Merge pull request #16 from floschu/feature/state-flow

Use StateFlow
floschu · May 10, 2020 · e98c862 · e98c862
2 parents 2e011f3 + 9b9cc3a
commit e98c862
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Showing 5 changed files with 36 additions and 11 deletions.
diff --git a/control-core/src/main/kotlin/at/florianschuster/control/implementation.kt b/control-core/src/main/kotlin/at/florianschuster/control/implementation.kt
@@ -9,8 +9,8 @@ import kotlinx.coroutines.FlowPreview
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.channels.BroadcastChannel
 import kotlinx.coroutines.channels.Channel.Factory.BUFFERED
-import kotlinx.coroutines.channels.ConflatedBroadcastChannel
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.asFlow
 import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.collect
@@ -46,23 +46,23 @@ internal class ControllerImplementation<Action, Mutation, State>(
     internal val stateJob: Job // internal for testing
 
     private val actionChannel = BroadcastChannel<Action>(BUFFERED)
-    private val stateChannel = ConflatedBroadcastChannel<State>()
+    private val stateFlow = MutableStateFlow(initialState)
     private val controllerStub by lazy { ControllerStubImplementation<Action, State>(initialState) }
 
     override val state: Flow<State>
         get() = if (!stubEnabled) {
             if (!stateJob.isActive) startStateJob()
-            stateChannel.asFlow()
+            stateFlow
         } else {
-            controllerStub.stateChannel.asFlow()
+            controllerStub.stateFlow
         }
 
     override val currentState: State
         get() = if (!stubEnabled) {
             if (!stateJob.isActive) startStateJob()
-            stateChannel.value
+            stateFlow.value
         } else {
-            controllerStub.stateChannel.value
+            controllerStub.stateFlow.value
         }
 
     override fun dispatch(action: Action) {
@@ -117,7 +117,7 @@ internal class ControllerImplementation<Action, Mutation, State>(
                 .onStart { controllerLog.log(ControllerEvent.Started(tag)) }
                 .onEach { state ->
                     controllerLog.log(ControllerEvent.State(tag, state.toString()))
-                    stateChannel.send(state)
+                    this@ControllerImplementation.stateFlow.value = state
                 }
                 .onCompletion { controllerLog.log(ControllerEvent.Completed(tag)) }
                 .collect()

diff --git a/control-core/src/main/kotlin/at/florianschuster/control/stub.kt b/control-core/src/main/kotlin/at/florianschuster/control/stub.kt
@@ -1,7 +1,7 @@
 package at.florianschuster.control
 
 import kotlinx.coroutines.ExperimentalCoroutinesApi
-import kotlinx.coroutines.channels.ConflatedBroadcastChannel
+import kotlinx.coroutines.flow.MutableStateFlow
 
 /**
  * Use this [ControllerStub] for view testing.
@@ -30,11 +30,11 @@ internal class ControllerStubImplementation<Action, State>(
 ) : ControllerStub<Action, State> {
 
     internal val mutableActions = mutableListOf<Action>()
-    internal val stateChannel = ConflatedBroadcastChannel(initialState)
+    internal val stateFlow = MutableStateFlow(initialState)
 
     override val actions: List<Action> get() = mutableActions
 
     override fun setState(state: State) {
-        stateChannel.offer(state)
+        stateFlow.value = state
     }
 }
diff --git a/control-core/src/test/kotlin/at/florianschuster/control/ImplementationTest.kt b/control-core/src/test/kotlin/at/florianschuster/control/ImplementationTest.kt
@@ -82,7 +82,7 @@ internal class ImplementationTest {
     }
 
     @Test
-    fun `synchronous controller builder`() {
+    fun `synchronous controller`() {
         val counterSut = testCoroutineScope.createSynchronousController<Int, Int>(
             tag = "counter",
             initialState = 0,
@@ -96,6 +96,19 @@ internal class ImplementationTest {
         assertEquals(6, counterSut.currentState)
     }
 
+    @Test
+    fun `only distinct states are emitted`() {
+        val sut = testCoroutineScope.createSynchronousController<Unit, Int>(
+            0,
+            reducer = { _, previousState -> previousState }
+        )
+        val testFlow = sut.state.testIn(testCoroutineScope)
+        sut.dispatch(Unit)
+        sut.dispatch(Unit)
+        sut.dispatch(Unit)
+        testFlow expect emissionCount(1) // no state changes
+    }
+
     @Test
     fun `collector receives latest and following states`() {
         val sut = testCoroutineScope.counterController() // 0

diff --git a/examples/example-counter/lint.xml b/examples/example-counter/lint.xml
@@ -0,0 +1,6 @@
+<lint>
+    <!-- Temporary until https://github.com/Kotlin/kotlinx.coroutines/issues/2004 is resolved. -->
+    <issue id="InvalidPackage">
+        <ignore path="**/kotlinx-coroutines-core-*.jar"/>
+    </issue>
+</lint>
diff --git a/examples/example-github/lint.xml b/examples/example-github/lint.xml
@@ -0,0 +1,6 @@
+<lint>
+    <!-- Temporary until https://github.com/Kotlin/kotlinx.coroutines/issues/2004 is resolved. -->
+    <issue id="InvalidPackage">
+        <ignore path="**/kotlinx-coroutines-core-*.jar"/>
+    </issue>
+</lint>