in memory implementation

src/main/kotlin/dartzee/preferences/AbstractPreferenceService.kt

@@ -0,0 +1,28 @@
+package dartzee.preferences
+
+abstract class AbstractPreferenceService {
+    abstract fun <T : Any> delete(preference: Preference<T>)
+
+    protected abstract fun <T> getRaw(preference: Preference<T>): String
+
+    abstract fun <T : Any> save(preference: Preference<T>, value: T)
+
+    @Suppress("UNCHECKED_CAST")
+    fun <T : Any> get(preference: Preference<T>, useDefault: Boolean = false): T {
+        if (useDefault) {
+            return preference.default
+        }
+
+        val raw = getRaw(preference)
+        return when (val desiredType = preference.default::class) {
+            Boolean::class -> raw.toBoolean() as T
+            Double::class -> raw.toDouble() as T
+            Int::class -> raw.toInt() as T
+            String::class -> raw as T
+            else ->
+                throw TypeCastException(
+                    "Unhandled type [${desiredType}] for preference ${preference.name}"
+                )
+        }
+    }
+}

src/main/kotlin/dartzee/preferences/DefaultPreferenceService.kt

@@ -3,7 +3,7 @@ package dartzee.preferences
 import dartzee.utils.NODE_PREFERENCES
 import java.util.prefs.Preferences
 
-class DefaultPreferenceService : IPreferenceService {
+class DefaultPreferenceService : AbstractPreferenceService() {
     private val preferences = Preferences.userRoot().node(NODE_PREFERENCES)
 
     override fun <T : Any> delete(preference: Preference<T>) {
@@ -14,22 +14,6 @@ class DefaultPreferenceService : IPreferenceService {
         preferences.put(preference.name, value.toString())
     }
 
-    @Suppress("UNCHECKED_CAST")
-    override fun <T : Any> get(preference: Preference<T>, useDefault: Boolean): T {
-        if (useDefault) {
-            return preference.default
-        }
-
-        val raw = preferences.get(preference.name, preference.default.toString())
-        return when (val desiredType = preference.default::class) {
-            Boolean::class -> raw.toBoolean() as T
-            Double::class -> raw.toDouble() as T
-            Int::class -> raw.toInt() as T
-            String::class -> raw as T
-            else ->
-                throw TypeCastException(
-                    "Unhandled type [${desiredType}] for preference ${preference.name}"
-                )
-        }
-    }
+    override fun <T> getRaw(preference: Preference<T>): String =
+        preferences.get(preference.name, preference.default.toString())
 }

src/test/kotlin/dartzee/preferences/InMemoryPreferenceService.kt

@@ -0,0 +1,16 @@
+package dartzee.preferences
+
+class InMemoryPreferenceService : AbstractPreferenceService() {
+    private val hmPreferences = mutableMapOf<String, String>()
+
+    override fun <T : Any> delete(preference: Preference<T>) {
+        hmPreferences.remove(preference.name)
+    }
+
+    override fun <T> getRaw(preference: Preference<T>) =
+        hmPreferences.getOrDefault(preference.name, preference.default.toString())
+
+    override fun <T : Any> save(preference: Preference<T>, value: T) {
+        hmPreferences[preference.name] = value.toString()
+    }
+}

src/test/kotlin/dartzee/preferences/PreferenceServiceTest.kt

@@ -13,12 +13,16 @@ private val INT_PREF = Preference("fake_int", 20)
 private val DOUBLE_PREF = Preference("fake_double", 2.5)
 private val BOOLEAN_PREF = Preference("fake_boolean", false)
 
+class InMemoryPreferenceServiceTest : AbstractTest(), PreferenceServiceTest {
+    override val implementation = InMemoryPreferenceService()
+}
+
 class DefaultPreferenceServiceTest : AbstractTest(), PreferenceServiceTest {
     override val implementation = DefaultPreferenceService()
 }
 
 interface PreferenceServiceTest {
-    val implementation: IPreferenceService
+    val implementation: AbstractPreferenceService
 
     @AfterEach
     fun afterEach() {