Merge pull request #3 from hpost/feature/base-model-framework

Base model framework additions

README.md

@@ -18,6 +18,6 @@ and:
 
 ```gradle
 dependencies {
-    implementation "cc.femto:kommon-mvi:2.1.1"
+    implementation "cc.femto:kommon-mvi:2.2.0"
 }
 ```

build.gradle

@@ -2,7 +2,7 @@
 
 buildscript {
     ext.gradle_version = '3.0.1'
-    ext.kotlin_version = '1.2.41'
+    ext.kotlin_version = '1.2.60'
     ext.rxjava_version = '2.1.7'
 
     repositories {

mvi/build.gradle

@@ -20,8 +20,8 @@ android {
     defaultConfig {
         minSdkVersion 16
         targetSdkVersion 27
-        versionCode 5
-        versionName "2.1.1"
+        versionCode 6
+        versionName "2.2.0"
     }
     buildTypes {
         release {

mvi/src/main/kotlin/cc/femto/kommon/mvi/BaseModel.kt

@@ -16,10 +16,53 @@ abstract class BaseModel<INTENT : Intent, ACTION : Action, VM> : Model<INTENT, A
 
     override fun actions(): Observable<ACTION> = actions
 
+    override fun attach(intents: Observable<INTENT>) {
+        makeViewModel(
+                eventsFrom(intents),
+                initialViewModel(),
+                ::reduce
+        )
+        disposables.add(sideEffectsFrom(intents))
+    }
+
     override fun detach() {
         disposables.clear()
     }
 
+    /**
+     * @return instance of [VM] representing the initial state
+     */
+    protected abstract fun initialViewModel(): VM
+
+    /**
+     * Define state mutation events that result in view model changes
+     *
+     * NB: Operations that don't cause a state mutation reside in [sideEffectsFrom]
+     *
+     * @return [Observable] of [Event] feeding into [reduce]
+     */
+    protected abstract fun eventsFrom(intents: Observable<INTENT>): Observable<out Event>
+
+    /**
+     * Reduce state mutations to updated view models
+     *
+     * NB: Should be a pure function without side effects
+     */
+    protected abstract fun reduce(model: VM, event: Event): VM
+
+    /**
+     * Define side effects that don't result in state mutations, if any
+     *
+     * Default implementation results in no-op.
+     *
+     * NB: Returned subscriptions will be added to [disposables] and disposed in [detach]
+     *
+     * @return [CompositeDisposable] containing subscriptions that need to be managed
+     */
+    protected open fun sideEffectsFrom(intents: Observable<INTENT>): CompositeDisposable {
+        return CompositeDisposable()
+    }
+
     /**
      * Exposes the internal [Event] stream that passes through the reducer
      */