need to add the following snippet to your `Application`'s `onCreate` method. If you don't have it, then create it and reference it in your `AndroidManifest.xml` file:
 
 ```kotlin
-val stores = listOf<Store<*>>(...) // Here you'll set-up you store list, you can retrieve it using your preferred DI framework
+val stores = listOf<Store<*>>() // Here you'll set-up you store list, you can retrieve it using your preferred DI framework
 val dispatcher = MiniGen.newDispatcher() // Create a new dispatcher
 
 // Initialize Mini
@@ -211,9 +217,9 @@ stores.forEach { store ->
 }
 
 // Optional: add logging interceptor to log action events
-dispatcher.addInterceptor(LoggerInterceptor(stores, { tag, msg ->
+dispatcher.addInterceptor(LoggerInterceptor(stores)) { tag, msg ->
     Log.d(tag, msg)
-}))
+}
 ```
 
 ## License

mini-common/src/main/java/mini/Resource.kt

@@ -72,17 +72,19 @@ open class Resource<out T> @PublishedApi internal constructor(val value: Any?) {
 }
 
 /**
- * An empty resource that just abstracts asynchronous operation but with idle
+ * A resource that abstracts asynchronous operation but with idle
  * state instead of empty.
+ *
+ * It accepts temporary metadata objects as value.
  */
-class Task(value: Any?) : Resource<Unit>(value) {
+open class TypedTask<T> @PublishedApi internal constructor(value: Any?) : Resource<T>(value) {
     val isIdle: Boolean get() = isEmpty
 
     companion object {
-        fun success(): Task = Task(Unit)
-        fun idle(): Task = Task(Empty)
-        fun loading(): Task = Task(Loading<Unit>())
-        fun failure(exception: Throwable? = null): Task = Task(Failure(exception))
+        fun <T> success(value: T): TypedTask<T> = TypedTask(value)
+        fun <T> idle(): TypedTask<T> = TypedTask(Empty)
+        fun <T> loading(value: T? = null): TypedTask<T> = TypedTask(Loading(value))
+        fun <T> failure(exception: Throwable? = null): TypedTask<T> = TypedTask(Failure(exception))
     }
 
     override fun toString(): String {
@@ -94,6 +96,19 @@ class Task(value: Any?) : Resource<Unit>(value) {
     }
 }
 
+/**
+ * An empty resource that just abstracts asynchronous operation but with idle
+ * state instead of empty.
+ */
+class Task(value: Any?) : TypedTask<Unit>(value) {
+    companion object {
+        fun success(): Task = Task(Unit)
+        fun idle(): Task = Task(Empty)
+        fun loading(): Task = Task(Loading<Unit>())
+        fun failure(exception: Throwable? = null): Task = Task(Failure(exception))
+    }
+}
+
 inline fun <T> Resource<T>.onSuccess(crossinline action: (data: T) -> Unit): Resource<T> {
     if (isSuccess) action(value as T)
     return this
@@ -109,7 +124,7 @@ inline fun <T> Resource<T>.onLoading(crossinline action: (data: T?) -> Unit): Re
     return this
 }
 
-inline fun Task.onIdle(crossinline action: () -> Unit): Task {
+inline fun <T> TypedTask<T>.onIdle(crossinline action: () -> Unit): TypedTask<T> {
     if (isEmpty) action()
     return this
 }