Merge remote-tracking branch 'origin/more-ktx' into dev

# Conflicts:
#	build.gradle

Author: greenrobot

objectbox-kotlin/src/main/kotlin/io/objectbox/kotlin/Extensions.kt

@@ -14,12 +14,16 @@
  * limitations under the License.
  */
 
+@file:Suppress("unused") // tested in integration test project
+
 package io.objectbox.kotlin
 
 import io.objectbox.Box
 import io.objectbox.BoxStore
 import io.objectbox.Property
+import io.objectbox.query.Query
 import io.objectbox.query.QueryBuilder
+import io.objectbox.relation.ToMany
 import kotlin.reflect.KClass
 
 inline fun <reified T> BoxStore.boxFor(): Box<T> = boxFor(T::class.java)
@@ -28,9 +32,39 @@ inline fun <reified T> BoxStore.boxFor(): Box<T> = boxFor(T::class.java)
 inline fun <T : Any> BoxStore.boxFor(clazz: KClass<T>): Box<T> = boxFor(clazz.java)
 
 /** An alias for the "in" method, which is a reserved keyword in Kotlin. */
-inline fun <reified T> QueryBuilder<T>.inValues(property: Property, values: LongArray): QueryBuilder<T>?
+inline fun <reified T> QueryBuilder<T>.inValues(property: Property, values: LongArray): QueryBuilder<T>
         = `in`(property, values)
 
 /** An alias for the "in" method, which is a reserved keyword in Kotlin. */
-inline fun <reified T> QueryBuilder<T>.inValues(property: Property, values: IntArray): QueryBuilder<T>?
+inline fun <reified T> QueryBuilder<T>.inValues(property: Property, values: IntArray): QueryBuilder<T>
         = `in`(property, values)
+
+/**
+ * Allows building a query for this Box instance with a call to [build][QueryBuilder.build] to return a [Query] instance.
+ * ```
+ * val query = box.query {
+ *     equal(Entity_.property, value)
+ * }
+ * ```
+ */
+inline fun <T> Box<T>.query(block: QueryBuilder<T>.() -> Unit) : Query<T> {
+    val builder = query()
+    block(builder)
+    return builder.build()
+}
+
+/**
+ * Allows making changes (adding and removing entities) to this ToMany with a call to
+ * [apply][ToMany.applyChangesToDb] the changes to the database.
+ * Can [reset][ToMany.reset] the ToMany before making changes.
+ * ```
+ * toMany.applyChangesToDb {
+ *     add(entity)
+ * }
+ * ```
+ */
+inline fun <T> ToMany<T>.applyChangesToDb(resetFirst: Boolean = false, body: ToMany<T>.() -> Unit) {
+    if (resetFirst) reset()
+    body()
+    applyChangesToDb()
+}