Delegation model

README.md

@@ -1,5 +1,8 @@
 [ ![Download](https://api.bintray.com/packages/elementsinteractive/maven/ObjectStore/images/download.svg) ](https://bintray.com/elementsinteractive/maven/ObjectStore/_latestVersion)
 # ObjectStore
+
+[![kotlin](https://img.shields.io/badge/kotlin-1.3.31-blue.svg)]()
+
 ###### Convenient interface for persisting objects.
 ``` groovy
 implementation "nl.elements.objectstore:objectstore:+"
@@ -19,6 +22,21 @@ fun example(store: ObjectStore) {
 }
 ```
 
+#### Define a model
+
+```kotlin
+class AppData : ObjectStoreModel(InMemoryStore()) {
+    var username by stringItem()
+    val lastname by nullableStringItem()
+    var age by intItem()
+    var hasSeenOnboarding by booleanItem()
+    val landedOnDashboard by booleanNullabeItem()
+    var lastSeen by longItem()
+    var rating by floatItem()
+}
+```
+
+
 ## Observing
 Each `ObjectStore` is (Rx) observable and will emit whenever something changes in store. 
 

library/src/androidTest/java/nl/elements/objectstore/PreferencesStoreTest.kt

@@ -28,7 +28,7 @@ class PreferencesStoreTest {
         val key = "contains"
         val name = "Danny"
 
-        store.set(key, name)
+        store[key] = name
 
         assertTrue(store.contains(key))
     }
@@ -92,7 +92,7 @@ class PreferencesStoreTest {
         val key = "name"
         val value = "Danny"
 
-        store.set(key, value)
+        store[key] = value
 
         val actual = store.keys
 
@@ -102,7 +102,7 @@ class PreferencesStoreTest {
     }
 }
 
-private fun <T : Any> ObjectStore.setAndGet(key: String, value: T): T {
+private fun <T : Any> ObjectStore.setAndGet(key: String, value: T): T? {
     set(key, value)
     return this[key]
 }

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

@@ -15,24 +15,24 @@ interface Converter {
      * Convert the value into bytes that will be used for IO.
      */
 
-    fun serialize(key: String, value: Any, output: OutputStream)
+    fun serialize(key: String, value: Any?, output: OutputStream)
 
     /**
      * Convert the bytes from IO into the desired object.
      */
 
-    fun <T : Any> deserialize(key: String, input: InputStream): T
+    fun <T : Any> deserialize(key: String, input: InputStream): T?
 
     companion object {
 
         val DEFAULT = object : Converter {
 
-            override fun serialize(key: String, value: Any, output: OutputStream) =
+            override fun serialize(key: String, value: Any?, output: OutputStream) =
                 ObjectOutputStream(output).writeObject(value)
 
             @Suppress("UNCHECKED_CAST")
-            override fun <T : Any> deserialize(key: String, input: InputStream): T =
-                ObjectInputStream(input).readObject() as T
+            override fun <T : Any> deserialize(key: String, input: InputStream): T? =
+                ObjectInputStream(input).readObject() as T?
 
         }
 

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

@@ -18,18 +18,18 @@ interface ObjectStore : ReadableObjectStore, ObservableSource<ObjectStore.Event>
     val converter: Converter
     val transformer: Transformer
 
-    operator fun set(key: String, value: Any)
+    operator fun set(key: String, value: Any?)
 
     fun remove(key: String)
 
-    fun OutputStream.write(key: String, value: Any) =
+    fun OutputStream.write(key: String, value: Any?) =
         ByteArrayOutputStream()
             .also { converter.serialize(key, value, it) }
             .toByteArray()
             .inputStream()
             .let { transformer.write(key, it, this@write) }
 
-    fun <T : Any> InputStream.read(key: String): T =
+    fun <T : Any> InputStream.read(key: String): T? =
         ByteArrayOutputStream()
             .also { transformer.read(key, this@read, it) }
             .toByteArray()
@@ -57,7 +57,7 @@ fun ObjectStore.toObservable(): Observable<ObjectStore.Event> = Observable.defer
 
 fun ObjectStore.toReadableObjectStore(): ReadableObjectStore = this
 
-fun ObjectStore.writeToBytes(key: String, value: Any): ByteArray =
+fun ObjectStore.writeToBytes(key: String, value: Any?): ByteArray =
     ByteArrayOutputStream()
         .also { it.write(key, value) }
         .toByteArray()
@@ -114,13 +114,13 @@ private fun ObjectStore.withNamespace(namespace: String, next: ObjectStore): Obj
         override val keys: Set<String>
             get() = store.keys.map { namespace + it }.toMutableSet().apply { addAll(next.keys) }
 
-        override fun <T : Any> get(key: String): T =
+        override fun <T : Any> get(key: String): T? =
             key.removeNamespace()?.let(store::get) ?: next[key]
 
         override fun contains(key: String): Boolean =
             key.removeNamespace()?.let(store::contains) ?: next.contains(key)
 
-        override fun set(key: String, value: Any) =
+        override fun set(key: String, value: Any?) =
             key.removeNamespace()?.let { store[it] = value } ?: next.set(key, value)
 
         override fun remove(key: String) = key.removeNamespace()?.let(store::remove) ?: next.remove(key)
@@ -148,7 +148,7 @@ private fun unknownNamespaceObjectStore(): ObjectStore = object : ObjectStore {
     override val transformer: Transformer = Transformer.DEFAULT
     override val keys: Set<String> = emptySet()
 
-    override fun set(key: String, value: Any) = throw UnknownNamespaceException(key)
+    override fun set(key: String, value: Any?) = throw UnknownNamespaceException(key)
 
     override fun remove(key: String) = throw UnknownNamespaceException(key)
 

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

@@ -0,0 +1,86 @@
+package nl.elements.objectstore
+
+import nl.elements.objectstore.model.AnyItem
+import nl.elements.objectstore.model.AnyNullableItem
+import kotlin.properties.ReadWriteProperty
+
+abstract class ObjectStoreModel(
+    internal val store: ObjectStore
+) {
+    /**
+     * Clears all items in this store
+     */
+    fun clear() {
+        store.keys.forEach(store::remove)
+    }
+
+    /**
+     * Delegate a string item
+     * @param default value
+     * @param key custom key (optional)
+     */
+    protected fun stringItem(
+        default: String = "",
+        key: String? = null
+    ): ReadWriteProperty<ObjectStoreModel, String> = AnyItem(default, key)
+
+    /**
+     * Delegate a nullable string item
+     * @param default value
+     * @param key custom key (optional)
+     */
+    protected fun nullableStringItem(
+        default: String? = null,
+        key: String? = null
+    ): ReadWriteProperty<ObjectStoreModel, String?> = AnyNullableItem(default, key)
+
+    /**
+     * Delegate a boolean item
+     * @param default value
+     * @param key custom key (optional)
+     */
+    protected fun booleanItem(
+        default: Boolean = false,
+        key: String? = null
+    ): ReadWriteProperty<ObjectStoreModel, Boolean> = AnyItem(default, key)
+
+    /**
+     * Delegate a nullable boolean item
+     * @param default value
+     * @param key custom key (optional)
+     */
+    protected fun booleanNullabeItem(
+        default: Boolean? = null,
+        key: String? = null
+    ): ReadWriteProperty<ObjectStoreModel, Boolean?> = AnyNullableItem(default, key)
+
+    /**
+     * Delegate an int item
+     * @param default value
+     * @param key custom key (optional)
+     */
+    protected fun intItem(
+        default: Int = 0,
+        key: String? = null
+    ): ReadWriteProperty<ObjectStoreModel, Int> = AnyItem(default, key)
+
+    /**
+     * Delegate a long item
+     * @param default value
+     * @param key custom key (optional)
+     */
+    protected fun longItem(
+        default: Long = 0L,
+        key: String? = null
+    ): ReadWriteProperty<ObjectStoreModel, Long> = AnyItem(default, key)
+
+    /**
+     * Delegate a float item
+     * @param default value
+     * @param key custom key (optional)
+     */
+    protected fun floatItem(
+        default: Float = 0F,
+        key: String? = null
+    ): ReadWriteProperty<ObjectStoreModel, Float> = AnyItem(default, key)
+}

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

@@ -4,7 +4,7 @@ interface ReadableObjectStore {
 
     val keys: Set<String>
 
-    operator fun <T : Any> get(key: String): T
+    operator fun <T : Any> get(key: String): T?
 
     operator fun contains(key: String): Boolean
 
@@ -39,7 +39,7 @@ private fun combine(l: ReadableObjectStore, r: ReadableObjectStore): ReadableObj
         override val keys: Set<String>
             get() = l.keys.toMutableSet().apply { addAll(r.keys) }
 
-        override fun <T : Any> get(key: String): T =
+        override fun <T : Any> get(key: String): T? =
             when (key) {
                 in l -> l[key]
                 else -> r[key]

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

@@ -0,0 +1,10 @@
+package nl.elements.objectstore.model
+
+import nl.elements.objectstore.ObjectStoreModel
+import kotlin.properties.ReadWriteProperty
+
+abstract class AbstractItem<T : Any?> : ReadWriteProperty<ObjectStoreModel, T>, ItemKey {
+}
+
+abstract class NullableAbstractItem<T : Any?> : ReadWriteProperty<ObjectStoreModel, T?>, ItemKey {
+}

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

@@ -0,0 +1,23 @@
+package nl.elements.objectstore.model
+
+import nl.elements.objectstore.ObjectStoreModel
+import kotlin.reflect.KProperty
+
+internal class AnyItem<T : Any>(
+    val default: T,
+    override val key: String?
+) : AbstractItem<T>() {
+
+    override fun getValue(thisRef: ObjectStoreModel, property: KProperty<*>): T =
+        (key ?: property.name).let { key ->
+            if (thisRef.store.contains(key)) {
+                thisRef.store[key] ?: default
+            } else {
+                default
+            }
+        }
+
+    override fun setValue(thisRef: ObjectStoreModel, property: KProperty<*>, value: T) {
+        thisRef.store[key ?: property.name] = value
+    }
+}

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

@@ -0,0 +1,23 @@
+package nl.elements.objectstore.model
+
+import nl.elements.objectstore.ObjectStoreModel
+import kotlin.reflect.KProperty
+
+internal class AnyNullableItem<T : Any>(
+    val default: T?,
+    override val key: String?
+) : NullableAbstractItem<T>() {
+
+    override fun getValue(thisRef: ObjectStoreModel, property: KProperty<*>): T? =
+        (key ?: property.name).let { key ->
+            if (thisRef.store.contains(key)) {
+                thisRef.store[key] ?: default
+            } else {
+                default
+            }
+        }
+
+    override fun setValue(thisRef: ObjectStoreModel, property: KProperty<*>, value: T?) {
+        thisRef.store[key ?: property.name] = value
+    }
+}

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/stores/DatabaseStore.kt

@@ -36,14 +36,14 @@ class DatabaseStore(
             """
                 CREATE TABLE IF NOT EXISTS $table (
                     $_ID STRING PRIMARY KEY UNIQUE,
-                    $VALUE BLOB NOT NULL
+                    $VALUE BLOB
                 )
             """
 
         database.rawQuery(query, null).close()
     }
 
-    override fun set(key: String, value: Any) {
+    override fun set(key: String, value: Any?) {
         val bytes = writeToBytes(key, value)
         val values = ContentValues().apply {
             put(_ID, key)
@@ -54,13 +54,13 @@ class DatabaseStore(
         emit(Updated(key))
     }
 
-    override fun <T : Any> get(key: String): T =
+    override fun <T : Any> get(key: String): T? =
         queryById(key, VALUE).use { cursor ->
             cursor
                 .takeIf { it.moveToFirst() }
                 ?.value
                 ?.inputStream()
-                ?.read(key)!!
+                ?.read(key)
         }
 
     override fun contains(key: String): Boolean =

library/src/main/java/nl/elements/objectstore/stores/DirectoryStore.kt

@@ -24,7 +24,7 @@ class DirectoryStore(
     override val keys: Set<String>
         get() = directory.list().toSet()
 
-    override fun set(key: String, value: Any) {
+    override fun set(key: String, value: Any?) {
         fileOf(key)
             .ensure()
             .outputStream()
@@ -33,7 +33,7 @@ class DirectoryStore(
         emit(Updated(key))
     }
 
-    override fun <T : Any> get(key: String): T =
+    override fun <T : Any> get(key: String): T? =
         fileOf(key)
             .ensure()
             .inputStream()

library/src/main/java/nl/elements/objectstore/stores/MemoryStore.kt

@@ -17,12 +17,12 @@ class MemoryStore(
     override val keys: Set<String>
         get() = synchronized { data.keys.toSet() }
 
-    override fun <T : Any> get(key: String): T =
+    override fun <T : Any> get(key: String): T? =
         synchronized { data[key]!! }
             .inputStream()
             .read(key)
 
-    override fun set(key: String, value: Any) {
+    override fun set(key: String, value: Any?) {
         val bytes = writeToBytes(key, value)
 
         synchronized { data[key] = bytes }