Create Observable class

core/src/commonMain/kotlin/org/isoron/platform/concurrency/Observable.kt

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2016-2019 Álinson Santos Xavier <isoron@gmail.com>
+ *
+ * This file is part of Loop Habit Tracker.
+ *
+ * Loop Habit Tracker is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * Loop Habit Tracker is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.isoron.platform.concurrency
+
+class Observable<T> {
+    private val listeners = mutableListOf<T>()
+
+    fun addListener(listener: T) {
+        listeners.add(listener)
+    }
+
+    fun notifyListeners(action: (T) -> Unit) {
+        for (l in listeners) action.invoke(l)
+    }
+
+    fun removeListener(listener: T) {
+        listeners.remove(listener)
+    }
+}

core/src/commonMain/kotlin/org/isoron/uhabits/backend/MainScreenDataSource.kt

@@ -36,15 +36,7 @@ class MainScreenDataSource(val habits: MutableMap<Int, Habit>,
                     val colors: List<PaletteColor>,
                     val checkmarks: List<List<Int>>)
 
-    private val listeners = mutableListOf<Listener>()
-
-    fun addListener(listener: Listener) {
-        listeners.add(listener)
-    }
-
-    fun removeListener(listener: Listener) {
-        listeners.remove(listener)
-    }
+    val observable = Observable<Listener>()
 
     interface Listener {
         fun onDataChanged(newData: Data)
@@ -64,7 +56,7 @@ class MainScreenDataSource(val habits: MutableMap<Int, Habit>,
             }
             val data = Data(ids, scores, names, colors, ck)
             taskRunner.runInForeground {
-                listeners.forEach { listener ->
+                observable.notifyListeners { listener ->
                     listener.onDataChanged(data)
                 }
             }

core/src/commonTest/kotlin/org/isoron/platform/io/StringsTest.kt

@@ -19,9 +19,7 @@
 
 package org.isoron.platform.io
 
-import org.isoron.platform.io.*
-import kotlin.test.Test
-import kotlin.test.assertEquals
+import kotlin.test.*
 
 class StringsTest {
     @Test

core/src/jvmTest/kotlin/org/isoron/platform/concurrency/ObservableTest.kt

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2016-2019 Álinson Santos Xavier <isoron@gmail.com>
+ *
+ * This file is part of Loop Habit Tracker.
+ *
+ * Loop Habit Tracker is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or (at your
+ * option) any later version.
+ *
+ * Loop Habit Tracker is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.isoron.platform.concurrency
+
+import java.util.concurrent.*
+import kotlin.test.*
+
+class ObservableTest {
+
+    interface TestListener {
+        fun onDataChanged(data: Int)
+    }
+
+    @Test
+    fun test() {
+        val latch = CountDownLatch(1)
+        val listener = object : TestListener {
+            override fun onDataChanged(data: Int) {
+                assertEquals(42, data)
+                latch.countDown()
+            }
+        }
+        val observable = Observable<TestListener>()
+        observable.addListener(listener)
+        observable.notifyListeners { l ->
+            l.onDataChanged(42)
+        }
+        observable.removeListener(listener)
+        assertTrue(latch.await(3, TimeUnit.SECONDS))
+    }
+}

core/src/jvmTest/kotlin/org/isoron/uhabits/backend/BackendTest.kt

@@ -82,7 +82,7 @@ class BackendTest : BaseTest() {
                 latch.countDown()
             }
         }
-        backend.mainScreenDataSource.addListener(listener)
+        backend.mainScreenDataSource.observable.addListener(listener)
         backend.mainScreenDataSource.requestData()
         assertTrue(latch.await(3, TimeUnit.SECONDS))
     }