Adds initial set-up for model delegation

Author: jeffreydelooff

library/src/main/java/nl/elements/objectstore/ObjectStoreModel.kt

@@ -0,0 +1,25 @@
+package nl.elements.objectstore
+
+import nl.elements.objectstore.model.StringItem
+import kotlin.properties.ReadWriteProperty
+
+abstract class ObjectStoreModel(
+    internal val store: ObjectStore
+) {
+    /**
+     * Clear all items in this store
+     */
+    fun clear() {
+        store.keys.forEach(store::remove)
+    }
+
+    /**
+     * Delegate an item with type string
+     * @param default default string value
+     * @param key custom key
+     */
+    protected fun stringPref(
+        default: String = "",
+        key: String? = null
+    ): ReadWriteProperty<ObjectStoreModel, String> = StringItem(default, key)
+}

library/src/main/java/nl/elements/objectstore/model/AbstractItem.kt

@@ -0,0 +1,8 @@
+package nl.elements.objectstore.model
+
+import nl.elements.objectstore.ObjectStoreModel
+import kotlin.properties.ReadWriteProperty
+
+abstract class AbstractItem<T : Any?> : ReadWriteProperty<ObjectStoreModel, T>, ItemKey {
+    abstract override val key: String?
+}

library/src/main/java/nl/elements/objectstore/model/ItemKey.kt

@@ -0,0 +1,5 @@
+package nl.elements.objectstore.model
+
+interface ItemKey {
+    val key: String?
+}

library/src/main/java/nl/elements/objectstore/model/StringItem.kt

@@ -0,0 +1,24 @@
+package nl.elements.objectstore.model
+
+import nl.elements.objectstore.ObjectStoreModel
+import kotlin.reflect.KProperty
+
+internal class StringItem(
+    val default: String,
+    override val key: String?
+) : AbstractItem<String>() {
+
+    override fun getValue(model: ObjectStoreModel, property: KProperty<*>): String {
+        val realKey = key ?: property.name
+
+        return if (model.store.contains(realKey)) {
+            model.store.get(realKey)
+        } else {
+           default
+        }
+    }
+
+    override fun setValue(model: ObjectStoreModel, property: KProperty<*>, value: String) {
+        model.store[key ?: property.name] = value
+    }
+}

library/src/test/java/nl/elements/objectstore/ObjectStoreModelTest.kt

@@ -0,0 +1,31 @@
+package nl.elements.objectstore
+
+import nl.elements.objectstore.stores.MemoryStore
+import org.junit.Test
+import kotlin.test.assertEquals
+
+class ObjectStoreModelTest {
+
+    @Test
+    fun `Test Store Model with MemoryStore`() {
+        val model = InMemoryModel()
+
+        val newValue = "Test"
+
+        assertEquals("", model.name)
+
+        model.name = newValue
+
+        assertEquals(newValue, model.name)
+        assertEquals(DEFAULT_VALUE, model.nameWithDefault)
+    }
+
+    companion object {
+        class InMemoryModel : ObjectStoreModel(MemoryStore()) {
+            var name by stringPref()
+            var nameWithDefault by stringPref(DEFAULT_VALUE)
+        }
+
+        const val DEFAULT_VALUE = "default"
+    }
+}